client: splitted client.c into several pieces

The soure file client.c has nearly 1000 lines, time for splitting it
into smaller pieces to improve readability.

12 files changed, 1138 insertions, 875 deletions

diff --git a/Makefile.am b/Makefile.am
index af3089ee1..c3d8b4a18 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -204,6 +204,15 @@ src_mpd_SOURCES = \
 	src/filter_registry.c \
 	src/update.c \
 	src/client.c \
+	src/client_event.c \
+	src/client_expire.c \
+	src/client_global.c \
+	src/client_idle.c \
+	src/client_list.c \
+	src/client_new.c \
+	src/client_process.c \
+	src/client_read.c \
+	src/client_write.c \
 	src/listen.c \
 	src/log.c \
 	src/ls.c \
diff --git a/src/client.c b/src/client.c
index 68474bb2d..827f1d752 100644
--- a/src/client.c
+++ b/src/client.c
@@ -18,99 +18,6 @@
  */
 
 #include "client_internal.h"
-#include "fifo_buffer.h"
-#include "command.h"
-#include "conf.h"
-#include "listen.h"
-#include "socket_util.h"
-#include "permission.h"
-#include "event_pipe.h"
-#include "idle.h"
-#include "main.h"
-#include "config.h"
-
-#include <glib.h>
-#include <assert.h>
-#include <unistd.h>
-#include <string.h>
-#include <stdlib.h>
-#include <stdio.h>
-
-#undef G_LOG_DOMAIN
-#define G_LOG_DOMAIN "client"
-#define LOG_LEVEL_SECURE G_LOG_LEVEL_INFO
-
-static const char GREETING[] = "OK MPD " PROTOCOL_VERSION "\n";
-
-#define CLIENT_LIST_MODE_BEGIN			"command_list_begin"
-#define CLIENT_LIST_OK_MODE_BEGIN			"command_list_ok_begin"
-#define CLIENT_LIST_MODE_END				"command_list_end"
-#define CLIENT_TIMEOUT_DEFAULT			(60)
-#define CLIENT_MAX_CONNECTIONS_DEFAULT		(10)
-#define CLIENT_MAX_COMMAND_LIST_DEFAULT		(2048*1024)
-#define CLIENT_MAX_OUTPUT_BUFFER_SIZE_DEFAULT	(8192*1024)
-
-/* set this to zero to indicate we have no possible clients */
-static unsigned int client_max_connections;	/*CLIENT_MAX_CONNECTIONS_DEFAULT; */
-static int client_timeout;
-static size_t client_max_command_list_size;
-static size_t client_max_output_buffer_size;
-
-static GList *clients;
-static unsigned num_clients;
-static guint expire_source_id;
-
-static bool
-client_list_is_empty(void)
-{
-	return num_clients == 0;
-}
-
-static bool
-client_list_is_full(void)
-{
-	return num_clients >= client_max_connections;
-}
-
-static struct client *
-client_list_get_first(void)
-{
-	assert(clients != NULL);
-
-	return clients->data;
-}
-
-static void
-client_list_foreach(GFunc func, gpointer user_data)
-{
-	g_list_foreach(clients, func, user_data);
-}
-
-static void
-client_list_add(struct client *client)
-{
-	clients = g_list_prepend(clients, client);
-	++num_clients;
-}
-
-static void
-client_list_remove(struct client *client)
-{
-	assert(num_clients > 0);
-	assert(clients != NULL);
-
-	clients = g_list_remove(clients, client);
-	--num_clients;
-}
-
-static void client_write_deferred(struct client *client);
-
-static void client_write_output(struct client *client);
-
-static void client_manager_expire(void);
-
-static gboolean
-client_in_event(GIOChannel *source, GIOCondition condition, gpointer data);
 
 bool client_is_expired(const struct client *client)
 {
@@ -131,785 +38,3 @@ void client_set_permission(struct client *client, unsigned permission)
 {
 	client->permission = permission;
 }
-
-/**
- * An idle event which calls client_manager_expire().
- */
-static gboolean
-client_manager_expire_event(G_GNUC_UNUSED gpointer data)
-{
-	expire_source_id = 0;
-	client_manager_expire();
-	return false;
-}
-
-static inline void client_set_expired(struct client *client)
-{
-	if (expire_source_id == 0 && !client_is_expired(client))
-		/* delayed deletion */
-		expire_source_id = g_idle_add(client_manager_expire_event,
-					      NULL);
-
-	if (client->source_id != 0) {
-		g_source_remove(client->source_id);
-		client->source_id = 0;
-	}
-
-	if (client->channel != NULL) {
-		g_io_channel_unref(client->channel);
-		client->channel = NULL;
-	}
-}
-
-static void client_init(struct client *client, int fd)
-{
-	static unsigned int next_client_num;
-
-	assert(fd >= 0);
-
-	client->cmd_list_size = 0;
-	client->cmd_list_OK = -1;
-
-#ifndef G_OS_WIN32
-	client->channel = g_io_channel_unix_new(fd);
-#else
-	client->channel = g_io_channel_win32_new_socket(fd);
-#endif
-	/* GLib is responsible for closing the file descriptor */
-	g_io_channel_set_close_on_unref(client->channel, true);
-	/* NULL encoding means the stream is binary safe; the MPD
-	   protocol is UTF-8 only, but we are doing this call anyway
-	   to prevent GLib from messing around with the stream */
-	g_io_channel_set_encoding(client->channel, NULL, NULL);
-	/* we prefer to do buffering */
-	g_io_channel_set_buffered(client->channel, false);
-
-	client->source_id = g_io_add_watch(client->channel,
-					   G_IO_IN|G_IO_ERR|G_IO_HUP,
-					   client_in_event, client);
-
-	client->input = fifo_buffer_new(4096);
-
-	client->cmd_list = NULL;
-	client->deferred_send = g_queue_new();
-	client->deferred_bytes = 0;
-	client->num = next_client_num++;
-	client->send_buf_used = 0;
-
-	client->permission = getDefaultPermissions();
-
-	(void)write(fd, GREETING, sizeof(GREETING) - 1);
-}
-
-static void free_cmd_list(GSList *list)
-{
-	for (GSList *tmp = list; tmp != NULL; tmp = g_slist_next(tmp))
-		g_free(tmp->data);
-
-	g_slist_free(list);
-}
-
-static void new_cmd_list_ptr(struct client *client, char *s)
-{
-	client->cmd_list = g_slist_prepend(client->cmd_list, g_strdup(s));
-}
-
-static void
-deferred_buffer_free(gpointer data, G_GNUC_UNUSED gpointer user_data)
-{
-	struct deferred_buffer *buffer = data;
-	g_free(buffer);
-}
-
-static void client_close(struct client *client)
-{
-	client_list_remove(client);
-
-	client_set_expired(client);
-
-	g_timer_destroy(client->last_activity);
-
-	if (client->cmd_list) {
-		free_cmd_list(client->cmd_list);
-		client->cmd_list = NULL;
-	}
-
-	g_queue_foreach(client->deferred_send, deferred_buffer_free, NULL);
-	g_queue_free(client->deferred_send);
-
-	fifo_buffer_free(client->input);
-
-	g_log(G_LOG_DOMAIN, LOG_LEVEL_SECURE,
-	      "[%u] closed", client->num);
-	g_free(client);
-}
-
-void client_new(int fd, const struct sockaddr *sa, size_t sa_length, int uid)
-{
-	struct client *client;
-	char *remote;
-
-	if (client_list_is_full()) {
-		g_warning("Max Connections Reached!");
-		close(fd);
-		return;
-	}
-
-	client = g_new0(struct client, 1);
-	client_list_add(client);
-
-	client_init(client, fd);
-	client->uid = uid;
-
-	client->last_activity = g_timer_new();
-
-	remote = sockaddr_to_string(sa, sa_length, NULL);
-	g_log(G_LOG_DOMAIN, LOG_LEVEL_SECURE,
-	      "[%u] opened from %s", client->num, remote);
-	g_free(remote);
-}
-
-static enum command_return
-client_process_line(struct client *client, char *line)
-{
-	enum command_return ret;
-
-	if (strcmp(line, "noidle") == 0) {
-		if (client->idle_waiting) {
-			/* send empty idle response and leave idle mode */
-			client->idle_waiting = false;
-			command_success(client);
-			client_write_output(client);
-		}
-
-		/* do nothing if the client wasn't idling: the client
-		   has already received the full idle response from
-		   client_idle_notify(), which he can now evaluate */
-
-		return COMMAND_RETURN_OK;
-	} else if (client->idle_waiting) {
-		/* during idle mode, clients must not send anything
-		   except "noidle" */
-		g_warning("[%u] command \"%s\" during idle",
-			  client->num, line);
-		return COMMAND_RETURN_CLOSE;
-	}
-
-	if (client->cmd_list_OK >= 0) {
-		if (strcmp(line, CLIENT_LIST_MODE_END) == 0) {
-			g_debug("[%u] process command list",
-				client->num);
-
-			/* for scalability reasons, we have prepended
-			   each new command; now we have to reverse it
-			   to restore the correct order */
-			client->cmd_list = g_slist_reverse(client->cmd_list);
-
-			ret = command_process_list(client,
-						   client->cmd_list_OK,
-						   client->cmd_list);
-			g_debug("[%u] process command "
-				"list returned %i", client->num, ret);
-
-			if (ret == COMMAND_RETURN_CLOSE ||
-			    client_is_expired(client))
-				return COMMAND_RETURN_CLOSE;
-
-			if (ret == COMMAND_RETURN_OK)
-				command_success(client);
-
-			client_write_output(client);
-			free_cmd_list(client->cmd_list);
-			client->cmd_list = NULL;
-			client->cmd_list_OK = -1;
-		} else {
-			size_t len = strlen(line) + 1;
-			client->cmd_list_size += len;
-			if (client->cmd_list_size >
-			    client_max_command_list_size) {
-				g_warning("[%u] command list size (%lu) "
-					  "is larger than the max (%lu)",
-					  client->num,
-					  (unsigned long)client->cmd_list_size,
-					  (unsigned long)client_max_command_list_size);
-				return COMMAND_RETURN_CLOSE;
-			}
-
-			new_cmd_list_ptr(client, line);
-			ret = COMMAND_RETURN_OK;
-		}
-	} else {
-		if (strcmp(line, CLIENT_LIST_MODE_BEGIN) == 0) {
-			client->cmd_list_OK = 0;
-			ret = COMMAND_RETURN_OK;
-		} else if (strcmp(line, CLIENT_LIST_OK_MODE_BEGIN) == 0) {
-			client->cmd_list_OK = 1;
-			ret = COMMAND_RETURN_OK;
-		} else {
-			g_debug("[%u] process command \"%s\"",
-				client->num, line);
-			ret = command_process(client, line);
-			g_debug("[%u] command returned %i",
-				client->num, ret);
-
-			if (ret == COMMAND_RETURN_CLOSE ||
-			    client_is_expired(client))
-				return COMMAND_RETURN_CLOSE;
-
-			if (ret == COMMAND_RETURN_OK)
-				command_success(client);
-
-			client_write_output(client);
-		}
-	}
-
-	return ret;
-}
-
-static char *
-client_read_line(struct client *client)
-{
-	const char *p, *newline;
-	size_t length;
-	char *line;
-
-	p = fifo_buffer_read(client->input, &length);
-	if (p == NULL)
-		return NULL;
-
-	newline = memchr(p, '\n', length);
-	if (newline == NULL)
-		return NULL;
-
-	line = g_strndup(p, newline - p);
-	fifo_buffer_consume(client->input, newline - p + 1);
-
-	return g_strchomp(line);
-}
-
-static enum command_return
-client_input_received(struct client *client, size_t bytesRead)
-{
-	char *line;
-
-	fifo_buffer_append(client->input, bytesRead);
-
-	/* process all lines */
-
-	while ((line = client_read_line(client)) != NULL) {
-		enum command_return ret = client_process_line(client, line);
-		g_free(line);
-
-		if (ret == COMMAND_RETURN_KILL ||
-		    ret == COMMAND_RETURN_CLOSE)
-			return ret;
-		if (client_is_expired(client))
-			return COMMAND_RETURN_CLOSE;
-	}
-
-	return COMMAND_RETURN_OK;
-}
-
-static enum command_return
-client_read(struct client *client)
-{
-	char *p;
-	size_t max_length;
-	GError *error = NULL;
-	GIOStatus status;
-	gsize bytes_read;
-
-	assert(client != NULL);
-	assert(client->channel != NULL);
-
-	p = fifo_buffer_write(client->input, &max_length);
-	if (p == NULL) {
-		g_warning("[%u] buffer overflow", client->num);
-		return COMMAND_RETURN_CLOSE;
-	}
-
-	status = g_io_channel_read_chars(client->channel, p, max_length,
-					 &bytes_read, &error);
-	switch (status) {
-	case G_IO_STATUS_NORMAL:
-		return client_input_received(client, bytes_read);
-
-	case G_IO_STATUS_AGAIN:
-		/* try again later, after select() */
-		return COMMAND_RETURN_OK;
-
-	case G_IO_STATUS_EOF:
-		/* peer disconnected */
-		return COMMAND_RETURN_CLOSE;
-
-	case G_IO_STATUS_ERROR:
-		/* I/O error */
-		g_warning("failed to read from client %d: %s",
-			  client->num, error->message);
-		g_error_free(error);
-		return COMMAND_RETURN_CLOSE;
-	}
-
-	/* unreachable */
-	return COMMAND_RETURN_CLOSE;
-}
-
-static gboolean
-client_out_event(G_GNUC_UNUSED GIOChannel *source, GIOCondition condition,
-		 gpointer data);
-
-static gboolean
-client_in_event(G_GNUC_UNUSED GIOChannel *source,
-		GIOCondition condition,
-		gpointer data)
-{
-	struct client *client = data;
-	enum command_return ret;
-
-	assert(!client_is_expired(client));
-
-	if (condition != G_IO_IN) {
-		client_set_expired(client);
-		return false;
-	}
-
-	g_timer_start(client->last_activity);
-
-	ret = client_read(client);
-	switch (ret) {
-	case COMMAND_RETURN_OK:
-	case COMMAND_RETURN_ERROR:
-		break;
-
-	case COMMAND_RETURN_KILL:
-		client_close(client);
-		g_main_loop_quit(main_loop);
-		return false;
-
-	case COMMAND_RETURN_CLOSE:
-		client_close(client);
-		return false;
-	}
-
-	if (client_is_expired(client)) {
-		client_close(client);
-		return false;
-	}
-
-	if (!g_queue_is_empty(client->deferred_send)) {
-		/* deferred buffers exist: schedule write */
-		client->source_id = g_io_add_watch(client->channel,
-						   G_IO_OUT|G_IO_ERR|G_IO_HUP,
-						   client_out_event, client);
-		return false;
-	}
-
-	/* read more */
-	return true;
-}
-
-static gboolean
-client_out_event(G_GNUC_UNUSED GIOChannel *source, GIOCondition condition,
-		 gpointer data)
-{
-	struct client *client = data;
-
-	assert(!client_is_expired(client));
-
-	if (condition != G_IO_OUT) {
-		client_set_expired(client);
-		return false;
-	}
-
-	client_write_deferred(client);
-
-	if (client_is_expired(client)) {
-		client_close(client);
-		return false;
-	}
-
-	g_timer_start(client->last_activity);
-
-	if (g_queue_is_empty(client->deferred_send)) {
-		/* done sending deferred buffers exist: schedule
-		   read */
-		client->source_id = g_io_add_watch(client->channel,
-						   G_IO_IN|G_IO_ERR|G_IO_HUP,
-						   client_in_event, client);
-		return false;
-	}
-
-	/* write more */
-	return true;
-}
-
-void client_manager_init(void)
-{
-	client_timeout = config_get_positive(CONF_CONN_TIMEOUT,
-					     CLIENT_TIMEOUT_DEFAULT);
-	client_max_connections =
-		config_get_positive(CONF_MAX_CONN,
-				    CLIENT_MAX_CONNECTIONS_DEFAULT);
-	client_max_command_list_size =
-		config_get_positive(CONF_MAX_COMMAND_LIST_SIZE,
-				    CLIENT_MAX_COMMAND_LIST_DEFAULT / 1024)
-		* 1024;
-
-	client_max_output_buffer_size =
-		config_get_positive(CONF_MAX_OUTPUT_BUFFER_SIZE,
-				    CLIENT_MAX_OUTPUT_BUFFER_SIZE_DEFAULT / 1024)
-		* 1024;
-}
-
-static void client_close_all(void)
-{
-	while (!client_list_is_empty()) {
-		struct client *client = client_list_get_first();
-
-		client_close(client);
-	}
-
-	assert(client_list_is_empty());
-}
-
-void client_manager_deinit(void)
-{
-	client_close_all();
-
-	client_max_connections = 0;
-
-	if (expire_source_id != 0)
-		g_source_remove(expire_source_id);
-}
-
-static void
-client_check_expired_callback(gpointer data, G_GNUC_UNUSED gpointer user_data)
-{
-	struct client *client = data;
-
-	if (client_is_expired(client)) {
-		g_debug("[%u] expired", client->num);
-		client_close(client);
-	} else if (!client->idle_waiting && /* idle clients
-					       never expire */
-		   (int)g_timer_elapsed(client->last_activity, NULL) >
-		   client_timeout) {
-		g_debug("[%u] timeout", client->num);
-		client_close(client);
-	}
-}
-
-static void
-client_manager_expire(void)
-{
-	client_list_foreach(client_check_expired_callback, NULL);
-}
-
-static size_t
-client_write_deferred_buffer(struct client *client,
-			     const struct deferred_buffer *buffer)
-{
-	GError *error = NULL;
-	GIOStatus status;
-	gsize bytes_written;
-
-	assert(client != NULL);
-	assert(client->channel != NULL);
-	assert(buffer != NULL);
-
-	status = g_io_channel_write_chars
-		(client->channel, buffer->data, buffer->size,
-		 &bytes_written, &error);
-	switch (status) {
-	case G_IO_STATUS_NORMAL:
-		return bytes_written;
-
-	case G_IO_STATUS_AGAIN:
-		return 0;
-
-	case G_IO_STATUS_EOF:
-		/* client has disconnected */
-
-		client_set_expired(client);
-		return 0;
-
-	case G_IO_STATUS_ERROR:
-		/* I/O error */
-
-		client_set_expired(client);
-		g_warning("failed to flush buffer for %i: %s",
-			  client->num, error->message);
-		g_error_free(error);
-		return 0;
-	}
-
-	/* unreachable */
-	return 0;
-}
-
-static void client_write_deferred(struct client *client)
-{
-	size_t ret;
-
-	while (!g_queue_is_empty(client->deferred_send)) {
-		struct deferred_buffer *buf =
-			g_queue_peek_head(client->deferred_send);
-
-		assert(buf->size > 0);
-		assert(buf->size <= client->deferred_bytes);
-
-		ret = client_write_deferred_buffer(client, buf);
-		if (ret == 0)
-			break;
-
-		if (ret < buf->size) {
-			assert(client->deferred_bytes >= (size_t)ret);
-			client->deferred_bytes -= ret;
-			buf->size -= ret;
-			memmove(buf->data, buf->data + ret, buf->size);
-			break;
-		} else {
-			size_t decr = sizeof(*buf) -
-				sizeof(buf->data) + buf->size;
-
-			assert(client->deferred_bytes >= decr);
-			client->deferred_bytes -= decr;
-			g_free(buf);
-			g_queue_pop_head(client->deferred_send);
-		}
-
-		g_timer_start(client->last_activity);
-	}
-
-	if (g_queue_is_empty(client->deferred_send)) {
-		g_debug("[%u] buffer empty %lu", client->num,
-			(unsigned long)client->deferred_bytes);
-		assert(client->deferred_bytes == 0);
-	}
-}
-
-static void client_defer_output(struct client *client,
-				const void *data, size_t length)
-{
-	size_t alloc;
-	struct deferred_buffer *buf;
-
-	assert(length > 0);
-
-	alloc = sizeof(*buf) - sizeof(buf->data) + length;
-	client->deferred_bytes += alloc;
-	if (client->deferred_bytes > client_max_output_buffer_size) {
-		g_warning("[%u] output buffer size (%lu) is "
-			  "larger than the max (%lu)",
-			  client->num,
-			  (unsigned long)client->deferred_bytes,
-			  (unsigned long)client_max_output_buffer_size);
-		/* cause client to close */
-		client_set_expired(client);
-		return;
-	}
-
-	buf = g_malloc(alloc);
-	buf->size = length;
-	memcpy(buf->data, data, length);
-
-	g_queue_push_tail(client->deferred_send, buf);
-}
-
-static void client_write_direct(struct client *client,
-				const char *data, size_t length)
-{
-	GError *error = NULL;
-	GIOStatus status;
-	gsize bytes_written;
-
-	assert(client != NULL);
-	assert(client->channel != NULL);
-	assert(data != NULL);
-	assert(length > 0);
-	assert(g_queue_is_empty(client->deferred_send));
-
-	status = g_io_channel_write_chars(client->channel, data, length,
-					  &bytes_written, &error);
-	switch (status) {
-	case G_IO_STATUS_NORMAL:
-	case G_IO_STATUS_AGAIN:
-		break;
-
-	case G_IO_STATUS_EOF:
-		/* client has disconnected */
-
-		client_set_expired(client);
-		return;
-
-	case G_IO_STATUS_ERROR:
-		/* I/O error */
-
-		client_set_expired(client);
-		g_warning("failed to write to %i: %s",
-			  client->num, error->message);
-		g_error_free(error);
-		return;
-	}
-
-	if (bytes_written < length)
-		client_defer_output(client, data + bytes_written,
-				    length - bytes_written);
-
-	if (!g_queue_is_empty(client->deferred_send))
-		g_debug("[%u] buffer created", client->num);
-}
-
-static void client_write_output(struct client *client)
-{
-	if (client_is_expired(client) || !client->send_buf_used)
-		return;
-
-	if (!g_queue_is_empty(client->deferred_send)) {
-		client_defer_output(client, client->send_buf,
-				    client->send_buf_used);
-
-		if (client_is_expired(client))
-			return;
-
-		/* try to flush the deferred buffers now; the current
-		   server command may take too long to finish, and
-		   meanwhile try to feed output to the client,
-		   otherwise it will time out.  One reason why
-		   deferring is slow might be that currently each
-		   client_write() allocates a new deferred buffer.
-		   This should be optimized after MPD 0.14. */
-		client_write_deferred(client);
-	} else
-		client_write_direct(client, client->send_buf,
-				    client->send_buf_used);
-
-	client->send_buf_used = 0;
-}
-
-/**
- * Write a block of data to the client.
- */
-static void client_write(struct client *client, const char *buffer, size_t buflen)
-{
-	/* if the client is going to be closed, do nothing */
-	if (client_is_expired(client))
-		return;
-
-	while (buflen > 0 && !client_is_expired(client)) {
-		size_t copylen;
-
-		assert(client->send_buf_used < sizeof(client->send_buf));
-
-		copylen = sizeof(client->send_buf) - client->send_buf_used;
-		if (copylen > buflen)
-			copylen = buflen;
-
-		memcpy(client->send_buf + client->send_buf_used, buffer,
-		       copylen);
-		buflen -= copylen;
-		client->send_buf_used += copylen;
-		buffer += copylen;
-		if (client->send_buf_used >= sizeof(client->send_buf))
-			client_write_output(client);
-	}
-}
-
-void client_puts(struct client *client, const char *s)
-{
-	client_write(client, s, strlen(s));
-}
-
-void client_vprintf(struct client *client, const char *fmt, va_list args)
-{
-	va_list tmp;
-	int length;
-	char *buffer;
-
-	va_copy(tmp, args);
-	length = vsnprintf(NULL, 0, fmt, tmp);
-	va_end(tmp);
-
-	if (length <= 0)
-		/* wtf.. */
-		return;
-
-	buffer = g_malloc(length + 1);
-	vsnprintf(buffer, length + 1, fmt, args);
-	client_write(client, buffer, length);
-	g_free(buffer);
-}
-
-G_GNUC_PRINTF(2, 3) void client_printf(struct client *client, const char *fmt, ...)
-{
-	va_list args;
-
-	va_start(args, fmt);
-	client_vprintf(client, fmt, args);
-	va_end(args);
-}
-
-/**
- * Send "idle" response to this client.
- */
-static void
-client_idle_notify(struct client *client)
-{
-	unsigned flags, i;
-	const char *const* idle_names;
-
-	assert(client->idle_waiting);
-	assert(client->idle_flags != 0);
-
-	flags = client->idle_flags;
-	client->idle_flags = 0;
-	client->idle_waiting = false;
-
-	idle_names = idle_get_names();
-	for (i = 0; idle_names[i]; ++i) {
-		if (flags & (1 << i) & client->idle_subscriptions)
-			client_printf(client, "changed: %s\n",
-				      idle_names[i]);
-	}
-
-	client_puts(client, "OK\n");
-	g_timer_start(client->last_activity);
-}
-
-static void
-client_idle_callback(gpointer data, gpointer user_data)
-{
-	struct client *client = data;
-	unsigned flags = GPOINTER_TO_UINT(user_data);
-
-	if (client_is_expired(client))
-		return;
-
-	client->idle_flags |= flags;
-	if (client->idle_waiting
-	    && (client->idle_flags & client->idle_subscriptions)) {
-		client_idle_notify(client);
-		client_write_output(client);
-	}
-}
-
-void client_manager_idle_add(unsigned flags)
-{
-	assert(flags != 0);
-
-	client_list_foreach(client_idle_callback, GUINT_TO_POINTER(flags));
-}
-
-bool client_idle_wait(struct client *client, unsigned flags)
-{
-	assert(!client->idle_waiting);
-
-	client->idle_waiting = true;
-	client->idle_subscriptions = flags;
-
-	if (client->idle_flags & client->idle_subscriptions) {
-		client_idle_notify(client);
-		return true;
-	} else
-		return false;
-}
diff --git a/src/client_event.c b/src/client_event.c
new file mode 100644
index 000000000..93279b283
--- /dev/null
+++ b/src/client_event.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "client_internal.h"
+#include "main.h"
+
+#include <assert.h>
+
+static gboolean
+client_out_event(G_GNUC_UNUSED GIOChannel *source, GIOCondition condition,
+		 gpointer data)
+{
+	struct client *client = data;
+
+	assert(!client_is_expired(client));
+
+	if (condition != G_IO_OUT) {
+		client_set_expired(client);
+		return false;
+	}
+
+	client_write_deferred(client);
+
+	if (client_is_expired(client)) {
+		client_close(client);
+		return false;
+	}
+
+	g_timer_start(client->last_activity);
+
+	if (g_queue_is_empty(client->deferred_send)) {
+		/* done sending deferred buffers exist: schedule
+		   read */
+		client->source_id = g_io_add_watch(client->channel,
+						   G_IO_IN|G_IO_ERR|G_IO_HUP,
+						   client_in_event, client);
+		return false;
+	}
+
+	/* write more */
+	return true;
+}
+
+gboolean
+client_in_event(G_GNUC_UNUSED GIOChannel *source, GIOCondition condition,
+		gpointer data)
+{
+	struct client *client = data;
+	enum command_return ret;
+
+	assert(!client_is_expired(client));
+
+	if (condition != G_IO_IN) {
+		client_set_expired(client);
+		return false;
+	}
+
+	g_timer_start(client->last_activity);
+
+	ret = client_read(client);
+	switch (ret) {
+	case COMMAND_RETURN_OK:
+	case COMMAND_RETURN_ERROR:
+		break;
+
+	case COMMAND_RETURN_KILL:
+		client_close(client);
+		g_main_loop_quit(main_loop);
+		return false;
+
+	case COMMAND_RETURN_CLOSE:
+		client_close(client);
+		return false;
+	}
+
+	if (client_is_expired(client)) {
+		client_close(client);
+		return false;
+	}
+
+	if (!g_queue_is_empty(client->deferred_send)) {
+		/* deferred buffers exist: schedule write */
+		client->source_id = g_io_add_watch(client->channel,
+						   G_IO_OUT|G_IO_ERR|G_IO_HUP,
+						   client_out_event, client);
+		return false;
+	}
+
+	/* read more */
+	return true;
+}
diff --git a/src/client_expire.c b/src/client_expire.c
new file mode 100644
index 000000000..372af1774
--- /dev/null
+++ b/src/client_expire.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "client_internal.h"
+
+static guint expire_source_id;
+
+void
+client_set_expired(struct client *client)
+{
+	if (!client_is_expired(client))
+		client_schedule_expire();
+
+	if (client->source_id != 0) {
+		g_source_remove(client->source_id);
+		client->source_id = 0;
+	}
+
+	if (client->channel != NULL) {
+		g_io_channel_unref(client->channel);
+		client->channel = NULL;
+	}
+}
+
+static void
+client_check_expired_callback(gpointer data, G_GNUC_UNUSED gpointer user_data)
+{
+	struct client *client = data;
+
+	if (client_is_expired(client)) {
+		g_debug("[%u] expired", client->num);
+		client_close(client);
+	} else if (!client->idle_waiting && /* idle clients
+					       never expire */
+		   (int)g_timer_elapsed(client->last_activity, NULL) >
+		   client_timeout) {
+		g_debug("[%u] timeout", client->num);
+		client_close(client);
+	}
+}
+
+static void
+client_manager_expire(void)
+{
+	client_list_foreach(client_check_expired_callback, NULL);
+}
+
+/**
+ * An idle event which calls client_manager_expire().
+ */
+static gboolean
+client_manager_expire_event(G_GNUC_UNUSED gpointer data)
+{
+	expire_source_id = 0;
+	client_manager_expire();
+	return false;
+}
+
+void
+client_schedule_expire(void)
+{
+	if (expire_source_id == 0)
+		/* delayed deletion */
+		expire_source_id = g_idle_add(client_manager_expire_event,
+					      NULL);
+}
+
+void
+client_deinit_expire(void)
+{
+	if (expire_source_id != 0)
+		g_source_remove(expire_source_id);
+}
diff --git a/src/client_global.c b/src/client_global.c
new file mode 100644
index 000000000..d99e00b82
--- /dev/null
+++ b/src/client_global.c
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "client_internal.h"
+#include "conf.h"
+
+#include <assert.h>
+
+#define CLIENT_TIMEOUT_DEFAULT			(60)
+#define CLIENT_MAX_CONNECTIONS_DEFAULT		(10)
+#define CLIENT_MAX_COMMAND_LIST_DEFAULT		(2048*1024)
+#define CLIENT_MAX_OUTPUT_BUFFER_SIZE_DEFAULT	(8192*1024)
+
+/* set this to zero to indicate we have no possible clients */
+unsigned int client_max_connections;
+int client_timeout;
+size_t client_max_command_list_size;
+size_t client_max_output_buffer_size;
+
+void client_manager_init(void)
+{
+	client_timeout = config_get_positive(CONF_CONN_TIMEOUT,
+					     CLIENT_TIMEOUT_DEFAULT);
+	client_max_connections =
+		config_get_positive(CONF_MAX_CONN,
+				    CLIENT_MAX_CONNECTIONS_DEFAULT);
+	client_max_command_list_size =
+		config_get_positive(CONF_MAX_COMMAND_LIST_SIZE,
+				    CLIENT_MAX_COMMAND_LIST_DEFAULT / 1024)
+		* 1024;
+
+	client_max_output_buffer_size =
+		config_get_positive(CONF_MAX_OUTPUT_BUFFER_SIZE,
+				    CLIENT_MAX_OUTPUT_BUFFER_SIZE_DEFAULT / 1024)
+		* 1024;
+}
+
+static void client_close_all(void)
+{
+	while (!client_list_is_empty()) {
+		struct client *client = client_list_get_first();
+
+		client_close(client);
+	}
+
+	assert(client_list_is_empty());
+}
+
+void client_manager_deinit(void)
+{
+	client_close_all();
+
+	client_max_connections = 0;
+
+	client_deinit_expire();
+}
diff --git a/src/client_idle.c b/src/client_idle.c
new file mode 100644
index 000000000..c6d0bc006
--- /dev/null
+++ b/src/client_idle.c
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "client_internal.h"
+#include "idle.h"
+
+#include <assert.h>
+
+/**
+ * Send "idle" response to this client.
+ */
+static void
+client_idle_notify(struct client *client)
+{
+	unsigned flags, i;
+	const char *const* idle_names;
+
+	assert(client->idle_waiting);
+	assert(client->idle_flags != 0);
+
+	flags = client->idle_flags;
+	client->idle_flags = 0;
+	client->idle_waiting = false;
+
+	idle_names = idle_get_names();
+	for (i = 0; idle_names[i]; ++i) {
+		if (flags & (1 << i) & client->idle_subscriptions)
+			client_printf(client, "changed: %s\n",
+				      idle_names[i]);
+	}
+
+	client_puts(client, "OK\n");
+	g_timer_start(client->last_activity);
+}
+
+static void
+client_idle_callback(gpointer data, gpointer user_data)
+{
+	struct client *client = data;
+	unsigned flags = GPOINTER_TO_UINT(user_data);
+
+	if (client_is_expired(client))
+		return;
+
+	client->idle_flags |= flags;
+	if (client->idle_waiting
+	    && (client->idle_flags & client->idle_subscriptions)) {
+		client_idle_notify(client);
+		client_write_output(client);
+	}
+}
+
+void client_manager_idle_add(unsigned flags)
+{
+	assert(flags != 0);
+
+	client_list_foreach(client_idle_callback, GUINT_TO_POINTER(flags));
+}
+
+bool client_idle_wait(struct client *client, unsigned flags)
+{
+	assert(!client->idle_waiting);
+
+	client->idle_waiting = true;
+	client->idle_subscriptions = flags;
+
+	if (client->idle_flags & client->idle_subscriptions) {
+		client_idle_notify(client);
+		return true;
+	} else
+		return false;
+}
diff --git a/src/client_internal.h b/src/client_internal.h
index 630da59c2..91e360fe0 100644
--- a/src/client_internal.h
+++ b/src/client_internal.h
@@ -21,6 +21,10 @@
 #define MPD_CLIENT_INTERNAL_H
 
 #include "client.h"
+#include "command.h"
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "client"
 
 struct deferred_buffer {
 	size_t size;
@@ -65,4 +69,77 @@ struct client {
 	unsigned idle_subscriptions;
 };
 
+extern unsigned int client_max_connections;
+extern int client_timeout;
+extern size_t client_max_command_list_size;
+extern size_t client_max_output_buffer_size;
+
+bool
+client_list_is_empty(void);
+
+bool
+client_list_is_full(void);
+
+struct client *
+client_list_get_first(void);
+
+void
+client_list_add(struct client *client);
+
+void
+client_list_foreach(GFunc func, gpointer user_data);
+
+void
+client_list_remove(struct client *client);
+
+void
+client_close(struct client *client);
+
+static inline void
+new_cmd_list_ptr(struct client *client, const char *s)
+{
+	client->cmd_list = g_slist_prepend(client->cmd_list, g_strdup(s));
+}
+
+static inline void
+free_cmd_list(GSList *list)
+{
+	for (GSList *tmp = list; tmp != NULL; tmp = g_slist_next(tmp))
+		g_free(tmp->data);
+
+	g_slist_free(list);
+}
+
+void
+client_set_expired(struct client *client);
+
+/**
+ * Schedule an "expired" check for all clients: permanently delete
+ * clients which have been set "expired" with client_set_expired().
+ */
+void
+client_schedule_expire(void);
+
+/**
+ * Removes a scheduled "expired" check.
+ */
+void
+client_deinit_expire(void);
+
+enum command_return
+client_read(struct client *client);
+
+enum command_return
+client_process_line(struct client *client, char *line);
+
+void
+client_write_deferred(struct client *client);
+
+void
+client_write_output(struct client *client);
+
+gboolean
+client_in_event(GIOChannel *source, GIOCondition condition,
+		gpointer data);
+
 #endif
diff --git a/src/client_list.c b/src/client_list.c
new file mode 100644
index 000000000..80eb7a29d
--- /dev/null
+++ b/src/client_list.c
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "client_internal.h"
+
+#include <assert.h>
+
+static GList *clients;
+static unsigned num_clients;
+
+bool
+client_list_is_empty(void)
+{
+	return num_clients == 0;
+}
+
+bool
+client_list_is_full(void)
+{
+	return num_clients >= client_max_connections;
+}
+
+struct client *
+client_list_get_first(void)
+{
+	assert(clients != NULL);
+
+	return clients->data;
+}
+
+void
+client_list_add(struct client *client)
+{
+	clients = g_list_prepend(clients, client);
+	++num_clients;
+}
+
+void
+client_list_foreach(GFunc func, gpointer user_data)
+{
+	g_list_foreach(clients, func, user_data);
+}
+
+void
+client_list_remove(struct client *client)
+{
+	assert(num_clients > 0);
+	assert(clients != NULL);
+
+	clients = g_list_remove(clients, client);
+	--num_clients;
+}
diff --git a/src/client_new.c b/src/client_new.c
new file mode 100644
index 000000000..bc7ee2140
--- /dev/null
+++ b/src/client_new.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "client_internal.h"
+#include "fifo_buffer.h"
+#include "socket_util.h"
+#include "permission.h"
+#include "config.h"
+
+#include <assert.h>
+#include <unistd.h>
+
+#define LOG_LEVEL_SECURE G_LOG_LEVEL_INFO
+
+static const char GREETING[] = "OK MPD " PROTOCOL_VERSION "\n";
+
+void client_new(int fd, const struct sockaddr *sa, size_t sa_length, int uid)
+{
+	static unsigned int next_client_num;
+	struct client *client;
+	char *remote;
+
+	assert(fd >= 0);
+
+	if (client_list_is_full()) {
+		g_warning("Max Connections Reached!");
+		close(fd);
+		return;
+	}
+
+	client = g_new0(struct client, 1);
+
+#ifndef G_OS_WIN32
+	client->channel = g_io_channel_unix_new(fd);
+#else
+	client->channel = g_io_channel_win32_new_socket(fd);
+#endif
+	/* GLib is responsible for closing the file descriptor */
+	g_io_channel_set_close_on_unref(client->channel, true);
+	/* NULL encoding means the stream is binary safe; the MPD
+	   protocol is UTF-8 only, but we are doing this call anyway
+	   to prevent GLib from messing around with the stream */
+	g_io_channel_set_encoding(client->channel, NULL, NULL);
+	/* we prefer to do buffering */
+	g_io_channel_set_buffered(client->channel, false);
+
+	client->source_id = g_io_add_watch(client->channel,
+					   G_IO_IN|G_IO_ERR|G_IO_HUP,
+					   client_in_event, client);
+
+	client->input = fifo_buffer_new(4096);
+
+	client->permission = getDefaultPermissions();
+	client->uid = uid;
+
+	client->last_activity = g_timer_new();
+
+	client->cmd_list = NULL;
+	client->cmd_list_OK = -1;
+	client->cmd_list_size = 0;
+
+	client->deferred_send = g_queue_new();
+	client->deferred_bytes = 0;
+	client->num = next_client_num++;
+
+	client->send_buf_used = 0;
+
+	(void)write(fd, GREETING, sizeof(GREETING) - 1);
+
+	client_list_add(client);
+
+	remote = sockaddr_to_string(sa, sa_length, NULL);
+	g_log(G_LOG_DOMAIN, LOG_LEVEL_SECURE,
+	      "[%u] opened from %s", client->num, remote);
+	g_free(remote);
+}
+
+static void
+deferred_buffer_free(gpointer data, G_GNUC_UNUSED gpointer user_data)
+{
+	struct deferred_buffer *buffer = data;
+	g_free(buffer);
+}
+
+void
+client_close(struct client *client)
+{
+	client_list_remove(client);
+
+	client_set_expired(client);
+
+	g_timer_destroy(client->last_activity);
+
+	if (client->cmd_list) {
+		free_cmd_list(client->cmd_list);
+		client->cmd_list = NULL;
+	}
+
+	g_queue_foreach(client->deferred_send, deferred_buffer_free, NULL);
+	g_queue_free(client->deferred_send);
+
+	fifo_buffer_free(client->input);
+
+	g_log(G_LOG_DOMAIN, LOG_LEVEL_SECURE,
+	      "[%u] closed", client->num);
+	g_free(client);
+}
diff --git a/src/client_process.c b/src/client_process.c
new file mode 100644
index 000000000..5579b70ed
--- /dev/null
+++ b/src/client_process.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "client_internal.h"
+
+#include <string.h>
+
+#define CLIENT_LIST_MODE_BEGIN "command_list_begin"
+#define CLIENT_LIST_OK_MODE_BEGIN "command_list_ok_begin"
+#define CLIENT_LIST_MODE_END "command_list_end"
+
+enum command_return
+client_process_line(struct client *client, char *line)
+{
+	enum command_return ret;
+
+	if (strcmp(line, "noidle") == 0) {
+		if (client->idle_waiting) {
+			/* send empty idle response and leave idle mode */
+			client->idle_waiting = false;
+			command_success(client);
+			client_write_output(client);
+		}
+
+		/* do nothing if the client wasn't idling: the client
+		   has already received the full idle response from
+		   client_idle_notify(), which he can now evaluate */
+
+		return COMMAND_RETURN_OK;
+	} else if (client->idle_waiting) {
+		/* during idle mode, clients must not send anything
+		   except "noidle" */
+		g_warning("[%u] command \"%s\" during idle",
+			  client->num, line);
+		return COMMAND_RETURN_CLOSE;
+	}
+
+	if (client->cmd_list_OK >= 0) {
+		if (strcmp(line, CLIENT_LIST_MODE_END) == 0) {
+			g_debug("[%u] process command list",
+				client->num);
+
+			/* for scalability reasons, we have prepended
+			   each new command; now we have to reverse it
+			   to restore the correct order */
+			client->cmd_list = g_slist_reverse(client->cmd_list);
+
+			ret = command_process_list(client,
+						   client->cmd_list_OK,
+						   client->cmd_list);
+			g_debug("[%u] process command "
+				"list returned %i", client->num, ret);
+
+			if (ret == COMMAND_RETURN_CLOSE ||
+			    client_is_expired(client))
+				return COMMAND_RETURN_CLOSE;
+
+			if (ret == COMMAND_RETURN_OK)
+				command_success(client);
+
+			client_write_output(client);
+			free_cmd_list(client->cmd_list);
+			client->cmd_list = NULL;
+			client->cmd_list_OK = -1;
+		} else {
+			size_t len = strlen(line) + 1;
+			client->cmd_list_size += len;
+			if (client->cmd_list_size >
+			    client_max_command_list_size) {
+				g_warning("[%u] command list size (%lu) "
+					  "is larger than the max (%lu)",
+					  client->num,
+					  (unsigned long)client->cmd_list_size,
+					  (unsigned long)client_max_command_list_size);
+				return COMMAND_RETURN_CLOSE;
+			}
+
+			new_cmd_list_ptr(client, line);
+			ret = COMMAND_RETURN_OK;
+		}
+	} else {
+		if (strcmp(line, CLIENT_LIST_MODE_BEGIN) == 0) {
+			client->cmd_list_OK = 0;
+			ret = COMMAND_RETURN_OK;
+		} else if (strcmp(line, CLIENT_LIST_OK_MODE_BEGIN) == 0) {
+			client->cmd_list_OK = 1;
+			ret = COMMAND_RETURN_OK;
+		} else {
+			g_debug("[%u] process command \"%s\"",
+				client->num, line);
+			ret = command_process(client, line);
+			g_debug("[%u] command returned %i",
+				client->num, ret);
+
+			if (ret == COMMAND_RETURN_CLOSE ||
+			    client_is_expired(client))
+				return COMMAND_RETURN_CLOSE;
+
+			if (ret == COMMAND_RETURN_OK)
+				command_success(client);
+
+			client_write_output(client);
+		}
+	}
+
+	return ret;
+}
diff --git a/src/client_read.c b/src/client_read.c
new file mode 100644
index 000000000..1d64035e3
--- /dev/null
+++ b/src/client_read.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "client_internal.h"
+#include "fifo_buffer.h"
+
+#include <assert.h>
+#include <string.h>
+
+static char *
+client_read_line(struct client *client)
+{
+	const char *p, *newline;
+	size_t length;
+	char *line;
+
+	p = fifo_buffer_read(client->input, &length);
+	if (p == NULL)
+		return NULL;
+
+	newline = memchr(p, '\n', length);
+	if (newline == NULL)
+		return NULL;
+
+	line = g_strndup(p, newline - p);
+	fifo_buffer_consume(client->input, newline - p + 1);
+
+	return g_strchomp(line);
+}
+
+static enum command_return
+client_input_received(struct client *client, size_t bytesRead)
+{
+	char *line;
+
+	fifo_buffer_append(client->input, bytesRead);
+
+	/* process all lines */
+
+	while ((line = client_read_line(client)) != NULL) {
+		enum command_return ret = client_process_line(client, line);
+		g_free(line);
+
+		if (ret == COMMAND_RETURN_KILL ||
+		    ret == COMMAND_RETURN_CLOSE)
+			return ret;
+		if (client_is_expired(client))
+			return COMMAND_RETURN_CLOSE;
+	}
+
+	return COMMAND_RETURN_OK;
+}
+
+enum command_return
+client_read(struct client *client)
+{
+	char *p;
+	size_t max_length;
+	GError *error = NULL;
+	GIOStatus status;
+	gsize bytes_read;
+
+	assert(client != NULL);
+	assert(client->channel != NULL);
+
+	p = fifo_buffer_write(client->input, &max_length);
+	if (p == NULL) {
+		g_warning("[%u] buffer overflow", client->num);
+		return COMMAND_RETURN_CLOSE;
+	}
+
+	status = g_io_channel_read_chars(client->channel, p, max_length,
+					 &bytes_read, &error);
+	switch (status) {
+	case G_IO_STATUS_NORMAL:
+		return client_input_received(client, bytes_read);
+
+	case G_IO_STATUS_AGAIN:
+		/* try again later, after select() */
+		return COMMAND_RETURN_OK;
+
+	case G_IO_STATUS_EOF:
+		/* peer disconnected */
+		return COMMAND_RETURN_CLOSE;
+
+	case G_IO_STATUS_ERROR:
+		/* I/O error */
+		g_warning("failed to read from client %d: %s",
+			  client->num, error->message);
+		g_error_free(error);
+		return COMMAND_RETURN_CLOSE;
+	}
+
+	/* unreachable */
+	return COMMAND_RETURN_CLOSE;
+}
diff --git a/src/client_write.c b/src/client_write.c
new file mode 100644
index 000000000..686c7d96a
--- /dev/null
+++ b/src/client_write.c
@@ -0,0 +1,270 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "client_internal.h"
+
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+
+static size_t
+client_write_deferred_buffer(struct client *client,
+			     const struct deferred_buffer *buffer)
+{
+	GError *error = NULL;
+	GIOStatus status;
+	gsize bytes_written;
+
+	assert(client != NULL);
+	assert(client->channel != NULL);
+	assert(buffer != NULL);
+
+	status = g_io_channel_write_chars
+		(client->channel, buffer->data, buffer->size,
+		 &bytes_written, &error);
+	switch (status) {
+	case G_IO_STATUS_NORMAL:
+		return bytes_written;
+
+	case G_IO_STATUS_AGAIN:
+		return 0;
+
+	case G_IO_STATUS_EOF:
+		/* client has disconnected */
+
+		client_set_expired(client);
+		return 0;
+
+	case G_IO_STATUS_ERROR:
+		/* I/O error */
+
+		client_set_expired(client);
+		g_warning("failed to flush buffer for %i: %s",
+			  client->num, error->message);
+		g_error_free(error);
+		return 0;
+	}
+
+	/* unreachable */
+	return 0;
+}
+
+void
+client_write_deferred(struct client *client)
+{
+	size_t ret;
+
+	while (!g_queue_is_empty(client->deferred_send)) {
+		struct deferred_buffer *buf =
+			g_queue_peek_head(client->deferred_send);
+
+		assert(buf->size > 0);
+		assert(buf->size <= client->deferred_bytes);
+
+		ret = client_write_deferred_buffer(client, buf);
+		if (ret == 0)
+			break;
+
+		if (ret < buf->size) {
+			assert(client->deferred_bytes >= (size_t)ret);
+			client->deferred_bytes -= ret;
+			buf->size -= ret;
+			memmove(buf->data, buf->data + ret, buf->size);
+			break;
+		} else {
+			size_t decr = sizeof(*buf) -
+				sizeof(buf->data) + buf->size;
+
+			assert(client->deferred_bytes >= decr);
+			client->deferred_bytes -= decr;
+			g_free(buf);
+			g_queue_pop_head(client->deferred_send);
+		}
+
+		g_timer_start(client->last_activity);
+	}
+
+	if (g_queue_is_empty(client->deferred_send)) {
+		g_debug("[%u] buffer empty %lu", client->num,
+			(unsigned long)client->deferred_bytes);
+		assert(client->deferred_bytes == 0);
+	}
+}
+
+static void client_defer_output(struct client *client,
+				const void *data, size_t length)
+{
+	size_t alloc;
+	struct deferred_buffer *buf;
+
+	assert(length > 0);
+
+	alloc = sizeof(*buf) - sizeof(buf->data) + length;
+	client->deferred_bytes += alloc;
+	if (client->deferred_bytes > client_max_output_buffer_size) {
+		g_warning("[%u] output buffer size (%lu) is "
+			  "larger than the max (%lu)",
+			  client->num,
+			  (unsigned long)client->deferred_bytes,
+			  (unsigned long)client_max_output_buffer_size);
+		/* cause client to close */
+		client_set_expired(client);
+		return;
+	}
+
+	buf = g_malloc(alloc);
+	buf->size = length;
+	memcpy(buf->data, data, length);
+
+	g_queue_push_tail(client->deferred_send, buf);
+}
+
+static void client_write_direct(struct client *client,
+				const char *data, size_t length)
+{
+	GError *error = NULL;
+	GIOStatus status;
+	gsize bytes_written;
+
+	assert(client != NULL);
+	assert(client->channel != NULL);
+	assert(data != NULL);
+	assert(length > 0);
+	assert(g_queue_is_empty(client->deferred_send));
+
+	status = g_io_channel_write_chars(client->channel, data, length,
+					  &bytes_written, &error);
+	switch (status) {
+	case G_IO_STATUS_NORMAL:
+	case G_IO_STATUS_AGAIN:
+		break;
+
+	case G_IO_STATUS_EOF:
+		/* client has disconnected */
+
+		client_set_expired(client);
+		return;
+
+	case G_IO_STATUS_ERROR:
+		/* I/O error */
+
+		client_set_expired(client);
+		g_warning("failed to write to %i: %s",
+			  client->num, error->message);
+		g_error_free(error);
+		return;
+	}
+
+	if (bytes_written < length)
+		client_defer_output(client, data + bytes_written,
+				    length - bytes_written);
+
+	if (!g_queue_is_empty(client->deferred_send))
+		g_debug("[%u] buffer created", client->num);
+}
+
+void
+client_write_output(struct client *client)
+{
+	if (client_is_expired(client) || !client->send_buf_used)
+		return;
+
+	if (!g_queue_is_empty(client->deferred_send)) {
+		client_defer_output(client, client->send_buf,
+				    client->send_buf_used);
+
+		if (client_is_expired(client))
+			return;
+
+		/* try to flush the deferred buffers now; the current
+		   server command may take too long to finish, and
+		   meanwhile try to feed output to the client,
+		   otherwise it will time out.  One reason why
+		   deferring is slow might be that currently each
+		   client_write() allocates a new deferred buffer.
+		   This should be optimized after MPD 0.14. */
+		client_write_deferred(client);
+	} else
+		client_write_direct(client, client->send_buf,
+				    client->send_buf_used);
+
+	client->send_buf_used = 0;
+}
+
+/**
+ * Write a block of data to the client.
+ */
+static void client_write(struct client *client, const char *buffer, size_t buflen)
+{
+	/* if the client is going to be closed, do nothing */
+	if (client_is_expired(client))
+		return;
+
+	while (buflen > 0 && !client_is_expired(client)) {
+		size_t copylen;
+
+		assert(client->send_buf_used < sizeof(client->send_buf));
+
+		copylen = sizeof(client->send_buf) - client->send_buf_used;
+		if (copylen > buflen)
+			copylen = buflen;
+
+		memcpy(client->send_buf + client->send_buf_used, buffer,
+		       copylen);
+		buflen -= copylen;
+		client->send_buf_used += copylen;
+		buffer += copylen;
+		if (client->send_buf_used >= sizeof(client->send_buf))
+			client_write_output(client);
+	}
+}
+
+void client_puts(struct client *client, const char *s)
+{
+	client_write(client, s, strlen(s));
+}
+
+void client_vprintf(struct client *client, const char *fmt, va_list args)
+{
+	va_list tmp;
+	int length;
+	char *buffer;
+
+	va_copy(tmp, args);
+	length = vsnprintf(NULL, 0, fmt, tmp);
+	va_end(tmp);
+
+	if (length <= 0)
+		/* wtf.. */
+		return;
+
+	buffer = g_malloc(length + 1);
+	vsnprintf(buffer, length + 1, fmt, args);
+	client_write(client, buffer, length);
+	g_free(buffer);
+}
+
+G_GNUC_PRINTF(2, 3) void client_printf(struct client *client, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	client_vprintf(client, fmt, args);
+	va_end(args);
+}