*: use references instead of pointers

122 files changed, 1077 insertions, 1083 deletions

diff --git a/src/AllCommands.cxx b/src/AllCommands.cxx
index 562bbeb49..73dd7d218 100644
--- a/src/AllCommands.cxx
+++ b/src/AllCommands.cxx
@@ -56,15 +56,15 @@ struct command {
 	unsigned permission;
 	int min;
 	int max;
-	enum command_return (*handler)(Client *client, int argc, char **argv);
+	enum command_return (*handler)(Client &client, int argc, char **argv);
 };
 
 /* don't be fooled, this is the command handler for "commands" command */
 static enum command_return
-handle_commands(Client *client, int argc, char *argv[]);
+handle_commands(Client &client, int argc, char *argv[]);
 
 static enum command_return
-handle_not_commands(Client *client, int argc, char *argv[]);
+handle_not_commands(Client &client, int argc, char *argv[]);
 
 /**
  * The command registry.
@@ -179,7 +179,7 @@ command_available(gcc_unused const struct command *cmd)
 
 /* don't be fooled, this is the command handler for "commands" command */
 static enum command_return
-handle_commands(Client *client,
+handle_commands(Client &client,
 		gcc_unused int argc, gcc_unused char *argv[])
 {
 	const unsigned permission = client_get_permission(client);
@@ -197,7 +197,7 @@ handle_commands(Client *client,
 }
 
 static enum command_return
-handle_not_commands(Client *client,
+handle_not_commands(Client &client,
 		    gcc_unused int argc, gcc_unused char *argv[])
 {
 	const unsigned permission = client_get_permission(client);
@@ -249,17 +249,16 @@ command_lookup(const char *name)
 }
 
 static bool
-command_check_request(const struct command *cmd, Client *client,
+command_check_request(const struct command *cmd, Client &client,
 		      unsigned permission, int argc, char *argv[])
 {
 	int min = cmd->min + 1;
 	int max = cmd->max + 1;
 
 	if (cmd->permission != (permission & cmd->permission)) {
-		if (client != nullptr)
-			command_error(client, ACK_ERROR_PERMISSION,
-				      "you don't have permission for \"%s\"",
-				      cmd->cmd);
+		command_error(client, ACK_ERROR_PERMISSION,
+			      "you don't have permission for \"%s\"",
+			      cmd->cmd);
 		return false;
 	}
 
@@ -267,27 +266,24 @@ command_check_request(const struct command *cmd, Client *client,
 		return true;
 
 	if (min == max && max != argc) {
-		if (client != nullptr)
-			command_error(client, ACK_ERROR_ARG,
-				      "wrong number of arguments for \"%s\"",
-				      argv[0]);
+		command_error(client, ACK_ERROR_ARG,
+			      "wrong number of arguments for \"%s\"",
+			      argv[0]);
 		return false;
 	} else if (argc < min) {
-		if (client != nullptr)
-			command_error(client, ACK_ERROR_ARG,
-				      "too few arguments for \"%s\"", argv[0]);
+		command_error(client, ACK_ERROR_ARG,
+			      "too few arguments for \"%s\"", argv[0]);
 		return false;
 	} else if (argc > max && max /* != 0 */ ) {
-		if (client != nullptr)
-			command_error(client, ACK_ERROR_ARG,
-				      "too many arguments for \"%s\"", argv[0]);
+		command_error(client, ACK_ERROR_ARG,
+			      "too many arguments for \"%s\"", argv[0]);
 		return false;
 	} else
 		return true;
 }
 
 static const struct command *
-command_checked_lookup(Client *client, unsigned permission,
+command_checked_lookup(Client &client, unsigned permission,
 		       int argc, char *argv[])
 {
 	const struct command *cmd;
@@ -299,9 +295,8 @@ command_checked_lookup(Client *client, unsigned permission,
 
 	cmd = command_lookup(argv[0]);
 	if (cmd == nullptr) {
-		if (client != nullptr)
-			command_error(client, ACK_ERROR_UNKNOWN,
-				      "unknown command \"%s\"", argv[0]);
+		command_error(client, ACK_ERROR_UNKNOWN,
+			      "unknown command \"%s\"", argv[0]);
 		return nullptr;
 	}
 
@@ -314,7 +309,7 @@ command_checked_lookup(Client *client, unsigned permission,
 }
 
 enum command_return
-command_process(Client *client, unsigned num, char *line)
+command_process(Client &client, unsigned num, char *line)
 {
 	Error error;
 	char *argv[COMMAND_ARGV_MAX] = { nullptr };
diff --git a/src/AllCommands.hxx b/src/AllCommands.hxx
index a55eb5a3b..4ab69755a 100644
--- a/src/AllCommands.hxx
+++ b/src/AllCommands.hxx
@@ -29,6 +29,6 @@ void command_init(void);
 void command_finish(void);
 
 enum command_return
-command_process(Client *client, unsigned num, char *line);
+command_process(Client &client, unsigned num, char *line);
 
 #endif
diff --git a/src/Client.cxx b/src/Client.cxx
index e7da3d1da..b60061a60 100644
--- a/src/Client.cxx
+++ b/src/Client.cxx
@@ -23,17 +23,20 @@
 
 const Domain client_domain("client");
 
-int client_get_uid(const Client *client)
+int
+client_get_uid(const Client &client)
 {
-	return client->uid;
+	return client.uid;
 }
 
-unsigned client_get_permission(const Client *client)
+unsigned
+client_get_permission(const Client &client)
 {
-	return client->permission;
+	return client.permission;
 }
 
-void client_set_permission(Client *client, unsigned permission)
+void
+client_set_permission(Client &client, unsigned permission)
 {
-	client->permission = permission;
+	client.permission = permission;
 }
diff --git a/src/Client.hxx b/src/Client.hxx
index a2e17e533..e9d3b56c8 100644
--- a/src/Client.hxx
+++ b/src/Client.hxx
@@ -41,7 +41,8 @@ client_new(EventLoop &loop, Partition &partition,
  * uid is unknown
  */
 gcc_pure
-int client_get_uid(const Client *client);
+int
+client_get_uid(const Client &client);
 
 /**
  * Is this client running on the same machine, connected with a local
@@ -49,31 +50,32 @@ int client_get_uid(const Client *client);
  */
 gcc_pure
 static inline bool
-client_is_local(const Client *client)
+client_is_local(const Client &client)
 {
 	return client_get_uid(client) > 0;
 }
 
 gcc_pure
-unsigned client_get_permission(const Client *client);
+unsigned
+client_get_permission(const Client &client);
 
-void client_set_permission(Client *client, unsigned permission);
+void client_set_permission(Client &client, unsigned permission);
 
 /**
  * Write a C string to the client.
  */
-void client_puts(Client *client, const char *s);
+void client_puts(Client &client, const char *s);
 
 /**
  * Write a printf-like formatted string to the client.
  */
-void client_vprintf(Client *client, const char *fmt, va_list args);
+void client_vprintf(Client &client, const char *fmt, va_list args);
 
 /**
  * Write a printf-like formatted string to the client.
  */
 gcc_printf(2,3)
 void
-client_printf(Client *client, const char *fmt, ...);
+client_printf(Client &client, const char *fmt, ...);
 
 #endif
diff --git a/src/ClientFile.cxx b/src/ClientFile.cxx
index f2cb01aff..6d9fa474e 100644
--- a/src/ClientFile.cxx
+++ b/src/ClientFile.cxx
@@ -32,7 +32,7 @@
 #include <unistd.h>
 
 bool
-client_allow_file(const Client *client, Path path_fs, Error &error)
+client_allow_file(const Client &client, Path path_fs, Error &error)
 {
 #ifdef WIN32
 	(void)client;
diff --git a/src/ClientFile.hxx b/src/ClientFile.hxx
index 43af72e93..b06fbf212 100644
--- a/src/ClientFile.hxx
+++ b/src/ClientFile.hxx
@@ -35,6 +35,6 @@ class Error;
  * @return true if access is allowed
  */
 bool
-client_allow_file(const Client *client, Path path_fs, Error &error);
+client_allow_file(const Client &client, Path path_fs, Error &error);
 
 #endif
diff --git a/src/ClientIdle.cxx b/src/ClientIdle.cxx
index 714438123..f9778a645 100644
--- a/src/ClientIdle.cxx
+++ b/src/ClientIdle.cxx
@@ -36,11 +36,11 @@ Client::IdleNotify()
 	const char *const*idle_names = idle_get_names();
 	for (unsigned i = 0; idle_names[i]; ++i) {
 		if (flags & (1 << i) & idle_subscriptions)
-			client_printf(this, "changed: %s\n",
+			client_printf(*this, "changed: %s\n",
 				      idle_names[i]);
 	}
 
-	client_puts(this, "OK\n");
+	client_puts(*this, "OK\n");
 
 	TimeoutMonitor::ScheduleSeconds(client_timeout);
 }
diff --git a/src/ClientInternal.hxx b/src/ClientInternal.hxx
index 37054fc00..4e252a24c 100644
--- a/src/ClientInternal.hxx
+++ b/src/ClientInternal.hxx
@@ -43,7 +43,7 @@ class Client final : private FullyBufferedSocket, TimeoutMonitor {
 public:
 	Partition &partition;
 	struct playlist &playlist;
-	struct player_control *player_control;
+	struct player_control &player_control;
 
 	unsigned permission;
 
@@ -126,6 +126,6 @@ extern size_t client_max_command_list_size;
 extern size_t client_max_output_buffer_size;
 
 enum command_return
-client_process_line(Client *client, char *line);
+client_process_line(Client &client, char *line);
 
 #endif
diff --git a/src/ClientNew.cxx b/src/ClientNew.cxx
index efc5b0bbb..e84887072 100644
--- a/src/ClientNew.cxx
+++ b/src/ClientNew.cxx
@@ -50,7 +50,7 @@ Client::Client(EventLoop &_loop, Partition &_partition,
 	:FullyBufferedSocket(_fd, _loop, 16384, client_max_output_buffer_size),
 	 TimeoutMonitor(_loop),
 	 partition(_partition),
-	 playlist(partition.playlist), player_control(&partition.pc),
+	 playlist(partition.playlist), player_control(partition.pc),
 	 permission(getDefaultPermissions()),
 	 uid(_uid),
 	 num(_num),
diff --git a/src/ClientProcess.cxx b/src/ClientProcess.cxx
index 0e361fb30..808599ac6 100644
--- a/src/ClientProcess.cxx
+++ b/src/ClientProcess.cxx
@@ -30,7 +30,7 @@
 #define CLIENT_LIST_MODE_END "command_list_end"
 
 static enum command_return
-client_process_command_list(Client *client, bool list_ok,
+client_process_command_list(Client &client, bool list_ok,
 			    std::list<std::string> &&list)
 {
 	enum command_return ret = COMMAND_RETURN_OK;
@@ -42,7 +42,7 @@ client_process_command_list(Client *client, bool list_ok,
 		FormatDebug(client_domain, "process command \"%s\"", cmd);
 		ret = command_process(client, num++, cmd);
 		FormatDebug(client_domain, "command returned %i", ret);
-		if (ret != COMMAND_RETURN_OK || client->IsExpired())
+		if (ret != COMMAND_RETURN_OK || client.IsExpired())
 			break;
 		else if (list_ok)
 			client_puts(client, "list_OK\n");
@@ -52,14 +52,14 @@ client_process_command_list(Client *client, bool list_ok,
 }
 
 enum command_return
-client_process_line(Client *client, char *line)
+client_process_line(Client &client, char *line)
 {
 	enum command_return ret;
 
 	if (strcmp(line, "noidle") == 0) {
-		if (client->idle_waiting) {
+		if (client.idle_waiting) {
 			/* send empty idle response and leave idle mode */
-			client->idle_waiting = false;
+			client.idle_waiting = false;
 			command_success(client);
 		}
 
@@ -68,44 +68,44 @@ client_process_line(Client *client, char *line)
 		   client_idle_notify(), which he can now evaluate */
 
 		return COMMAND_RETURN_OK;
-	} else if (client->idle_waiting) {
+	} else if (client.idle_waiting) {
 		/* during idle mode, clients must not send anything
 		   except "noidle" */
 		FormatWarning(client_domain,
 			      "[%u] command \"%s\" during idle",
-			      client->num, line);
+			      client.num, line);
 		return COMMAND_RETURN_CLOSE;
 	}
 
-	if (client->cmd_list.IsActive()) {
+	if (client.cmd_list.IsActive()) {
 		if (strcmp(line, CLIENT_LIST_MODE_END) == 0) {
 			FormatDebug(client_domain,
 				    "[%u] process command list",
-				    client->num);
+				    client.num);
 
-			auto &&cmd_list = client->cmd_list.Commit();
+			auto &&cmd_list = client.cmd_list.Commit();
 
 			ret = client_process_command_list(client,
-							  client->cmd_list.IsOKMode(),
+							  client.cmd_list.IsOKMode(),
 							  std::move(cmd_list));
 			FormatDebug(client_domain,
 				    "[%u] process command "
-				    "list returned %i", client->num, ret);
+				    "list returned %i", client.num, ret);
 
 			if (ret == COMMAND_RETURN_CLOSE ||
-			    client->IsExpired())
+			    client.IsExpired())
 				return COMMAND_RETURN_CLOSE;
 
 			if (ret == COMMAND_RETURN_OK)
 				command_success(client);
 
-			client->cmd_list.Reset();
+			client.cmd_list.Reset();
 		} else {
-			if (!client->cmd_list.Add(line)) {
+			if (!client.cmd_list.Add(line)) {
 				FormatWarning(client_domain,
 					      "[%u] command list size "
 					      "is larger than the max (%lu)",
-					      client->num,
+					      client.num,
 					      (unsigned long)client_max_command_list_size);
 				return COMMAND_RETURN_CLOSE;
 			}
@@ -114,22 +114,22 @@ client_process_line(Client *client, char *line)
 		}
 	} else {
 		if (strcmp(line, CLIENT_LIST_MODE_BEGIN) == 0) {
-			client->cmd_list.Begin(false);
+			client.cmd_list.Begin(false);
 			ret = COMMAND_RETURN_OK;
 		} else if (strcmp(line, CLIENT_LIST_OK_MODE_BEGIN) == 0) {
-			client->cmd_list.Begin(true);
+			client.cmd_list.Begin(true);
 			ret = COMMAND_RETURN_OK;
 		} else {
 			FormatDebug(client_domain,
 				    "[%u] process command \"%s\"",
-				    client->num, line);
+				    client.num, line);
 			ret = command_process(client, 0, line);
 			FormatDebug(client_domain,
 				    "[%u] command returned %i",
-				    client->num, ret);
+				    client.num, ret);
 
 			if (ret == COMMAND_RETURN_CLOSE ||
-			    client->IsExpired())
+			    client.IsExpired())
 				return COMMAND_RETURN_CLOSE;
 
 			if (ret == COMMAND_RETURN_OK)
diff --git a/src/ClientRead.cxx b/src/ClientRead.cxx
index ed4d0285a..956f4f71b 100644
--- a/src/ClientRead.cxx
+++ b/src/ClientRead.cxx
@@ -40,7 +40,7 @@ Client::OnSocketInput(void *data, size_t length)
 
 	BufferedSocket::ConsumeInput(newline + 1 - p);
 
-	enum command_return result = client_process_line(this, p);
+	enum command_return result = client_process_line(*this, p);
 	switch (result) {
 	case COMMAND_RETURN_OK:
 	case COMMAND_RETURN_IDLE:
diff --git a/src/ClientSubscribe.cxx b/src/ClientSubscribe.cxx
index 6bdb3e021..4d5511b4f 100644
--- a/src/ClientSubscribe.cxx
+++ b/src/ClientSubscribe.cxx
@@ -26,22 +26,21 @@
 #include <string.h>
 
 enum client_subscribe_result
-client_subscribe(Client *client, const char *channel)
+client_subscribe(Client &client, const char *channel)
 {
-	assert(client != nullptr);
 	assert(channel != nullptr);
 
 	if (!client_message_valid_channel_name(channel))
 		return CLIENT_SUBSCRIBE_INVALID;
 
-	if (client->num_subscriptions >= CLIENT_MAX_SUBSCRIPTIONS)
+	if (client.num_subscriptions >= CLIENT_MAX_SUBSCRIPTIONS)
 		return CLIENT_SUBSCRIBE_FULL;
 
-	auto r = client->subscriptions.insert(channel);
+	auto r = client.subscriptions.insert(channel);
 	if (!r.second)
 		return CLIENT_SUBSCRIBE_ALREADY;
 
-	++client->num_subscriptions;
+	++client.num_subscriptions;
 
 	idle_add(IDLE_SUBSCRIPTION);
 
@@ -49,44 +48,42 @@ client_subscribe(Client *client, const char *channel)
 }
 
 bool
-client_unsubscribe(Client *client, const char *channel)
+client_unsubscribe(Client &client, const char *channel)
 {
-	const auto i = client->subscriptions.find(channel);
-	if (i == client->subscriptions.end())
+	const auto i = client.subscriptions.find(channel);
+	if (i == client.subscriptions.end())
 		return false;
 
-	assert(client->num_subscriptions > 0);
+	assert(client.num_subscriptions > 0);
 
-	client->subscriptions.erase(i);
-	--client->num_subscriptions;
+	client.subscriptions.erase(i);
+	--client.num_subscriptions;
 
 	idle_add(IDLE_SUBSCRIPTION);
 
-	assert((client->num_subscriptions == 0) ==
-	       client->subscriptions.empty());
+	assert((client.num_subscriptions == 0) ==
+	       client.subscriptions.empty());
 
 	return true;
 }
 
 void
-client_unsubscribe_all(Client *client)
+client_unsubscribe_all(Client &client)
 {
-	client->subscriptions.clear();
-	client->num_subscriptions = 0;
+	client.subscriptions.clear();
+	client.num_subscriptions = 0;
 }
 
 bool
-client_push_message(Client *client, const ClientMessage &msg)
+client_push_message(Client &client, const ClientMessage &msg)
 {
-	assert(client != nullptr);
-
-	if (client->messages.size() >= CLIENT_MAX_MESSAGES ||
-	    !client->IsSubscribed(msg.GetChannel()))
+	if (client.messages.size() >= CLIENT_MAX_MESSAGES ||
+	    !client.IsSubscribed(msg.GetChannel()))
 		return false;
 
-	if (client->messages.empty())
-		client->IdleAdd(IDLE_MESSAGE);
+	if (client.messages.empty())
+		client.IdleAdd(IDLE_MESSAGE);
 
-	client->messages.push_back(msg);
+	client.messages.push_back(msg);
 	return true;
 }
diff --git a/src/ClientSubscribe.hxx b/src/ClientSubscribe.hxx
index 83319b465..cf64fda90 100644
--- a/src/ClientSubscribe.hxx
+++ b/src/ClientSubscribe.hxx
@@ -40,15 +40,15 @@ enum client_subscribe_result {
 };
 
 enum client_subscribe_result
-client_subscribe(Client *client, const char *channel);
+client_subscribe(Client &client, const char *channel);
 
 bool
-client_unsubscribe(Client *client, const char *channel);
+client_unsubscribe(Client &client, const char *channel);
 
 void
-client_unsubscribe_all(Client *client);
+client_unsubscribe_all(Client &client);
 
 bool
-client_push_message(Client *client, const ClientMessage &msg);
+client_push_message(Client &client, const ClientMessage &msg);
 
 #endif
diff --git a/src/ClientWrite.cxx b/src/ClientWrite.cxx
index 547f72bb5..e66197eb7 100644
--- a/src/ClientWrite.cxx
+++ b/src/ClientWrite.cxx
@@ -27,23 +27,23 @@
  * Write a block of data to the client.
  */
 static void
-client_write(Client *client, const char *data, size_t length)
+client_write(Client &client, const char *data, size_t length)
 {
 	/* if the client is going to be closed, do nothing */
-	if (client->IsExpired() || length == 0)
+	if (client.IsExpired() || length == 0)
 		return;
 
-	client->Write(data, length);
+	client.Write(data, length);
 }
 
 void
-client_puts(Client *client, const char *s)
+client_puts(Client &client, const char *s)
 {
 	client_write(client, s, strlen(s));
 }
 
 void
-client_vprintf(Client *client, const char *fmt, va_list args)
+client_vprintf(Client &client, const char *fmt, va_list args)
 {
 	char *p = FormatNewV(fmt, args);
 	client_write(client, p, strlen(p));
@@ -51,7 +51,7 @@ client_vprintf(Client *client, const char *fmt, va_list args)
 }
 
 void
-client_printf(Client *client, const char *fmt, ...)
+client_printf(Client &client, const char *fmt, ...)
 {
 	va_list args;
 
diff --git a/src/CommandError.cxx b/src/CommandError.cxx
index 30c739128..d606f5df9 100644
--- a/src/CommandError.cxx
+++ b/src/CommandError.cxx
@@ -30,7 +30,7 @@
 #include <errno.h>
 
 enum command_return
-print_playlist_result(Client *client, enum playlist_result result)
+print_playlist_result(Client &client, enum playlist_result result)
 {
 	switch (result) {
 	case PLAYLIST_RESULT_SUCCESS:
@@ -89,9 +89,8 @@ print_playlist_result(Client *client, enum playlist_result result)
 }
 
 enum command_return
-print_error(Client *client, const Error &error)
+print_error(Client &client, const Error &error)
 {
-	assert(client != NULL);
 	assert(error.IsDefined());
 
 	LogError(error);
diff --git a/src/CommandError.hxx b/src/CommandError.hxx
index 06f76390a..99de5c6b5 100644
--- a/src/CommandError.hxx
+++ b/src/CommandError.hxx
@@ -27,12 +27,12 @@ class Client;
 class Error;
 
 enum command_return
-print_playlist_result(Client *client, enum playlist_result result);
+print_playlist_result(Client &client, enum playlist_result result);
 
 /**
  * Send the #Error to the client.
  */
 enum command_return
-print_error(Client *client, const Error &error);
+print_error(Client &client, const Error &error);
 
 #endif
diff --git a/src/DatabaseCommands.cxx b/src/DatabaseCommands.cxx
index cc9e0937b..fe6746a74 100644
--- a/src/DatabaseCommands.cxx
+++ b/src/DatabaseCommands.cxx
@@ -35,7 +35,7 @@
 #include <string.h>
 
 enum command_return
-handle_lsinfo2(Client *client, int argc, char *argv[])
+handle_lsinfo2(Client &client, int argc, char *argv[])
 {
 	const char *uri;
 
@@ -55,7 +55,7 @@ handle_lsinfo2(Client *client, int argc, char *argv[])
 }
 
 static enum command_return
-handle_match(Client *client, int argc, char *argv[], bool fold_case)
+handle_match(Client &client, int argc, char *argv[], bool fold_case)
 {
 	SongFilter filter;
 	if (!filter.Parse(argc - 1, argv + 1, fold_case)) {
@@ -72,19 +72,19 @@ handle_match(Client *client, int argc, char *argv[], bool fold_case)
 }
 
 enum command_return
-handle_find(Client *client, int argc, char *argv[])
+handle_find(Client &client, int argc, char *argv[])
 {
 	return handle_match(client, argc, argv, false);
 }
 
 enum command_return
-handle_search(Client *client, int argc, char *argv[])
+handle_search(Client &client, int argc, char *argv[])
 {
 	return handle_match(client, argc, argv, true);
 }
 
 static enum command_return
-handle_match_add(Client *client, int argc, char *argv[], bool fold_case)
+handle_match_add(Client &client, int argc, char *argv[], bool fold_case)
 {
 	SongFilter filter;
 	if (!filter.Parse(argc - 1, argv + 1, fold_case)) {
@@ -94,25 +94,25 @@ handle_match_add(Client *client, int argc, char *argv[], bool fold_case)
 
 	const DatabaseSelection selection("", true, &filter);
 	Error error;
-	return AddFromDatabase(client->partition, selection, error)
+	return AddFromDatabase(client.partition, selection, error)
 		? COMMAND_RETURN_OK
 		: print_error(client, error);
 }
 
 enum command_return
-handle_findadd(Client *client, int argc, char *argv[])
+handle_findadd(Client &client, int argc, char *argv[])
 {
 	return handle_match_add(client, argc, argv, false);
 }
 
 enum command_return
-handle_searchadd(Client *client, int argc, char *argv[])
+handle_searchadd(Client &client, int argc, char *argv[])
 {
 	return handle_match_add(client, argc, argv, true);
 }
 
 enum command_return
-handle_searchaddpl(Client *client, int argc, char *argv[])
+handle_searchaddpl(Client &client, int argc, char *argv[])
 {
 	const char *playlist = argv[1];
 
@@ -129,7 +129,7 @@ handle_searchaddpl(Client *client, int argc, char *argv[])
 }
 
 enum command_return
-handle_count(Client *client, int argc, char *argv[])
+handle_count(Client &client, int argc, char *argv[])
 {
 	SongFilter filter;
 	if (!filter.Parse(argc - 1, argv + 1, false)) {
@@ -144,7 +144,7 @@ handle_count(Client *client, int argc, char *argv[])
 }
 
 enum command_return
-handle_listall(Client *client, gcc_unused int argc, char *argv[])
+handle_listall(Client &client, gcc_unused int argc, char *argv[])
 {
 	const char *directory = "";
 
@@ -158,7 +158,7 @@ handle_listall(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_list(Client *client, int argc, char *argv[])
+handle_list(Client &client, int argc, char *argv[])
 {
 	unsigned tagType = locate_parse_type(argv[1]);
 
@@ -207,7 +207,7 @@ handle_list(Client *client, int argc, char *argv[])
 }
 
 enum command_return
-handle_listallinfo(Client *client, gcc_unused int argc, char *argv[])
+handle_listallinfo(Client &client, gcc_unused int argc, char *argv[])
 {
 	const char *directory = "";
 
diff --git a/src/DatabaseCommands.hxx b/src/DatabaseCommands.hxx
index 335adc4d6..5e4130aba 100644
--- a/src/DatabaseCommands.hxx
+++ b/src/DatabaseCommands.hxx
@@ -25,33 +25,33 @@
 class Client;
 
 enum command_return
-handle_lsinfo2(Client *client, int argc, char *argv[]);
+handle_lsinfo2(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_find(Client *client, int argc, char *argv[]);
+handle_find(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_findadd(Client *client, int argc, char *argv[]);
+handle_findadd(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_search(Client *client, int argc, char *argv[]);
+handle_search(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_searchadd(Client *client, int argc, char *argv[]);
+handle_searchadd(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_searchaddpl(Client *client, int argc, char *argv[]);
+handle_searchaddpl(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_count(Client *client, int argc, char *argv[]);
+handle_count(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_listall(Client *client, int argc, char *argv[]);
+handle_listall(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_list(Client *client, int argc, char *argv[]);
+handle_list(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_listallinfo(Client *client, int argc, char *argv[]);
+handle_listallinfo(Client &client, int argc, char *argv[]);
 
 #endif
diff --git a/src/DatabasePlaylist.cxx b/src/DatabasePlaylist.cxx
index 8404a39c9..32b90f39f 100644
--- a/src/DatabasePlaylist.cxx
+++ b/src/DatabasePlaylist.cxx
@@ -30,7 +30,7 @@ static bool
 AddSong(const char *playlist_path_utf8,
 	Song &song, Error &error)
 {
-	return spl_append_song(playlist_path_utf8, &song, error);
+	return spl_append_song(playlist_path_utf8, song, error);
 }
 
 bool
diff --git a/src/DatabasePrint.cxx b/src/DatabasePrint.cxx
index e6bae9942..101383488 100644
--- a/src/DatabasePrint.cxx
+++ b/src/DatabasePrint.cxx
@@ -34,7 +34,7 @@
 #include <functional>
 
 static bool
-PrintDirectoryBrief(Client *client, const Directory &directory)
+PrintDirectoryBrief(Client &client, const Directory &directory)
 {
 	if (!directory.IsRoot())
 		client_printf(client, "directory: %s\n", directory.GetPath());
@@ -43,7 +43,7 @@ PrintDirectoryBrief(Client *client, const Directory &directory)
 }
 
 static bool
-PrintDirectoryFull(Client *client, const Directory &directory)
+PrintDirectoryFull(Client &client, const Directory &directory)
 {
 	if (!directory.IsRoot()) {
 		client_printf(client, "directory: %s\n", directory.GetPath());
@@ -55,7 +55,7 @@ PrintDirectoryFull(Client *client, const Directory &directory)
 
 
 static void
-print_playlist_in_directory(Client *client,
+print_playlist_in_directory(Client &client,
 			    const Directory &directory,
 			    const char *name_utf8)
 {
@@ -67,11 +67,11 @@ print_playlist_in_directory(Client *client,
 }
 
 static bool
-PrintSongBrief(Client *client, Song &song)
+PrintSongBrief(Client &client, const Song &song)
 {
 	assert(song.parent != nullptr);
 
-	song_print_uri(client, &song);
+	song_print_uri(client, song);
 
 	if (song.tag != nullptr && song.tag->has_playlist)
 		/* this song file has an embedded CUE sheet */
@@ -81,11 +81,11 @@ PrintSongBrief(Client *client, Song &song)
 }
 
 static bool
-PrintSongFull(Client *client, Song &song)
+PrintSongFull(Client &client, const Song &song)
 {
 	assert(song.parent != nullptr);
 
-	song_print_info(client, &song);
+	song_print_info(client, song);
 
 	if (song.tag != nullptr && song.tag->has_playlist)
 		/* this song file has an embedded CUE sheet */
@@ -95,7 +95,7 @@ PrintSongFull(Client *client, Song &song)
 }
 
 static bool
-PrintPlaylistBrief(Client *client,
+PrintPlaylistBrief(Client &client,
 		   const PlaylistInfo &playlist,
 		   const Directory &directory)
 {
@@ -104,7 +104,7 @@ PrintPlaylistBrief(Client *client,
 }
 
 static bool
-PrintPlaylistFull(Client *client,
+PrintPlaylistFull(Client &client,
 		  const PlaylistInfo &playlist,
 		  const Directory &directory)
 {
@@ -117,7 +117,7 @@ PrintPlaylistFull(Client *client,
 }
 
 bool
-db_selection_print(Client *client, const DatabaseSelection &selection,
+db_selection_print(Client &client, const DatabaseSelection &selection,
 		   bool full, Error &error)
 {
 	const Database *db = GetDatabase(error);
@@ -127,13 +127,13 @@ db_selection_print(Client *client, const DatabaseSelection &selection,
 	using namespace std::placeholders;
 	const auto d = selection.filter == nullptr
 		? std::bind(full ? PrintDirectoryFull : PrintDirectoryBrief,
-			    client, _1)
+			    std::ref(client), _1)
 		: VisitDirectory();
 	const auto s = std::bind(full ? PrintSongFull : PrintSongBrief,
-				 client, _1);
+				 std::ref(client), _1);
 	const auto p = selection.filter == nullptr
 		? std::bind(full ? PrintPlaylistFull : PrintPlaylistBrief,
-			    client, _1, _2)
+			    std::ref(client), _1, _2)
 		: VisitPlaylist();
 
 	return db->Visit(selection, d, s, p, error);
@@ -144,7 +144,7 @@ struct SearchStats {
 	unsigned long playTime;
 };
 
-static void printSearchStats(Client *client, SearchStats *stats)
+static void printSearchStats(Client &client, SearchStats *stats)
 {
 	client_printf(client, "songs: %i\n", stats->numberOfSongs);
 	client_printf(client, "playtime: %li\n", stats->playTime);
@@ -160,7 +160,7 @@ stats_visitor_song(SearchStats &stats, Song &song)
 }
 
 bool
-searchStatsForSongsIn(Client *client, const char *name,
+searchStatsForSongsIn(Client &client, const char *name,
 		      const SongFilter *filter,
 		      Error &error)
 {
@@ -185,14 +185,14 @@ searchStatsForSongsIn(Client *client, const char *name,
 }
 
 bool
-printAllIn(Client *client, const char *uri_utf8, Error &error)
+printAllIn(Client &client, const char *uri_utf8, Error &error)
 {
 	const DatabaseSelection selection(uri_utf8, true);
 	return db_selection_print(client, selection, false, error);
 }
 
 bool
-printInfoForAllIn(Client *client, const char *uri_utf8,
+printInfoForAllIn(Client &client, const char *uri_utf8,
 		  Error &error)
 {
 	const DatabaseSelection selection(uri_utf8, true);
@@ -200,15 +200,15 @@ printInfoForAllIn(Client *client, const char *uri_utf8,
 }
 
 static bool
-PrintSongURIVisitor(Client *client, Song &song)
+PrintSongURIVisitor(Client &client, Song &song)
 {
-	song_print_uri(client, &song);
+	song_print_uri(client, song);
 
 	return true;
 }
 
 static bool
-PrintUniqueTag(Client *client, enum tag_type tag_type,
+PrintUniqueTag(Client &client, enum tag_type tag_type,
 	       const char *value)
 {
 	client_printf(client, "%s: %s\n", tag_item_names[tag_type], value);
@@ -216,7 +216,7 @@ PrintUniqueTag(Client *client, enum tag_type tag_type,
 }
 
 bool
-listAllUniqueTags(Client *client, int type,
+listAllUniqueTags(Client &client, int type,
 		  const SongFilter *filter,
 		  Error &error)
 {
@@ -228,11 +228,12 @@ listAllUniqueTags(Client *client, int type,
 
 	if (type == LOCATE_TAG_FILE_TYPE) {
 		using namespace std::placeholders;
-		const auto f = std::bind(PrintSongURIVisitor, client, _1);
+		const auto f = std::bind(PrintSongURIVisitor,
+					 std::ref(client), _1);
 		return db->Visit(selection, f, error);
 	} else {
 		using namespace std::placeholders;
-		const auto f = std::bind(PrintUniqueTag, client,
+		const auto f = std::bind(PrintUniqueTag, std::ref(client),
 					 (enum tag_type)type, _1);
 		return db->VisitUniqueTags(selection, (enum tag_type)type,
 					   f, error);
diff --git a/src/DatabasePrint.hxx b/src/DatabasePrint.hxx
index cebed15a8..1503209a4 100644
--- a/src/DatabasePrint.hxx
+++ b/src/DatabasePrint.hxx
@@ -28,29 +28,27 @@ struct db_visitor;
 class Client;
 class Error;
 
-gcc_nonnull(1)
 bool
-db_selection_print(Client *client, const DatabaseSelection &selection,
+db_selection_print(Client &client, const DatabaseSelection &selection,
 		   bool full, Error &error);
 
-gcc_nonnull(1,2)
+gcc_nonnull(2)
 bool
-printAllIn(Client *client, const char *uri_utf8, Error &error);
+printAllIn(Client &client, const char *uri_utf8, Error &error);
 
-gcc_nonnull(1,2)
+gcc_nonnull(2)
 bool
-printInfoForAllIn(Client *client, const char *uri_utf8,
+printInfoForAllIn(Client &client, const char *uri_utf8,
 		  Error &error);
 
-gcc_nonnull(1,2)
+gcc_nonnull(2)
 bool
-searchStatsForSongsIn(Client *client, const char *name,
+searchStatsForSongsIn(Client &client, const char *name,
 		      const SongFilter *filter,
 		      Error &error);
 
-gcc_nonnull(1)
 bool
-listAllUniqueTags(Client *client, int type,
+listAllUniqueTags(Client &client, int type,
 		  const SongFilter *filter,
 		  Error &error);
 
diff --git a/src/DatabaseSave.cxx b/src/DatabaseSave.cxx
index 7c6e34a4e..0fb00c8c0 100644
--- a/src/DatabaseSave.cxx
+++ b/src/DatabaseSave.cxx
@@ -49,10 +49,8 @@ enum {
 };
 
 void
-db_save_internal(FILE *fp, const Directory *music_root)
+db_save_internal(FILE *fp, const Directory &music_root)
 {
-	assert(music_root != nullptr);
-
 	fprintf(fp, "%s\n", DIRECTORY_INFO_BEGIN);
 	fprintf(fp, DB_FORMAT_PREFIX "%u\n", DB_FORMAT);
 	fprintf(fp, "%s%s\n", DIRECTORY_MPD_VERSION, VERSION);
@@ -68,7 +66,7 @@ db_save_internal(FILE *fp, const Directory *music_root)
 }
 
 bool
-db_load_internal(TextFile &file, Directory *music_root, Error &error)
+db_load_internal(TextFile &file, Directory &music_root, Error &error)
 {
 	char *line;
 	int format = 0;
@@ -76,8 +74,6 @@ db_load_internal(TextFile &file, Directory *music_root, Error &error)
 	bool success;
 	bool tags[TAG_NUM_OF_ITEM_TYPES];
 
-	assert(music_root != nullptr);
-
 	/* get initial info */
 	line = file.ReadLine();
 	if (line == nullptr || strcmp(DIRECTORY_INFO_BEGIN, line) != 0) {
diff --git a/src/DatabaseSave.hxx b/src/DatabaseSave.hxx
index 2410b0a71..741189973 100644
--- a/src/DatabaseSave.hxx
+++ b/src/DatabaseSave.hxx
@@ -27,9 +27,9 @@ class TextFile;
 class Error;
 
 void
-db_save_internal(FILE *file, const Directory *root);
+db_save_internal(FILE *file, const Directory &root);
 
 bool
-db_load_internal(TextFile &file, Directory *root, Error &error);
+db_load_internal(TextFile &file, Directory &root, Error &error);
 
 #endif
diff --git a/src/DecoderAPI.cxx b/src/DecoderAPI.cxx
index 7f3533233..06fa787f9 100644
--- a/src/DecoderAPI.cxx
+++ b/src/DecoderAPI.cxx
@@ -41,11 +41,11 @@ decoder_initialized(struct decoder *decoder,
 		    const AudioFormat audio_format,
 		    bool seekable, float total_time)
 {
-	struct decoder_control *dc = decoder->dc;
+	decoder_control &dc = decoder->dc;
 	struct audio_format_string af_string;
 
-	assert(dc->state == DecoderState::START);
-	assert(dc->pipe != nullptr);
+	assert(dc.state == DecoderState::START);
+	assert(dc.pipe != nullptr);
 	assert(decoder != nullptr);
 	assert(decoder->stream_tag == nullptr);
 	assert(decoder->decoder_tag == nullptr);
@@ -53,24 +53,24 @@ decoder_initialized(struct decoder *decoder,
 	assert(audio_format.IsDefined());
 	assert(audio_format.IsValid());
 
-	dc->in_audio_format = audio_format;
-	dc->out_audio_format = getOutputAudioFormat(audio_format);
+	dc.in_audio_format = audio_format;
+	dc.out_audio_format = getOutputAudioFormat(audio_format);
 
-	dc->seekable = seekable;
-	dc->total_time = total_time;
+	dc.seekable = seekable;
+	dc.total_time = total_time;
 
-	dc->Lock();
-	dc->state = DecoderState::DECODE;
-	dc->client_cond.signal();
-	dc->Unlock();
+	dc.Lock();
+	dc.state = DecoderState::DECODE;
+	dc.client_cond.signal();
+	dc.Unlock();
 
 	FormatDebug(decoder_domain, "audio_format=%s, seekable=%s",
-		    audio_format_to_string(dc->in_audio_format, &af_string),
+		    audio_format_to_string(dc.in_audio_format, &af_string),
 		    seekable ? "true" : "false");
 
-	if (dc->in_audio_format != dc->out_audio_format)
+	if (dc.in_audio_format != dc.out_audio_format)
 		FormatDebug(decoder_domain, "converting to %s",
-			    audio_format_to_string(dc->out_audio_format,
+			    audio_format_to_string(dc.out_audio_format,
 						   &af_string));
 }
 
@@ -82,10 +82,10 @@ gcc_pure
 static bool
 decoder_prepare_initial_seek(struct decoder *decoder)
 {
-	const struct decoder_control *dc = decoder->dc;
-	assert(dc->pipe != nullptr);
+	const decoder_control &dc = decoder->dc;
+	assert(dc.pipe != nullptr);
 
-	if (dc->state != DecoderState::DECODE)
+	if (dc.state != DecoderState::DECODE)
 		/* wait until the decoder has finished initialisation
 		   (reading file headers etc.) before emitting the
 		   virtual "SEEK" command */
@@ -97,13 +97,13 @@ decoder_prepare_initial_seek(struct decoder *decoder)
 		return true;
 
 	if (decoder->initial_seek_pending) {
-		if (!dc->seekable) {
+		if (!dc.seekable) {
 			/* seeking is not possible */
 			decoder->initial_seek_pending = false;
 			return false;
 		}
 
-		if (dc->command == DecoderCommand::NONE) {
+		if (dc.command == DecoderCommand::NONE) {
 			/* begin initial seek */
 
 			decoder->initial_seek_pending = false;
@@ -129,13 +129,13 @@ gcc_pure
 static DecoderCommand
 decoder_get_virtual_command(struct decoder *decoder)
 {
-	const struct decoder_control *dc = decoder->dc;
-	assert(dc->pipe != nullptr);
+	const decoder_control &dc = decoder->dc;
+	assert(dc.pipe != nullptr);
 
 	if (decoder_prepare_initial_seek(decoder))
 		return DecoderCommand::SEEK;
 
-	return dc->command;
+	return dc.command;
 }
 
 DecoderCommand
@@ -147,25 +147,25 @@ decoder_get_command(struct decoder *decoder)
 void
 decoder_command_finished(struct decoder *decoder)
 {
-	struct decoder_control *dc = decoder->dc;
+	decoder_control &dc = decoder->dc;
 
-	dc->Lock();
+	dc.Lock();
 
-	assert(dc->command != DecoderCommand::NONE ||
+	assert(dc.command != DecoderCommand::NONE ||
 	       decoder->initial_seek_running);
-	assert(dc->command != DecoderCommand::SEEK ||
+	assert(dc.command != DecoderCommand::SEEK ||
 	       decoder->initial_seek_running ||
-	       dc->seek_error || decoder->seeking);
-	assert(dc->pipe != nullptr);
+	       dc.seek_error || decoder->seeking);
+	assert(dc.pipe != nullptr);
 
 	if (decoder->initial_seek_running) {
 		assert(!decoder->seeking);
 		assert(decoder->chunk == nullptr);
-		assert(dc->pipe->IsEmpty());
+		assert(dc.pipe->IsEmpty());
 
 		decoder->initial_seek_running = false;
-		decoder->timestamp = dc->start_ms / 1000.;
-		dc->Unlock();
+		decoder->timestamp = dc.start_ms / 1000.;
+		dc.Unlock();
 		return;
 	}
 
@@ -175,41 +175,41 @@ decoder_command_finished(struct decoder *decoder)
 		/* delete frames from the old song position */
 
 		if (decoder->chunk != nullptr) {
-			dc->buffer->Return(decoder->chunk);
+			dc.buffer->Return(decoder->chunk);
 			decoder->chunk = nullptr;
 		}
 
-		dc->pipe->Clear(*dc->buffer);
+		dc.pipe->Clear(*dc.buffer);
 
-		decoder->timestamp = dc->seek_where;
+		decoder->timestamp = dc.seek_where;
 	}
 
-	dc->command = DecoderCommand::NONE;
-	dc->client_cond.signal();
-	dc->Unlock();
+	dc.command = DecoderCommand::NONE;
+	dc.client_cond.signal();
+	dc.Unlock();
 }
 
 double decoder_seek_where(gcc_unused struct decoder * decoder)
 {
-	const struct decoder_control *dc = decoder->dc;
+	const decoder_control &dc = decoder->dc;
 
-	assert(dc->pipe != nullptr);
+	assert(dc.pipe != nullptr);
 
 	if (decoder->initial_seek_running)
-		return dc->start_ms / 1000.;
+		return dc.start_ms / 1000.;
 
-	assert(dc->command == DecoderCommand::SEEK);
+	assert(dc.command == DecoderCommand::SEEK);
 
 	decoder->seeking = true;
 
-	return dc->seek_where;
+	return dc.seek_where;
 }
 
 void decoder_seek_error(struct decoder * decoder)
 {
-	struct decoder_control *dc = decoder->dc;
+	decoder_control &dc = decoder->dc;
 
-	assert(dc->pipe != nullptr);
+	assert(dc.pipe != nullptr);
 
 	if (decoder->initial_seek_running) {
 		/* d'oh, we can't seek to the sub-song start position,
@@ -218,9 +218,9 @@ void decoder_seek_error(struct decoder * decoder)
 		return;
 	}
 
-	assert(dc->command == DecoderCommand::SEEK);
+	assert(dc.command == DecoderCommand::SEEK);
 
-	dc->seek_error = true;
+	dc.seek_error = true;
 	decoder->seeking = false;
 
 	decoder_command_finished(decoder);
@@ -237,14 +237,14 @@ decoder_check_cancel_read(const struct decoder *decoder)
 	if (decoder == nullptr)
 		return false;
 
-	const struct decoder_control *dc = decoder->dc;
-	if (dc->command == DecoderCommand::NONE)
+	const decoder_control &dc = decoder->dc;
+	if (dc.command == DecoderCommand::NONE)
 		return false;
 
 	/* ignore the SEEK command during initialization, the plugin
 	   should handle that after it has initialized successfully */
-	if (dc->command == DecoderCommand::SEEK &&
-	    (dc->state == DecoderState::START || decoder->seeking))
+	if (dc.command == DecoderCommand::SEEK &&
+	    (dc.state == DecoderState::START || decoder->seeking))
 		return false;
 
 	return true;
@@ -257,8 +257,8 @@ size_t decoder_read(struct decoder *decoder,
 	/* XXX don't allow decoder==nullptr */
 
 	assert(decoder == nullptr ||
-	       decoder->dc->state == DecoderState::START ||
-	       decoder->dc->state == DecoderState::DECODE);
+	       decoder->dc.state == DecoderState::START ||
+	       decoder->dc.state == DecoderState::DECODE);
 	assert(is != nullptr);
 	assert(buffer != nullptr);
 
@@ -314,15 +314,15 @@ do_send_tag(struct decoder *decoder, const Tag &tag)
 		/* there is a partial chunk - flush it, we want the
 		   tag in a new chunk */
 		decoder_flush_chunk(decoder);
-		decoder->dc->client_cond.signal();
+		decoder->dc.client_cond.signal();
 	}
 
 	assert(decoder->chunk == nullptr);
 
 	chunk = decoder_get_chunk(decoder);
 	if (chunk == nullptr) {
-		assert(decoder->dc->command != DecoderCommand::NONE);
-		return decoder->dc->command;
+		assert(decoder->dc.command != DecoderCommand::NONE);
+		return decoder->dc.command;
 	}
 
 	chunk->tag = new Tag(tag);
@@ -358,16 +358,16 @@ decoder_data(struct decoder *decoder,
 	     const void *data, size_t length,
 	     uint16_t kbit_rate)
 {
-	struct decoder_control *dc = decoder->dc;
+	decoder_control &dc = decoder->dc;
 	DecoderCommand cmd;
 
-	assert(dc->state == DecoderState::DECODE);
-	assert(dc->pipe != nullptr);
-	assert(length % dc->in_audio_format.GetFrameSize() == 0);
+	assert(dc.state == DecoderState::DECODE);
+	assert(dc.pipe != nullptr);
+	assert(length % dc.in_audio_format.GetFrameSize() == 0);
 
-	dc->Lock();
+	dc.Lock();
 	cmd = decoder_get_virtual_command(decoder);
-	dc->Unlock();
+	dc.Unlock();
 
 	if (cmd == DecoderCommand::STOP || cmd == DecoderCommand::SEEK ||
 	    length == 0)
@@ -390,11 +390,11 @@ decoder_data(struct decoder *decoder,
 			return cmd;
 	}
 
-	if (dc->in_audio_format != dc->out_audio_format) {
+	if (dc.in_audio_format != dc.out_audio_format) {
 		Error error;
-		data = decoder->conv_state.Convert(dc->in_audio_format,
+		data = decoder->conv_state.Convert(dc.in_audio_format,
 						   data, length,
-						   dc->out_audio_format,
+						   dc.out_audio_format,
 						   &length,
 						   error);
 		if (data == nullptr) {
@@ -413,18 +413,18 @@ decoder_data(struct decoder *decoder,
 
 		chunk = decoder_get_chunk(decoder);
 		if (chunk == nullptr) {
-			assert(dc->command != DecoderCommand::NONE);
-			return dc->command;
+			assert(dc.command != DecoderCommand::NONE);
+			return dc.command;
 		}
 
-		void *dest = chunk->Write(dc->out_audio_format,
+		void *dest = chunk->Write(dc.out_audio_format,
 					  decoder->timestamp -
-					  dc->song->start_ms / 1000.0,
+					  dc.song->start_ms / 1000.0,
 					  kbit_rate, &nbytes);
 		if (dest == nullptr) {
 			/* the chunk is full, flush it */
 			decoder_flush_chunk(decoder);
-			dc->client_cond.signal();
+			dc.client_cond.signal();
 			continue;
 		}
 
@@ -439,21 +439,21 @@ decoder_data(struct decoder *decoder,
 
 		/* expand the music pipe chunk */
 
-		full = chunk->Expand(dc->out_audio_format, nbytes);
+		full = chunk->Expand(dc.out_audio_format, nbytes);
 		if (full) {
 			/* the chunk is full, flush it */
 			decoder_flush_chunk(decoder);
-			dc->client_cond.signal();
+			dc.client_cond.signal();
 		}
 
 		data = (const uint8_t *)data + nbytes;
 		length -= nbytes;
 
 		decoder->timestamp += (double)nbytes /
-			dc->out_audio_format.GetTimeToSize();
+			dc.out_audio_format.GetTimeToSize();
 
-		if (dc->end_ms > 0 &&
-		    decoder->timestamp >= dc->end_ms / 1000.0)
+		if (dc.end_ms > 0 &&
+		    decoder->timestamp >= dc.end_ms / 1000.0)
 			/* the end of this range has been reached:
 			   stop decoding */
 			return DecoderCommand::STOP;
@@ -466,11 +466,11 @@ DecoderCommand
 decoder_tag(gcc_unused struct decoder *decoder, struct input_stream *is,
 	    Tag &&tag)
 {
-	gcc_unused const struct decoder_control *dc = decoder->dc;
+	gcc_unused const decoder_control &dc = decoder->dc;
 	DecoderCommand cmd;
 
-	assert(dc->state == DecoderState::DECODE);
-	assert(dc->pipe != nullptr);
+	assert(dc.state == DecoderState::DECODE);
+	assert(dc.pipe != nullptr);
 
 	/* save the tag */
 
@@ -522,7 +522,7 @@ decoder_replay_gain(struct decoder *decoder,
 			if (rgm != REPLAY_GAIN_ALBUM)
 				rgm = REPLAY_GAIN_TRACK;
 
-			decoder->dc->replay_gain_db = 20.0 * log10f(
+			decoder->dc.replay_gain_db = 20.0 * log10f(
 				replay_gain_tuple_scale(
 					&replay_gain_info->tuples[rgm],
 					replay_gain_preamp, replay_gain_missing_preamp,
@@ -537,7 +537,7 @@ decoder_replay_gain(struct decoder *decoder,
 			   replay gain values affect the following
 			   samples */
 			decoder_flush_chunk(decoder);
-			decoder->dc->client_cond.signal();
+			decoder->dc.client_cond.signal();
 		}
 	} else
 		decoder->replay_gain_serial = 0;
@@ -548,9 +548,8 @@ decoder_mixramp(struct decoder *decoder,
 		char *mixramp_start, char *mixramp_end)
 {
 	assert(decoder != nullptr);
-	struct decoder_control *dc = decoder->dc;
-	assert(dc != nullptr);
+	decoder_control &dc = decoder->dc;
 
-	dc->MixRampStart(mixramp_start);
-	dc->MixRampEnd(mixramp_end);
+	dc.MixRampStart(mixramp_start);
+	dc.MixRampEnd(mixramp_end);
 }
diff --git a/src/DecoderInternal.cxx b/src/DecoderInternal.cxx
index 43536686b..8d89155cc 100644
--- a/src/DecoderInternal.cxx
+++ b/src/DecoderInternal.cxx
@@ -42,17 +42,17 @@ decoder::~decoder()
  * one.
  */
 static DecoderCommand
-need_chunks(struct decoder_control *dc, bool do_wait)
+need_chunks(decoder_control &dc, bool do_wait)
 {
-	if (dc->command == DecoderCommand::STOP ||
-	    dc->command == DecoderCommand::SEEK)
-		return dc->command;
+	if (dc.command == DecoderCommand::STOP ||
+	    dc.command == DecoderCommand::SEEK)
+		return dc.command;
 
 	if (do_wait) {
-		dc->Wait();
-		dc->client_cond.signal();
+		dc.Wait();
+		dc.client_cond.signal();
 
-		return dc->command;
+		return dc.command;
 	}
 
 	return DecoderCommand::NONE;
@@ -61,7 +61,7 @@ need_chunks(struct decoder_control *dc, bool do_wait)
 struct music_chunk *
 decoder_get_chunk(struct decoder *decoder)
 {
-	struct decoder_control *dc = decoder->dc;
+	decoder_control &dc = decoder->dc;
 	DecoderCommand cmd;
 
 	assert(decoder != nullptr);
@@ -70,7 +70,7 @@ decoder_get_chunk(struct decoder *decoder)
 		return decoder->chunk;
 
 	do {
-		decoder->chunk = dc->buffer->Allocate();
+		decoder->chunk = dc.buffer->Allocate();
 		if (decoder->chunk != nullptr) {
 			decoder->chunk->replay_gain_serial =
 				decoder->replay_gain_serial;
@@ -81,9 +81,9 @@ decoder_get_chunk(struct decoder *decoder)
 			return decoder->chunk;
 		}
 
-		dc->Lock();
+		dc.Lock();
 		cmd = need_chunks(dc, true);
-		dc->Unlock();
+		dc.Unlock();
 	} while (cmd == DecoderCommand::NONE);
 
 	return nullptr;
@@ -92,15 +92,15 @@ decoder_get_chunk(struct decoder *decoder)
 void
 decoder_flush_chunk(struct decoder *decoder)
 {
-	struct decoder_control *dc = decoder->dc;
+	decoder_control &dc = decoder->dc;
 
 	assert(decoder != nullptr);
 	assert(decoder->chunk != nullptr);
 
 	if (decoder->chunk->IsEmpty())
-		dc->buffer->Return(decoder->chunk);
+		dc.buffer->Return(decoder->chunk);
 	else
-		dc->pipe->Push(decoder->chunk);
+		dc.pipe->Push(decoder->chunk);
 
 	decoder->chunk = nullptr;
 }
diff --git a/src/DecoderInternal.hxx b/src/DecoderInternal.hxx
index 5e0570c62..fa776c26f 100644
--- a/src/DecoderInternal.hxx
+++ b/src/DecoderInternal.hxx
@@ -24,11 +24,12 @@
 #include "pcm/PcmConvert.hxx"
 #include "ReplayGainInfo.hxx"
 
+struct decoder_control;
 struct input_stream;
 struct Tag;
 
 struct decoder {
-	struct decoder_control *dc;
+	decoder_control &dc;
 
 	PcmConvert conv_state;
 
@@ -82,7 +83,7 @@ struct decoder {
 	 */
 	unsigned replay_gain_serial;
 
-	decoder(decoder_control *_dc, bool _initial_seek_pending, Tag *_tag)
+	decoder(decoder_control &_dc, bool _initial_seek_pending, Tag *_tag)
 		:dc(_dc),
 		 timestamp(0),
 		 initial_seek_pending(_initial_seek_pending),
diff --git a/src/DecoderList.cxx b/src/DecoderList.cxx
index fc3ef89cd..be6749966 100644
--- a/src/DecoderList.cxx
+++ b/src/DecoderList.cxx
@@ -149,7 +149,7 @@ decoder_plugin_from_suffix(const char *suffix,
 	     decoder_plugins[i] != nullptr; ++i) {
 		plugin = decoder_plugins[i];
 		if (decoder_plugins_enabled[i] &&
-		    decoder_plugin_supports_suffix(plugin, suffix))
+		    decoder_plugin_supports_suffix(*plugin, suffix))
 			return plugin;
 	}
 
@@ -169,7 +169,7 @@ decoder_plugin_from_mime_type(const char *mimeType, unsigned int next)
 	for (; decoder_plugins[i] != nullptr; ++i) {
 		const struct decoder_plugin *plugin = decoder_plugins[i];
 		if (decoder_plugins_enabled[i] &&
-		    decoder_plugin_supports_mime_type(plugin, mimeType)) {
+		    decoder_plugin_supports_mime_type(*plugin, mimeType)) {
 			++i;
 			return plugin;
 		}
@@ -217,9 +217,9 @@ void decoder_plugin_init_all(void)
 	struct config_param empty;
 
 	for (unsigned i = 0; decoder_plugins[i] != nullptr; ++i) {
-		const struct decoder_plugin *plugin = decoder_plugins[i];
+		const decoder_plugin &plugin = *decoder_plugins[i];
 		const struct config_param *param =
-			decoder_plugin_config(plugin->name);
+			decoder_plugin_config(plugin.name);
 
 		if (param == nullptr)
 			param = &empty;
@@ -235,5 +235,5 @@ void decoder_plugin_init_all(void)
 void decoder_plugin_deinit_all(void)
 {
 	decoder_plugins_for_each_enabled(plugin)
-		decoder_plugin_finish(plugin);
+		decoder_plugin_finish(*plugin);
 }
diff --git a/src/DecoderPlugin.cxx b/src/DecoderPlugin.cxx
index 9dce4b21f..db5d9304f 100644
--- a/src/DecoderPlugin.cxx
+++ b/src/DecoderPlugin.cxx
@@ -24,24 +24,22 @@
 #include <assert.h>
 
 bool
-decoder_plugin_supports_suffix(const struct decoder_plugin *plugin,
+decoder_plugin_supports_suffix(const decoder_plugin &plugin,
 			       const char *suffix)
 {
-	assert(plugin != nullptr);
 	assert(suffix != nullptr);
 
-	return plugin->suffixes != nullptr &&
-		string_array_contains(plugin->suffixes, suffix);
+	return plugin.suffixes != nullptr &&
+		string_array_contains(plugin.suffixes, suffix);
 
 }
 
 bool
-decoder_plugin_supports_mime_type(const struct decoder_plugin *plugin,
+decoder_plugin_supports_mime_type(const decoder_plugin &plugin,
 				  const char *mime_type)
 {
-	assert(plugin != nullptr);
 	assert(mime_type != nullptr);
 
-	return plugin->mime_types != nullptr &&
-		string_array_contains(plugin->mime_types, mime_type);
+	return plugin.mime_types != nullptr &&
+		string_array_contains(plugin.mime_types, mime_type);
 }
diff --git a/src/DecoderPlugin.hxx b/src/DecoderPlugin.hxx
index 693b8feee..0bfae90e1 100644
--- a/src/DecoderPlugin.hxx
+++ b/src/DecoderPlugin.hxx
@@ -111,11 +111,11 @@ struct decoder_plugin {
  * the plugin is not available
  */
 static inline bool
-decoder_plugin_init(const struct decoder_plugin *plugin,
+decoder_plugin_init(const decoder_plugin &plugin,
 		    const config_param &param)
 {
-	return plugin->init != nullptr
-		? plugin->init(param)
+	return plugin.init != nullptr
+		? plugin.init(param)
 		: true;
 }
 
@@ -123,42 +123,42 @@ decoder_plugin_init(const struct decoder_plugin *plugin,
  * Deinitialize a decoder plugin which was initialized successfully.
  */
 static inline void
-decoder_plugin_finish(const struct decoder_plugin *plugin)
+decoder_plugin_finish(const decoder_plugin &plugin)
 {
-	if (plugin->finish != nullptr)
-		plugin->finish();
+	if (plugin.finish != nullptr)
+		plugin.finish();
 }
 
 /**
  * Decode a stream.
  */
 static inline void
-decoder_plugin_stream_decode(const struct decoder_plugin *plugin,
+decoder_plugin_stream_decode(const decoder_plugin &plugin,
 			     struct decoder *decoder, struct input_stream *is)
 {
-	plugin->stream_decode(decoder, is);
+	plugin.stream_decode(decoder, is);
 }
 
 /**
  * Decode a file.
  */
 static inline void
-decoder_plugin_file_decode(const struct decoder_plugin *plugin,
+decoder_plugin_file_decode(const decoder_plugin &plugin,
 			   struct decoder *decoder, const char *path_fs)
 {
-	plugin->file_decode(decoder, path_fs);
+	plugin.file_decode(decoder, path_fs);
 }
 
 /**
  * Read the tag of a file.
  */
 static inline bool
-decoder_plugin_scan_file(const struct decoder_plugin *plugin,
+decoder_plugin_scan_file(const decoder_plugin &plugin,
 			 const char *path_fs,
 			 const struct tag_handler *handler, void *handler_ctx)
 {
-	return plugin->scan_file != nullptr
-		? plugin->scan_file(path_fs, handler, handler_ctx)
+	return plugin.scan_file != nullptr
+		? plugin.scan_file(path_fs, handler, handler_ctx)
 		: false;
 }
 
@@ -166,13 +166,13 @@ decoder_plugin_scan_file(const struct decoder_plugin *plugin,
  * Read the tag of a stream.
  */
 static inline bool
-decoder_plugin_scan_stream(const struct decoder_plugin *plugin,
+decoder_plugin_scan_stream(const decoder_plugin &plugin,
 			   struct input_stream *is,
 			   const struct tag_handler *handler,
 			   void *handler_ctx)
 {
-	return plugin->scan_stream != nullptr
-		? plugin->scan_stream(is, handler, handler_ctx)
+	return plugin.scan_stream != nullptr
+		? plugin.scan_stream(is, handler, handler_ctx)
 		: false;
 }
 
@@ -180,25 +180,25 @@ decoder_plugin_scan_stream(const struct decoder_plugin *plugin,
  * return "virtual" tracks in a container
  */
 static inline char *
-decoder_plugin_container_scan(	const struct decoder_plugin *plugin,
+decoder_plugin_container_scan(	const decoder_plugin &plugin,
 				const char* pathname,
 				const unsigned int tnum)
 {
-	return plugin->container_scan(pathname, tnum);
+	return plugin.container_scan(pathname, tnum);
 }
 
 /**
  * Does the plugin announce the specified file name suffix?
  */
 bool
-decoder_plugin_supports_suffix(const struct decoder_plugin *plugin,
+decoder_plugin_supports_suffix(const decoder_plugin &plugin,
 			       const char *suffix);
 
 /**
  * Does the plugin announce the specified MIME type?
  */
 bool
-decoder_plugin_supports_mime_type(const struct decoder_plugin *plugin,
+decoder_plugin_supports_mime_type(const decoder_plugin &plugin,
 				  const char *mime_type);
 
 #endif
diff --git a/src/DecoderPrint.cxx b/src/DecoderPrint.cxx
index 6d5bd4f30..f9e4d1472 100644
--- a/src/DecoderPrint.cxx
+++ b/src/DecoderPrint.cxx
@@ -26,7 +26,7 @@
 #include <assert.h>
 
 static void
-decoder_plugin_print(Client *client,
+decoder_plugin_print(Client &client,
 		     const struct decoder_plugin *plugin)
 {
 	const char *const*p;
@@ -46,7 +46,7 @@ decoder_plugin_print(Client *client,
 }
 
 void
-decoder_list_print(Client *client)
+decoder_list_print(Client &client)
 {
 	decoder_plugins_for_each_enabled(plugin)
 		decoder_plugin_print(client, plugin);
diff --git a/src/DecoderPrint.hxx b/src/DecoderPrint.hxx
index d94ba2cef..693608746 100644
--- a/src/DecoderPrint.hxx
+++ b/src/DecoderPrint.hxx
@@ -23,6 +23,6 @@
 class Client;
 
 void
-decoder_list_print(Client *client);
+decoder_list_print(Client &client);
 
 #endif
diff --git a/src/DecoderThread.cxx b/src/DecoderThread.cxx
index 39aa4b395..551b96a13 100644
--- a/src/DecoderThread.cxx
+++ b/src/DecoderThread.cxx
@@ -52,13 +52,13 @@ static constexpr Domain decoder_thread_domain("decoder_thread");
  * @param dc the #decoder_control object; must be locked
  */
 static void
-decoder_command_finished_locked(struct decoder_control *dc)
+decoder_command_finished_locked(decoder_control &dc)
 {
-	assert(dc->command != DecoderCommand::NONE);
+	assert(dc.command != DecoderCommand::NONE);
 
-	dc->command = DecoderCommand::NONE;
+	dc.command = DecoderCommand::NONE;
 
-	dc->client_cond.signal();
+	dc.client_cond.signal();
 }
 
 /**
@@ -73,11 +73,11 @@ decoder_command_finished_locked(struct decoder_control *dc)
  * received, nullptr on error
  */
 static struct input_stream *
-decoder_input_stream_open(struct decoder_control *dc, const char *uri)
+decoder_input_stream_open(decoder_control &dc, const char *uri)
 {
 	Error error;
 
-	input_stream *is = input_stream::Open(uri, dc->mutex, dc->cond, error);
+	input_stream *is = input_stream::Open(uri, dc.mutex, dc.cond, error);
 	if (is == nullptr) {
 		if (error.IsDefined())
 			LogError(error);
@@ -88,90 +88,88 @@ decoder_input_stream_open(struct decoder_control *dc, const char *uri)
 	/* wait for the input stream to become ready; its metadata
 	   will be available then */
 
-	dc->Lock();
+	dc.Lock();
 
 	is->Update();
 	while (!is->ready &&
-	       dc->command != DecoderCommand::STOP) {
-		dc->Wait();
+	       dc.command != DecoderCommand::STOP) {
+		dc.Wait();
 
 		is->Update();
 	}
 
 	if (!is->Check(error)) {
-		dc->Unlock();
+		dc.Unlock();
 
 		LogError(error);
 		return nullptr;
 	}
 
-	dc->Unlock();
+	dc.Unlock();
 
 	return is;
 }
 
 static bool
-decoder_stream_decode(const struct decoder_plugin *plugin,
+decoder_stream_decode(const decoder_plugin &plugin,
 		      struct decoder *decoder,
 		      struct input_stream *input_stream)
 {
-	assert(plugin != nullptr);
-	assert(plugin->stream_decode != nullptr);
+	assert(plugin.stream_decode != nullptr);
 	assert(decoder != nullptr);
 	assert(decoder->stream_tag == nullptr);
 	assert(decoder->decoder_tag == nullptr);
 	assert(input_stream != nullptr);
 	assert(input_stream->ready);
-	assert(decoder->dc->state == DecoderState::START);
+	assert(decoder->dc.state == DecoderState::START);
 
-	FormatDebug(decoder_thread_domain, "probing plugin %s", plugin->name);
+	FormatDebug(decoder_thread_domain, "probing plugin %s", plugin.name);
 
-	if (decoder->dc->command == DecoderCommand::STOP)
+	if (decoder->dc.command == DecoderCommand::STOP)
 		return true;
 
 	/* rewind the stream, so each plugin gets a fresh start */
 	input_stream->Seek(0, SEEK_SET, IgnoreError());
 
-	decoder->dc->Unlock();
+	decoder->dc.Unlock();
 
 	decoder_plugin_stream_decode(plugin, decoder, input_stream);
 
-	decoder->dc->Lock();
+	decoder->dc.Lock();
 
-	assert(decoder->dc->state == DecoderState::START ||
-	       decoder->dc->state == DecoderState::DECODE);
+	assert(decoder->dc.state == DecoderState::START ||
+	       decoder->dc.state == DecoderState::DECODE);
 
-	return decoder->dc->state != DecoderState::START;
+	return decoder->dc.state != DecoderState::START;
 }
 
 static bool
-decoder_file_decode(const struct decoder_plugin *plugin,
+decoder_file_decode(const decoder_plugin &plugin,
 		    struct decoder *decoder, const char *path)
 {
-	assert(plugin != nullptr);
-	assert(plugin->file_decode != nullptr);
+	assert(plugin.file_decode != nullptr);
 	assert(decoder != nullptr);
 	assert(decoder->stream_tag == nullptr);
 	assert(decoder->decoder_tag == nullptr);
 	assert(path != nullptr);
 	assert(PathTraits::IsAbsoluteFS(path));
-	assert(decoder->dc->state == DecoderState::START);
+	assert(decoder->dc.state == DecoderState::START);
 
-	FormatDebug(decoder_thread_domain, "probing plugin %s", plugin->name);
+	FormatDebug(decoder_thread_domain, "probing plugin %s", plugin.name);
 
-	if (decoder->dc->command == DecoderCommand::STOP)
+	if (decoder->dc.command == DecoderCommand::STOP)
 		return true;
 
-	decoder->dc->Unlock();
+	decoder->dc.Unlock();
 
 	decoder_plugin_file_decode(plugin, decoder, path);
 
-	decoder->dc->Lock();
+	decoder->dc.Lock();
 
-	assert(decoder->dc->state == DecoderState::START ||
-	       decoder->dc->state == DecoderState::DECODE);
+	assert(decoder->dc.state == DecoderState::START ||
+	       decoder->dc.state == DecoderState::DECODE);
 
-	return decoder->dc->state != DecoderState::START;
+	return decoder->dc.state != DecoderState::START;
 }
 
 /**
@@ -209,7 +207,7 @@ decoder_run_stream_mime_type(struct decoder *decoder, struct input_stream *is,
 			/* don't try a plugin twice */
 			continue;
 
-		if (decoder_stream_decode(plugin, decoder, is))
+		if (decoder_stream_decode(*plugin, decoder, is))
 			return true;
 
 		*tried_r = g_slist_prepend(*tried_r, deconst_plugin(plugin));
@@ -244,7 +242,7 @@ decoder_run_stream_suffix(struct decoder *decoder, struct input_stream *is,
 			/* don't try a plugin twice */
 			continue;
 
-		if (decoder_stream_decode(plugin, decoder, is))
+		if (decoder_stream_decode(*plugin, decoder, is))
 			return true;
 
 		*tried_r = g_slist_prepend(*tried_r, deconst_plugin(plugin));
@@ -263,7 +261,7 @@ decoder_run_stream_fallback(struct decoder *decoder, struct input_stream *is)
 
 	plugin = decoder_plugin_from_name("mad");
 	return plugin != nullptr && plugin->stream_decode != nullptr &&
-		decoder_stream_decode(plugin, decoder, is);
+		decoder_stream_decode(*plugin, decoder, is);
 }
 
 /**
@@ -272,23 +270,23 @@ decoder_run_stream_fallback(struct decoder *decoder, struct input_stream *is)
 static bool
 decoder_run_stream(struct decoder *decoder, const char *uri)
 {
-	struct decoder_control *dc = decoder->dc;
+	decoder_control &dc = decoder->dc;
 	struct input_stream *input_stream;
 	bool success;
 
-	dc->Unlock();
+	dc.Unlock();
 
 	input_stream = decoder_input_stream_open(dc, uri);
 	if (input_stream == nullptr) {
-		dc->Lock();
+		dc.Lock();
 		return false;
 	}
 
-	dc->Lock();
+	dc.Lock();
 
 	GSList *tried = nullptr;
 
-	success = dc->command == DecoderCommand::STOP ||
+	success = dc.command == DecoderCommand::STOP ||
 		/* first we try mime types: */
 		decoder_run_stream_mime_type(decoder, input_stream, &tried) ||
 		/* if that fails, try suffix matching the URL: */
@@ -301,9 +299,9 @@ decoder_run_stream(struct decoder *decoder, const char *uri)
 
 	g_slist_free(tried);
 
-	dc->Unlock();
+	dc.Unlock();
 	input_stream->Close();
-	dc->Lock();
+	dc.Lock();
 
 	return success;
 }
@@ -326,25 +324,25 @@ decoder_load_replay_gain(struct decoder *decoder, const char *path_fs)
 static bool
 decoder_run_file(struct decoder *decoder, const char *path_fs)
 {
-	struct decoder_control *dc = decoder->dc;
+	decoder_control &dc = decoder->dc;
 	const char *suffix = uri_get_suffix(path_fs);
 	const struct decoder_plugin *plugin = nullptr;
 
 	if (suffix == nullptr)
 		return false;
 
-	dc->Unlock();
+	dc.Unlock();
 
 	decoder_load_replay_gain(decoder, path_fs);
 
 	while ((plugin = decoder_plugin_from_suffix(suffix, plugin)) != nullptr) {
 		if (plugin->file_decode != nullptr) {
-			dc->Lock();
+			dc.Lock();
 
-			if (decoder_file_decode(plugin, decoder, path_fs))
+			if (decoder_file_decode(*plugin, decoder, path_fs))
 				return true;
 
-			dc->Unlock();
+			dc.Unlock();
 		} else if (plugin->stream_decode != nullptr) {
 			struct input_stream *input_stream;
 			bool success;
@@ -353,36 +351,36 @@ decoder_run_file(struct decoder *decoder, const char *path_fs)
 			if (input_stream == nullptr)
 				continue;
 
-			dc->Lock();
+			dc.Lock();
 
-			success = decoder_stream_decode(plugin, decoder,
+			success = decoder_stream_decode(*plugin, decoder,
 							input_stream);
 
-			dc->Unlock();
+			dc.Unlock();
 
 			input_stream->Close();
 
 			if (success) {
-				dc->Lock();
+				dc.Lock();
 				return true;
 			}
 		}
 	}
 
-	dc->Lock();
+	dc.Lock();
 	return false;
 }
 
 static void
-decoder_run_song(struct decoder_control *dc,
+decoder_run_song(decoder_control &dc,
 		 const Song *song, const char *uri)
 {
-	decoder decoder(dc, dc->start_ms > 0,
+	decoder decoder(dc, dc.start_ms > 0,
 			song->tag != nullptr && song->IsFile()
 			? new Tag(*song->tag) : nullptr);
 	int ret;
 
-	dc->state = DecoderState::START;
+	dc.state = DecoderState::START;
 
 	decoder_command_finished_locked(dc);
 
@@ -390,48 +388,48 @@ decoder_run_song(struct decoder_control *dc,
 		? decoder_run_file(&decoder, uri)
 		: decoder_run_stream(&decoder, uri);
 
-	dc->Unlock();
+	dc.Unlock();
 
 	/* flush the last chunk */
 
 	if (decoder.chunk != nullptr)
 		decoder_flush_chunk(&decoder);
 
-	dc->Lock();
+	dc.Lock();
 
 	if (ret)
-		dc->state = DecoderState::STOP;
+		dc.state = DecoderState::STOP;
 	else {
-		dc->state = DecoderState::ERROR;
+		dc.state = DecoderState::ERROR;
 
 		const char *error_uri = song->uri;
 		char *allocated = uri_remove_auth(error_uri);
 		if (allocated != nullptr)
 			error_uri = allocated;
 
-		dc->error.Format(decoder_domain,
+		dc.error.Format(decoder_domain,
 				 "Failed to decode %s", error_uri);
 		g_free(allocated);
 	}
 
-	dc->client_cond.signal();
+	dc.client_cond.signal();
 }
 
 static void
-decoder_run(struct decoder_control *dc)
+decoder_run(decoder_control &dc)
 {
-	dc->ClearError();
+	dc.ClearError();
 
-	const Song *song = dc->song;
+	const Song *song = dc.song;
 	assert(song != nullptr);
 
 	const std::string uri = song->IsFile()
-		? std::string(map_song_fs(song).c_str())
+		? std::string(map_song_fs(*song).c_str())
 		: song->GetURI();
 
 	if (uri.empty()) {
-		dc->state = DecoderState::ERROR;
-		dc->error.Set(decoder_domain, "Failed to map song");
+		dc.state = DecoderState::ERROR;
+		dc.error.Set(decoder_domain, "Failed to map song");
 
 		decoder_command_finished_locked(dc);
 		return;
@@ -444,21 +442,21 @@ decoder_run(struct decoder_control *dc)
 static void
 decoder_task(void *arg)
 {
-	struct decoder_control *dc = (struct decoder_control *)arg;
+	decoder_control &dc = *(decoder_control *)arg;
 
-	dc->Lock();
+	dc.Lock();
 
 	do {
-		assert(dc->state == DecoderState::STOP ||
-		       dc->state == DecoderState::ERROR);
+		assert(dc.state == DecoderState::STOP ||
+		       dc.state == DecoderState::ERROR);
 
-		switch (dc->command) {
+		switch (dc.command) {
 		case DecoderCommand::START:
-			dc->MixRampStart(nullptr);
-			dc->MixRampPrevEnd(dc->mixramp_end);
-			dc->mixramp_end = nullptr; /* Don't free, it's copied above. */
-			dc->replay_gain_prev_db = dc->replay_gain_db;
-			dc->replay_gain_db = 0;
+			dc.MixRampStart(nullptr);
+			dc.MixRampPrevEnd(dc.mixramp_end);
+			dc.mixramp_end = nullptr; /* Don't free, it's copied above. */
+			dc.replay_gain_prev_db = dc.replay_gain_db;
+			dc.replay_gain_db = 0;
 
 			/* fall through */
 
@@ -471,22 +469,22 @@ decoder_task(void *arg)
 			break;
 
 		case DecoderCommand::NONE:
-			dc->Wait();
+			dc.Wait();
 			break;
 		}
-	} while (dc->command != DecoderCommand::NONE || !dc->quit);
+	} while (dc.command != DecoderCommand::NONE || !dc.quit);
 
-	dc->Unlock();
+	dc.Unlock();
 }
 
 void
-decoder_thread_start(struct decoder_control *dc)
+decoder_thread_start(decoder_control &dc)
 {
-	assert(!dc->thread.IsDefined());
+	assert(!dc.thread.IsDefined());
 
-	dc->quit = false;
+	dc.quit = false;
 
 	Error error;
-	if (!dc->thread.Start(decoder_task, dc, error))
+	if (!dc.thread.Start(decoder_task, &dc, error))
 		FatalError(error);
 }
diff --git a/src/DecoderThread.hxx b/src/DecoderThread.hxx
index 8efaa2fca..f92cce0cc 100644
--- a/src/DecoderThread.hxx
+++ b/src/DecoderThread.hxx
@@ -23,6 +23,6 @@
 struct decoder_control;
 
 void
-decoder_thread_start(struct decoder_control *dc);
+decoder_thread_start(decoder_control &dc);
 
 #endif
diff --git a/src/Directory.cxx b/src/Directory.cxx
index 4cd95a40c..25568bb19 100644
--- a/src/Directory.cxx
+++ b/src/Directory.cxx
@@ -70,11 +70,11 @@ Directory::Directory(const char *_path)
 Directory::~Directory()
 {
 	Song *song, *ns;
-	directory_for_each_song_safe(song, ns, this)
+	directory_for_each_song_safe(song, ns, *this)
 		song->Free();
 
 	Directory *child, *n;
-	directory_for_each_child_safe(child, n, this)
+	directory_for_each_child_safe(child, n, *this)
 		child->Free();
 }
 
@@ -153,7 +153,7 @@ Directory::FindChild(const char *name) const
 	assert(holding_db_lock());
 
 	const Directory *child;
-	directory_for_each_child(child, this)
+	directory_for_each_child(child, *this)
 		if (strcmp(child->GetName(), name) == 0)
 			return child;
 
@@ -166,7 +166,7 @@ Directory::PruneEmpty()
 	assert(holding_db_lock());
 
 	Directory *child, *n;
-	directory_for_each_child_safe(child, n, this) {
+	directory_for_each_child_safe(child, n, *this) {
 		child->PruneEmpty();
 
 		if (child->IsEmpty())
@@ -235,7 +235,7 @@ Directory::FindSong(const char *name_utf8) const
 	assert(name_utf8 != nullptr);
 
 	Song *song;
-	directory_for_each_song(song, this) {
+	directory_for_each_song(song, *this) {
 		assert(song->parent == this);
 
 		if (strcmp(song->uri, name_utf8) == 0)
@@ -293,7 +293,7 @@ Directory::Sort()
 	song_list_sort(&songs);
 
 	Directory *child;
-	directory_for_each_child(child, this)
+	directory_for_each_child(child, *this)
 		child->Sort();
 }
 
@@ -307,7 +307,7 @@ Directory::Walk(bool recursive, const SongFilter *filter,
 
 	if (visit_song) {
 		Song *song;
-		directory_for_each_song(song, this)
+		directory_for_each_song(song, *this)
 			if ((filter == nullptr || filter->Match(*song)) &&
 			    !visit_song(*song, error))
 				return false;
@@ -320,7 +320,7 @@ Directory::Walk(bool recursive, const SongFilter *filter,
 	}
 
 	Directory *child;
-	directory_for_each_child(child, this) {
+	directory_for_each_child(child, *this) {
 		if (visit_directory &&
 		    !visit_directory(*child, error))
 			return false;
diff --git a/src/Directory.hxx b/src/Directory.hxx
index 2c46227c4..380a6b790 100644
--- a/src/Directory.hxx
+++ b/src/Directory.hxx
@@ -32,16 +32,16 @@
 #define DEVICE_CONTAINER (dev_t)(-2)
 
 #define directory_for_each_child(pos, directory) \
-	list_for_each_entry(pos, &directory->children, siblings)
+	list_for_each_entry(pos, &(directory).children, siblings)
 
 #define directory_for_each_child_safe(pos, n, directory) \
-	list_for_each_entry_safe(pos, n, &directory->children, siblings)
+	list_for_each_entry_safe(pos, n, &(directory).children, siblings)
 
 #define directory_for_each_song(pos, directory) \
-	list_for_each_entry(pos, &directory->songs, siblings)
+	list_for_each_entry(pos, &(directory).songs, siblings)
 
 #define directory_for_each_song_safe(pos, n, directory) \
-	list_for_each_entry_safe(pos, n, &directory->songs, siblings)
+	list_for_each_entry_safe(pos, n, &(directory).songs, siblings)
 
 struct Song;
 struct db_visitor;
diff --git a/src/DirectorySave.cxx b/src/DirectorySave.cxx
index 621346819..0ed79dde2 100644
--- a/src/DirectorySave.cxx
+++ b/src/DirectorySave.cxx
@@ -40,13 +40,13 @@
 static constexpr Domain directory_domain("directory");
 
 void
-directory_save(FILE *fp, const Directory *directory)
+directory_save(FILE *fp, const Directory &directory)
 {
-	if (!directory->IsRoot()) {
+	if (!directory.IsRoot()) {
 		fprintf(fp, DIRECTORY_MTIME "%lu\n",
-			(unsigned long)directory->mtime);
+			(unsigned long)directory.mtime);
 
-		fprintf(fp, "%s%s\n", DIRECTORY_BEGIN, directory->GetPath());
+		fprintf(fp, "%s%s\n", DIRECTORY_BEGIN, directory.GetPath());
 	}
 
 	Directory *cur;
@@ -56,7 +56,7 @@ directory_save(FILE *fp, const Directory *directory)
 		fprintf(fp, DIRECTORY_DIR "%s\n", base);
 		g_free(base);
 
-		directory_save(fp, cur);
+		directory_save(fp, *cur);
 
 		if (ferror(fp))
 			return;
@@ -64,27 +64,27 @@ directory_save(FILE *fp, const Directory *directory)
 
 	Song *song;
 	directory_for_each_song(song, directory)
-		song_save(fp, song);
+		song_save(fp, *song);
 
-	playlist_vector_save(fp, directory->playlists);
+	playlist_vector_save(fp, directory.playlists);
 
-	if (!directory->IsRoot())
-		fprintf(fp, DIRECTORY_END "%s\n", directory->GetPath());
+	if (!directory.IsRoot())
+		fprintf(fp, DIRECTORY_END "%s\n", directory.GetPath());
 }
 
 static Directory *
-directory_load_subdir(TextFile &file, Directory *parent, const char *name,
+directory_load_subdir(TextFile &file, Directory &parent, const char *name,
 		      Error &error)
 {
 	bool success;
 
-	if (parent->FindChild(name) != nullptr) {
+	if (parent.FindChild(name) != nullptr) {
 		error.Format(directory_domain,
 			     "Duplicate subdirectory '%s'", name);
 		return nullptr;
 	}
 
-	Directory *directory = parent->CreateChild(name);
+	Directory *directory = parent.CreateChild(name);
 
 	const char *line = file.ReadLine();
 	if (line == nullptr) {
@@ -112,7 +112,7 @@ directory_load_subdir(TextFile &file, Directory *parent, const char *name,
 		return nullptr;
 	}
 
-	success = directory_load(file, directory, error);
+	success = directory_load(file, *directory, error);
 	if (!success) {
 		directory->Delete();
 		return nullptr;
@@ -122,7 +122,7 @@ directory_load_subdir(TextFile &file, Directory *parent, const char *name,
 }
 
 bool
-directory_load(TextFile &file, Directory *directory, Error &error)
+directory_load(TextFile &file, Directory &directory, Error &error)
 {
 	const char *line;
 
@@ -139,24 +139,24 @@ directory_load(TextFile &file, Directory *directory, Error &error)
 			const char *name = line + sizeof(SONG_BEGIN) - 1;
 			Song *song;
 
-			if (directory->FindSong(name) != nullptr) {
+			if (directory.FindSong(name) != nullptr) {
 				error.Format(directory_domain,
 					     "Duplicate song '%s'", name);
 				return false;
 			}
 
-			song = song_load(file, directory, name, error);
+			song = song_load(file, &directory, name, error);
 			if (song == nullptr)
 				return false;
 
-			directory->AddSong(song);
+			directory.AddSong(song);
 		} else if (g_str_has_prefix(line, PLAYLIST_META_BEGIN)) {
 			/* duplicate the name, because
 			   playlist_metadata_load() will overwrite the
 			   buffer */
 			char *name = g_strdup(line + sizeof(PLAYLIST_META_BEGIN) - 1);
 
-			if (!playlist_metadata_load(file, directory->playlists,
+			if (!playlist_metadata_load(file, directory.playlists,
 						    name, error)) {
 				g_free(name);
 				return false;
diff --git a/src/DirectorySave.hxx b/src/DirectorySave.hxx
index 46a3b4462..02814490a 100644
--- a/src/DirectorySave.hxx
+++ b/src/DirectorySave.hxx
@@ -27,9 +27,9 @@ class TextFile;
 class Error;
 
 void
-directory_save(FILE *fp, const Directory *directory);
+directory_save(FILE *fp, const Directory &directory);
 
 bool
-directory_load(TextFile &file, Directory *directory, Error &error);
+directory_load(TextFile &file, Directory &directory, Error &error);
 
 #endif
diff --git a/src/Main.cxx b/src/Main.cxx
index 45d173e78..05f7eeac0 100644
--- a/src/Main.cxx
+++ b/src/Main.cxx
@@ -446,7 +446,7 @@ int mpd_main(int argc, char *argv[])
 	initialize_decoder_and_player();
 	volume_init();
 	initAudioConfig();
-	audio_output_all_init(&instance->partition->pc);
+	audio_output_all_init(instance->partition->pc);
 	client_manager_init();
 	replay_gain_global_init();
 
diff --git a/src/Mapper.cxx b/src/Mapper.cxx
index e19117feb..ebc9f89df 100644
--- a/src/Mapper.cxx
+++ b/src/Mapper.cxx
@@ -170,18 +170,18 @@ map_uri_fs(const char *uri)
 }
 
 AllocatedPath
-map_directory_fs(const Directory *directory)
+map_directory_fs(const Directory &directory)
 {
 	assert(!music_dir_fs.IsNull());
 
-	if (directory->IsRoot())
+	if (directory.IsRoot())
 		return music_dir_fs;
 
-	return map_uri_fs(directory->GetPath());
+	return map_uri_fs(directory.GetPath());
 }
 
 AllocatedPath
-map_directory_child_fs(const Directory *directory, const char *name)
+map_directory_child_fs(const Directory &directory, const char *name)
 {
 	assert(!music_dir_fs.IsNull());
 
@@ -217,16 +217,16 @@ map_detached_song_fs(const char *uri_utf8)
 }
 
 AllocatedPath
-map_song_fs(const Song *song)
+map_song_fs(const Song &song)
 {
-	assert(song->IsFile());
+	assert(song.IsFile());
 
-	if (song->IsInDatabase())
-		return song->IsDetached()
-			? map_detached_song_fs(song->uri)
-			: map_directory_child_fs(song->parent, song->uri);
+	if (song.IsInDatabase())
+		return song.IsDetached()
+			? map_detached_song_fs(song.uri)
+			: map_directory_child_fs(*song.parent, song.uri);
 	else
-		return AllocatedPath::FromUTF8(song->uri);
+		return AllocatedPath::FromUTF8(song.uri);
 }
 
 std::string
diff --git a/src/Mapper.hxx b/src/Mapper.hxx
index c340e6d64..be69a7110 100644
--- a/src/Mapper.hxx
+++ b/src/Mapper.hxx
@@ -91,7 +91,7 @@ map_uri_fs(const char *uri);
  */
 gcc_pure
 AllocatedPath
-map_directory_fs(const Directory *directory);
+map_directory_fs(const Directory &directory);
 
 /**
  * Determines the file system path of a directory's child (may be a
@@ -103,7 +103,7 @@ map_directory_fs(const Directory *directory);
  */
 gcc_pure
 AllocatedPath
-map_directory_child_fs(const Directory *directory, const char *name);
+map_directory_child_fs(const Directory &directory, const char *name);
 
 /**
  * Determines the file system path of a song.  This must not be a
@@ -114,7 +114,7 @@ map_directory_child_fs(const Directory *directory, const char *name);
  */
 gcc_pure
 AllocatedPath
-map_song_fs(const Song *song);
+map_song_fs(const Song &song);
 
 /**
  * Maps a file system path (relative to the music directory or
diff --git a/src/MessageCommands.cxx b/src/MessageCommands.cxx
index 2971b4cde..21067f1a9 100644
--- a/src/MessageCommands.cxx
+++ b/src/MessageCommands.cxx
@@ -33,7 +33,7 @@
 #include <assert.h>
 
 enum command_return
-handle_subscribe(Client *client, gcc_unused int argc, char *argv[])
+handle_subscribe(Client &client, gcc_unused int argc, char *argv[])
 {
 	assert(argc == 2);
 
@@ -62,7 +62,7 @@ handle_subscribe(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_unsubscribe(Client *client, gcc_unused int argc, char *argv[])
+handle_unsubscribe(Client &client, gcc_unused int argc, char *argv[])
 {
 	assert(argc == 2);
 
@@ -76,7 +76,7 @@ handle_unsubscribe(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_channels(Client *client,
+handle_channels(Client &client,
 		gcc_unused int argc, gcc_unused char *argv[])
 {
 	assert(argc == 1);
@@ -93,24 +93,24 @@ handle_channels(Client *client,
 }
 
 enum command_return
-handle_read_messages(Client *client,
+handle_read_messages(Client &client,
 		     gcc_unused int argc, gcc_unused char *argv[])
 {
 	assert(argc == 1);
 
-	while (!client->messages.empty()) {
-		const ClientMessage &msg = client->messages.front();
+	while (!client.messages.empty()) {
+		const ClientMessage &msg = client.messages.front();
 
 		client_printf(client, "channel: %s\nmessage: %s\n",
 			      msg.GetChannel(), msg.GetMessage());
-		client->messages.pop_front();
+		client.messages.pop_front();
 	}
 
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_send_message(Client *client,
+handle_send_message(Client &client,
 		    gcc_unused int argc, gcc_unused char *argv[])
 {
 	assert(argc == 3);
@@ -124,7 +124,7 @@ handle_send_message(Client *client,
 	bool sent = false;
 	const ClientMessage msg(argv[1], argv[2]);
 	for (const auto &c : *instance->client_list)
-		if (client_push_message(c, msg))
+		if (client_push_message(*c, msg))
 			sent = true;
 
 	if (sent)
diff --git a/src/MessageCommands.hxx b/src/MessageCommands.hxx
index b10f3d8e8..150e0a2a2 100644
--- a/src/MessageCommands.hxx
+++ b/src/MessageCommands.hxx
@@ -25,18 +25,18 @@
 class Client;
 
 enum command_return
-handle_subscribe(Client *client, int argc, char *argv[]);
+handle_subscribe(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_unsubscribe(Client *client, int argc, char *argv[]);
+handle_unsubscribe(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_channels(Client *client, int argc, char *argv[]);
+handle_channels(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_read_messages(Client *client, int argc, char *argv[]);
+handle_read_messages(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_send_message(Client *client, int argc, char *argv[]);
+handle_send_message(Client &client, int argc, char *argv[]);
 
 #endif
diff --git a/src/OtherCommands.cxx b/src/OtherCommands.cxx
index 7df76a3e1..2250c37b4 100644
--- a/src/OtherCommands.cxx
+++ b/src/OtherCommands.cxx
@@ -53,7 +53,7 @@
 #include <string.h>
 
 static void
-print_spl_list(Client *client, const PlaylistVector &list)
+print_spl_list(Client &client, const PlaylistVector &list)
 {
 	for (const auto &i : list) {
 		client_printf(client, "playlist: %s\n", i.name.c_str());
@@ -64,7 +64,7 @@ print_spl_list(Client *client, const PlaylistVector &list)
 }
 
 enum command_return
-handle_urlhandlers(Client *client,
+handle_urlhandlers(Client &client,
 		   gcc_unused int argc, gcc_unused char *argv[])
 {
 	if (client_is_local(client))
@@ -74,7 +74,7 @@ handle_urlhandlers(Client *client,
 }
 
 enum command_return
-handle_decoders(Client *client,
+handle_decoders(Client &client,
 		gcc_unused int argc, gcc_unused char *argv[])
 {
 	decoder_list_print(client);
@@ -82,7 +82,7 @@ handle_decoders(Client *client,
 }
 
 enum command_return
-handle_tagtypes(Client *client,
+handle_tagtypes(Client &client,
 		gcc_unused int argc, gcc_unused char *argv[])
 {
 	tag_print_types(client);
@@ -90,21 +90,21 @@ handle_tagtypes(Client *client,
 }
 
 enum command_return
-handle_kill(gcc_unused Client *client,
+handle_kill(gcc_unused Client &client,
 	    gcc_unused int argc, gcc_unused char *argv[])
 {
 	return COMMAND_RETURN_KILL;
 }
 
 enum command_return
-handle_close(gcc_unused Client *client,
+handle_close(gcc_unused Client &client,
 	     gcc_unused int argc, gcc_unused char *argv[])
 {
 	return COMMAND_RETURN_CLOSE;
 }
 
 enum command_return
-handle_lsinfo(Client *client, int argc, char *argv[])
+handle_lsinfo(Client &client, int argc, char *argv[])
 {
 	const char *uri;
 
@@ -136,7 +136,7 @@ handle_lsinfo(Client *client, int argc, char *argv[])
 			return COMMAND_RETURN_ERROR;
 		}
 
-		song_print_info(client, song);
+		song_print_info(client, *song);
 		song->Free();
 		return COMMAND_RETURN_OK;
 	}
@@ -155,7 +155,7 @@ handle_lsinfo(Client *client, int argc, char *argv[])
 }
 
 enum command_return
-handle_update(Client *client, gcc_unused int argc, char *argv[])
+handle_update(Client &client, gcc_unused int argc, char *argv[])
 {
 	const char *path = "";
 	unsigned ret;
@@ -186,7 +186,7 @@ handle_update(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_rescan(Client *client, gcc_unused int argc, char *argv[])
+handle_rescan(Client &client, gcc_unused int argc, char *argv[])
 {
 	const char *path = "";
 	unsigned ret;
@@ -214,7 +214,7 @@ handle_rescan(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_setvol(Client *client, gcc_unused int argc, char *argv[])
+handle_setvol(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned level;
 	bool success;
@@ -238,7 +238,7 @@ handle_setvol(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_stats(Client *client,
+handle_stats(Client &client,
 	     gcc_unused int argc, gcc_unused char *argv[])
 {
 	stats_print(client);
@@ -246,14 +246,14 @@ handle_stats(Client *client,
 }
 
 enum command_return
-handle_ping(gcc_unused Client *client,
+handle_ping(gcc_unused Client &client,
 	    gcc_unused int argc, gcc_unused char *argv[])
 {
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_password(Client *client, gcc_unused int argc, char *argv[])
+handle_password(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned permission = 0;
 
@@ -268,7 +268,7 @@ handle_password(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_config(Client *client,
+handle_config(Client &client,
 	      gcc_unused int argc, gcc_unused char *argv[])
 {
 	if (!client_is_local(client)) {
@@ -285,7 +285,7 @@ handle_config(Client *client,
 }
 
 enum command_return
-handle_idle(Client *client,
+handle_idle(Client &client,
 	    gcc_unused int argc, gcc_unused char *argv[])
 {
 	unsigned flags = 0, j;
@@ -309,7 +309,7 @@ handle_idle(Client *client,
 		flags = ~0;
 
 	/* enable "idle" mode on this client */
-	client->IdleWait(flags);
+	client.IdleWait(flags);
 
 	return COMMAND_RETURN_IDLE;
 }
diff --git a/src/OtherCommands.hxx b/src/OtherCommands.hxx
index 564ad38e7..b0968d302 100644
--- a/src/OtherCommands.hxx
+++ b/src/OtherCommands.hxx
@@ -25,45 +25,45 @@
 class Client;
 
 enum command_return
-handle_urlhandlers(Client *client, int argc, char *argv[]);
+handle_urlhandlers(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_decoders(Client *client, int argc, char *argv[]);
+handle_decoders(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_tagtypes(Client *client, int argc, char *argv[]);
+handle_tagtypes(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_kill(Client *client, int argc, char *argv[]);
+handle_kill(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_close(Client *client, int argc, char *argv[]);
+handle_close(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_lsinfo(Client *client, int argc, char *argv[]);
+handle_lsinfo(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_update(Client *client, int argc, char *argv[]);
+handle_update(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_rescan(Client *client, int argc, char *argv[]);
+handle_rescan(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_setvol(Client *client, int argc, char *argv[]);
+handle_setvol(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_stats(Client *client, int argc, char *argv[]);
+handle_stats(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_ping(Client *client, int argc, char *argv[]);
+handle_ping(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_password(Client *client, int argc, char *argv[]);
+handle_password(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_config(Client *client, int argc, char *argv[]);
+handle_config(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_idle(Client *client, int argc, char *argv[]);
+handle_idle(Client &client, int argc, char *argv[]);
 
 #endif
diff --git a/src/OutputAll.cxx b/src/OutputAll.cxx
index 6f935ed44..15662f034 100644
--- a/src/OutputAll.cxx
+++ b/src/OutputAll.cxx
@@ -103,7 +103,7 @@ audio_output_config_count(void)
 }
 
 void
-audio_output_all_init(struct player_control *pc)
+audio_output_all_init(player_control &pc)
 {
 	const struct config_param *param = nullptr;
 	unsigned int i;
@@ -469,17 +469,17 @@ audio_output_all_check(void)
 }
 
 bool
-audio_output_all_wait(struct player_control *pc, unsigned threshold)
+audio_output_all_wait(player_control &pc, unsigned threshold)
 {
-	pc->Lock();
+	pc.Lock();
 
 	if (audio_output_all_check() < threshold) {
-		pc->Unlock();
+		pc.Unlock();
 		return true;
 	}
 
-	pc->Wait();
-	pc->Unlock();
+	pc.Wait();
+	pc.Unlock();
 
 	return audio_output_all_check() < threshold;
 }
diff --git a/src/OutputAll.hxx b/src/OutputAll.hxx
index 5b555e5a1..e1bba68ed 100644
--- a/src/OutputAll.hxx
+++ b/src/OutputAll.hxx
@@ -40,7 +40,7 @@ class Error;
  * file and initialize them.
  */
 void
-audio_output_all_init(struct player_control *pc);
+audio_output_all_init(player_control &pc);
 
 /**
  * Global finalization: free memory occupied by audio outputs.  All
@@ -135,7 +135,7 @@ audio_output_all_check(void);
  * @return true if there are less than #threshold chunks in the pipe
  */
 bool
-audio_output_all_wait(struct player_control *pc, unsigned threshold);
+audio_output_all_wait(player_control &pc, unsigned threshold);
 
 /**
  * Puts all audio outputs into pause mode.  Most implementations will
diff --git a/src/OutputCommands.cxx b/src/OutputCommands.cxx
index 3281104d1..ef35ba8ec 100644
--- a/src/OutputCommands.cxx
+++ b/src/OutputCommands.cxx
@@ -27,7 +27,7 @@
 #include <string.h>
 
 enum command_return
-handle_enableoutput(Client *client, gcc_unused int argc, char *argv[])
+handle_enableoutput(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned device;
 	bool ret;
@@ -46,7 +46,7 @@ handle_enableoutput(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_disableoutput(Client *client, gcc_unused int argc, char *argv[])
+handle_disableoutput(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned device;
 	bool ret;
@@ -65,7 +65,7 @@ handle_disableoutput(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_toggleoutput(Client *client, gcc_unused int argc, char *argv[])
+handle_toggleoutput(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned device;
 	if (!check_unsigned(client, &device, argv[1]))
@@ -81,7 +81,7 @@ handle_toggleoutput(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_devices(Client *client,
+handle_devices(Client &client,
 	       gcc_unused int argc, gcc_unused char *argv[])
 {
 	printAudioDevices(client);
diff --git a/src/OutputCommands.hxx b/src/OutputCommands.hxx
index 5642a0680..c0d3b9030 100644
--- a/src/OutputCommands.hxx
+++ b/src/OutputCommands.hxx
@@ -25,15 +25,15 @@
 class Client;
 
 enum command_return
-handle_enableoutput(Client *client, int argc, char *argv[]);
+handle_enableoutput(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_disableoutput(Client *client, int argc, char *argv[]);
+handle_disableoutput(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_toggleoutput(Client *client, int argc, char *argv[]);
+handle_toggleoutput(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_devices(Client *client, int argc, char *argv[]);
+handle_devices(Client &client, int argc, char *argv[]);
 
 #endif
diff --git a/src/OutputInit.cxx b/src/OutputInit.cxx
index ab525feb0..af777ca17 100644
--- a/src/OutputInit.cxx
+++ b/src/OutputInit.cxx
@@ -281,7 +281,7 @@ audio_output_setup(struct audio_output *ao, const config_param &param,
 
 struct audio_output *
 audio_output_new(const config_param &param,
-		 struct player_control *pc,
+		 player_control &pc,
 		 Error &error)
 {
 	const struct audio_output_plugin *plugin;
@@ -324,6 +324,6 @@ audio_output_new(const config_param &param,
 		return nullptr;
 	}
 
-	ao->player_control = pc;
+	ao->player_control = &pc;
 	return ao;
 }
diff --git a/src/OutputInternal.hxx b/src/OutputInternal.hxx
index db2c2b557..a6233c5b5 100644
--- a/src/OutputInternal.hxx
+++ b/src/OutputInternal.hxx
@@ -264,7 +264,7 @@ audio_output_command_is_finished(const struct audio_output *ao)
 
 struct audio_output *
 audio_output_new(const config_param &param,
-		 struct player_control *pc,
+		 player_control &pc,
 		 Error &error);
 
 bool
diff --git a/src/OutputPrint.cxx b/src/OutputPrint.cxx
index 4e1cf9ced..30f2c6732 100644
--- a/src/OutputPrint.cxx
+++ b/src/OutputPrint.cxx
@@ -29,7 +29,7 @@
 #include "Client.hxx"
 
 void
-printAudioDevices(Client *client)
+printAudioDevices(Client &client)
 {
 	const unsigned n = audio_output_count();
 
diff --git a/src/OutputPrint.hxx b/src/OutputPrint.hxx
index 78717d0af..5d446d702 100644
--- a/src/OutputPrint.hxx
+++ b/src/OutputPrint.hxx
@@ -1,3 +1,4 @@
+
 /*
  * Copyright (C) 2003-2013 The Music Player Daemon Project
  * http://www.musicpd.org
@@ -28,6 +29,6 @@
 class Client;
 
 void
-printAudioDevices(Client *client);
+printAudioDevices(Client &client);
 
 #endif
diff --git a/src/PlayerCommands.cxx b/src/PlayerCommands.cxx
index 9f427d121..8b9a96ca5 100644
--- a/src/PlayerCommands.cxx
+++ b/src/PlayerCommands.cxx
@@ -53,46 +53,46 @@
 #define COMMAND_STATUS_UPDATING_DB	"updating_db"
 
 enum command_return
-handle_play(Client *client, int argc, char *argv[])
+handle_play(Client &client, int argc, char *argv[])
 {
 	int song = -1;
 
 	if (argc == 2 && !check_int(client, &song, argv[1]))
 		return COMMAND_RETURN_ERROR;
-	enum playlist_result result = client->partition.PlayPosition(song);
+	enum playlist_result result = client.partition.PlayPosition(song);
 	return print_playlist_result(client, result);
 }
 
 enum command_return
-handle_playid(Client *client, int argc, char *argv[])
+handle_playid(Client &client, int argc, char *argv[])
 {
 	int id = -1;
 
 	if (argc == 2 && !check_int(client, &id, argv[1]))
 		return COMMAND_RETURN_ERROR;
 
-	enum playlist_result result = client->partition.PlayId(id);
+	enum playlist_result result = client.partition.PlayId(id);
 	return print_playlist_result(client, result);
 }
 
 enum command_return
-handle_stop(Client *client,
+handle_stop(Client &client,
 	    gcc_unused int argc, gcc_unused char *argv[])
 {
-	client->partition.Stop();
+	client.partition.Stop();
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_currentsong(Client *client,
+handle_currentsong(Client &client,
 		   gcc_unused int argc, gcc_unused char *argv[])
 {
-	playlist_print_current(client, &client->playlist);
+	playlist_print_current(client, client.playlist);
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_pause(Client *client,
+handle_pause(Client &client,
 	     int argc, char *argv[])
 {
 	if (argc == 2) {
@@ -100,22 +100,22 @@ handle_pause(Client *client,
 		if (!check_bool(client, &pause_flag, argv[1]))
 			return COMMAND_RETURN_ERROR;
 
-		client->player_control->SetPause(pause_flag);
+		client.player_control.SetPause(pause_flag);
 	} else
-		client->player_control->Pause();
+		client.player_control.Pause();
 
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_status(Client *client,
+handle_status(Client &client,
 	      gcc_unused int argc, gcc_unused char *argv[])
 {
 	const char *state = NULL;
 	int updateJobId;
 	int song;
 
-	const auto player_status = client->player_control->GetStatus();
+	const auto player_status = client.player_control.GetStatus();
 
 	switch (player_status.state) {
 	case PlayerState::STOP:
@@ -129,7 +129,7 @@ handle_status(Client *client,
 		break;
 	}
 
-	const playlist &playlist = client->playlist;
+	const playlist &playlist = client.playlist;
 	client_printf(client,
 		      "volume: %i\n"
 		      COMMAND_STATUS_REPEAT ": %i\n"
@@ -149,9 +149,9 @@ handle_status(Client *client,
 		      playlist.GetConsume(),
 		      (unsigned long)playlist.GetVersion(),
 		      playlist.GetLength(),
-		      (int)(client->player_control->GetCrossFade() + 0.5),
-		      client->player_control->GetMixRampDb(),
-		      client->player_control->GetMixRampDelay(),
+		      (int)(client.player_control.GetCrossFade() + 0.5),
+		      client.player_control.GetMixRampDb(),
+		      client.player_control.GetMixRampDelay(),
 		      state);
 
 	song = playlist.GetCurrentPosition();
@@ -188,7 +188,7 @@ handle_status(Client *client,
 			      updateJobId);
 	}
 
-	Error error = client->player_control->LockGetError();
+	Error error = client.player_control.LockGetError();
 	if (error.IsDefined())
 		client_printf(client,
 			      COMMAND_STATUS_ERROR ": %s\n",
@@ -206,85 +206,85 @@ handle_status(Client *client,
 }
 
 enum command_return
-handle_next(Client *client,
+handle_next(Client &client,
 	    gcc_unused int argc, gcc_unused char *argv[])
 {
-	playlist &playlist = client->playlist;
+	playlist &playlist = client.playlist;
 
 	/* single mode is not considered when this is user who
 	 * wants to change song. */
 	const bool single = playlist.queue.single;
 	playlist.queue.single = false;
 
-	client->partition.PlayNext();
+	client.partition.PlayNext();
 
 	playlist.queue.single = single;
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_previous(Client *client,
+handle_previous(Client &client,
 		gcc_unused int argc, gcc_unused char *argv[])
 {
-	client->partition.PlayPrevious();
+	client.partition.PlayPrevious();
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_repeat(Client *client, gcc_unused int argc, char *argv[])
+handle_repeat(Client &client, gcc_unused int argc, char *argv[])
 {
 	bool status;
 	if (!check_bool(client, &status, argv[1]))
 		return COMMAND_RETURN_ERROR;
 
-	client->partition.SetRepeat(status);
+	client.partition.SetRepeat(status);
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_single(Client *client, gcc_unused int argc, char *argv[])
+handle_single(Client &client, gcc_unused int argc, char *argv[])
 {
 	bool status;
 	if (!check_bool(client, &status, argv[1]))
 		return COMMAND_RETURN_ERROR;
 
-	client->partition.SetSingle(status);
+	client.partition.SetSingle(status);
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_consume(Client *client, gcc_unused int argc, char *argv[])
+handle_consume(Client &client, gcc_unused int argc, char *argv[])
 {
 	bool status;
 	if (!check_bool(client, &status, argv[1]))
 		return COMMAND_RETURN_ERROR;
 
-	client->partition.SetConsume(status);
+	client.partition.SetConsume(status);
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_random(Client *client, gcc_unused int argc, char *argv[])
+handle_random(Client &client, gcc_unused int argc, char *argv[])
 {
 	bool status;
 	if (!check_bool(client, &status, argv[1]))
 		return COMMAND_RETURN_ERROR;
 
-	client->partition.SetRandom(status);
-	audio_output_all_set_replay_gain_mode(replay_gain_get_real_mode(client->partition.GetRandom()));
+	client.partition.SetRandom(status);
+	audio_output_all_set_replay_gain_mode(replay_gain_get_real_mode(client.partition.GetRandom()));
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_clearerror(gcc_unused Client *client,
+handle_clearerror(gcc_unused Client &client,
 		  gcc_unused int argc, gcc_unused char *argv[])
 {
-	client->player_control->ClearError();
+	client.player_control.ClearError();
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_seek(Client *client, gcc_unused int argc, char *argv[])
+handle_seek(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned song, seek_time;
 
@@ -294,12 +294,12 @@ handle_seek(Client *client, gcc_unused int argc, char *argv[])
 		return COMMAND_RETURN_ERROR;
 
 	enum playlist_result result =
-		client->partition.SeekSongPosition(song, seek_time);
+		client.partition.SeekSongPosition(song, seek_time);
 	return print_playlist_result(client, result);
 }
 
 enum command_return
-handle_seekid(Client *client, gcc_unused int argc, char *argv[])
+handle_seekid(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned id, seek_time;
 
@@ -309,12 +309,12 @@ handle_seekid(Client *client, gcc_unused int argc, char *argv[])
 		return COMMAND_RETURN_ERROR;
 
 	enum playlist_result result =
-		client->partition.SeekSongId(id, seek_time);
+		client.partition.SeekSongId(id, seek_time);
 	return print_playlist_result(client, result);
 }
 
 enum command_return
-handle_seekcur(Client *client, gcc_unused int argc, char *argv[])
+handle_seekcur(Client &client, gcc_unused int argc, char *argv[])
 {
 	const char *p = argv[1];
 	bool relative = *p == '+' || *p == '-';
@@ -323,48 +323,48 @@ handle_seekcur(Client *client, gcc_unused int argc, char *argv[])
 		return COMMAND_RETURN_ERROR;
 
 	enum playlist_result result =
-		client->partition.SeekCurrent(seek_time, relative);
+		client.partition.SeekCurrent(seek_time, relative);
 	return print_playlist_result(client, result);
 }
 
 enum command_return
-handle_crossfade(Client *client, gcc_unused int argc, char *argv[])
+handle_crossfade(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned xfade_time;
 
 	if (!check_unsigned(client, &xfade_time, argv[1]))
 		return COMMAND_RETURN_ERROR;
-	client->player_control->SetCrossFade(xfade_time);
+	client.player_control.SetCrossFade(xfade_time);
 
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_mixrampdb(Client *client, gcc_unused int argc, char *argv[])
+handle_mixrampdb(Client &client, gcc_unused int argc, char *argv[])
 {
 	float db;
 
 	if (!check_float(client, &db, argv[1]))
 		return COMMAND_RETURN_ERROR;
-	client->player_control->SetMixRampDb(db);
+	client.player_control.SetMixRampDb(db);
 
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_mixrampdelay(Client *client, gcc_unused int argc, char *argv[])
+handle_mixrampdelay(Client &client, gcc_unused int argc, char *argv[])
 {
 	float delay_secs;
 
 	if (!check_float(client, &delay_secs, argv[1]))
 		return COMMAND_RETURN_ERROR;
-	client->player_control->SetMixRampDelay(delay_secs);
+	client.player_control.SetMixRampDelay(delay_secs);
 
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_replay_gain_mode(Client *client,
+handle_replay_gain_mode(Client &client,
 			gcc_unused int argc, char *argv[])
 {
 	if (!replay_gain_set_mode_string(argv[1])) {
@@ -373,13 +373,13 @@ handle_replay_gain_mode(Client *client,
 		return COMMAND_RETURN_ERROR;
 	}
 
-	audio_output_all_set_replay_gain_mode(replay_gain_get_real_mode(client->playlist.queue.random));
+	audio_output_all_set_replay_gain_mode(replay_gain_get_real_mode(client.playlist.queue.random));
 
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_replay_gain_status(Client *client,
+handle_replay_gain_status(Client &client,
 			  gcc_unused int argc, gcc_unused char *argv[])
 {
 	client_printf(client, "replay_gain_mode: %s\n",
diff --git a/src/PlayerCommands.hxx b/src/PlayerCommands.hxx
index a2fed5853..6bef71a01 100644
--- a/src/PlayerCommands.hxx
+++ b/src/PlayerCommands.hxx
@@ -25,66 +25,66 @@
 class Client;
 
 enum command_return
-handle_play(Client *client, int argc, char *argv[]);
+handle_play(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_playid(Client *client, int argc, char *argv[]);
+handle_playid(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_stop(Client *client, int argc, char *argv[]);
+handle_stop(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_currentsong(Client *client, int argc, char *argv[]);
+handle_currentsong(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_pause(Client *client, int argc, char *argv[]);
+handle_pause(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_status(Client *client, int argc, char *argv[]);
+handle_status(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_next(Client *client, int argc, char *argv[]);
+handle_next(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_previous(Client *client, int argc, char *avg[]);
+handle_previous(Client &client, int argc, char *avg[]);
 
 enum command_return
-handle_repeat(Client *client, int argc, char *argv[]);
+handle_repeat(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_single(Client *client, int argc, char *argv[]);
+handle_single(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_consume(Client *client, int argc, char *argv[]);
+handle_consume(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_random(Client *client, int argc, char *argv[]);
+handle_random(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_clearerror(Client *client, int argc, char *argv[]);
+handle_clearerror(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_seek(Client *client, int argc, char *argv[]);
+handle_seek(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_seekid(Client *client, int argc, char *argv[]);
+handle_seekid(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_seekcur(Client *client, int argc, char *argv[]);
+handle_seekcur(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_crossfade(Client *client, int argc, char *argv[]);
+handle_crossfade(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_mixrampdb(Client *client, int argc, char *argv[]);
+handle_mixrampdb(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_mixrampdelay(Client *client, int argc, char *argv[]);
+handle_mixrampdelay(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_replay_gain_mode(Client *client, int argc, char *argv[]);
+handle_replay_gain_mode(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_replay_gain_status(Client *client, int argc, char *argv[]);
+handle_replay_gain_status(Client &client, int argc, char *argv[]);
 
 #endif
diff --git a/src/PlayerThread.cxx b/src/PlayerThread.cxx
index f3db5507d..830039fc3 100644
--- a/src/PlayerThread.cxx
+++ b/src/PlayerThread.cxx
@@ -445,7 +445,7 @@ Player::CheckDecoderStartup()
 		dc.Unlock();
 
 		if (output_open &&
-		    !audio_output_all_wait(&pc, 1))
+		    !audio_output_all_wait(pc, 1))
 			/* the output devices havn't finished playing
 			   all chunks yet - wait for that */
 			return true;
@@ -746,7 +746,7 @@ play_chunk(player_control &pc,
 inline bool
 Player::PlayNextChunk()
 {
-	if (!audio_output_all_wait(&pc, 64))
+	if (!audio_output_all_wait(pc, 64))
 		/* the output pipe is still large enough, don't send
 		   another chunk */
 		return true;
@@ -1102,7 +1102,7 @@ player_task(void *arg)
 	player_control &pc = *(player_control *)arg;
 
 	decoder_control dc;
-	decoder_thread_start(&dc);
+	decoder_thread_start(dc);
 
 	MusicBuffer buffer(pc.buffer_chunks);
 
diff --git a/src/Playlist.cxx b/src/Playlist.cxx
index 2932c2ca0..570d64b19 100644
--- a/src/Playlist.cxx
+++ b/src/Playlist.cxx
@@ -50,42 +50,42 @@ playlist::TagChanged()
  * Queue a song, addressed by its order number.
  */
 static void
-playlist_queue_song_order(struct playlist *playlist, struct player_control *pc,
+playlist_queue_song_order(playlist &playlist, player_control &pc,
 			  unsigned order)
 {
-	assert(playlist->queue.IsValidOrder(order));
+	assert(playlist.queue.IsValidOrder(order));
 
-	playlist->queued = order;
+	playlist.queued = order;
 
-	Song *song = playlist->queue.GetOrder(order)->DupDetached();
+	Song *song = playlist.queue.GetOrder(order).DupDetached();
 
 	{
 		const auto uri = song->GetURI();
 		FormatDebug(playlist_domain, "queue song %i:\"%s\"",
-			    playlist->queued, uri.c_str());
+			    playlist.queued, uri.c_str());
 	}
 
-	pc->EnqueueSong(song);
+	pc.EnqueueSong(song);
 }
 
 /**
  * Called if the player thread has started playing the "queued" song.
  */
 static void
-playlist_song_started(struct playlist *playlist, struct player_control *pc)
+playlist_song_started(playlist &playlist, player_control &pc)
 {
-	assert(pc->next_song == nullptr);
-	assert(playlist->queued >= -1);
+	assert(pc.next_song == nullptr);
+	assert(playlist.queued >= -1);
 
 	/* queued song has started: copy queued to current,
 	   and notify the clients */
 
-	int current = playlist->current;
-	playlist->current = playlist->queued;
-	playlist->queued = -1;
+	int current = playlist.current;
+	playlist.current = playlist.queued;
+	playlist.queued = -1;
 
-	if(playlist->queue.consume)
-		playlist->DeleteOrder(*pc, current);
+	if(playlist.queue.consume)
+		playlist.DeleteOrder(pc, current);
 
 	idle_add(IDLE_PLAYER);
 }
@@ -94,7 +94,7 @@ const Song *
 playlist::GetQueuedSong() const
 {
 	return playing && queued >= 0
-		? queue.GetOrder(queued)
+		? &queue.GetOrder(queued)
 		: nullptr;
 }
 
@@ -127,7 +127,7 @@ playlist::UpdateQueuedSong(player_control &pc, const Song *prev)
 	}
 
 	const Song *const next_song = next_order >= 0
-		? queue.GetOrder(next_order)
+		? &queue.GetOrder(next_order)
 		: nullptr;
 
 	if (prev != nullptr && next_song != prev) {
@@ -138,7 +138,7 @@ playlist::UpdateQueuedSong(player_control &pc, const Song *prev)
 
 	if (next_order >= 0) {
 		if (next_song != prev)
-			playlist_queue_song_order(this, &pc, next_order);
+			playlist_queue_song_order(*this, pc, next_order);
 		else
 			queued = next_order;
 	}
@@ -150,7 +150,7 @@ playlist::PlayOrder(player_control &pc, int order)
 	playing = true;
 	queued = -1;
 
-	Song *song = queue.GetOrder(order)->DupDetached();
+	Song *song = queue.GetOrder(order).DupDetached();
 
 	{
 		const auto uri = song->GetURI();
@@ -163,7 +163,7 @@ playlist::PlayOrder(player_control &pc, int order)
 }
 
 static void
-playlist_resume_playback(struct playlist *playlist, struct player_control *pc);
+playlist_resume_playback(playlist &playlist, player_control &pc);
 
 void
 playlist::SyncWithPlayer(player_control &pc)
@@ -183,12 +183,12 @@ playlist::SyncWithPlayer(player_control &pc)
 		   should be restarted with the next song.  That can
 		   happen if the playlist isn't filling the queue fast
 		   enough */
-		playlist_resume_playback(this, &pc);
+		playlist_resume_playback(*this, pc);
 	else {
 		/* check if the player thread has already started
 		   playing the queued song */
 		if (pc_next_song == nullptr && queued != -1)
-			playlist_song_started(this, &pc);
+			playlist_song_started(*this, pc);
 
 		pc.Lock();
 		pc_next_song = pc.next_song;
@@ -206,26 +206,26 @@ playlist::SyncWithPlayer(player_control &pc)
  * decide whether to re-start playback
  */
 static void
-playlist_resume_playback(struct playlist *playlist, struct player_control *pc)
+playlist_resume_playback(playlist &playlist, player_control &pc)
 {
-	assert(playlist->playing);
-	assert(pc->GetState() == PlayerState::STOP);
+	assert(playlist.playing);
+	assert(pc.GetState() == PlayerState::STOP);
 
-	const auto error = pc->GetErrorType();
+	const auto error = pc.GetErrorType();
 	if (error == PlayerError::NONE)
-		playlist->error_count = 0;
+		playlist.error_count = 0;
 	else
-		++playlist->error_count;
+		++playlist.error_count;
 
-	if ((playlist->stop_on_error && error != PlayerError::NONE) ||
+	if ((playlist.stop_on_error && error != PlayerError::NONE) ||
 	    error == PlayerError::OUTPUT ||
-	    playlist->error_count >= playlist->queue.GetLength())
+	    playlist.error_count >= playlist.queue.GetLength())
 		/* too many errors, or critical error: stop
 		   playback */
-		playlist->Stop(*pc);
+		playlist.Stop(pc);
 	else
 		/* continue playback at the next song */
-		playlist->PlayNext(*pc);
+		playlist.PlayNext(pc);
 }
 
 void
@@ -246,13 +246,13 @@ playlist::SetRepeat(player_control &pc, bool status)
 }
 
 static void
-playlist_order(struct playlist *playlist)
+playlist_order(playlist &playlist)
 {
-	if (playlist->current >= 0)
+	if (playlist.current >= 0)
 		/* update playlist.current, order==position now */
-		playlist->current = playlist->queue.OrderToPosition(playlist->current);
+		playlist.current = playlist.queue.OrderToPosition(playlist.current);
 
-	playlist->queue.RestoreOrder();
+	playlist.queue.RestoreOrder();
 }
 
 void
@@ -310,7 +310,7 @@ playlist::SetRandom(player_control &pc, bool status)
 		} else
 			current = -1;
 	} else
-		playlist_order(this);
+		playlist_order(*this);
 
 	UpdateQueuedSong(pc, queued_song);
 
diff --git a/src/PlaylistCommands.cxx b/src/PlaylistCommands.cxx
index 785267c1d..57be3453a 100644
--- a/src/PlaylistCommands.cxx
+++ b/src/PlaylistCommands.cxx
@@ -39,7 +39,7 @@
 #include <stdlib.h>
 
 static void
-print_spl_list(Client *client, const PlaylistVector &list)
+print_spl_list(Client &client, const PlaylistVector &list)
 {
 	for (const auto &i : list) {
 		client_printf(client, "playlist: %s\n", i.name.c_str());
@@ -50,16 +50,16 @@ print_spl_list(Client *client, const PlaylistVector &list)
 }
 
 enum command_return
-handle_save(Client *client, gcc_unused int argc, char *argv[])
+handle_save(Client &client, gcc_unused int argc, char *argv[])
 {
 	enum playlist_result result;
 
-	result = spl_save_playlist(argv[1], &client->playlist);
+	result = spl_save_playlist(argv[1], client.playlist);
 	return print_playlist_result(client, result);
 }
 
 enum command_return
-handle_load(Client *client, int argc, char *argv[])
+handle_load(Client &client, int argc, char *argv[])
 {
 	unsigned start_index, end_index;
 
@@ -73,13 +73,13 @@ handle_load(Client *client, int argc, char *argv[])
 
 	result = playlist_open_into_queue(argv[1],
 					  start_index, end_index,
-					  &client->playlist,
-					  client->player_control, true);
+					  client.playlist,
+					  client.player_control, true);
 	if (result != PLAYLIST_RESULT_NO_SUCH_LIST)
 		return print_playlist_result(client, result);
 
 	Error error;
-	if (playlist_load_spl(&client->playlist, client->player_control,
+	if (playlist_load_spl(client.playlist, client.player_control,
 			      argv[1], start_index, end_index,
 			      error))
 		return COMMAND_RETURN_OK;
@@ -99,7 +99,7 @@ handle_load(Client *client, int argc, char *argv[])
 }
 
 enum command_return
-handle_listplaylist(Client *client, gcc_unused int argc, char *argv[])
+handle_listplaylist(Client &client, gcc_unused int argc, char *argv[])
 {
 	if (playlist_file_print(client, argv[1], false))
 		return COMMAND_RETURN_OK;
@@ -111,7 +111,7 @@ handle_listplaylist(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_listplaylistinfo(Client *client,
+handle_listplaylistinfo(Client &client,
 			gcc_unused int argc, char *argv[])
 {
 	if (playlist_file_print(client, argv[1], true))
@@ -124,7 +124,7 @@ handle_listplaylistinfo(Client *client,
 }
 
 enum command_return
-handle_rm(Client *client, gcc_unused int argc, char *argv[])
+handle_rm(Client &client, gcc_unused int argc, char *argv[])
 {
 	Error error;
 	return spl_delete(argv[1], error)
@@ -133,7 +133,7 @@ handle_rm(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_rename(Client *client, gcc_unused int argc, char *argv[])
+handle_rename(Client &client, gcc_unused int argc, char *argv[])
 {
 	Error error;
 	return spl_rename(argv[1], argv[2], error)
@@ -142,7 +142,7 @@ handle_rename(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_playlistdelete(Client *client,
+handle_playlistdelete(Client &client,
 		      gcc_unused int argc, char *argv[]) {
 	char *playlist = argv[1];
 	unsigned from;
@@ -157,7 +157,7 @@ handle_playlistdelete(Client *client,
 }
 
 enum command_return
-handle_playlistmove(Client *client, gcc_unused int argc, char *argv[])
+handle_playlistmove(Client &client, gcc_unused int argc, char *argv[])
 {
 	char *playlist = argv[1];
 	unsigned from, to;
@@ -174,7 +174,7 @@ handle_playlistmove(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_playlistclear(Client *client, gcc_unused int argc, char *argv[])
+handle_playlistclear(Client &client, gcc_unused int argc, char *argv[])
 {
 	Error error;
 	return spl_clear(argv[1], error)
@@ -183,7 +183,7 @@ handle_playlistclear(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_playlistadd(Client *client, gcc_unused int argc, char *argv[])
+handle_playlistadd(Client &client, gcc_unused int argc, char *argv[])
 {
 	char *playlist = argv[1];
 	char *uri = argv[2];
@@ -212,7 +212,7 @@ handle_playlistadd(Client *client, gcc_unused int argc, char *argv[])
 }
 
 enum command_return
-handle_listplaylists(Client *client,
+handle_listplaylists(Client &client,
 		     gcc_unused int argc, gcc_unused char *argv[])
 {
 	Error error;
diff --git a/src/PlaylistCommands.hxx b/src/PlaylistCommands.hxx
index 067f428b6..a34ee6b32 100644
--- a/src/PlaylistCommands.hxx
+++ b/src/PlaylistCommands.hxx
@@ -25,36 +25,36 @@
 class Client;
 
 enum command_return
-handle_save(Client *client, int argc, char *argv[]);
+handle_save(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_load(Client *client, int argc, char *argv[]);
+handle_load(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_listplaylist(Client *client, int argc, char *argv[]);
+handle_listplaylist(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_listplaylistinfo(Client *client, int argc, char *argv[]);
+handle_listplaylistinfo(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_rm(Client *client, int argc, char *argv[]);
+handle_rm(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_rename(Client *client, int argc, char *argv[]);
+handle_rename(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_playlistdelete(Client *client, int argc, char *argv[]);
+handle_playlistdelete(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_playlistmove(Client *client, int argc, char *argv[]);
+handle_playlistmove(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_playlistclear(Client *client, int argc, char *argv[]);
+handle_playlistclear(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_playlistadd(Client *client, int argc, char *argv[]);
+handle_playlistadd(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_listplaylists(Client *client, int argc, char *argv[]);
+handle_listplaylists(Client &client, int argc, char *argv[]);
 
 #endif
diff --git a/src/PlaylistControl.cxx b/src/PlaylistControl.cxx
index c6b5690bb..896dbaaa8 100644
--- a/src/PlaylistControl.cxx
+++ b/src/PlaylistControl.cxx
@@ -215,7 +215,7 @@ playlist::SeekSongPosition(player_control &pc, unsigned song, float seek_time)
 		queued_song = nullptr;
 	}
 
-	Song *the_song = queue.GetOrder(i)->DupDetached();
+	Song *the_song = queue.GetOrder(i).DupDetached();
 	if (!pc.Seek(the_song, seek_time)) {
 		UpdateQueuedSong(pc, queued_song);
 
diff --git a/src/PlaylistEdit.cxx b/src/PlaylistEdit.cxx
index 9ef671a19..30a7bdca3 100644
--- a/src/PlaylistEdit.cxx
+++ b/src/PlaylistEdit.cxx
@@ -324,7 +324,7 @@ playlist::DeleteSong(struct player_control &pc, const struct Song &song)
 {
 	for (int i = queue.GetLength() - 1; i >= 0; --i)
 		// TODO: compare URI instead of pointer
-		if (&song == queue.Get(i))
+		if (&song == &queue.Get(i))
 			DeletePosition(pc, i);
 }
 
diff --git a/src/PlaylistFile.cxx b/src/PlaylistFile.cxx
index 68e0cfcf1..5e14e7ec7 100644
--- a/src/PlaylistFile.cxx
+++ b/src/PlaylistFile.cxx
@@ -365,7 +365,7 @@ spl_remove_index(const char *utf8path, unsigned pos, Error &error)
 }
 
 bool
-spl_append_song(const char *utf8path, Song *song, Error &error)
+spl_append_song(const char *utf8path, const Song &song, Error &error)
 {
 	if (spl_map(error).IsNull())
 		return false;
@@ -407,7 +407,7 @@ spl_append_uri(const char *url, const char *utf8file, Error &error)
 {
 	if (uri_has_scheme(url)) {
 		Song *song = Song::NewRemote(url);
-		bool success = spl_append_song(utf8file, song, error);
+		bool success = spl_append_song(utf8file, *song, error);
 		song->Free();
 		return success;
 	} else {
@@ -419,7 +419,7 @@ spl_append_uri(const char *url, const char *utf8file, Error &error)
 		if (song == nullptr)
 			return false;
 
-		bool success = spl_append_song(utf8file, song, error);
+		bool success = spl_append_song(utf8file, *song, error);
 		db->ReturnSong(song);
 		return success;
 	}
diff --git a/src/PlaylistFile.hxx b/src/PlaylistFile.hxx
index 7d9ab5478..9bf23b22a 100644
--- a/src/PlaylistFile.hxx
+++ b/src/PlaylistFile.hxx
@@ -69,7 +69,7 @@ bool
 spl_remove_index(const char *utf8path, unsigned pos, Error &error);
 
 bool
-spl_append_song(const char *utf8path, Song *song, Error &error);
+spl_append_song(const char *utf8path, const Song &song, Error &error);
 
 bool
 spl_append_uri(const char *file, const char *utf8file, Error &error);
diff --git a/src/PlaylistPrint.cxx b/src/PlaylistPrint.cxx
index 0a9b5c4bc..35f360eec 100644
--- a/src/PlaylistPrint.cxx
+++ b/src/PlaylistPrint.cxx
@@ -39,22 +39,22 @@
 #include <glib.h>
 
 void
-playlist_print_uris(Client *client, const struct playlist *playlist)
+playlist_print_uris(Client &client, const playlist &playlist)
 {
-	const struct queue *queue = &playlist->queue;
+	const queue &queue = playlist.queue;
 
-	queue_print_uris(client, queue, 0, queue->GetLength());
+	queue_print_uris(client, queue, 0, queue.GetLength());
 }
 
 bool
-playlist_print_info(Client *client, const struct playlist *playlist,
+playlist_print_info(Client &client, const playlist &playlist,
 		    unsigned start, unsigned end)
 {
-	const struct queue *queue = &playlist->queue;
+	const queue &queue = playlist.queue;
 
-	if (end > queue->GetLength())
+	if (end > queue.GetLength())
 		/* correct the "end" offset */
-		end = queue->GetLength();
+		end = queue.GetLength();
 
 	if (start > end)
 		/* an invalid "start" offset is fatal */
@@ -65,13 +65,12 @@ playlist_print_info(Client *client, const struct playlist *playlist,
 }
 
 bool
-playlist_print_id(Client *client, const struct playlist *playlist,
+playlist_print_id(Client &client, const playlist &playlist,
 		  unsigned id)
 {
-	const struct queue *queue = &playlist->queue;
 	int position;
 
-	position = queue->IdToPosition(id);
+	position = playlist.queue.IdToPosition(id);
 	if (position < 0)
 		/* no such song */
 		return false;
@@ -80,42 +79,42 @@ playlist_print_id(Client *client, const struct playlist *playlist,
 }
 
 bool
-playlist_print_current(Client *client, const struct playlist *playlist)
+playlist_print_current(Client &client, const playlist &playlist)
 {
-	int current_position = playlist->GetCurrentPosition();
+	int current_position = playlist.GetCurrentPosition();
 	if (current_position < 0)
 		return false;
 
-	queue_print_info(client, &playlist->queue,
+	queue_print_info(client, playlist.queue,
 			 current_position, current_position + 1);
 	return true;
 }
 
 void
-playlist_print_find(Client *client, const struct playlist *playlist,
+playlist_print_find(Client &client, const playlist &playlist,
 		    const SongFilter &filter)
 {
-	queue_find(client, &playlist->queue, filter);
+	queue_find(client, playlist.queue, filter);
 }
 
 void
-playlist_print_changes_info(Client *client,
-			    const struct playlist *playlist,
+playlist_print_changes_info(Client &client,
+			    const playlist &playlist,
 			    uint32_t version)
 {
-	queue_print_changes_info(client, &playlist->queue, version);
+	queue_print_changes_info(client, playlist.queue, version);
 }
 
 void
-playlist_print_changes_position(Client *client,
-				const struct playlist *playlist,
+playlist_print_changes_position(Client &client,
+				const playlist &playlist,
 				uint32_t version)
 {
-	queue_print_changes_position(client, &playlist->queue, version);
+	queue_print_changes_position(client, playlist.queue, version);
 }
 
 static bool
-PrintSongDetails(Client *client, const char *uri_utf8)
+PrintSongDetails(Client &client, const char *uri_utf8)
 {
 	const Database *db = GetDatabase(IgnoreError());
 	if (db == nullptr)
@@ -125,13 +124,13 @@ PrintSongDetails(Client *client, const char *uri_utf8)
 	if (song == nullptr)
 		return false;
 
-	song_print_info(client, song);
+	song_print_info(client, *song);
 	db->ReturnSong(song);
 	return true;
 }
 
 bool
-spl_print(Client *client, const char *name_utf8, bool detail,
+spl_print(Client &client, const char *name_utf8, bool detail,
 	  Error &error)
 {
 	PlaylistFileContents contents = LoadPlaylistFile(name_utf8, error);
@@ -148,7 +147,7 @@ spl_print(Client *client, const char *name_utf8, bool detail,
 }
 
 static void
-playlist_provider_print(Client *client, const char *uri,
+playlist_provider_print(Client &client, const char *uri,
 			SongEnumerator &e, bool detail)
 {
 	Song *song;
@@ -160,9 +159,9 @@ playlist_provider_print(Client *client, const char *uri,
 			continue;
 
 		if (detail)
-			song_print_info(client, song);
+			song_print_info(client, *song);
 		else
-			song_print_uri(client, song);
+			song_print_uri(client, *song);
 
 		song->Free();
 	}
@@ -171,7 +170,7 @@ playlist_provider_print(Client *client, const char *uri,
 }
 
 bool
-playlist_file_print(Client *client, const char *uri, bool detail)
+playlist_file_print(Client &client, const char *uri, bool detail)
 {
 	Mutex mutex;
 	Cond cond;
diff --git a/src/PlaylistPrint.hxx b/src/PlaylistPrint.hxx
index c8c353d0c..cea6928ca 100644
--- a/src/PlaylistPrint.hxx
+++ b/src/PlaylistPrint.hxx
@@ -1,3 +1,4 @@
+
 /*
  * Copyright (C) 2003-2012 The Music Player Daemon Project
  * http://www.musicpd.org
@@ -31,7 +32,7 @@ class Error;
  * Sends the whole playlist to the client, song URIs only.
  */
 void
-playlist_print_uris(Client *client, const struct playlist *playlist);
+playlist_print_uris(Client &client, const playlist &playlist);
 
 /**
  * Sends a range of the playlist to the client, including all known
@@ -40,7 +41,7 @@ playlist_print_uris(Client *client, const struct playlist *playlist);
  * This function however fails when the start offset is invalid.
  */
 bool
-playlist_print_info(Client *client, const struct playlist *playlist,
+playlist_print_info(Client &client, const playlist &playlist,
 		    unsigned start, unsigned end);
 
 /**
@@ -49,7 +50,7 @@ playlist_print_info(Client *client, const struct playlist *playlist,
  * @return true on suite, false if there is no such song
  */
 bool
-playlist_print_id(Client *client, const struct playlist *playlist,
+playlist_print_id(Client &client, const playlist &playlist,
 		  unsigned id);
 
 /**
@@ -58,29 +59,29 @@ playlist_print_id(Client *client, const struct playlist *playlist,
  * @return true on success, false if there is no current song
  */
 bool
-playlist_print_current(Client *client, const struct playlist *playlist);
+playlist_print_current(Client &client, const playlist &playlist);
 
 /**
  * Find songs in the playlist.
  */
 void
-playlist_print_find(Client *client, const struct playlist *playlist,
+playlist_print_find(Client &client, const playlist &playlist,
 		    const SongFilter &filter);
 
 /**
  * Print detailed changes since the specified playlist version.
  */
 void
-playlist_print_changes_info(Client *client,
-			    const struct playlist *playlist,
+playlist_print_changes_info(Client &client,
+			    const playlist &playlist,
 			    uint32_t version);
 
 /**
  * Print changes since the specified playlist version, position only.
  */
 void
-playlist_print_changes_position(Client *client,
-				const struct playlist *playlist,
+playlist_print_changes_position(Client &client,
+				const playlist &playlist,
 				uint32_t version);
 
 /**
@@ -92,7 +93,7 @@ playlist_print_changes_position(Client *client,
  * @return true on success, false if the playlist does not exist
  */
 bool
-spl_print(Client *client, const char *name_utf8, bool detail,
+spl_print(Client &client, const char *name_utf8, bool detail,
 	  Error &error);
 
 /**
@@ -104,6 +105,6 @@ spl_print(Client *client, const char *name_utf8, bool detail,
  * @return true on success, false if the playlist does not exist
  */
 bool
-playlist_file_print(Client *client, const char *uri, bool detail);
+playlist_file_print(Client &client, const char *uri, bool detail);
 
 #endif
diff --git a/src/PlaylistQueue.cxx b/src/PlaylistQueue.cxx
index 28a1ff22d..200ce542f 100644
--- a/src/PlaylistQueue.cxx
+++ b/src/PlaylistQueue.cxx
@@ -33,7 +33,7 @@
 enum playlist_result
 playlist_load_into_queue(const char *uri, SongEnumerator &e,
 			 unsigned start_index, unsigned end_index,
-			 struct playlist *dest, struct player_control *pc,
+			 playlist &dest, player_control &pc,
 			 bool secure)
 {
 	enum playlist_result result;
@@ -53,7 +53,7 @@ playlist_load_into_queue(const char *uri, SongEnumerator &e,
 		if (song == nullptr)
 			continue;
 
-		result = dest->AppendSong(*pc, song);
+		result = dest.AppendSong(pc, song);
 		song->Free();
 		if (result != PLAYLIST_RESULT_SUCCESS) {
 			g_free(base_uri);
@@ -69,7 +69,7 @@ playlist_load_into_queue(const char *uri, SongEnumerator &e,
 enum playlist_result
 playlist_open_into_queue(const char *uri,
 			 unsigned start_index, unsigned end_index,
-			 struct playlist *dest, struct player_control *pc,
+			 playlist &dest, player_control &pc,
 			 bool secure)
 {
 	Mutex mutex;
diff --git a/src/PlaylistQueue.hxx b/src/PlaylistQueue.hxx
index 71768ecb4..2860190f1 100644
--- a/src/PlaylistQueue.hxx
+++ b/src/PlaylistQueue.hxx
@@ -42,7 +42,7 @@ struct player_control;
 enum playlist_result
 playlist_load_into_queue(const char *uri, SongEnumerator &e,
 			 unsigned start_index, unsigned end_index,
-			 struct playlist *dest, struct player_control *pc,
+			 playlist &dest, player_control &pc,
 			 bool secure);
 
 /**
@@ -52,7 +52,7 @@ playlist_load_into_queue(const char *uri, SongEnumerator &e,
 enum playlist_result
 playlist_open_into_queue(const char *uri,
 			 unsigned start_index, unsigned end_index,
-			 struct playlist *dest, struct player_control *pc,
+			 playlist &dest, player_control &pc,
 			 bool secure);
 
 #endif
diff --git a/src/PlaylistSave.cxx b/src/PlaylistSave.cxx
index 60270bc98..0980869b6 100644
--- a/src/PlaylistSave.cxx
+++ b/src/PlaylistSave.cxx
@@ -37,14 +37,14 @@
 #include <string.h>
 
 void
-playlist_print_song(FILE *file, const Song *song)
+playlist_print_song(FILE *file, const Song &song)
 {
-	if (playlist_saveAbsolutePaths && song->IsInDatabase()) {
+	if (playlist_saveAbsolutePaths && song.IsInDatabase()) {
 		const auto path = map_song_fs(song);
 		if (!path.IsNull())
 			fprintf(file, "%s\n", path.c_str());
 	} else {
-		const auto uri_utf8 = song->GetURI();
+		const auto uri_utf8 = song.GetURI();
 		const auto uri_fs = AllocatedPath::FromUTF8(uri_utf8.c_str());
 
 		if (!uri_fs.IsNull())
@@ -65,7 +65,7 @@ playlist_print_uri(FILE *file, const char *uri)
 }
 
 enum playlist_result
-spl_save_queue(const char *name_utf8, const struct queue *queue)
+spl_save_queue(const char *name_utf8, const queue &queue)
 {
 	if (map_spl_path().IsNull())
 		return PLAYLIST_RESULT_DISABLED;
@@ -85,8 +85,8 @@ spl_save_queue(const char *name_utf8, const struct queue *queue)
 	if (file == nullptr)
 		return PLAYLIST_RESULT_ERRNO;
 
-	for (unsigned i = 0; i < queue->GetLength(); i++)
-		playlist_print_song(file, queue->Get(i));
+	for (unsigned i = 0; i < queue.GetLength(); i++)
+		playlist_print_song(file, queue.Get(i));
 
 	fclose(file);
 
@@ -95,13 +95,13 @@ spl_save_queue(const char *name_utf8, const struct queue *queue)
 }
 
 enum playlist_result
-spl_save_playlist(const char *name_utf8, const struct playlist *playlist)
+spl_save_playlist(const char *name_utf8, const playlist &playlist)
 {
-	return spl_save_queue(name_utf8, &playlist->queue);
+	return spl_save_queue(name_utf8, playlist.queue);
 }
 
 bool
-playlist_load_spl(struct playlist *playlist, struct player_control *pc,
+playlist_load_spl(struct playlist &playlist, player_control &pc,
 		  const char *name_utf8,
 		  unsigned start_index, unsigned end_index,
 		  Error &error)
@@ -119,13 +119,13 @@ playlist_load_spl(struct playlist *playlist, struct player_control *pc,
 		if (memcmp(uri_utf8.c_str(), "file:///", 8) == 0) {
 			const char *path_utf8 = uri_utf8.c_str() + 7;
 
-			if (playlist->AppendFile(*pc, path_utf8) != PLAYLIST_RESULT_SUCCESS)
+			if (playlist.AppendFile(pc, path_utf8) != PLAYLIST_RESULT_SUCCESS)
 				FormatError(playlist_domain,
 					    "can't add file \"%s\"", path_utf8);
 			continue;
 		}
 
-		if ((playlist->AppendURI(*pc, uri_utf8.c_str())) != PLAYLIST_RESULT_SUCCESS) {
+		if ((playlist.AppendURI(pc, uri_utf8.c_str())) != PLAYLIST_RESULT_SUCCESS) {
 			/* for windows compatibility, convert slashes */
 			char *temp2 = g_strdup(uri_utf8.c_str());
 			char *p = temp2;
@@ -135,7 +135,7 @@ playlist_load_spl(struct playlist *playlist, struct player_control *pc,
 				p++;
 			}
 
-			if (playlist->AppendURI(*pc, temp2) != PLAYLIST_RESULT_SUCCESS)
+			if (playlist.AppendURI(pc, temp2) != PLAYLIST_RESULT_SUCCESS)
 				FormatError(playlist_domain,
 					    "can't add file \"%s\"", temp2);
 
diff --git a/src/PlaylistSave.hxx b/src/PlaylistSave.hxx
index f85558755..54f48f4b8 100644
--- a/src/PlaylistSave.hxx
+++ b/src/PlaylistSave.hxx
@@ -31,7 +31,7 @@ struct player_control;
 class Error;
 
 void
-playlist_print_song(FILE *fp, const Song *song);
+playlist_print_song(FILE *fp, const Song &song);
 
 void
 playlist_print_uri(FILE *fp, const char *uri);
@@ -40,20 +40,20 @@ playlist_print_uri(FILE *fp, const char *uri);
  * Saves a queue object into a stored playlist file.
  */
 enum playlist_result
-spl_save_queue(const char *name_utf8, const struct queue *queue);
+spl_save_queue(const char *name_utf8, const queue &queue);
 
 /**
  * Saves a playlist object into a stored playlist file.
  */
 enum playlist_result
-spl_save_playlist(const char *name_utf8, const struct playlist *playlist);
+spl_save_playlist(const char *name_utf8, const playlist &playlist);
 
 /**
  * Loads a stored playlist file, and append all songs to the global
  * playlist.
  */
 bool
-playlist_load_spl(struct playlist *playlist, struct player_control *pc,
+playlist_load_spl(struct playlist &playlist, player_control &pc,
 		  const char *name_utf8,
 		  unsigned start_index, unsigned end_index,
 		  Error &error);
diff --git a/src/PlaylistSong.cxx b/src/PlaylistSong.cxx
index b7a2e441c..ce60174fe 100644
--- a/src/PlaylistSong.cxx
+++ b/src/PlaylistSong.cxx
@@ -64,7 +64,7 @@ apply_song_metadata(Song *dest, const Song *src)
 		return dest;
 
 	if (dest->IsInDatabase()) {
-		const auto path_fs = map_song_fs(dest);
+		const auto path_fs = map_song_fs(*dest);
 		if (path_fs.IsNull())
 			return dest;
 
diff --git a/src/PlaylistState.cxx b/src/PlaylistState.cxx
index 6a2cf18ca..64b30f066 100644
--- a/src/PlaylistState.cxx
+++ b/src/PlaylistState.cxx
@@ -59,14 +59,14 @@
 #define PLAYLIST_BUFFER_SIZE	2*MPD_PATH_MAX
 
 void
-playlist_state_save(FILE *fp, const struct playlist *playlist,
-		    struct player_control *pc)
+playlist_state_save(FILE *fp, const struct playlist &playlist,
+		    player_control &pc)
 {
-	const auto player_status = pc->GetStatus();
+	const auto player_status = pc.GetStatus();
 
 	fputs(PLAYLIST_STATE_FILE_STATE, fp);
 
-	if (playlist->playing) {
+	if (playlist.playing) {
 		switch (player_status.state) {
 		case PlayerState::PAUSE:
 			fputs(PLAYLIST_STATE_FILE_STATE_PAUSE "\n", fp);
@@ -75,35 +75,35 @@ playlist_state_save(FILE *fp, const struct playlist *playlist,
 			fputs(PLAYLIST_STATE_FILE_STATE_PLAY "\n", fp);
 		}
 		fprintf(fp, PLAYLIST_STATE_FILE_CURRENT "%i\n",
-			playlist->queue.OrderToPosition(playlist->current));
+			playlist.queue.OrderToPosition(playlist.current));
 		fprintf(fp, PLAYLIST_STATE_FILE_TIME "%i\n",
 			(int)player_status.elapsed_time);
 	} else {
 		fputs(PLAYLIST_STATE_FILE_STATE_STOP "\n", fp);
 
-		if (playlist->current >= 0)
+		if (playlist.current >= 0)
 			fprintf(fp, PLAYLIST_STATE_FILE_CURRENT "%i\n",
-				playlist->queue.OrderToPosition(playlist->current));
+				playlist.queue.OrderToPosition(playlist.current));
 	}
 
-	fprintf(fp, PLAYLIST_STATE_FILE_RANDOM "%i\n", playlist->queue.random);
-	fprintf(fp, PLAYLIST_STATE_FILE_REPEAT "%i\n", playlist->queue.repeat);
-	fprintf(fp, PLAYLIST_STATE_FILE_SINGLE "%i\n", playlist->queue.single);
+	fprintf(fp, PLAYLIST_STATE_FILE_RANDOM "%i\n", playlist.queue.random);
+	fprintf(fp, PLAYLIST_STATE_FILE_REPEAT "%i\n", playlist.queue.repeat);
+	fprintf(fp, PLAYLIST_STATE_FILE_SINGLE "%i\n", playlist.queue.single);
 	fprintf(fp, PLAYLIST_STATE_FILE_CONSUME "%i\n",
-		playlist->queue.consume);
+		playlist.queue.consume);
 	fprintf(fp, PLAYLIST_STATE_FILE_CROSSFADE "%i\n",
-		(int)pc->GetCrossFade());
+		(int)pc.GetCrossFade());
 	fprintf(fp, PLAYLIST_STATE_FILE_MIXRAMPDB "%f\n",
-		pc->GetMixRampDb());
+		pc.GetMixRampDb());
 	fprintf(fp, PLAYLIST_STATE_FILE_MIXRAMPDELAY "%f\n",
-		pc->GetMixRampDelay());
+		pc.GetMixRampDelay());
 	fputs(PLAYLIST_STATE_FILE_PLAYLIST_BEGIN "\n", fp);
-	queue_save(fp, &playlist->queue);
+	queue_save(fp, playlist.queue);
 	fputs(PLAYLIST_STATE_FILE_PLAYLIST_END "\n", fp);
 }
 
 static void
-playlist_state_load(TextFile &file, struct playlist *playlist)
+playlist_state_load(TextFile &file, struct playlist &playlist)
 {
 	const char *line = file.ReadLine();
 	if (line == nullptr) {
@@ -112,7 +112,7 @@ playlist_state_load(TextFile &file, struct playlist *playlist)
 	}
 
 	while (!g_str_has_prefix(line, PLAYLIST_STATE_FILE_PLAYLIST_END)) {
-		queue_load_song(file, line, &playlist->queue);
+		queue_load_song(file, line, playlist.queue);
 
 		line = file.ReadLine();
 		if (line == nullptr) {
@@ -123,12 +123,12 @@ playlist_state_load(TextFile &file, struct playlist *playlist)
 		}
 	}
 
-	playlist->queue.IncrementVersion();
+	playlist.queue.IncrementVersion();
 }
 
 bool
 playlist_state_restore(const char *line, TextFile &file,
-		       struct playlist *playlist, struct player_control *pc)
+		       struct playlist &playlist, player_control &pc)
 {
 	int current = -1;
 	int seek_time = 0;
@@ -150,24 +150,24 @@ playlist_state_restore(const char *line, TextFile &file,
 	while ((line = file.ReadLine()) != nullptr) {
 		if (g_str_has_prefix(line, PLAYLIST_STATE_FILE_TIME)) {
 			seek_time =
-			    atoi(&(line[strlen(PLAYLIST_STATE_FILE_TIME)]));
+				atoi(&(line[strlen(PLAYLIST_STATE_FILE_TIME)]));
 		} else if (g_str_has_prefix(line, PLAYLIST_STATE_FILE_REPEAT)) {
-			playlist->SetRepeat(*pc,
-					    strcmp(&(line[strlen(PLAYLIST_STATE_FILE_REPEAT)]),
-						   "1") == 0);
+			playlist.SetRepeat(pc,
+					   strcmp(&(line[strlen(PLAYLIST_STATE_FILE_REPEAT)]),
+						  "1") == 0);
 		} else if (g_str_has_prefix(line, PLAYLIST_STATE_FILE_SINGLE)) {
-			playlist->SetSingle(*pc,
-					    strcmp(&(line[strlen(PLAYLIST_STATE_FILE_SINGLE)]),
-						   "1") == 0);
+			playlist.SetSingle(pc,
+					   strcmp(&(line[strlen(PLAYLIST_STATE_FILE_SINGLE)]),
+						  "1") == 0);
 		} else if (g_str_has_prefix(line, PLAYLIST_STATE_FILE_CONSUME)) {
-			playlist->SetConsume(strcmp(&(line[strlen(PLAYLIST_STATE_FILE_CONSUME)]),
-						    "1") == 0);
+			playlist.SetConsume(strcmp(&(line[strlen(PLAYLIST_STATE_FILE_CONSUME)]),
+						   "1") == 0);
 		} else if (g_str_has_prefix(line, PLAYLIST_STATE_FILE_CROSSFADE)) {
-			pc->SetCrossFade(atoi(line + strlen(PLAYLIST_STATE_FILE_CROSSFADE)));
+			pc.SetCrossFade(atoi(line + strlen(PLAYLIST_STATE_FILE_CROSSFADE)));
 		} else if (g_str_has_prefix(line, PLAYLIST_STATE_FILE_MIXRAMPDB)) {
-			pc->SetMixRampDb(atof(line + strlen(PLAYLIST_STATE_FILE_MIXRAMPDB)));
+			pc.SetMixRampDb(atof(line + strlen(PLAYLIST_STATE_FILE_MIXRAMPDB)));
 		} else if (g_str_has_prefix(line, PLAYLIST_STATE_FILE_MIXRAMPDELAY)) {
-			pc->SetMixRampDelay(atof(line + strlen(PLAYLIST_STATE_FILE_MIXRAMPDELAY)));
+			pc.SetMixRampDelay(atof(line + strlen(PLAYLIST_STATE_FILE_MIXRAMPDELAY)));
 		} else if (g_str_has_prefix(line, PLAYLIST_STATE_FILE_RANDOM)) {
 			random_mode =
 				strcmp(line + strlen(PLAYLIST_STATE_FILE_RANDOM),
@@ -182,10 +182,10 @@ playlist_state_restore(const char *line, TextFile &file,
 		}
 	}
 
-	playlist->SetRandom(*pc, random_mode);
+	playlist.SetRandom(pc, random_mode);
 
-	if (!playlist->queue.IsEmpty()) {
-		if (!playlist->queue.IsValidPosition(current))
+	if (!playlist.queue.IsEmpty()) {
+		if (!playlist.queue.IsValidPosition(current))
 			current = 0;
 
 		if (state == PlayerState::PLAY &&
@@ -199,40 +199,40 @@ playlist_state_restore(const char *line, TextFile &file,
 		   called here, after the audio output states were
 		   restored, before playback begins */
 		if (state != PlayerState::STOP)
-			pc->UpdateAudio();
+			pc.UpdateAudio();
 
 		if (state == PlayerState::STOP /* && config_option */)
-			playlist->current = current;
+			playlist.current = current;
 		else if (seek_time == 0)
-			playlist->PlayPosition(*pc, current);
+			playlist.PlayPosition(pc, current);
 		else
-			playlist->SeekSongPosition(*pc, current, seek_time);
+			playlist.SeekSongPosition(pc, current, seek_time);
 
 		if (state == PlayerState::PAUSE)
-			pc->Pause();
+			pc.Pause();
 	}
 
 	return true;
 }
 
 unsigned
-playlist_state_get_hash(const struct playlist *playlist,
-			struct player_control *pc)
+playlist_state_get_hash(const playlist &playlist,
+			player_control &pc)
 {
-	const auto player_status = pc->GetStatus();
+	const auto player_status = pc.GetStatus();
 
-	return playlist->queue.version ^
+	return playlist.queue.version ^
 		(player_status.state != PlayerState::STOP
 		 ? ((int)player_status.elapsed_time << 8)
 		 : 0) ^
-		(playlist->current >= 0
-		 ? (playlist->queue.OrderToPosition(playlist->current) << 16)
+		(playlist.current >= 0
+		 ? (playlist.queue.OrderToPosition(playlist.current) << 16)
 		 : 0) ^
-		((int)pc->GetCrossFade() << 20) ^
+		((int)pc.GetCrossFade() << 20) ^
 		(unsigned(player_status.state) << 24) ^
-		(playlist->queue.random << 27) ^
-		(playlist->queue.repeat << 28) ^
-		(playlist->queue.single << 29) ^
-		(playlist->queue.consume << 30) ^
-		(playlist->queue.random << 31);
+		(playlist.queue.random << 27) ^
+		(playlist.queue.repeat << 28) ^
+		(playlist.queue.single << 29) ^
+		(playlist.queue.consume << 30) ^
+		(playlist.queue.random << 31);
 }
diff --git a/src/PlaylistState.hxx b/src/PlaylistState.hxx
index 7e9944789..339ac1061 100644
--- a/src/PlaylistState.hxx
+++ b/src/PlaylistState.hxx
@@ -32,12 +32,12 @@ struct player_control;
 class TextFile;
 
 void
-playlist_state_save(FILE *fp, const struct playlist *playlist,
-		    struct player_control *pc);
+playlist_state_save(FILE *fp, const struct playlist &playlist,
+		    player_control &pc);
 
 bool
 playlist_state_restore(const char *line, TextFile &file,
-		       struct playlist *playlist, struct player_control *pc);
+		       struct playlist &playlist, player_control &pc);
 
 /**
  * Generates a hash number for the current state of the playlist and
@@ -46,7 +46,7 @@ playlist_state_restore(const char *line, TextFile &file,
  * be saved.
  */
 unsigned
-playlist_state_get_hash(const struct playlist *playlist,
-			struct player_control *pc);
+playlist_state_get_hash(const struct playlist &playlist,
+			player_control &c);
 
 #endif
diff --git a/src/Queue.cxx b/src/Queue.cxx
index 4226592c0..73628d02e 100644
--- a/src/Queue.cxx
+++ b/src/Queue.cxx
@@ -232,9 +232,11 @@ queue::DeletePosition(unsigned position)
 {
 	assert(position < length);
 
-	Song *song = Get(position);
-	assert(!song->IsInDatabase() || song->IsDetached());
-	song->Free();
+	{
+		Song &song = Get(position);
+		assert(!song.IsInDatabase() || song.IsDetached());
+		song.Free();
+	}
 
 	const unsigned id = PositionToId(position);
 	const unsigned _order = PositionToOrder(position);
diff --git a/src/Queue.hxx b/src/Queue.hxx
index ae9b0b829..0088e080f 100644
--- a/src/Queue.hxx
+++ b/src/Queue.hxx
@@ -200,16 +200,16 @@ struct queue {
 	/**
 	 * Returns the song at the specified position.
 	 */
-	Song *Get(unsigned position) const {
+	Song &Get(unsigned position) const {
 		assert(position < length);
 
-		return items[position].song;
+		return *items[position].song;
 	}
 
 	/**
 	 * Returns the song at the specified order number.
 	 */
-	Song *GetOrder(unsigned _order) const {
+	Song &GetOrder(unsigned _order) const {
 		return Get(OrderToPosition(_order));
 	}
 
diff --git a/src/QueueCommands.cxx b/src/QueueCommands.cxx
index f58263872..9ab6244bb 100644
--- a/src/QueueCommands.cxx
+++ b/src/QueueCommands.cxx
@@ -40,7 +40,7 @@
 #include <string.h>
 
 enum command_return
-handle_add(Client *client, gcc_unused int argc, char *argv[])
+handle_add(Client &client, gcc_unused int argc, char *argv[])
 {
 	char *uri = argv[1];
 	enum playlist_result result;
@@ -59,7 +59,7 @@ handle_add(Client *client, gcc_unused int argc, char *argv[])
 		if (!client_allow_file(client, path_fs, error))
 			return print_error(client, error);
 
-		result = client->partition.AppendFile(path_utf8);
+		result = client.partition.AppendFile(path_utf8);
 		return print_playlist_result(client, result);
 	}
 
@@ -70,19 +70,19 @@ handle_add(Client *client, gcc_unused int argc, char *argv[])
 			return COMMAND_RETURN_ERROR;
 		}
 
-		result = client->partition.AppendURI(uri);
+		result = client.partition.AppendURI(uri);
 		return print_playlist_result(client, result);
 	}
 
 	const DatabaseSelection selection(uri, true);
 	Error error;
-	return AddFromDatabase(client->partition, selection, error)
+	return AddFromDatabase(client.partition, selection, error)
 		? COMMAND_RETURN_OK
 		: print_error(client, error);
 }
 
 enum command_return
-handle_addid(Client *client, int argc, char *argv[])
+handle_addid(Client &client, int argc, char *argv[])
 {
 	char *uri = argv[1];
 	unsigned added_id;
@@ -102,7 +102,7 @@ handle_addid(Client *client, int argc, char *argv[])
 		if (!client_allow_file(client, path_fs, error))
 			return print_error(client, error);
 
-		result = client->partition.AppendFile(path_utf8, &added_id);
+		result = client.partition.AppendFile(path_utf8, &added_id);
 	} else {
 		if (uri_has_scheme(uri) && !uri_supported_scheme(uri)) {
 			command_error(client, ACK_ERROR_NO_EXIST,
@@ -110,7 +110,7 @@ handle_addid(Client *client, int argc, char *argv[])
 			return COMMAND_RETURN_ERROR;
 		}
 
-		result = client->partition.AppendURI(uri, &added_id);
+		result = client.partition.AppendURI(uri, &added_id);
 	}
 
 	if (result != PLAYLIST_RESULT_SUCCESS)
@@ -120,11 +120,11 @@ handle_addid(Client *client, int argc, char *argv[])
 		unsigned to;
 		if (!check_unsigned(client, &to, argv[2]))
 			return COMMAND_RETURN_ERROR;
-		result = client->partition.MoveId(added_id, to);
+		result = client.partition.MoveId(added_id, to);
 		if (result != PLAYLIST_RESULT_SUCCESS) {
 			enum command_return ret =
 				print_playlist_result(client, result);
-			client->partition.DeleteId(added_id);
+			client.partition.DeleteId(added_id);
 			return ret;
 		}
 	}
@@ -134,83 +134,83 @@ handle_addid(Client *client, int argc, char *argv[])
 }
 
 enum command_return
-handle_delete(Client *client, gcc_unused int argc, char *argv[])
+handle_delete(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned start, end;
 
 	if (!check_range(client, &start, &end, argv[1]))
 		return COMMAND_RETURN_ERROR;
 
-	enum playlist_result result = client->partition.DeleteRange(start, end);
+	enum playlist_result result = client.partition.DeleteRange(start, end);
 	return print_playlist_result(client, result);
 }
 
 enum command_return
-handle_deleteid(Client *client, gcc_unused int argc, char *argv[])
+handle_deleteid(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned id;
 
 	if (!check_unsigned(client, &id, argv[1]))
 		return COMMAND_RETURN_ERROR;
 
-	enum playlist_result result = client->partition.DeleteId(id);
+	enum playlist_result result = client.partition.DeleteId(id);
 	return print_playlist_result(client, result);
 }
 
 enum command_return
-handle_playlist(Client *client,
+handle_playlist(Client &client,
 		gcc_unused int argc, gcc_unused char *argv[])
 {
-	playlist_print_uris(client, &client->playlist);
+	playlist_print_uris(client, client.playlist);
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_shuffle(gcc_unused Client *client,
+handle_shuffle(gcc_unused Client &client,
 	       gcc_unused int argc, gcc_unused char *argv[])
 {
-	unsigned start = 0, end = client->playlist.queue.GetLength();
+	unsigned start = 0, end = client.playlist.queue.GetLength();
 	if (argc == 2 && !check_range(client, &start, &end, argv[1]))
 		return COMMAND_RETURN_ERROR;
 
-	client->partition.Shuffle(start, end);
+	client.partition.Shuffle(start, end);
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_clear(gcc_unused Client *client,
+handle_clear(gcc_unused Client &client,
 	     gcc_unused int argc, gcc_unused char *argv[])
 {
-	client->partition.ClearQueue();
+	client.partition.ClearQueue();
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_plchanges(Client *client, gcc_unused int argc, char *argv[])
+handle_plchanges(Client &client, gcc_unused int argc, char *argv[])
 {
 	uint32_t version;
 
 	if (!check_uint32(client, &version, argv[1]))
 		return COMMAND_RETURN_ERROR;
 
-	playlist_print_changes_info(client, &client->playlist, version);
+	playlist_print_changes_info(client, client.playlist, version);
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_plchangesposid(Client *client, gcc_unused int argc, char *argv[])
+handle_plchangesposid(Client &client, gcc_unused int argc, char *argv[])
 {
 	uint32_t version;
 
 	if (!check_uint32(client, &version, argv[1]))
 		return COMMAND_RETURN_ERROR;
 
-	playlist_print_changes_position(client, &client->playlist, version);
+	playlist_print_changes_position(client, client.playlist, version);
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_playlistinfo(Client *client, int argc, char *argv[])
+handle_playlistinfo(Client &client, int argc, char *argv[])
 {
 	unsigned start = 0, end = std::numeric_limits<unsigned>::max();
 	bool ret;
@@ -218,7 +218,7 @@ handle_playlistinfo(Client *client, int argc, char *argv[])
 	if (argc == 2 && !check_range(client, &start, &end, argv[1]))
 		return COMMAND_RETURN_ERROR;
 
-	ret = playlist_print_info(client, &client->playlist, start, end);
+	ret = playlist_print_info(client, client.playlist, start, end);
 	if (!ret)
 		return print_playlist_result(client,
 					     PLAYLIST_RESULT_BAD_RANGE);
@@ -227,19 +227,19 @@ handle_playlistinfo(Client *client, int argc, char *argv[])
 }
 
 enum command_return
-handle_playlistid(Client *client, int argc, char *argv[])
+handle_playlistid(Client &client, int argc, char *argv[])
 {
 	if (argc >= 2) {
 		unsigned id;
 		if (!check_unsigned(client, &id, argv[1]))
 			return COMMAND_RETURN_ERROR;
 
-		bool ret = playlist_print_id(client, &client->playlist, id);
+		bool ret = playlist_print_id(client, client.playlist, id);
 		if (!ret)
 			return print_playlist_result(client,
 						     PLAYLIST_RESULT_NO_SUCH_SONG);
 	} else {
-		playlist_print_info(client, &client->playlist,
+		playlist_print_info(client, client.playlist,
 				    0, std::numeric_limits<unsigned>::max());
 	}
 
@@ -247,7 +247,7 @@ handle_playlistid(Client *client, int argc, char *argv[])
 }
 
 static enum command_return
-handle_playlist_match(Client *client, int argc, char *argv[],
+handle_playlist_match(Client &client, int argc, char *argv[],
 		      bool fold_case)
 {
 	SongFilter filter;
@@ -256,24 +256,24 @@ handle_playlist_match(Client *client, int argc, char *argv[],
 		return COMMAND_RETURN_ERROR;
 	}
 
-	playlist_print_find(client, &client->playlist, filter);
+	playlist_print_find(client, client.playlist, filter);
 	return COMMAND_RETURN_OK;
 }
 
 enum command_return
-handle_playlistfind(Client *client, int argc, char *argv[])
+handle_playlistfind(Client &client, int argc, char *argv[])
 {
 	return handle_playlist_match(client, argc, argv, false);
 }
 
 enum command_return
-handle_playlistsearch(Client *client, int argc, char *argv[])
+handle_playlistsearch(Client &client, int argc, char *argv[])
 {
 	return handle_playlist_match(client, argc, argv, true);
 }
 
 enum command_return
-handle_prio(Client *client, int argc, char *argv[])
+handle_prio(Client &client, int argc, char *argv[])
 {
 	unsigned priority;
 
@@ -293,7 +293,7 @@ handle_prio(Client *client, int argc, char *argv[])
 			return COMMAND_RETURN_ERROR;
 
 		enum playlist_result result =
-			client->partition.SetPriorityRange(start_position,
+			client.partition.SetPriorityRange(start_position,
 							   end_position,
 							   priority);
 		if (result != PLAYLIST_RESULT_SUCCESS)
@@ -304,7 +304,7 @@ handle_prio(Client *client, int argc, char *argv[])
 }
 
 enum command_return
-handle_prioid(Client *client, int argc, char *argv[])
+handle_prioid(Client &client, int argc, char *argv[])
 {
 	unsigned priority;
 
@@ -323,7 +323,7 @@ handle_prioid(Client *client, int argc, char *argv[])
 			return COMMAND_RETURN_ERROR;
 
 		enum playlist_result result =
-			client->partition.SetPriorityId(song_id, priority);
+			client.partition.SetPriorityId(song_id, priority);
 		if (result != PLAYLIST_RESULT_SUCCESS)
 			return print_playlist_result(client, result);
 	}
@@ -332,7 +332,7 @@ handle_prioid(Client *client, int argc, char *argv[])
 }
 
 enum command_return
-handle_move(Client *client, gcc_unused int argc, char *argv[])
+handle_move(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned start, end;
 	int to;
@@ -343,12 +343,12 @@ handle_move(Client *client, gcc_unused int argc, char *argv[])
 		return COMMAND_RETURN_ERROR;
 
 	enum playlist_result result =
-		client->partition.MoveRange(start, end, to);
+		client.partition.MoveRange(start, end, to);
 	return print_playlist_result(client, result);
 }
 
 enum command_return
-handle_moveid(Client *client, gcc_unused int argc, char *argv[])
+handle_moveid(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned id;
 	int to;
@@ -357,12 +357,12 @@ handle_moveid(Client *client, gcc_unused int argc, char *argv[])
 		return COMMAND_RETURN_ERROR;
 	if (!check_int(client, &to, argv[2]))
 		return COMMAND_RETURN_ERROR;
-	enum playlist_result result = client->partition.MoveId(id, to);
+	enum playlist_result result = client.partition.MoveId(id, to);
 	return print_playlist_result(client, result);
 }
 
 enum command_return
-handle_swap(Client *client, gcc_unused int argc, char *argv[])
+handle_swap(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned song1, song2;
 
@@ -372,12 +372,12 @@ handle_swap(Client *client, gcc_unused int argc, char *argv[])
 		return COMMAND_RETURN_ERROR;
 
 	enum playlist_result result =
-		client->partition.SwapPositions(song1, song2);
+		client.partition.SwapPositions(song1, song2);
 	return print_playlist_result(client, result);
 }
 
 enum command_return
-handle_swapid(Client *client, gcc_unused int argc, char *argv[])
+handle_swapid(Client &client, gcc_unused int argc, char *argv[])
 {
 	unsigned id1, id2;
 
@@ -386,6 +386,6 @@ handle_swapid(Client *client, gcc_unused int argc, char *argv[])
 	if (!check_unsigned(client, &id2, argv[2]))
 		return COMMAND_RETURN_ERROR;
 
-	enum playlist_result result = client->partition.SwapIds(id1, id2);
+	enum playlist_result result = client.partition.SwapIds(id1, id2);
 	return print_playlist_result(client, result);
 }
diff --git a/src/QueueCommands.hxx b/src/QueueCommands.hxx
index 97b61e212..09b489212 100644
--- a/src/QueueCommands.hxx
+++ b/src/QueueCommands.hxx
@@ -25,60 +25,60 @@
 class Client;
 
 enum command_return
-handle_add(Client *client, int argc, char *argv[]);
+handle_add(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_addid(Client *client, int argc, char *argv[]);
+handle_addid(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_delete(Client *client, int argc, char *argv[]);
+handle_delete(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_deleteid(Client *client, int argc, char *argv[]);
+handle_deleteid(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_playlist(Client *client, int argc, char *argv[]);
+handle_playlist(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_shuffle(Client *client, int argc, char *argv[]);
+handle_shuffle(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_clear(Client *client, int argc, char *argv[]);
+handle_clear(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_plchanges(Client *client, int argc, char *argv[]);
+handle_plchanges(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_plchangesposid(Client *client, int argc, char *argv[]);
+handle_plchangesposid(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_playlistinfo(Client *client, int argc, char *argv[]);
+handle_playlistinfo(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_playlistid(Client *client, int argc, char *argv[]);
+handle_playlistid(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_playlistfind(Client *client, int argc, char *argv[]);
+handle_playlistfind(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_playlistsearch(Client *client, int argc, char *argv[]);
+handle_playlistsearch(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_prio(Client *client, int argc, char *argv[]);
+handle_prio(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_prioid(Client *client, int argc, char *argv[]);
+handle_prioid(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_move(Client *client, int argc, char *argv[]);
+handle_move(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_moveid(Client *client, int argc, char *argv[]);
+handle_moveid(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_swap(Client *client, int argc, char *argv[]);
+handle_swap(Client &client, int argc, char *argv[]);
 
 enum command_return
-handle_swapid(Client *client, int argc, char *argv[]);
+handle_swapid(Client &client, int argc, char *argv[]);
 
 #endif
diff --git a/src/QueuePrint.cxx b/src/QueuePrint.cxx
index d8d94d3b0..d5651cde0 100644
--- a/src/QueuePrint.cxx
+++ b/src/QueuePrint.cxx
@@ -38,70 +38,70 @@ extern "C" {
  * @param end the index of the last song (excluding)
  */
 static void
-queue_print_song_info(Client *client, const struct queue *queue,
+queue_print_song_info(Client &client, const queue &queue,
 		      unsigned position)
 {
-	song_print_info(client, queue->Get(position));
+	song_print_info(client, queue.Get(position));
 	client_printf(client, "Pos: %u\nId: %u\n",
-		      position, queue->PositionToId(position));
+		      position, queue.PositionToId(position));
 
-	uint8_t priority = queue->GetPriorityAtPosition(position);
+	uint8_t priority = queue.GetPriorityAtPosition(position);
 	if (priority != 0)
 		client_printf(client, "Prio: %u\n", priority);
 }
 
 void
-queue_print_info(Client *client, const struct queue *queue,
+queue_print_info(Client &client, const queue &queue,
 		 unsigned start, unsigned end)
 {
 	assert(start <= end);
-	assert(end <= queue->GetLength());
+	assert(end <= queue.GetLength());
 
 	for (unsigned i = start; i < end; ++i)
 		queue_print_song_info(client, queue, i);
 }
 
 void
-queue_print_uris(Client *client, const struct queue *queue,
+queue_print_uris(Client &client, const queue &queue,
 		 unsigned start, unsigned end)
 {
 	assert(start <= end);
-	assert(end <= queue->GetLength());
+	assert(end <= queue.GetLength());
 
 	for (unsigned i = start; i < end; ++i) {
 		client_printf(client, "%i:", i);
-		song_print_uri(client, queue->Get(i));
+		song_print_uri(client, queue.Get(i));
 	}
 }
 
 void
-queue_print_changes_info(Client *client, const struct queue *queue,
+queue_print_changes_info(Client &client, const queue &queue,
 			 uint32_t version)
 {
-	for (unsigned i = 0; i < queue->GetLength(); i++) {
-		if (queue->IsNewerAtPosition(i, version))
+	for (unsigned i = 0; i < queue.GetLength(); i++) {
+		if (queue.IsNewerAtPosition(i, version))
 			queue_print_song_info(client, queue, i);
 	}
 }
 
 void
-queue_print_changes_position(Client *client, const struct queue *queue,
+queue_print_changes_position(Client &client, const queue &queue,
 			     uint32_t version)
 {
-	for (unsigned i = 0; i < queue->GetLength(); i++)
-		if (queue->IsNewerAtPosition(i, version))
+	for (unsigned i = 0; i < queue.GetLength(); i++)
+		if (queue.IsNewerAtPosition(i, version))
 			client_printf(client, "cpos: %i\nId: %i\n",
-				      i, queue->PositionToId(i));
+				      i, queue.PositionToId(i));
 }
 
 void
-queue_find(Client *client, const struct queue *queue,
+queue_find(Client &client, const queue &queue,
 	   const SongFilter &filter)
 {
-	for (unsigned i = 0; i < queue->GetLength(); i++) {
-		const Song *song = queue->Get(i);
+	for (unsigned i = 0; i < queue.GetLength(); i++) {
+		const Song &song = queue.Get(i);
 
-		if (filter.Match(*song))
+		if (filter.Match(song))
 			queue_print_song_info(client, queue, i);
 	}
 }
diff --git a/src/QueuePrint.hxx b/src/QueuePrint.hxx
index 6b3a29fb6..7e4e1d6e8 100644
--- a/src/QueuePrint.hxx
+++ b/src/QueuePrint.hxx
@@ -32,23 +32,23 @@ class SongFilter;
 class Client;
 
 void
-queue_print_info(Client *client, const struct queue *queue,
+queue_print_info(Client &client, const queue &queue,
 		 unsigned start, unsigned end);
 
 void
-queue_print_uris(Client *client, const struct queue *queue,
+queue_print_uris(Client &client, const queue &queue,
 		 unsigned start, unsigned end);
 
 void
-queue_print_changes_info(Client *client, const struct queue *queue,
+queue_print_changes_info(Client &client, const queue &queue,
 			 uint32_t version);
 
 void
-queue_print_changes_position(Client *client, const struct queue *queue,
+queue_print_changes_position(Client &client, const queue &queue,
 			     uint32_t version);
 
 void
-queue_find(Client *client, const struct queue *queue,
+queue_find(Client &client, const queue &queue,
 	   const SongFilter &filter);
 
 #endif
diff --git a/src/QueueSave.cxx b/src/QueueSave.cxx
index 43fb69846..1875a1270 100644
--- a/src/QueueSave.cxx
+++ b/src/QueueSave.cxx
@@ -38,43 +38,43 @@
 #define PRIO_LABEL "Prio: "
 
 static void
-queue_save_database_song(FILE *fp, int idx, const Song *song)
+queue_save_database_song(FILE *fp, int idx, const Song &song)
 {
-	const auto uri = song->GetURI();
+	const auto uri = song.GetURI();
 	fprintf(fp, "%i:%s\n", idx, uri.c_str());
 }
 
 static void
-queue_save_full_song(FILE *fp, const Song *song)
+queue_save_full_song(FILE *fp, const Song &song)
 {
 	song_save(fp, song);
 }
 
 static void
-queue_save_song(FILE *fp, int idx, const Song *song)
+queue_save_song(FILE *fp, int idx, const Song &song)
 {
-	if (song->IsInDatabase())
+	if (song.IsInDatabase())
 		queue_save_database_song(fp, idx, song);
 	else
 		queue_save_full_song(fp, song);
 }
 
 void
-queue_save(FILE *fp, const struct queue *queue)
+queue_save(FILE *fp, const queue &queue)
 {
-	for (unsigned i = 0; i < queue->GetLength(); i++) {
-		uint8_t prio = queue->GetPriorityAtPosition(i);
+	for (unsigned i = 0; i < queue.GetLength(); i++) {
+		uint8_t prio = queue.GetPriorityAtPosition(i);
 		if (prio != 0)
 			fprintf(fp, PRIO_LABEL "%u\n", prio);
 
-		queue_save_song(fp, i, queue->Get(i));
+		queue_save_song(fp, i, queue.Get(i));
 	}
 }
 
 void
-queue_load_song(TextFile &file, const char *line, queue *queue)
+queue_load_song(TextFile &file, const char *line, queue &queue)
 {
-	if (queue->IsFull())
+	if (queue.IsFull())
 		return;
 
 	uint8_t priority = 0;
@@ -124,7 +124,7 @@ queue_load_song(TextFile &file, const char *line, queue *queue)
 		}
 	}
 
-	queue->Append(song, priority);
+	queue.Append(song, priority);
 
 	if (db != nullptr)
 		db->ReturnSong(song);
diff --git a/src/QueueSave.hxx b/src/QueueSave.hxx
index 25d7804fb..13322cc95 100644
--- a/src/QueueSave.hxx
+++ b/src/QueueSave.hxx
@@ -31,12 +31,12 @@ struct queue;
 class TextFile;
 
 void
-queue_save(FILE *fp, const struct queue *queue);
+queue_save(FILE *fp, const queue &queue);
 
 /**
  * Loads one song from the state file and appends it to the queue.
  */
 void
-queue_load_song(TextFile &file, const char *line, queue *queue);
+queue_load_song(TextFile &file, const char *line, queue &queue);
 
 #endif
diff --git a/src/Song.hxx b/src/Song.hxx
index cafa17fd8..32158aedf 100644
--- a/src/Song.hxx
+++ b/src/Song.hxx
@@ -83,6 +83,10 @@ struct Song {
 	gcc_malloc
 	static Song *LoadFile(const char *path_utf8, Directory *parent);
 
+	static Song *LoadFile(const char *path_utf8, Directory &parent) {
+		return LoadFile(path_utf8, &parent);
+	}
+
 	/**
 	 * Replaces the URI of a song object.  The given song object
 	 * is destroyed, and a newly allocated one is returned.  It
diff --git a/src/SongPrint.cxx b/src/SongPrint.cxx
index 65d27ca77..721fa1b1a 100644
--- a/src/SongPrint.cxx
+++ b/src/SongPrint.cxx
@@ -30,18 +30,18 @@
 #include <glib.h>
 
 void
-song_print_uri(Client *client, Song *song)
+song_print_uri(Client &client, const Song &song)
 {
-	if (song->IsInDatabase() && !song->parent->IsRoot()) {
+	if (song.IsInDatabase() && !song.parent->IsRoot()) {
 		client_printf(client, "%s%s/%s\n", SONG_FILE,
-			      song->parent->GetPath(), song->uri);
+			      song.parent->GetPath(), song.uri);
 	} else {
 		char *allocated;
 		const char *uri;
 
-		uri = allocated = uri_remove_auth(song->uri);
+		uri = allocated = uri_remove_auth(song.uri);
 		if (uri == NULL)
-			uri = song->uri;
+			uri = song.uri;
 
 		client_printf(client, "%s%s\n", SONG_FILE,
 			      map_to_relative_path(uri));
@@ -51,24 +51,24 @@ song_print_uri(Client *client, Song *song)
 }
 
 void
-song_print_info(Client *client, Song *song)
+song_print_info(Client &client, const Song &song)
 {
 	song_print_uri(client, song);
 
-	if (song->end_ms > 0)
+	if (song.end_ms > 0)
 		client_printf(client, "Range: %u.%03u-%u.%03u\n",
-			      song->start_ms / 1000,
-			      song->start_ms % 1000,
-			      song->end_ms / 1000,
-			      song->end_ms % 1000);
-	else if (song->start_ms > 0)
+			      song.start_ms / 1000,
+			      song.start_ms % 1000,
+			      song.end_ms / 1000,
+			      song.end_ms % 1000);
+	else if (song.start_ms > 0)
 		client_printf(client, "Range: %u.%03u-\n",
-			      song->start_ms / 1000,
-			      song->start_ms % 1000);
+			      song.start_ms / 1000,
+			      song.start_ms % 1000);
 
-	if (song->mtime > 0)
-		time_print(client, "Last-Modified", song->mtime);
+	if (song.mtime > 0)
+		time_print(client, "Last-Modified", song.mtime);
 
-	if (song->tag != nullptr)
-		tag_print(client, *song->tag);
+	if (song.tag != nullptr)
+		tag_print(client, *song.tag);
 }
diff --git a/src/SongPrint.hxx b/src/SongPrint.hxx
index a82b54cfe..f8df89d38 100644
--- a/src/SongPrint.hxx
+++ b/src/SongPrint.hxx
@@ -24,9 +24,9 @@ struct Song;
 class Client;
 
 void
-song_print_info(Client *client, Song *song);
+song_print_info(Client &client, const Song &song);
 
 void
-song_print_uri(Client *client, Song *song);
+song_print_uri(Client &client, const Song &song);
 
 #endif
diff --git a/src/SongSave.cxx b/src/SongSave.cxx
index def4ef341..d5b00e270 100644
--- a/src/SongSave.cxx
+++ b/src/SongSave.cxx
@@ -37,19 +37,19 @@
 static constexpr Domain song_save_domain("song_save");
 
 void
-song_save(FILE *fp, const Song *song)
+song_save(FILE *fp, const Song &song)
 {
-	fprintf(fp, SONG_BEGIN "%s\n", song->uri);
+	fprintf(fp, SONG_BEGIN "%s\n", song.uri);
 
-	if (song->end_ms > 0)
-		fprintf(fp, "Range: %u-%u\n", song->start_ms, song->end_ms);
-	else if (song->start_ms > 0)
-		fprintf(fp, "Range: %u-\n", song->start_ms);
+	if (song.end_ms > 0)
+		fprintf(fp, "Range: %u-%u\n", song.start_ms, song.end_ms);
+	else if (song.start_ms > 0)
+		fprintf(fp, "Range: %u-\n", song.start_ms);
 
-	if (song->tag != nullptr)
-		tag_save(fp, *song->tag);
+	if (song.tag != nullptr)
+		tag_save(fp, *song.tag);
 
-	fprintf(fp, SONG_MTIME ": %li\n", (long)song->mtime);
+	fprintf(fp, SONG_MTIME ": %li\n", (long)song.mtime);
 	fprintf(fp, SONG_END "\n");
 }
 
diff --git a/src/SongSave.hxx b/src/SongSave.hxx
index f18aa9660..40fb4abf7 100644
--- a/src/SongSave.hxx
+++ b/src/SongSave.hxx
@@ -30,7 +30,7 @@ class TextFile;
 class Error;
 
 void
-song_save(FILE *fp, const Song *song);
+song_save(FILE *fp, const Song &song);
 
 /**
  * Loads a song from the input file.  Reading stops after the
diff --git a/src/SongSticker.cxx b/src/SongSticker.cxx
index 47ddc85b0..a0c4d3585 100644
--- a/src/SongSticker.cxx
+++ b/src/SongSticker.cxx
@@ -84,7 +84,7 @@ struct sticker_song_find_data {
 	const char *base_uri;
 	size_t base_uri_length;
 
-	void (*func)(Song *song, const char *value,
+	void (*func)(Song &song, const char *value,
 		     void *user_data);
 	void *user_data;
 };
@@ -101,22 +101,22 @@ sticker_song_find_cb(const char *uri, const char *value, void *user_data)
 
 	Song *song = data->directory->LookupSong(uri + data->base_uri_length);
 	if (song != nullptr)
-		data->func(song, value, data->user_data);
+		data->func(*song, value, data->user_data);
 }
 
 bool
-sticker_song_find(Directory *directory, const char *name,
-		  void (*func)(Song *song, const char *value,
+sticker_song_find(Directory &directory, const char *name,
+		  void (*func)(Song &song, const char *value,
 			       void *user_data),
 		  void *user_data)
 {
 	struct sticker_song_find_data data;
-	data.directory = directory;
+	data.directory = &directory;
 	data.func = func;
 	data.user_data = user_data;
 
 	char *allocated;
-	data.base_uri = directory->GetPath();
+	data.base_uri = directory.GetPath();
 	if (*data.base_uri != 0)
 		/* append slash to base_uri */
 		data.base_uri = allocated =
diff --git a/src/SongSticker.hxx b/src/SongSticker.hxx
index f3b818de4..0923f0c3a 100644
--- a/src/SongSticker.hxx
+++ b/src/SongSticker.hxx
@@ -78,8 +78,8 @@ sticker_song_get(const Song *song);
  * failure
  */
 bool
-sticker_song_find(Directory *directory, const char *name,
-		  void (*func)(Song *song, const char *value,
+sticker_song_find(Directory &directory, const char *name,
+		  void (*func)(Song &song, const char *value,
 			       void *user_data),
 		  void *user_data);
 
diff --git a/src/SongUpdate.cxx b/src/SongUpdate.cxx
index 8d8a2d686..092f5112d 100644
--- a/src/SongUpdate.cxx
+++ b/src/SongUpdate.cxx
@@ -99,7 +99,7 @@ Song::UpdateFile()
 	if (plugin == nullptr)
 		return false;
 
-	const auto path_fs = map_song_fs(this);
+	const auto path_fs = map_song_fs(*this);
 	if (path_fs.IsNull())
 		return false;
 
@@ -119,7 +119,7 @@ Song::UpdateFile()
 
 	do {
 		/* load file tag */
-		if (decoder_plugin_scan_file(plugin, path_fs.c_str(),
+		if (decoder_plugin_scan_file(*plugin, path_fs.c_str(),
 					     &full_tag_handler, &tag_builder))
 			break;
 
@@ -136,7 +136,7 @@ Song::UpdateFile()
 
 			/* now try the stream_tag() method */
 			if (is != nullptr) {
-				if (decoder_plugin_scan_stream(plugin, is,
+				if (decoder_plugin_scan_stream(*plugin, is,
 							       &full_tag_handler,
 							       &tag_builder))
 					break;
diff --git a/src/StateFile.cxx b/src/StateFile.cxx
index 7a427a6a9..75cef2c99 100644
--- a/src/StateFile.cxx
+++ b/src/StateFile.cxx
@@ -48,8 +48,8 @@ StateFile::RememberVersions()
 {
 	prev_volume_version = sw_volume_state_get_hash();
 	prev_output_version = audio_output_state_get_version();
-	prev_playlist_version = playlist_state_get_hash(&partition.playlist,
-							&partition.pc);
+	prev_playlist_version = playlist_state_get_hash(partition.playlist,
+							partition.pc);
 }
 
 bool
@@ -57,8 +57,8 @@ StateFile::IsModified() const
 {
 	return prev_volume_version != sw_volume_state_get_hash() ||
 		prev_output_version != audio_output_state_get_version() ||
-		prev_playlist_version != playlist_state_get_hash(&partition.playlist,
-								 &partition.pc);
+		prev_playlist_version != playlist_state_get_hash(partition.playlist,
+								 partition.pc);
 }
 
 void
@@ -76,7 +76,7 @@ StateFile::Write()
 
 	save_sw_volume_state(fp);
 	audio_output_state_save(fp);
-	playlist_state_save(fp, &partition.playlist, &partition.pc);
+	playlist_state_save(fp, partition.playlist, partition.pc);
 
 	fclose(fp);
 
@@ -101,8 +101,8 @@ StateFile::Read()
 	while ((line = file.ReadLine()) != NULL) {
 		success = read_sw_volume_state(line) ||
 			audio_output_state_read(line) ||
-			playlist_state_restore(line, file, &partition.playlist,
-					       &partition.pc);
+			playlist_state_restore(line, file, partition.playlist,
+					       partition.pc);
 		if (!success)
 			FormatError(state_file_domain,
 				    "Unrecognized line in state file: %s",
diff --git a/src/Stats.cxx b/src/Stats.cxx
index 463937b48..4c488e85e 100644
--- a/src/Stats.cxx
+++ b/src/Stats.cxx
@@ -65,7 +65,7 @@ void stats_update(void)
 }
 
 void
-stats_print(Client *client)
+stats_print(Client &client)
 {
 	client_printf(client,
 		      "artists: %u\n"
@@ -78,7 +78,7 @@ stats_print(Client *client)
 		      stats.album_count,
 		      stats.song_count,
 		      (long)g_timer_elapsed(stats.timer, NULL),
-		      (long)(client->player_control->GetTotalPlayTime() + 0.5),
+		      (long)(client.player_control.GetTotalPlayTime() + 0.5),
 		      stats.song_duration);
 
 	if (db_is_simple())
diff --git a/src/Stats.hxx b/src/Stats.hxx
index 1827b8847..1b141355c 100644
--- a/src/Stats.hxx
+++ b/src/Stats.hxx
@@ -49,6 +49,6 @@ void stats_global_finish(void);
 void stats_update(void);
 
 void
-stats_print(Client *client);
+stats_print(Client &client);
 
 #endif
diff --git a/src/StickerCommands.cxx b/src/StickerCommands.cxx
index 3a212a48b..6688c0820 100644
--- a/src/StickerCommands.cxx
+++ b/src/StickerCommands.cxx
@@ -36,12 +36,12 @@
 #include <string.h>
 
 struct sticker_song_find_data {
-	Client *client;
+	Client &client;
 	const char *name;
 };
 
 static void
-sticker_song_find_print_cb(Song *song, const char *value,
+sticker_song_find_print_cb(Song &song, const char *value,
 			   void *user_data)
 {
 	struct sticker_song_find_data *data =
@@ -52,7 +52,7 @@ sticker_song_find_print_cb(Song *song, const char *value,
 }
 
 static enum command_return
-handle_sticker_song(Client *client, int argc, char *argv[])
+handle_sticker_song(Client &client, int argc, char *argv[])
 {
 	Error error;
 	const Database *db = GetDatabase(error);
@@ -85,7 +85,7 @@ handle_sticker_song(Client *client, int argc, char *argv[])
 		sticker *sticker = sticker_song_get(song);
 		db->ReturnSong(song);
 		if (sticker) {
-			sticker_print(client, sticker);
+			sticker_print(client, *sticker);
 			sticker_free(sticker);
 		}
 
@@ -141,7 +141,7 @@ handle_sticker_song(Client *client, int argc, char *argv[])
 			return COMMAND_RETURN_ERROR;
 		}
 
-		success = sticker_song_find(directory, data.name,
+		success = sticker_song_find(*directory, data.name,
 					    sticker_song_find_print_cb, &data);
 		db_unlock();
 		if (!success) {
@@ -158,7 +158,7 @@ handle_sticker_song(Client *client, int argc, char *argv[])
 }
 
 enum command_return
-handle_sticker(Client *client, int argc, char *argv[])
+handle_sticker(Client &client, int argc, char *argv[])
 {
 	assert(argc >= 4);
 
diff --git a/src/StickerCommands.hxx b/src/StickerCommands.hxx
index 840bd33d5..0aaa74de0 100644
--- a/src/StickerCommands.hxx
+++ b/src/StickerCommands.hxx
@@ -25,6 +25,6 @@
 class Client;
 
 enum command_return
-handle_sticker(Client *client, int argc, char *argv[]);
+handle_sticker(Client &client, int argc, char *argv[]);
 
 #endif
diff --git a/src/StickerDatabase.cxx b/src/StickerDatabase.cxx
index ca72a6024..869b91474 100644
--- a/src/StickerDatabase.cxx
+++ b/src/StickerDatabase.cxx
@@ -507,22 +507,22 @@ sticker_free(struct sticker *sticker)
 }
 
 const char *
-sticker_get_value(const struct sticker *sticker, const char *name)
+sticker_get_value(const struct sticker &sticker, const char *name)
 {
-	auto i = sticker->table.find(name);
-	if (i == sticker->table.end())
+	auto i = sticker.table.find(name);
+	if (i == sticker.table.end())
 		return nullptr;
 
 	return i->second.c_str();
 }
 
 void
-sticker_foreach(const struct sticker *sticker,
+sticker_foreach(const sticker &sticker,
 		void (*func)(const char *name, const char *value,
 			     void *user_data),
 		void *user_data)
 {
-	for (const auto &i : sticker->table)
+	for (const auto &i : sticker.table)
 		func(i.first.c_str(), i.second.c_str(), user_data);
 }
 
diff --git a/src/StickerDatabase.hxx b/src/StickerDatabase.hxx
index 5b50c6e6f..42522b7b4 100644
--- a/src/StickerDatabase.hxx
+++ b/src/StickerDatabase.hxx
@@ -117,7 +117,7 @@ sticker_free(struct sticker *sticker);
  */
 gcc_pure
 const char *
-sticker_get_value(const struct sticker *sticker, const char *name);
+sticker_get_value(const struct sticker &sticker, const char *name);
 
 /**
  * Iterates over all sticker items in a sticker.
@@ -127,7 +127,7 @@ sticker_get_value(const struct sticker *sticker, const char *name);
  * @param user_data an opaque pointer for the callback function
  */
 void
-sticker_foreach(const struct sticker *sticker,
+sticker_foreach(const struct sticker &sticker,
 		void (*func)(const char *name, const char *value,
 			     void *user_data),
 		void *user_data);
diff --git a/src/StickerPrint.cxx b/src/StickerPrint.cxx
index 1708ee4f0..364d41356 100644
--- a/src/StickerPrint.cxx
+++ b/src/StickerPrint.cxx
@@ -23,7 +23,7 @@
 #include "Client.hxx"
 
 void
-sticker_print_value(Client *client,
+sticker_print_value(Client &client,
 		    const char *name, const char *value)
 {
 	client_printf(client, "sticker: %s=%s\n", name, value);
@@ -32,13 +32,13 @@ sticker_print_value(Client *client,
 static void
 print_sticker_cb(const char *name, const char *value, void *data)
 {
-	Client *client = (Client *)data;
+	Client &client = *(Client *)data;
 
 	sticker_print_value(client, name, value);
 }
 
 void
-sticker_print(Client *client, const struct sticker *sticker)
+sticker_print(Client &client, const sticker &sticker)
 {
-	sticker_foreach(sticker, print_sticker_cb, client);
+	sticker_foreach(sticker, print_sticker_cb, &client);
 }
diff --git a/src/StickerPrint.hxx b/src/StickerPrint.hxx
index 27225a494..be6708486 100644
--- a/src/StickerPrint.hxx
+++ b/src/StickerPrint.hxx
@@ -27,12 +27,12 @@ class Client;
  * Sends one sticker value to the client.
  */
 void
-sticker_print_value(Client *client, const char *name, const char *value);
+sticker_print_value(Client &client, const char *name, const char *value);
 
 /**
  * Sends all sticker values to the client.
  */
 void
-sticker_print(Client *client, const struct sticker *sticker);
+sticker_print(Client &client, const sticker &sticker);
 
 #endif
diff --git a/src/TagFile.cxx b/src/TagFile.cxx
index 70a38196c..60ed4a117 100644
--- a/src/TagFile.cxx
+++ b/src/TagFile.cxx
@@ -53,7 +53,7 @@ tag_file_scan(const char *path_fs,
 
 	do {
 		/* load file tag */
-		if (decoder_plugin_scan_file(plugin, path_fs,
+		if (decoder_plugin_scan_file(*plugin, path_fs,
 					     handler, handler_ctx))
 			break;
 
@@ -69,7 +69,7 @@ tag_file_scan(const char *path_fs,
 
 			/* now try the stream_tag() method */
 			if (is != nullptr) {
-				if (decoder_plugin_scan_stream(plugin, is,
+				if (decoder_plugin_scan_stream(*plugin, is,
 							       handler,
 							       handler_ctx))
 					break;
diff --git a/src/TagPrint.cxx b/src/TagPrint.cxx
index e3c2c8c9e..1191bd37c 100644
--- a/src/TagPrint.cxx
+++ b/src/TagPrint.cxx
@@ -24,7 +24,7 @@
 #include "Song.hxx"
 #include "Client.hxx"
 
-void tag_print_types(Client *client)
+void tag_print_types(Client &client)
 {
 	int i;
 
@@ -35,7 +35,7 @@ void tag_print_types(Client *client)
 	}
 }
 
-void tag_print(Client *client, const Tag &tag)
+void tag_print(Client &client, const Tag &tag)
 {
 	if (tag.time >= 0)
 		client_printf(client, SONG_TIME "%i\n", tag.time);
diff --git a/src/TagPrint.hxx b/src/TagPrint.hxx
index 48bfc72cc..ccc0c9aa4 100644
--- a/src/TagPrint.hxx
+++ b/src/TagPrint.hxx
@@ -23,9 +23,9 @@
 struct Tag;
 class Client;
 
-void tag_print_types(Client *client);
+void tag_print_types(Client &client);
 
 void
-tag_print(Client *client, const Tag &tag);
+tag_print(Client &client, const Tag &tag);
 
 #endif
diff --git a/src/TimePrint.cxx b/src/TimePrint.cxx
index 6dd4061e6..ee165d8e9 100644
--- a/src/TimePrint.cxx
+++ b/src/TimePrint.cxx
@@ -22,7 +22,7 @@
 #include "Client.hxx"
 
 void
-time_print(Client *client, const char *name, time_t t)
+time_print(Client &client, const char *name, time_t t)
 {
 #ifdef WIN32
 	const struct tm *tm2 = gmtime(&t);
diff --git a/src/TimePrint.hxx b/src/TimePrint.hxx
index f45101256..55e235b66 100644
--- a/src/TimePrint.hxx
+++ b/src/TimePrint.hxx
@@ -28,6 +28,6 @@ class Client;
  * Write a line with a time stamp to the client.
  */
 void
-time_print(Client *client, const char *name, time_t t);
+time_print(Client &client, const char *name, time_t t);
 
 #endif
diff --git a/src/UpdateArchive.cxx b/src/UpdateArchive.cxx
index f3f4cd65e..8e1936bb4 100644
--- a/src/UpdateArchive.cxx
+++ b/src/UpdateArchive.cxx
@@ -38,7 +38,7 @@
 #include <string.h>
 
 static void
-update_archive_tree(Directory *directory, const char *name)
+update_archive_tree(Directory &directory, const char *name)
 {
 	const char *tmp = strchr(name, '/');
 	if (tmp) {
@@ -46,12 +46,12 @@ update_archive_tree(Directory *directory, const char *name)
 		//add dir is not there already
 		db_lock();
 		Directory *subdir =
-			directory->MakeChild(child_name.c_str());
+			directory.MakeChild(child_name.c_str());
 		subdir->device = DEVICE_INARCHIVE;
 		db_unlock();
 
 		//create directories first
-		update_archive_tree(subdir, tmp+1);
+		update_archive_tree(*subdir, tmp+1);
 	} else {
 		if (strlen(name) == 0) {
 			LogWarning(update_domain,
@@ -61,18 +61,18 @@ update_archive_tree(Directory *directory, const char *name)
 
 		//add file
 		db_lock();
-		Song *song = directory->FindSong(name);
+		Song *song = directory.FindSong(name);
 		db_unlock();
 		if (song == nullptr) {
 			song = Song::LoadFile(name, directory);
 			if (song != nullptr) {
 				db_lock();
-				directory->AddSong(song);
+				directory.AddSong(song);
 				db_unlock();
 
 				modified = true;
 				FormatInfo(update_domain, "added %s/%s",
-					   directory->GetPath(), name);
+					   directory.GetPath(), name);
 			}
 		}
 	}
@@ -87,12 +87,12 @@ update_archive_tree(Directory *directory, const char *name)
  * @param plugin the archive plugin which fits this archive type
  */
 static void
-update_archive_file2(Directory *parent, const char *name,
+update_archive_file2(Directory &parent, const char *name,
 		     const struct stat *st,
 		     const struct archive_plugin *plugin)
 {
 	db_lock();
-	Directory *directory = parent->FindChild(name);
+	Directory *directory = parent.FindChild(name);
 	db_unlock();
 
 	if (directory != nullptr && directory->mtime == st->st_mtime &&
@@ -117,7 +117,7 @@ update_archive_file2(Directory *parent, const char *name,
 		FormatDebug(update_domain,
 			    "creating archive directory: %s", name);
 		db_lock();
-		directory = parent->CreateChild(name);
+		directory = parent.CreateChild(name);
 		/* mark this directory as archive (we use device for
 		   this) */
 		directory->device = DEVICE_INARCHIVE;
@@ -136,7 +136,7 @@ update_archive_file2(Directory *parent, const char *name,
 		virtual void VisitArchiveEntry(const char *path_utf8) override {
 			FormatDebug(update_domain,
 				    "adding archive file: %s", path_utf8);
-			update_archive_tree(directory, path_utf8);
+			update_archive_tree(*directory, path_utf8);
 		}
 	};
 
@@ -146,7 +146,7 @@ update_archive_file2(Directory *parent, const char *name,
 }
 
 bool
-update_archive_file(Directory *directory,
+update_archive_file(Directory &directory,
 		    const char *name, const char *suffix,
 		    const struct stat *st)
 {
diff --git a/src/UpdateArchive.hxx b/src/UpdateArchive.hxx
index 8e9c4f8cb..8f52ca0b6 100644
--- a/src/UpdateArchive.hxx
+++ b/src/UpdateArchive.hxx
@@ -31,14 +31,14 @@ struct archive_plugin;
 #ifdef ENABLE_ARCHIVE
 
 bool
-update_archive_file(Directory *directory,
+update_archive_file(Directory &directory,
 		    const char *name, const char *suffix,
 		    const struct stat *st);
 
 #else
 
 static inline bool
-update_archive_file(gcc_unused Directory *directory,
+update_archive_file(gcc_unused Directory &directory,
 		    gcc_unused const char *name,
 		    gcc_unused const char *suffix,
 		    gcc_unused const struct stat *st)
diff --git a/src/UpdateContainer.cxx b/src/UpdateContainer.cxx
index 6e0cadfb7..87cc50268 100644
--- a/src/UpdateContainer.cxx
+++ b/src/UpdateContainer.cxx
@@ -43,10 +43,10 @@
  * The caller must lock the database.
  */
 static Directory *
-make_directory_if_modified(Directory *parent, const char *name,
+make_directory_if_modified(Directory &parent, const char *name,
 			   const struct stat *st)
 {
-	Directory *directory = parent->FindChild(name);
+	Directory *directory = parent.FindChild(name);
 
 	// directory exists already
 	if (directory != nullptr) {
@@ -59,18 +59,18 @@ make_directory_if_modified(Directory *parent, const char *name,
 		modified = true;
 	}
 
-	directory = parent->MakeChild(name);
+	directory = parent.MakeChild(name);
 	directory->mtime = st->st_mtime;
 	return directory;
 }
 
 bool
-update_container_file(Directory *directory,
+update_container_file(Directory &directory,
 		      const char *name,
 		      const struct stat *st,
-		      const struct decoder_plugin *plugin)
+		      const decoder_plugin &plugin)
 {
-	if (plugin->container_scan == nullptr)
+	if (plugin.container_scan == nullptr)
 		return false;
 
 	db_lock();
@@ -89,14 +89,14 @@ update_container_file(Directory *directory,
 	char *vtrack;
 	unsigned int tnum = 0;
 	TagBuilder tag_builder;
-	while ((vtrack = plugin->container_scan(pathname.c_str(), ++tnum)) != nullptr) {
+	while ((vtrack = plugin.container_scan(pathname.c_str(), ++tnum)) != nullptr) {
 		Song *song = Song::NewFile(vtrack, contdir);
 
 		// shouldn't be necessary but it's there..
 		song->mtime = st->st_mtime;
 
 		const auto child_path_fs =
-			map_directory_child_fs(contdir, vtrack);
+			map_directory_child_fs(*contdir, vtrack);
 
 		decoder_plugin_scan_file(plugin, child_path_fs.c_str(),
 					 &add_tag_handler, &tag_builder);
@@ -113,7 +113,7 @@ update_container_file(Directory *directory,
 		modified = true;
 
 		FormatInfo(update_domain, "added %s/%s",
-			   directory->GetPath(), vtrack);
+			   directory.GetPath(), vtrack);
 		g_free(vtrack);
 	}
 
diff --git a/src/UpdateContainer.hxx b/src/UpdateContainer.hxx
index 0078730d6..dc4ea77b0 100644
--- a/src/UpdateContainer.hxx
+++ b/src/UpdateContainer.hxx
@@ -28,9 +28,9 @@ struct Directory;
 struct decoder_plugin;
 
 bool
-update_container_file(Directory *directory,
+update_container_file(Directory &directory,
 		      const char *name,
 		      const struct stat *st,
-		      const struct decoder_plugin *plugin);
+		      const decoder_plugin &plugin);
 
 #endif
diff --git a/src/UpdateDatabase.cxx b/src/UpdateDatabase.cxx
index 684976d68..2550f288a 100644
--- a/src/UpdateDatabase.cxx
+++ b/src/UpdateDatabase.cxx
@@ -29,12 +29,12 @@
 #include <stddef.h>
 
 void
-delete_song(Directory *dir, Song *del)
+delete_song(Directory &dir, Song *del)
 {
-	assert(del->parent == dir);
+	assert(del->parent == &dir);
 
 	/* first, prevent traversers in main task from getting this */
-	dir->RemoveSong(del);
+	dir.RemoveSong(del);
 
 	db_unlock(); /* temporary unlock, because update_remove_song() blocks */
 
@@ -54,7 +54,7 @@ delete_song(Directory *dir, Song *del)
  * Caller must lock the #db_mutex.
  */
 static void
-clear_directory(Directory *directory)
+clear_directory(Directory &directory)
 {
 	Directory *child, *n;
 	directory_for_each_child_safe(child, n, directory)
@@ -62,7 +62,7 @@ clear_directory(Directory *directory)
 
 	Song *song, *ns;
 	directory_for_each_song_safe(song, ns, directory) {
-		assert(song->parent == directory);
+		assert(song->parent == &directory);
 		delete_song(directory, song);
 	}
 }
@@ -72,31 +72,31 @@ delete_directory(Directory *directory)
 {
 	assert(directory->parent != nullptr);
 
-	clear_directory(directory);
+	clear_directory(*directory);
 
 	directory->Delete();
 }
 
 bool
-delete_name_in(Directory *parent, const char *name)
+delete_name_in(Directory &parent, const char *name)
 {
 	bool modified = false;
 
 	db_lock();
-	Directory *directory = parent->FindChild(name);
+	Directory *directory = parent.FindChild(name);
 
 	if (directory != nullptr) {
 		delete_directory(directory);
 		modified = true;
 	}
 
-	Song *song = parent->FindSong(name);
+	Song *song = parent.FindSong(name);
 	if (song != nullptr) {
 		delete_song(parent, song);
 		modified = true;
 	}
 
-	parent->playlists.erase(name);
+	parent.playlists.erase(name);
 
 	db_unlock();
 
diff --git a/src/UpdateDatabase.hxx b/src/UpdateDatabase.hxx
index ab8f7ec26..0462dc778 100644
--- a/src/UpdateDatabase.hxx
+++ b/src/UpdateDatabase.hxx
@@ -29,7 +29,7 @@ struct Song;
  * Caller must lock the #db_mutex.
  */
 void
-delete_song(Directory *parent, Song *song);
+delete_song(Directory &parent, Song *song);
 
 /**
  * Recursively free a directory and all its contents.
@@ -45,6 +45,6 @@ delete_directory(Directory *directory);
  * @return true if the database was modified
  */
 bool
-delete_name_in(Directory *parent, const char *name);
+delete_name_in(Directory &parent, const char *name);
 
 #endif
diff --git a/src/UpdateIO.cxx b/src/UpdateIO.cxx
index 14c25249f..1c3b7cc52 100644
--- a/src/UpdateIO.cxx
+++ b/src/UpdateIO.cxx
@@ -30,7 +30,7 @@
 #include <unistd.h>
 
 int
-stat_directory(const Directory *directory, struct stat *st)
+stat_directory(const Directory &directory, struct stat *st)
 {
 	const auto path_fs = map_directory_fs(directory);
 	if (path_fs.IsNull())
@@ -48,7 +48,7 @@ stat_directory(const Directory *directory, struct stat *st)
 }
 
 int
-stat_directory_child(const Directory *parent, const char *name,
+stat_directory_child(const Directory &parent, const char *name,
 		     struct stat *st)
 {
 	const auto path_fs = map_directory_child_fs(parent, name);
@@ -67,21 +67,21 @@ stat_directory_child(const Directory *parent, const char *name,
 }
 
 bool
-directory_exists(const Directory *directory)
+directory_exists(const Directory &directory)
 {
 	const auto path_fs = map_directory_fs(directory);
 	if (path_fs.IsNull())
 		/* invalid path: cannot exist */
 		return false;
 
-	return directory->device == DEVICE_INARCHIVE ||
-		directory->device == DEVICE_CONTAINER
+	return directory.device == DEVICE_INARCHIVE ||
+		directory.device == DEVICE_CONTAINER
 		? FileExists(path_fs)
 		: DirectoryExists(path_fs);
 }
 
 bool
-directory_child_is_regular(const Directory *directory,
+directory_child_is_regular(const Directory &directory,
 			   const char *name_utf8)
 {
 	const auto path_fs = map_directory_child_fs(directory, name_utf8);
@@ -92,7 +92,7 @@ directory_child_is_regular(const Directory *directory,
 }
 
 bool
-directory_child_access(const Directory *directory,
+directory_child_access(const Directory &directory,
 		       const char *name, int mode)
 {
 #ifdef WIN32
diff --git a/src/UpdateIO.hxx b/src/UpdateIO.hxx
index ee47b2682..9d6c197f2 100644
--- a/src/UpdateIO.hxx
+++ b/src/UpdateIO.hxx
@@ -27,24 +27,24 @@
 struct Directory;
 
 int
-stat_directory(const Directory *directory, struct stat *st);
+stat_directory(const Directory &directory, struct stat *st);
 
 int
-stat_directory_child(const Directory *parent, const char *name,
+stat_directory_child(const Directory &parent, const char *name,
 		     struct stat *st);
 
 bool
-directory_exists(const Directory *directory);
+directory_exists(const Directory &directory);
 
 bool
-directory_child_is_regular(const Directory *directory,
+directory_child_is_regular(const Directory &directory,
 			   const char *name_utf8);
 
 /**
  * Checks if the given permissions on the mapped file are given.
  */
 bool
-directory_child_access(const Directory *directory,
+directory_child_access(const Directory &directory,
 		       const char *name, int mode);
 
 #endif
diff --git a/src/UpdateSong.cxx b/src/UpdateSong.cxx
index d8aa80088..084c57721 100644
--- a/src/UpdateSong.cxx
+++ b/src/UpdateSong.cxx
@@ -34,18 +34,18 @@
 #include <unistd.h>
 
 static void
-update_song_file2(Directory *directory,
+update_song_file2(Directory &directory,
 		  const char *name, const struct stat *st,
-		  const struct decoder_plugin *plugin)
+		  const decoder_plugin &plugin)
 {
 	db_lock();
-	Song *song = directory->FindSong(name);
+	Song *song = directory.FindSong(name);
 	db_unlock();
 
 	if (!directory_child_access(directory, name, R_OK)) {
 		FormatError(update_domain,
 			    "no read permissions on %s/%s",
-			    directory->GetPath(), name);
+			    directory.GetPath(), name);
 		if (song != nullptr) {
 			db_lock();
 			delete_song(directory, song);
@@ -69,29 +69,29 @@ update_song_file2(Directory *directory,
 
 	if (song == nullptr) {
 		FormatDebug(update_domain, "reading %s/%s",
-			    directory->GetPath(), name);
-		song = Song::LoadFile(name, directory);
+			    directory.GetPath(), name);
+		song = Song::LoadFile(name, &directory);
 		if (song == nullptr) {
 			FormatDebug(update_domain,
 				    "ignoring unrecognized file %s/%s",
-				    directory->GetPath(), name);
+				    directory.GetPath(), name);
 			return;
 		}
 
 		db_lock();
-		directory->AddSong(song);
+		directory.AddSong(song);
 		db_unlock();
 
 		modified = true;
 		FormatInfo(update_domain, "added %s/%s",
-			   directory->GetPath(), name);
+			   directory.GetPath(), name);
 	} else if (st->st_mtime != song->mtime || walk_discard) {
 		FormatInfo(update_domain, "updating %s/%s",
-			   directory->GetPath(), name);
+			   directory.GetPath(), name);
 		if (!song->UpdateFile()) {
 			FormatDebug(update_domain,
 				    "deleting unrecognized file %s/%s",
-				    directory->GetPath(), name);
+				    directory.GetPath(), name);
 			db_lock();
 			delete_song(directory, song);
 			db_unlock();
@@ -102,7 +102,7 @@ update_song_file2(Directory *directory,
 }
 
 bool
-update_song_file(Directory *directory,
+update_song_file(Directory &directory,
 		 const char *name, const char *suffix,
 		 const struct stat *st)
 {
@@ -111,6 +111,6 @@ update_song_file(Directory *directory,
 	if (plugin == nullptr)
 		return false;
 
-	update_song_file2(directory, name, st, plugin);
+	update_song_file2(directory, name, st, *plugin);
 	return true;
 }
diff --git a/src/UpdateSong.hxx b/src/UpdateSong.hxx
index 60a532e3a..00a7bfd27 100644
--- a/src/UpdateSong.hxx
+++ b/src/UpdateSong.hxx
@@ -27,7 +27,7 @@
 struct Directory;
 
 bool
-update_song_file(Directory *directory,
+update_song_file(Directory &directory,
 		 const char *name, const char *suffix,
 		 const struct stat *st);
 
diff --git a/src/UpdateWalk.cxx b/src/UpdateWalk.cxx
index acd58f9be..a156cf3e9 100644
--- a/src/UpdateWalk.cxx
+++ b/src/UpdateWalk.cxx
@@ -87,15 +87,15 @@ update_walk_global_finish(void)
 }
 
 static void
-directory_set_stat(Directory *dir, const struct stat *st)
+directory_set_stat(Directory &dir, const struct stat *st)
 {
-	dir->inode = st->st_ino;
-	dir->device = st->st_dev;
-	dir->have_stat = true;
+	dir.inode = st->st_ino;
+	dir.device = st->st_dev;
+	dir.have_stat = true;
 }
 
 static void
-remove_excluded_from_directory(Directory *directory,
+remove_excluded_from_directory(Directory &directory,
 			       const ExcludeList &exclude_list)
 {
 	db_lock();
@@ -112,7 +112,7 @@ remove_excluded_from_directory(Directory *directory,
 
 	Song *song, *ns;
 	directory_for_each_song_safe(song, ns, directory) {
-		assert(song->parent == directory);
+		assert(song->parent == &directory);
 
 		const auto name_fs = AllocatedPath::FromUTF8(song->uri);
 		if (name_fs.IsNull() || exclude_list.Check(name_fs)) {
@@ -125,11 +125,11 @@ remove_excluded_from_directory(Directory *directory,
 }
 
 static void
-purge_deleted_from_directory(Directory *directory)
+purge_deleted_from_directory(Directory &directory)
 {
 	Directory *child, *n;
 	directory_for_each_child_safe(child, n, directory) {
-		if (directory_exists(child))
+		if (directory_exists(*child))
 			continue;
 
 		db_lock();
@@ -141,7 +141,7 @@ purge_deleted_from_directory(Directory *directory)
 
 	Song *song, *ns;
 	directory_for_each_song_safe(song, ns, directory) {
-		const auto path = map_song_fs(song);
+		const auto path = map_song_fs(*song);
 		if (path.IsNull() || !FileExists(path)) {
 			db_lock();
 			delete_song(directory, song);
@@ -151,12 +151,12 @@ purge_deleted_from_directory(Directory *directory)
 		}
 	}
 
-	for (auto i = directory->playlists.begin(),
-		     end = directory->playlists.end();
+	for (auto i = directory.playlists.begin(),
+		     end = directory.playlists.end();
 	     i != end;) {
 		if (!directory_child_is_regular(directory, i->name.c_str())) {
 			db_lock();
-			i = directory->playlists.erase(i);
+			i = directory.playlists.erase(i);
 			db_unlock();
 		} else
 			++i;
@@ -165,7 +165,7 @@ purge_deleted_from_directory(Directory *directory)
 
 #ifndef WIN32
 static int
-update_directory_stat(Directory *directory)
+update_directory_stat(Directory &directory)
 {
 	struct stat st;
 	if (stat_directory(directory, &st) < 0)
@@ -181,7 +181,7 @@ find_inode_ancestor(Directory *parent, ino_t inode, dev_t device)
 {
 #ifndef WIN32
 	while (parent) {
-		if (!parent->have_stat && update_directory_stat(parent) < 0)
+		if (!parent->have_stat && update_directory_stat(*parent) < 0)
 			return -1;
 
 		if (parent->inode == inode && parent->device == device) {
@@ -201,7 +201,7 @@ find_inode_ancestor(Directory *parent, ino_t inode, dev_t device)
 }
 
 static bool
-update_playlist_file2(Directory *directory,
+update_playlist_file2(Directory &directory,
 		      const char *name, const char *suffix,
 		      const struct stat *st)
 {
@@ -211,14 +211,14 @@ update_playlist_file2(Directory *directory,
 	PlaylistInfo pi(name, st->st_mtime);
 
 	db_lock();
-	if (directory->playlists.UpdateOrInsert(std::move(pi)))
+	if (directory.playlists.UpdateOrInsert(std::move(pi)))
 		modified = true;
 	db_unlock();
 	return true;
 }
 
 static bool
-update_regular_file(Directory *directory,
+update_regular_file(Directory &directory,
 		    const char *name, const struct stat *st)
 {
 	const char *suffix = uri_get_suffix(name);
@@ -231,10 +231,10 @@ update_regular_file(Directory *directory,
 }
 
 static bool
-update_directory(Directory *directory, const struct stat *st);
+update_directory(Directory &directory, const struct stat *st);
 
 static void
-update_directory_child(Directory *directory,
+update_directory_child(Directory &directory,
 		       const char *name, const struct stat *st)
 {
 	assert(strchr(name, '/') == nullptr);
@@ -242,16 +242,16 @@ update_directory_child(Directory *directory,
 	if (S_ISREG(st->st_mode)) {
 		update_regular_file(directory, name, st);
 	} else if (S_ISDIR(st->st_mode)) {
-		if (find_inode_ancestor(directory, st->st_ino, st->st_dev))
+		if (find_inode_ancestor(&directory, st->st_ino, st->st_dev))
 			return;
 
 		db_lock();
-		Directory *subdir = directory->MakeChild(name);
+		Directory *subdir = directory.MakeChild(name);
 		db_unlock();
 
-		assert(directory == subdir->parent);
+		assert(&directory == subdir->parent);
 
-		if (!update_directory(subdir, st)) {
+		if (!update_directory(*subdir, st)) {
 			db_lock();
 			delete_directory(subdir);
 			db_unlock();
@@ -277,7 +277,7 @@ static bool
 skip_symlink(const Directory *directory, const char *utf8_name)
 {
 #ifndef WIN32
-	const auto path_fs = map_directory_child_fs(directory, utf8_name);
+	const auto path_fs = map_directory_child_fs(*directory, utf8_name);
 	if (path_fs.IsNull())
 		return true;
 
@@ -339,7 +339,7 @@ skip_symlink(const Directory *directory, const char *utf8_name)
 }
 
 static bool
-update_directory(Directory *directory, const struct stat *st)
+update_directory(Directory &directory, const struct stat *st)
 {
 	assert(S_ISDIR(st->st_mode));
 
@@ -380,7 +380,7 @@ update_directory(Directory *directory, const struct stat *st)
 		if (utf8.empty())
 			continue;
 
-		if (skip_symlink(directory, utf8.c_str())) {
+		if (skip_symlink(&directory, utf8.c_str())) {
 			modified |= delete_name_in(directory, utf8.c_str());
 			continue;
 		}
@@ -391,16 +391,16 @@ update_directory(Directory *directory, const struct stat *st)
 			modified |= delete_name_in(directory, utf8.c_str());
 	}
 
-	directory->mtime = st->st_mtime;
+	directory.mtime = st->st_mtime;
 
 	return true;
 }
 
 static Directory *
-directory_make_child_checked(Directory *parent, const char *name_utf8)
+directory_make_child_checked(Directory &parent, const char *name_utf8)
 {
 	db_lock();
-	Directory *directory = parent->FindChild(name_utf8);
+	Directory *directory = parent.FindChild(name_utf8);
 	db_unlock();
 
 	if (directory != nullptr)
@@ -408,23 +408,23 @@ directory_make_child_checked(Directory *parent, const char *name_utf8)
 
 	struct stat st;
 	if (stat_directory_child(parent, name_utf8, &st) < 0 ||
-	    find_inode_ancestor(parent, st.st_ino, st.st_dev))
+	    find_inode_ancestor(&parent, st.st_ino, st.st_dev))
 		return nullptr;
 
-	if (skip_symlink(parent, name_utf8))
+	if (skip_symlink(&parent, name_utf8))
 		return nullptr;
 
 	/* if we're adding directory paths, make sure to delete filenames
 	   with potentially the same name */
 	db_lock();
-	Song *conflicting = parent->FindSong(name_utf8);
+	Song *conflicting = parent.FindSong(name_utf8);
 	if (conflicting)
 		delete_song(parent, conflicting);
 
-	directory = parent->CreateChild(name_utf8);
+	directory = parent.CreateChild(name_utf8);
 	db_unlock();
 
-	directory_set_stat(directory, &st);
+	directory_set_stat(*directory, &st);
 	return directory;
 }
 
@@ -441,7 +441,8 @@ directory_make_uri_parent_checked(const char *uri)
 		if (*name_utf8 == 0)
 			continue;
 
-		directory = directory_make_child_checked(directory, name_utf8);
+		directory = directory_make_child_checked(*directory,
+							 name_utf8);
 		if (directory == nullptr)
 			break;
 
@@ -463,10 +464,10 @@ update_uri(const char *uri)
 
 	struct stat st;
 	if (!skip_symlink(parent, name) &&
-	    stat_directory_child(parent, name, &st) == 0)
-		update_directory_child(parent, name, &st);
+	    stat_directory_child(*parent, name, &st) == 0)
+		update_directory_child(*parent, name, &st);
 	else
-		modified |= delete_name_in(parent, name);
+		modified |= delete_name_in(*parent, name);
 
 	g_free(name);
 }
@@ -483,8 +484,8 @@ update_walk(const char *path, bool discard)
 		Directory *directory = db_get_root();
 		struct stat st;
 
-		if (stat_directory(directory, &st) == 0)
-			update_directory(directory, &st);
+		if (stat_directory(*directory, &st) == 0)
+			update_directory(*directory, &st);
 	}
 
 	return modified;
diff --git a/src/db/SimpleDatabasePlugin.cxx b/src/db/SimpleDatabasePlugin.cxx
index 8f2571878..6f30e4b61 100644
--- a/src/db/SimpleDatabasePlugin.cxx
+++ b/src/db/SimpleDatabasePlugin.cxx
@@ -145,7 +145,7 @@ SimpleDatabase::Load(Error &error)
 		return false;
 	}
 
-	if (!db_load_internal(file, root, error))
+	if (!db_load_internal(file, *root, error))
 		return false;
 
 	struct stat st;
@@ -300,7 +300,7 @@ SimpleDatabase::Save(Error &error)
 		return false;
 	}
 
-	db_save_internal(fp, root);
+	db_save_internal(fp, *root);
 
 	if (ferror(fp)) {
 		error.SetErrno("Failed to write to database file");
diff --git a/src/ls.cxx b/src/ls.cxx
index 06237641e..b1a636416 100644
--- a/src/ls.cxx
+++ b/src/ls.cxx
@@ -75,7 +75,7 @@ void print_supported_uri_schemes_to_fp(FILE *fp)
 	fprintf(fp,"\n");
 }
 
-void print_supported_uri_schemes(Client *client)
+void print_supported_uri_schemes(Client &client)
 {
 	const char **prefixes = remoteUrlPrefixes;
 
diff --git a/src/ls.hxx b/src/ls.hxx
index 8ae5a58fd..3879563ee 100644
--- a/src/ls.hxx
+++ b/src/ls.hxx
@@ -35,7 +35,7 @@ bool uri_supported_scheme(const char *url);
  * Send a list of supported URI schemes to the client.  This is the
  * response to the "urlhandlers" command.
  */
-void print_supported_uri_schemes(Client *client);
+void print_supported_uri_schemes(Client &client);
 
 /**
  * Send a list of supported URI schemes to a file pointer.
diff --git a/src/protocol/ArgParser.cxx b/src/protocol/ArgParser.cxx
index e96aaf1c8..b13ea3f4e 100644
--- a/src/protocol/ArgParser.cxx
+++ b/src/protocol/ArgParser.cxx
@@ -26,7 +26,7 @@
 #include <stdlib.h>
 
 bool
-check_uint32(Client *client, uint32_t *dst, const char *s)
+check_uint32(Client &client, uint32_t *dst, const char *s)
 {
 	char *test;
 
@@ -40,7 +40,7 @@ check_uint32(Client *client, uint32_t *dst, const char *s)
 }
 
 bool
-check_int(Client *client, int *value_r, const char *s)
+check_int(Client &client, int *value_r, const char *s)
 {
 	char *test;
 	long value;
@@ -64,7 +64,7 @@ check_int(Client *client, int *value_r, const char *s)
 }
 
 bool
-check_range(Client *client, unsigned *value_r1, unsigned *value_r2,
+check_range(Client &client, unsigned *value_r1, unsigned *value_r2,
 	    const char *s)
 {
 	char *test, *test2;
@@ -131,7 +131,7 @@ check_range(Client *client, unsigned *value_r1, unsigned *value_r2,
 }
 
 bool
-check_unsigned(Client *client, unsigned *value_r, const char *s)
+check_unsigned(Client &client, unsigned *value_r, const char *s)
 {
 	unsigned long value;
 	char *endptr;
@@ -154,7 +154,7 @@ check_unsigned(Client *client, unsigned *value_r, const char *s)
 }
 
 bool
-check_bool(Client *client, bool *value_r, const char *s)
+check_bool(Client &client, bool *value_r, const char *s)
 {
 	long value;
 	char *endptr;
@@ -171,7 +171,7 @@ check_bool(Client *client, bool *value_r, const char *s)
 }
 
 bool
-check_float(Client *client, float *value_r, const char *s)
+check_float(Client &client, float *value_r, const char *s)
 {
 	float value;
 	char *endptr;
diff --git a/src/protocol/ArgParser.hxx b/src/protocol/ArgParser.hxx
index f69248d2d..ea28de79e 100644
--- a/src/protocol/ArgParser.hxx
+++ b/src/protocol/ArgParser.hxx
@@ -27,22 +27,22 @@
 class Client;
 
 bool
-check_uint32(Client *client, uint32_t *dst, const char *s);
+check_uint32(Client &client, uint32_t *dst, const char *s);
 
 bool
-check_int(Client *client, int *value_r, const char *s);
+check_int(Client &client, int *value_r, const char *s);
 
 bool
-check_range(Client *client, unsigned *value_r1, unsigned *value_r2,
+check_range(Client &client, unsigned *value_r1, unsigned *value_r2,
 	    const char *s);
 
 bool
-check_unsigned(Client *client, unsigned *value_r, const char *s);
+check_unsigned(Client &client, unsigned *value_r, const char *s);
 
 bool
-check_bool(Client *client, bool *value_r, const char *s);
+check_bool(Client &client, bool *value_r, const char *s);
 
 bool
-check_float(Client *client, float *value_r, const char *s);
+check_float(Client &client, float *value_r, const char *s);
 
 #endif
diff --git a/src/protocol/Result.cxx b/src/protocol/Result.cxx
index e10a731cc..48feee4d4 100644
--- a/src/protocol/Result.cxx
+++ b/src/protocol/Result.cxx
@@ -27,16 +27,15 @@ const char *current_command;
 int command_list_num;
 
 void
-command_success(Client *client)
+command_success(Client &client)
 {
 	client_puts(client, "OK\n");
 }
 
 void
-command_error_v(Client *client, enum ack error,
+command_error_v(Client &client, enum ack error,
 		const char *fmt, va_list args)
 {
-	assert(client != NULL);
 	assert(current_command != NULL);
 
 	client_printf(client, "ACK [%i@%i] {%s} ",
@@ -48,7 +47,7 @@ command_error_v(Client *client, enum ack error,
 }
 
 void
-command_error(Client *client, enum ack error, const char *fmt, ...)
+command_error(Client &client, enum ack error, const char *fmt, ...)
 {
 	va_list args;
 	va_start(args, fmt);
diff --git a/src/protocol/Result.hxx b/src/protocol/Result.hxx
index 541b00327..0f7339c1c 100644
--- a/src/protocol/Result.hxx
+++ b/src/protocol/Result.hxx
@@ -32,14 +32,14 @@ extern const char *current_command;
 extern int command_list_num;
 
 void
-command_success(Client *client);
+command_success(Client &client);
 
 void
-command_error_v(Client *client, enum ack error,
+command_error_v(Client &client, enum ack error,
 		const char *fmt, va_list args);
 
 gcc_printf(3,4)
 void
-command_error(Client *client, enum ack error, const char *fmt, ...);
+command_error(Client &client, enum ack error, const char *fmt, ...);
 
 #endif
diff --git a/test/read_tags.cxx b/test/read_tags.cxx
index f98de3d66..aae2a2df9 100644
--- a/test/read_tags.cxx
+++ b/test/read_tags.cxx
@@ -181,7 +181,7 @@ int main(int argc, char **argv)
 		return 1;
 	}
 
-	bool success = decoder_plugin_scan_file(plugin, path,
+	bool success = decoder_plugin_scan_file(*plugin, path,
 						&print_handler, NULL);
 	if (!success && plugin->scan_stream != NULL) {
 		Mutex mutex;
@@ -209,7 +209,7 @@ int main(int argc, char **argv)
 
 		mutex.unlock();
 
-		success = decoder_plugin_scan_stream(plugin, is,
+		success = decoder_plugin_scan_stream(*plugin, is,
 						     &print_handler, NULL);
 		is->Close();
 	}
diff --git a/test/run_decoder.cxx b/test/run_decoder.cxx
index 7efb9d906..9934429fc 100644
--- a/test/run_decoder.cxx
+++ b/test/run_decoder.cxx
@@ -184,7 +184,7 @@ int main(int argc, char **argv)
 	decoder.initialized = false;
 
 	if (decoder.plugin->file_decode != NULL) {
-		decoder_plugin_file_decode(decoder.plugin, &decoder,
+		decoder_plugin_file_decode(*decoder.plugin, &decoder,
 					   decoder.uri);
 	} else if (decoder.plugin->stream_decode != NULL) {
 		Mutex mutex;
@@ -201,7 +201,7 @@ int main(int argc, char **argv)
 			return 1;
 		}
 
-		decoder_plugin_stream_decode(decoder.plugin, &decoder, is);
+		decoder_plugin_stream_decode(*decoder.plugin, &decoder, is);
 
 		is->Close();
 	} else {
diff --git a/test/run_output.cxx b/test/run_output.cxx
index 91cffbaf8..0bcad149f 100644
--- a/test/run_output.cxx
+++ b/test/run_output.cxx
@@ -91,7 +91,7 @@ load_audio_output(const char *name)
 
 	Error error;
 	struct audio_output *ao =
-		audio_output_new(*param, &dummy_player_control, error);
+		audio_output_new(*param, dummy_player_control, error);
 	if (ao == nullptr)
 		g_printerr("%s\n", error.GetMessage());