update: store playlist files in database

Don't open the music directory for each "lsinfo" call.  Get the list
of playlist files from the memory database.

src/playlist_vector.c

@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2003-2010 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 "config.h"
+#include "playlist_vector.h"
+
+#include <assert.h>
+#include <string.h>
+#include <glib.h>
+
+static struct playlist_metadata *
+playlist_metadata_new(const char *name, time_t mtime)
+{
+	assert(name != NULL);
+
+	struct playlist_metadata *pm = g_slice_new(struct playlist_metadata);
+	pm->name = g_strdup(name);
+	pm->mtime = mtime;
+	return pm;
+}
+
+static void
+playlist_metadata_free(struct playlist_metadata *pm)
+{
+	assert(pm != NULL);
+	assert(pm->name != NULL);
+
+	g_free(pm->name);
+	g_slice_free(struct playlist_metadata, pm);
+}
+
+void
+playlist_vector_deinit(struct playlist_vector *pv)
+{
+	assert(pv != NULL);
+
+	while (pv->head != NULL) {
+		struct playlist_metadata *pm = pv->head;
+		pv->head = pm->next;
+		playlist_metadata_free(pm);
+	}
+}
+
+static struct playlist_metadata **
+playlist_vector_find_p(struct playlist_vector *pv, const char *name)
+{
+	assert(pv != NULL);
+	assert(name != NULL);
+
+	struct playlist_metadata **pmp = &pv->head;
+
+	for (;;) {
+		struct playlist_metadata *pm = *pmp;
+		if (pm == NULL)
+			return NULL;
+
+		if (strcmp(pm->name, name) == 0)
+			return pmp;
+
+		pmp = &pm->next;
+	}
+}
+
+struct playlist_metadata *
+playlist_vector_find(struct playlist_vector *pv, const char *name)
+{
+	struct playlist_metadata **pmp = playlist_vector_find_p(pv, name);
+	return pmp != NULL ? *pmp : NULL;
+}
+
+void
+playlist_vector_add(struct playlist_vector *pv,
+		    const char *name, time_t mtime)
+{
+	struct playlist_metadata *pm = playlist_metadata_new(name, mtime);
+	pm->next = pv->head;
+	pv->head = pm;
+}
+
+void
+playlist_vector_update_or_add(struct playlist_vector *pv,
+			      const char *name, time_t mtime)
+{
+	struct playlist_metadata **pmp = playlist_vector_find_p(pv, name);
+	if (pmp != NULL) {
+		struct playlist_metadata *pm = *pmp;
+		pm->mtime = mtime;
+	} else
+		playlist_vector_add(pv, name, mtime);
+}
+
+bool
+playlist_vector_remove(struct playlist_vector *pv, const char *name)
+{
+	struct playlist_metadata **pmp = playlist_vector_find_p(pv, name);
+	if (pmp == NULL)
+		return false;
+
+	struct playlist_metadata *pm = *pmp;
+	*pmp = pm->next;
+
+	playlist_metadata_free(pm);
+	return true;
+}