mpdclient: use the "idle" command to reduce CPU and network usage

[ncmpc.git] / src / main.c

diff --git a/src/main.c b/src/main.c
index e5afa359728fafaf8d3a3667ab7d56b8ff6c8b2f..2bc1b624e70767c330bfbaf014d539e2152d97cd 100644 (file)
--- a/src/main.c
+++ b/src/main.c
@@ -20,6 +20,7 @@
 #include "config.h"
 #include "ncmpc.h"
 #include "mpdclient.h"
+#include "gidle.h"
 #include "charset.h"
 #include "options.h"
 #include "command.h"
@@ -155,6 +156,12 @@ catch_sigwinch(G_GNUC_UNUSED int sig)
        timer_sigwinch_id = g_timeout_add(100, timer_sigwinch, NULL);
 }
 
+static void
+idle_callback(enum mpd_error error,
+             G_GNUC_UNUSED enum mpd_server_error server_error,
+             const char *message, enum mpd_idle events,
+             G_GNUC_UNUSED void *ctx);
+
 static gboolean
 timer_mpd_update(gpointer data);
 
@@ -181,7 +188,10 @@ disable_update_timer(void)
 static bool
 should_enable_update_timer(void)
 {
-       return mpdclient_is_connected(mpd)
+       return (mpdclient_is_connected(mpd) &&
+               (mpd->source == NULL || /* "idle" not supported */
+                (mpd->status != NULL &&
+                 mpd_status_get_state(mpd->status) == MPD_STATE_PLAY)))
 #ifndef NCMPC_MINI
                || options.display_time
 #endif
@@ -268,6 +278,11 @@ timer_reconnect(G_GNUC_UNUSED gpointer data)
        }
 #endif
 
+       if (mpd_connection_cmp_server_version(connection,
+                                             0, 14, 0) >= 0)
+               mpd->source = mpd_glib_new(connection,
+                                          idle_callback, mpd);
+
        screen_status_printf(_("Connected to %s"),
                             options.host != NULL
                             ? options.host : "localhost");
@@ -294,6 +309,67 @@ check_reconnect(void)
                                                    NULL);
 }
 
+/**
+ * This function is called by the gidle.c library when MPD sends us an
+ * idle event (or when the connectiond dies).
+ */
+static void
+idle_callback(enum mpd_error error, enum mpd_server_error server_error,
+             const char *message, enum mpd_idle events,
+             void *ctx)
+{
+       struct mpdclient *c = ctx;
+       struct mpd_connection *connection;
+
+       c->idle = false;
+
+       connection = mpdclient_get_connection(c);
+       assert(connection != NULL);
+
+       if (error != MPD_ERROR_SUCCESS) {
+               char *allocated;
+
+               if (error == MPD_ERROR_SERVER &&
+                   server_error == MPD_SERVER_ERROR_UNKNOWN_CMD) {
+                       /* the "idle" command is not supported - fall
+                          back to timer based polling */
+                       mpd_glib_free(c->source);
+                       c->source = NULL;
+                       auto_update_timer();
+                       return;
+               }
+
+               if (error == MPD_ERROR_SERVER)
+                       message = allocated = utf8_to_locale(message);
+               else
+                       allocated = NULL;
+               screen_status_message(message);
+               g_free(allocated);
+               screen_bell();
+               doupdate();
+
+               mpdclient_disconnect(c);
+               reconnect_source_id = g_timeout_add(1000, timer_reconnect,
+                                                   NULL);
+               return;
+       }
+
+       c->events |= events;
+       mpdclient_update(c);
+
+#ifndef NCMPC_MINI
+       if (options.enable_xterm_title)
+               update_xterm_title();
+#endif
+
+       screen_update(mpd);
+       c->events = 0;
+
+       mpdclient_put_connection(c);
+       check_reconnect();
+       auto_update_timer();
+}
+
 static gboolean
 timer_mpd_update(G_GNUC_UNUSED gpointer data)
 {