directory: simplify list update handling logic

Now the "update" command can be issued multiple times regardless
of whether the client is in list mode or not.

We serialize the update tasks to prevent updates from trampling
over each other and will spawn another update task
once the current one is finished updating and reaped.

Right now we cap the queue size to 32 which is probably enough (I
bet most people usually run update with no argument anyways);
but we can make it grow/shrink dynamically if needed.  There'll
still be a hard-coded limit to prevent DoS attacks, though.

1 files changed, 18 insertions, 61 deletions

diff --git a/src/command.c b/src/command.c
index 822ee05bf..3dda2f3c2 100644
--- a/src/command.c
+++ b/src/command.c
@@ -36,6 +36,7 @@
 #include "tag.h"
 #include "client.h"
 #include "tag_print.h"
+#include "path.h"
 #include "os_compat.h"
 
 #define COMMAND_PLAY           	"play"
@@ -153,8 +154,6 @@ static const char check_non_negative[] = "\"%s\" is not an integer >= 0";
 static const char *current_command;
 static int command_listNum;
 
-static CommandEntry *getCommandEntryFromString(char *string, int permission);
-
 static List *commandList;
 
 static CommandEntry *newCommandEntry(void)
@@ -814,55 +813,31 @@ static int handlePlaylistMove(struct client *client,
 	return print_playlist_result(client, result);
 }
 
-static int listHandleUpdate(struct client *client,
-			    mpd_unused int argc,
-			    char *argv[],
-			    struct strnode *cmdnode, CommandEntry * cmd)
+static int print_update_result(struct client *client, int ret)
 {
-	List *pathList = makeList(NULL, 1);
-	CommandEntry *nextCmd = NULL;
-	struct strnode *next = cmdnode->next;
-
-	if (argc == 2)
-		insertInList(pathList, argv[1], NULL);
-	else
-		insertInList(pathList, "", NULL);
-
-	if (next)
-		nextCmd = getCommandEntryFromString(next->data,
-						    client_get_permission(client));
-
-	if (cmd != nextCmd) {
-		int ret = updateInit(pathList);
-		if (ret == -1)
-			command_error(client, ACK_ERROR_UPDATE_ALREADY,
-				      "already updating");
-
-		return ret;
+	if (ret >= 0) {
+		client_printf(client, "updating_db: %i\n", ret);
+		return 0;
 	}
-
-	return 0;
+	if (ret == -2)
+		command_error(client, ACK_ERROR_ARG, "invalid path");
+	else
+		command_error(client, ACK_ERROR_UPDATE_ALREADY,
+			      "already updating");
+	return -1;
 }
 
 static int handleUpdate(struct client *client,
 			mpd_unused int argc, char *argv[])
 {
-	int ret;
+	char *path = NULL;
 
-	if (argc == 2) {
-		List *pathList = makeList(NULL, 1);
-		insertInList(pathList, argv[1], NULL);
-		ret = updateInit(pathList);
-	} else {
-		ret = updateInit(NULL);
+	assert(argc <= 2);
+	if (argc == 2 && !(path = sanitizePathDup(argv[1]))) {
+		command_error(client, ACK_ERROR_ARG, "invalid path");
+		return -1;
 	}
-
-	if (ret == -1)
-		command_error(client, ACK_ERROR_UPDATE_ALREADY,
-			      "already updating");
-
-	client_printf(client, "updating_db: %i\n", ret);
-	return 0;
+	return print_update_result(client, directory_update_init(path));
 }
 
 static int handleNext(mpd_unused struct client *client,
@@ -1307,7 +1282,7 @@ void initCommands(void)
 	addCommand(COMMAND_PLAYLISTINFO,     PERMISSION_READ,    0,   1,   handlePlaylistInfo,         NULL);
 	addCommand(COMMAND_FIND,             PERMISSION_READ,    2,   -1,  handleFind,                 NULL);
 	addCommand(COMMAND_SEARCH,           PERMISSION_READ,    2,   -1,  handleSearch,               NULL);
-	addCommand(COMMAND_UPDATE,           PERMISSION_ADMIN,   0,   1,   handleUpdate,               listHandleUpdate);
+	addCommand(COMMAND_UPDATE,           PERMISSION_ADMIN,   0,   1,   handleUpdate,               NULL);
 	addCommand(COMMAND_NEXT,             PERMISSION_CONTROL, 0,   0,   handleNext,                 NULL);
 	addCommand(COMMAND_PREVIOUS,         PERMISSION_CONTROL, 0,   0,   handlePrevious,             NULL);
 	addCommand(COMMAND_LISTALL,          PERMISSION_READ,    0,   1,   handleListAll,              NULL);
@@ -1420,24 +1395,6 @@ static CommandEntry *getCommandEntryAndCheckArgcAndPermission(struct client *cli
 	return cmd;
 }
 
-static CommandEntry *getCommandEntryFromString(char *string, int permission)
-{
-	CommandEntry *cmd = NULL;
-	char *argv[COMMAND_ARGV_MAX] = { NULL };
-	char *duplicated = xstrdup(string);
-	int argc = buffer2array(duplicated, argv, COMMAND_ARGV_MAX);
-
-	if (0 == argc)
-		goto out;
-
-	cmd = getCommandEntryAndCheckArgcAndPermission(0, permission,
-						       argc, argv);
-
-out:
-	free(duplicated);
-	return cmd;
-}
-
 static int processCommandInternal(struct client *client,
 				  char *commandString, struct strnode *cmdnode)
 {