command: added command "rescan"

"rescan" is the same as "update", but it discards existing songs in
the database.

doc/protocol.xml

@@ -1245,6 +1245,20 @@ OK
             </para>
           </listitem>
         </varlistentry>
+        <varlistentry id="command_rescan">
+          <term>
+            <cmdsynopsis>
+              <command>rescan</command>
+              <arg choice="opt"><replaceable>URI</replaceable></arg>
+            </cmdsynopsis>
+          </term>
+          <listitem>
+            <para>
+              Same as <command>update</command>, but also rescans
+              unmodified files.
+            </para>
+          </listitem>
+        </varlistentry>
       </variablelist>
     </section>
 

src/command.c

@@ -1025,7 +1025,28 @@ handle_update(struct client *client, G_GNUC_UNUSED int argc, char *argv[])
 	if (argc == 2)
 		path = argv[1];
 
-	ret = update_enqueue(path);
+	ret = update_enqueue(path, false);
+	if (ret > 0) {
+		client_printf(client, "updating_db: %i\n", ret);
+		return COMMAND_RETURN_OK;
+	} else {
+		command_error(client, ACK_ERROR_UPDATE_ALREADY,
+			      "already updating");
+		return COMMAND_RETURN_ERROR;
+	}
+}
+
+static enum command_return
+handle_rescan(struct client *client, G_GNUC_UNUSED int argc, char *argv[])
+{
+	const char *path = NULL;
+	unsigned ret;
+
+	assert(argc <= 2);
+	if (argc == 2)
+		path = argv[1];
+
+	ret = update_enqueue(path, true);
 	if (ret > 0) {
 		client_printf(client, "updating_db: %i\n", ret);
 		return COMMAND_RETURN_OK;
@@ -1731,6 +1752,7 @@ static const struct command commands[] = {
 	{ "random", PERMISSION_CONTROL, 1, 1, handle_random },
 	{ "rename", PERMISSION_CONTROL, 2, 2, handle_rename },
 	{ "repeat", PERMISSION_CONTROL, 1, 1, handle_repeat },
+	{ "rescan", PERMISSION_ADMIN, 0, 1, handle_rescan },
 	{ "rm", PERMISSION_CONTROL, 1, 1, handle_rm },
 	{ "save", PERMISSION_CONTROL, 1, 1, handle_save },
 	{ "search", PERMISSION_READ, 2, -1, handle_search },

src/main.c

@@ -362,7 +362,7 @@ int main(int argc, char *argv[])
 	if (create_db) {
 		/* the database failed to load: recreate the
 		   database */
-		unsigned job = update_enqueue(NULL);
+		unsigned job = update_enqueue(NULL, true);
 		if (job == 0)
 			g_error("directory update failed");
 	}

src/update.c

@@ -52,6 +52,9 @@ static unsigned update_task_id;
 /** used by the main thread to notify the update thread */
 struct notify update_notify;
 
+/* XXX this flag is passed to update_task() */
+static bool discard;
+
 unsigned
 isUpdatingDB(void)
 {
@@ -62,7 +65,7 @@ static void * update_task(void *_path)
 {
 	const char *path = _path;
 
-	modified = update_walk(path);
+	modified = update_walk(path, discard);
 	g_free(_path);
 
 	if (modified || !db_exists())
@@ -93,7 +96,7 @@ spawn_update_task(const char *path)
 }
 
 unsigned
-update_enqueue(const char *path)
+update_enqueue(const char *path, bool _discard)
 {
 	assert(g_thread_self() == main_task);
 
@@ -102,13 +105,14 @@ update_enqueue(const char *path)
 
 	if (progress != UPDATE_PROGRESS_IDLE) {
 		unsigned next_task_id =
-			update_queue_push(path, update_task_id);
+			update_queue_push(path, discard, update_task_id);
 		if (next_task_id == 0)
 			return 0;
 
 		return next_task_id > update_task_id_max ?  1 : next_task_id;
 	}
 
+	discard = _discard;
 	spawn_update_task(path);
 
 	idle_add(IDLE_UPDATE);
@@ -135,7 +139,7 @@ static void update_finished_event(void)
 		idle_add(IDLE_DATABASE);
 	}
 
-	path = update_queue_shift();
+	path = update_queue_shift(&discard);
 	if (path != NULL) {
 		/* schedule the next path */
 		spawn_update_task(path);

src/update.h

@@ -35,6 +35,6 @@ isUpdatingDB(void);
  * @return the job id, or 0 on error
  */
 unsigned
-update_enqueue(const char *path);
+update_enqueue(const char *path, bool discard);
 
 #endif

src/update_internal.h

@@ -33,10 +33,10 @@ struct directory;
 extern struct notify update_notify;
 
 unsigned
-update_queue_push(const char *path, unsigned base);
+update_queue_push(const char *path, bool discard, unsigned base);
 
 char *
-update_queue_shift(void);
+update_queue_shift(bool *discard_r);
 
 void
 update_walk_global_init(void);
@@ -48,7 +48,7 @@ update_walk_global_finish(void);
  * Returns true if the database was modified.
  */
 bool
-update_walk(const char *path);
+update_walk(const char *path, bool discard);
 
 void
 update_remove_global_init(void);

src/update_queue.c

@@ -25,31 +25,41 @@
 #include <string.h>
 
 /* make this dynamic?, or maybe this is big enough... */
-static char *update_paths[32];
-static size_t update_paths_nr;
+static struct {
+	char *path;
+	bool discard;
+} update_queue[32];
+
+static size_t update_queue_length;
 
 unsigned
-update_queue_push(const char *path, unsigned base)
+update_queue_push(const char *path, bool discard, unsigned base)
 {
-	assert(update_paths_nr <= G_N_ELEMENTS(update_paths));
+	assert(update_queue_length <= G_N_ELEMENTS(update_queue));
 
-	if (update_paths_nr == G_N_ELEMENTS(update_paths))
+	if (update_queue_length == G_N_ELEMENTS(update_queue))
 		return 0;
 
-	update_paths[update_paths_nr++] = g_strdup(path);
-	return base + update_paths_nr;
+	update_queue[update_queue_length].path = g_strdup(path);
+	update_queue[update_queue_length].discard = discard;
+
+	++update_queue_length;
+
+	return base + update_queue_length;
 }
 
 char *
-update_queue_shift(void)
+update_queue_shift(bool *discard_r)
 {
 	char *path;
 
-	if (update_paths_nr == 0)
+	if (update_queue_length == 0)
 		return NULL;
 
-	path = update_paths[0];
-	memmove(&update_paths[0], &update_paths[1],
-		--update_paths_nr * sizeof(char *));
+	path = update_queue[0].path;
+	*discard_r = update_queue[0].discard;
+
+	memmove(&update_queue[0], &update_queue[1],
+		--update_queue_length * sizeof(update_queue[0]));
 	return path;
 }

src/update_walk.c

@@ -39,6 +39,7 @@
 #include <stdlib.h>
 #include <errno.h>
 
+static bool walk_discard;
 static bool modified;
 
 #ifndef WIN32
@@ -350,7 +351,8 @@ update_archive_file(struct directory *parent, const char *name,
 	char *filepath;
 
 	directory = dirvec_find(&parent->children, name);
-	if (directory != NULL && directory->mtime == st->st_mtime)
+	if (directory != NULL && directory->mtime == st->st_mtime &&
+	    !walk_discard)
 		/* MPD has already scanned the archive, and it hasn't
 		   changed since - don't consider updating it */
 		return;
@@ -405,7 +407,7 @@ update_container_file(	struct directory* directory,
 	if (contdir != NULL)
 	{
 		// modification time not eq. file mod. time
-		if (contdir->mtime != st->st_mtime)
+		if (contdir->mtime != st->st_mtime || walk_discard)
 		{
 			g_message("removing container file: %s", pathname);
 
@@ -470,7 +472,8 @@ update_regular_file(struct directory *directory,
 	{
 		struct song* song = songvec_find(&directory->songs, name);
 
-		if (!(song != NULL && st->st_mtime == song->mtime) &&
+		if (!(song != NULL && st->st_mtime == song->mtime &&
+		      !walk_discard) &&
 			plugin->container_scan != NULL)
 		{
 			if (update_container_file(directory, name, st, plugin))
@@ -491,7 +494,7 @@ update_regular_file(struct directory *directory,
 			modified = true;
 			g_message("added %s/%s",
 				  directory_get_path(directory), name);
-		} else if (st->st_mtime != song->mtime) {
+		} else if (st->st_mtime != song->mtime || walk_discard) {
 			g_message("updating %s/%s",
 				  directory_get_path(directory), name);
 			if (!song_file_update(song))
@@ -737,8 +740,9 @@ updatePath(const char *path)
 }
 
 bool
-update_walk(const char *path)
+update_walk(const char *path, bool discard)
 {
+	walk_discard = discard;
 	modified = false;
 
 	if (path != NULL && !isRootDirectory(path)) {