playlist_list: pass configuration to playlist plugins

This patch completes the configuration support.

doc/user.xml

@@ -391,6 +391,68 @@ cd mpd-version</programlisting>
         </tgroup>
       </informaltable>
     </section>
+
+    <section>
+      <title>Configuring playlist plugins</title>
+
+      <para>
+        Playlist plugins are used to load remote playlists.  This is
+        not related to MPD's playlist directory.
+      </para>
+
+      <para>
+        To configure a filter, add a
+        <varname>playlist_plugin</varname> block to
+        <filename>mpd.conf</filename>:
+      </para>
+
+      <programlisting>playlist_plugin {
+    name "m3u"
+    enabled "true"
+}
+      </programlisting>
+
+      <para>
+        The following table lists the
+        <varname>playlist_plugin</varname> options valid for all
+        plugins:
+      </para>
+
+      <informaltable>
+        <tgroup cols="2">
+          <thead>
+            <row>
+              <entry>
+                Name
+              </entry>
+              <entry>
+                Description
+              </entry>
+            </row>
+          </thead>
+          <tbody>
+            <row>
+              <entry>
+                <varname>name</varname>
+              </entry>
+              <entry>
+                The name of the plugin.
+              </entry>
+            </row>
+            <row>
+              <entry>
+                <varname>enabled</varname>
+                <parameter>yes|no</parameter>
+              </entry>
+              <entry>
+                Allows you to disable a input plugin without
+                recompiling.  By default, all plugins are enabled.
+              </entry>
+            </row>
+          </tbody>
+        </tgroup>
+      </informaltable>
+    </section>
   </chapter>
 
   <chapter>

src/conf.c

@@ -90,6 +90,7 @@ static struct config_entry config_entries[] = {
 	{ .name = CONF_DECODER, true, true },
 	{ .name = CONF_INPUT, true, true },
 	{ .name = CONF_GAPLESS_MP3_PLAYBACK, false, false },
+	{ .name = CONF_PLAYLIST_PLUGIN, true, true },
 	{ .name = "filter", true, true },
 };
 

src/conf.h

@@ -67,6 +67,7 @@
 #define CONF_DECODER "decoder"
 #define CONF_INPUT "input"
 #define CONF_GAPLESS_MP3_PLAYBACK	"gapless_mp3_playback"
+#define CONF_PLAYLIST_PLUGIN "playlist_plugin"
 
 #define DEFAULT_PLAYLIST_MAX_LENGTH (1024*16)
 #define DEFAULT_PLAYLIST_SAVE_ABSOLUTE_PATHS false

src/playlist_list.c

@@ -23,10 +23,12 @@
 #include "input_stream.h"
 #include "uri.h"
 #include "utils.h"
+#include "conf.h"
 
 #include <glib.h>
 
 #include <assert.h>
+#include <string.h>
 
 static const struct playlist_plugin *const playlist_plugins[] = {
 	&m3u_playlist_plugin,
@@ -36,12 +38,48 @@ static const struct playlist_plugin *const playlist_plugins[] = {
 /** which plugins have been initialized successfully? */
 static bool playlist_plugins_enabled[G_N_ELEMENTS(playlist_plugins)];
 
+/**
+ * Find the "playlist" configuration block for the specified plugin.
+ *
+ * @param plugin_name the name of the playlist plugin
+ * @return the configuration block, or NULL if none was configured
+ */
+static const struct config_param *
+playlist_plugin_config(const char *plugin_name)
+{
+	const struct config_param *param = NULL;
+
+	assert(plugin_name != NULL);
+
+	while ((param = config_get_next_param(CONF_PLAYLIST_PLUGIN, param)) != NULL) {
+		const char *name =
+			config_get_block_string(param, "name", NULL);
+		if (name == NULL)
+			g_error("playlist configuration without 'plugin' name in line %d",
+				param->line);
+
+		if (strcmp(name, plugin_name) == 0)
+			return param;
+	}
+
+	return NULL;
+}
+
 void
 playlist_list_global_init(void)
 {
-	for (unsigned i = 0; playlist_plugins[i] != NULL; ++i)
+	for (unsigned i = 0; playlist_plugins[i] != NULL; ++i) {
+		const struct playlist_plugin *plugin = playlist_plugins[i];
+		const struct config_param *param =
+			playlist_plugin_config(plugin->name);
+
+		if (!config_get_block_bool(param, "enabled", true))
+			/* the plugin is disabled in mpd.conf */
+			continue;
+
 		playlist_plugins_enabled[i] =
-			playlist_plugin_init(playlist_plugins[i], NULL);
+			playlist_plugin_init(playlist_plugins[i], param);
+	}
 }
 
 void