gidle: work around nested leave/enter problem

Add the flag "leaving" which disables the mpd_glib_enter() function
while mpd_glib_leave() is running.

diff --git a/src/gidle.c b/src/gidle.c
index 9c720866770f415bfe504470c57dbf2cd2d39941..6f149a5292cb3b3f3b7624c55427914ff1532b8b 100644 (file)
--- a/src/gidle.c
+++ b/src/gidle.c
@@ -52,6 +52,15 @@ struct mpd_glib_source {
        guint id;
 
        enum mpd_idle idle_events;
+
+       /**
+        * This flag is a hack: it is set while mpd_glib_leave() is
+        * executed.  mpd_glib_leave() might invoke the callback, and
+        * the callback might invoke mpd_glib_enter(), awkwardly
+        * leaving mpd_glib_leave() in idle mode.  As long as this
+        * flag is set, mpd_glib_enter() is a no-op to prevent this.
+        */
+       bool leaving;
 };
 
 struct mpd_glib_source *
@@ -71,6 +80,7 @@ mpd_glib_new(struct mpd_connection *connection,
        source->channel = g_io_channel_unix_new(mpd_async_get_fd(source->async));
        source->io_events = 0;
        source->id = 0;
+       source->leaving = false;
 
        return source;
 }
@@ -316,6 +326,9 @@ mpd_glib_enter(struct mpd_glib_source *source)
        assert(source->io_events == 0);
        assert(source->id == 0);
 
+       if (source->leaving)
+               return;
+
        source->idle_events = 0;
 
        success = mpd_async_send_command(source->async, "idle", NULL);
@@ -344,6 +357,8 @@ mpd_glib_leave(struct mpd_glib_source *source)
                ? mpd_run_noidle(source->connection)
                : mpd_recv_idle(source->connection, false);
 
+       source->leaving = true;
+
        if (events == 0 &&
            mpd_connection_get_error(source->connection) != MPD_ERROR_SUCCESS) {
                enum mpd_error error =
@@ -355,9 +370,12 @@ mpd_glib_leave(struct mpd_glib_source *source)
 
                mpd_glib_invoke_error(source, error, server_error,
                                      mpd_connection_get_error_message(source->connection));
+               source->leaving = false;
                return;
        }
 
        source->idle_events |= events;
        mpd_glib_invoke(source);
+
+       source->leaving = false;
 }