Emotion VLC: fix the random-player-stop bug !!

Bug explanation:
VLC has 2 different async mechanism that we use, one is the event callback
system that report player status changes and one is the display func that
is called at every frame. They run independently and can occur "at the same time".
We use ecore_pipe_write() in both and the result is that occasionally we send to
the pipe 2 commands mixed togheter (the FRAME_NEW and the LENGTH_CHANGED).
So emotion (on the other side of the pipe) receive a wrong command and stop the player.

The fix:
Use a mutex (Eina_Lock) while sending commands to the pipe so that we can send 2
commands "at the same time".

The SPANK credits:
BIG BIG SPANK goes to cedric (of course) that removed the command lock mechanism in
revision 10ebda80419

1 files changed, 76 insertions, 15 deletions

diff --git a/src/vlc/emotion_generic_vlc.c b/src/vlc/emotion_generic_vlc.c
index 02d25ec..3f90bd7 100644
--- a/src/vlc/emotion_generic_vlc.c
+++ b/src/vlc/emotion_generic_vlc.c
@@ -42,6 +42,7 @@ struct _App {
 
    Ecore_Pipe *fd_read;  // read commands from emotion here
    Ecore_Pipe *fd_write; // write commands for emotion here
+   Eina_Lock   cmd_mutex;// lock used to send just one command at a time
    int last_order;       // current command received from emotion
 
    char *filename;
@@ -59,7 +60,8 @@ struct _App {
 
 static void _player_setup(App *app);
 
-/* Commands sent to the emotion pipe */
+
+/* Utilities to send commands back to emotion */
 #define SEND_CMD_PARAM(app, i)                                  \
   if ((app)->fd_write)                                          \
     if (!ecore_pipe_write((app)->fd_write, &(i), sizeof((i))))  \
@@ -68,9 +70,13 @@ static void _player_setup(App *app);
 static void
 _send_cmd(App *app, int cmd)
 {
-   if (app->fd_write)
-     if (!ecore_pipe_write(app->fd_write, &cmd, sizeof(cmd)))
-       ecore_main_loop_quit();
+   if (!app->fd_write)
+     return;
+
+   eina_lock_take(&app->cmd_mutex); /* LOCK HERE */
+   
+   if (!ecore_pipe_write(app->fd_write, &cmd, sizeof(cmd)))
+     ecore_main_loop_quit();
 }
 
 static void
@@ -88,9 +94,17 @@ _send_cmd_str(App *app, const char *str)
 }
 
 static void
+_send_cmd_finish(App *app)
+{
+   eina_lock_release(&app->cmd_mutex); /* UNLOCK HERE */
+}
+
+/* Commands sent to the emotion pipe */
+static void
 _send_file_closed(App *app)
 {
    _send_cmd(app, EM_RESULT_FILE_CLOSE);
+   _send_cmd_finish(app);
 }
 
 static void
@@ -105,6 +119,7 @@ _send_time_changed(App *app)
    new_time /= 1000;
    _send_cmd(app, EM_RESULT_POSITION_CHANGED);
    SEND_CMD_PARAM(app, new_time);
+   _send_cmd_finish(app);
 }
 
 static void
@@ -113,6 +128,7 @@ _send_resize(App *app, int width, int height)
    _send_cmd(app, EM_RESULT_FRAME_SIZE);
    SEND_CMD_PARAM(app, width);
    SEND_CMD_PARAM(app, height);
+   _send_cmd_finish(app);
 }
 
 static void
@@ -129,6 +145,7 @@ _send_track_info(App *app, int cmd, int current, int count, libvlc_track_descrip
         _send_cmd_str(app, name);
         desc = desc->p_next;
      }
+   _send_cmd_finish(app);
 }
 
 static void
@@ -186,6 +203,8 @@ _send_all_meta_info(App *app)
    _send_cmd_str(app, meta);
    meta = libvlc_media_get_meta(app->m, libvlc_meta_TrackNumber);
    _send_cmd_str(app, meta);
+
+   _send_cmd_finish(app);
 }
 
 static void
@@ -196,6 +215,7 @@ _send_length_changed(App *app)
    length /= 1000;
    _send_cmd(app, EM_RESULT_LENGTH_CHANGED);
    SEND_CMD_PARAM(app, length);
+   _send_cmd_finish(app);
 }
 
 static void
@@ -205,9 +225,48 @@ _send_seekable_changed(App *app, const struct libvlc_event_t *ev)
 
    _send_cmd(app, EM_RESULT_SEEKABLE_CHANGED);
    SEND_CMD_PARAM(app, seekable);
+   _send_cmd_finish(app);
+}
+
+static void
+_send_playback_started(App *app)
+{
+   _send_cmd(app, EM_RESULT_PLAYBACK_STARTED);
+   _send_cmd_finish(app);
 }
 
 static void
+_send_playback_stopped(App *app)
+{
+   _send_cmd(app, EM_RESULT_PLAYBACK_STOPPED);
+   _send_cmd_finish(app);
+}
+
+static void
+_send_init(App *app)
+{
+   _send_cmd(app, EM_RESULT_INIT);
+   _send_cmd_finish(app);
+}
+
+static void
+_send_file_set(App *app)
+{
+   _send_cmd(app, EM_RESULT_FILE_SET);
+   _send_cmd_finish(app);
+}
+
+static void
+_send_file_set_done(App *app, int success)
+{
+   _send_cmd(app, EM_RESULT_FILE_SET_DONE);
+   SEND_CMD_PARAM(app, success);
+   _send_cmd_finish(app);
+}
+
+
+/* VLC events and callbacks */
+static void
 _event_cb(const struct libvlc_event_t *ev, void *data)
 {
    App *app = data;
@@ -231,11 +290,11 @@ _event_cb(const struct libvlc_event_t *ev, void *data)
          DBG("libvlc_MediaPlayerPlaying");
          libvlc_audio_set_volume(app->mp, app->volume);
          libvlc_audio_set_mute(app->mp, app->audio_muted);
-         _send_cmd(app, EM_RESULT_PLAYBACK_STARTED);
+         _send_playback_started(app);
          break;
       case libvlc_MediaPlayerStopped:
          DBG("libvlc_MediaPlayerStopped");
-         _send_cmd(app, EM_RESULT_PLAYBACK_STOPPED);
+         _send_playback_stopped(app);
          if (app->closing)
            {
               free(app->filename);
@@ -258,7 +317,7 @@ _event_cb(const struct libvlc_event_t *ev, void *data)
          /* vlc had released the media_playere here, we create a new one */
          app->mp = libvlc_media_player_new_from_media(app->m);
          _player_setup(app);
-         _send_cmd(app, EM_RESULT_PLAYBACK_STOPPED);
+         _send_playback_stopped(app);
          break;
    }
    ecore_thread_main_loop_end();
@@ -291,10 +350,9 @@ _tmp_playing_event_cb(const struct libvlc_event_t *ev, void *data)
    _send_all_meta_info(app);
 
    /* ok, we are done! Now let emotion create the shmem for us */
-   _send_cmd(app, EM_RESULT_FILE_SET);
+   _send_file_set(app);
 }
 
-
 static void *
 _lock(void *data, void **pixels)
 {
@@ -326,7 +384,10 @@ _display(void *data, void *id EINA_UNUSED)
    app->vs->frame.player = app->vs->frame.next;
    app->vs->frame.next = app->vs->frame.last;
    if (!app->vs->frame_drop++)
-     _send_cmd(app, EM_RESULT_FRAME_NEW);
+     {
+        _send_cmd(app, EM_RESULT_FRAME_NEW);
+        _send_cmd_finish(app);
+     }
    eina_semaphore_release(&app->vs->lock, 1);
 }
 
@@ -348,8 +409,6 @@ _player_setup(App *app)
                        _event_cb, app);
    libvlc_event_attach(app->event_mgr, libvlc_MediaPlayerEndReached,
                        _event_cb, app);
-   libvlc_event_attach(app->event_mgr, libvlc_MediaPlayerPositionChanged,
-                       _event_cb, app);
    libvlc_event_attach(app->event_mgr, libvlc_MediaPlayerStopped,
                        _event_cb, app);
 }
@@ -408,8 +467,7 @@ _file_set_done(App *app)
         _player_setup(app);
      }
 
-   _send_cmd(app, EM_RESULT_FILE_SET_DONE);
-   SEND_CMD_PARAM(app, r);
+   _send_file_set_done(app, r);
 }
 
 static void
@@ -588,7 +646,7 @@ _remote_command(void *data, void *buffer, unsigned int nbyte)
            case EM_CMD_INIT:
               app->shmname = strdup(buffer);
               app->inited = EINA_TRUE;
-              _send_cmd(app, EM_RESULT_INIT);
+              _send_init(app);
               break;
            case EM_CMD_FILE_SET:
               app->filename = strdup(buffer);
@@ -688,6 +746,8 @@ main(int argc, const char *argv[])
 
    ecore_init();
 
+   eina_lock_new(&app.cmd_mutex);
+   
    app.fd_read = ecore_pipe_full_add(_remote_command, &app,
                                      atoi(argv[1]), -1, EINA_FALSE, EINA_FALSE);
    app.fd_write = ecore_pipe_full_add(_dummy, NULL,
@@ -712,6 +772,7 @@ main(int argc, const char *argv[])
    ecore_pipe_del(app.fd_read);
    ecore_pipe_del(app.fd_write);
    ecore_event_handler_del(hld);
+   eina_lock_free(&app.cmd_mutex);
 
    ecore_shutdown();
    eina_shutdown();