player: restructure cancel callback

As preparation for file prefetching, we basically have to get rid of
using mpctx->playback_abort for the main demuxer (i.e. the thing that
can be prefetched). It can't be changed on a running demuxer, and always
using the same cancel handle would either mean aborting playback would
also abort prefetching, or that playback can't be aborted anymore.

Make this more flexible with some refactoring.

Thi is a quite shitty solution if you ask me, but YOLO.

input/input.c

@@ -144,7 +144,8 @@ struct input_ctx {
 
     struct cmd_queue cmd_queue;
 
-    struct mp_cancel *cancel;
+    void (*cancel)(void *cancel_ctx);
+    void *cancel_ctx;
 
     void (*wakeup_cb)(void *ctx);
     void *wakeup_ctx;
@@ -809,7 +810,7 @@ int mp_input_queue_cmd(struct input_ctx *ictx, mp_cmd_t *cmd)
     input_lock(ictx);
     if (cmd) {
         if (ictx->cancel && test_abort_cmd(ictx, cmd))
-            mp_cancel_trigger(ictx->cancel);
+            ictx->cancel(ictx->cancel_ctx);
         queue_add_tail(&ictx->cmd_queue, cmd);
         mp_input_wakeup(ictx);
     }
@@ -1335,10 +1336,11 @@ void mp_input_uninit(struct input_ctx *ictx)
     talloc_free(ictx);
 }
 
-void mp_input_set_cancel(struct input_ctx *ictx, struct mp_cancel *cancel)
+void mp_input_set_cancel(struct input_ctx *ictx, void (*cb)(void *c), void *c)
 {
     input_lock(ictx);
-    ictx->cancel = cancel;
+    ictx->cancel = cb;
+    ictx->cancel_ctx = c;
     input_unlock(ictx);
 }
 

input/input.h

@@ -242,8 +242,7 @@ void mp_input_wakeup(struct input_ctx *ictx);
 
 // Used to asynchronously abort playback. Needed because the core still can
 // block on network in some situations.
-struct mp_cancel;
+void mp_input_set_cancel(struct input_ctx *ictx, void (*cb)(void *c), void *c);
-void mp_input_set_cancel(struct input_ctx *ictx, struct mp_cancel *cancel);
 
 // If this returns true, use Right Alt key as Alt Gr to produce special
 // characters. If false, count Right Alt as the modifier Alt key.

player/client.c

@@ -982,7 +982,7 @@ static int run_client_command(mpv_handle *ctx, struct mp_cmd *cmd, mpv_node *res
         return MPV_ERROR_INVALID_PARAMETER;
 
     if (mp_input_is_abort_cmd(cmd))
-        mp_cancel_trigger(ctx->mpctx->playback_abort);
+        mp_abort_playback_async(ctx->mpctx);
 
     cmd->sender = ctx->name;
 

player/core.h

@@ -430,6 +430,11 @@ typedef struct MPContext {
     struct mp_ipc_ctx *ipc_ctx;
 
     struct mpv_opengl_cb_context *gl_cb_ctx;
+
+    pthread_mutex_t lock;
+
+    // --- The following fields are protected by lock
+    struct mp_cancel *demuxer_cancel; // cancel handle for MPContext.demuxer
 } MPContext;
 
 // audio.c
@@ -460,6 +465,7 @@ struct playlist_entry *mp_check_playlist_resume(struct MPContext *mpctx,
                                                 struct playlist *playlist);
 
 // loadfile.c
+void mp_abort_playback_async(struct MPContext *mpctx);
 void uninit_player(struct MPContext *mpctx, unsigned int mask);
 struct track *mp_add_external_file(struct MPContext *mpctx, char *filename,
                                    enum stream_type filter);

player/loadfile.c

@@ -57,6 +57,17 @@
 #include "command.h"
 #include "libmpv/client.h"
 
+// Called by foreign threads when playback should be stopped and such.
+void mp_abort_playback_async(struct MPContext *mpctx)
+{
+    mp_cancel_trigger(mpctx->playback_abort);
+
+    pthread_mutex_lock(&mpctx->lock);
+    if (mpctx->demuxer_cancel)
+        mp_cancel_trigger(mpctx->demuxer_cancel);
+    pthread_mutex_unlock(&mpctx->lock);
+}
+
 static void uninit_demuxer(struct MPContext *mpctx)
 {
     for (int r = 0; r < NUM_PTRACKS; r++) {
@@ -80,6 +91,11 @@ static void uninit_demuxer(struct MPContext *mpctx)
 
     free_demuxer_and_stream(mpctx->demuxer);
     mpctx->demuxer = NULL;
+
+    pthread_mutex_lock(&mpctx->lock);
+    talloc_free(mpctx->demuxer_cancel);
+    mpctx->demuxer_cancel = NULL;
+    pthread_mutex_unlock(&mpctx->lock);
 }
 
 #define APPEND(s, ...) mp_snprintf_cat(s, sizeof(s), __VA_ARGS__)
@@ -808,11 +824,14 @@ static void open_demux_reentrant(struct MPContext *mpctx)
 {
     struct demux_open_args args = {
         .global = mpctx->global,
-        .cancel = mpctx->playback_abort,
+        .cancel = mp_cancel_new(NULL),
         .log = mpctx->log,
         .stream_flags = mpctx->playing->stream_flags,
         .url = talloc_strdup(NULL, mpctx->stream_open_filename),
     };
+    pthread_mutex_lock(&mpctx->lock);
+    mpctx->demuxer_cancel = args.cancel;
+    pthread_mutex_unlock(&mpctx->lock);
     if (mpctx->opts->load_unsafe_playlists)
         args.stream_flags = 0;
     mpctx_run_reentrant(mpctx, open_demux_thread, &args);
@@ -820,6 +839,10 @@ static void open_demux_reentrant(struct MPContext *mpctx)
         mpctx->demuxer = args.demux;
     } else {
         mpctx->error_playing = args.err;
+        pthread_mutex_lock(&mpctx->lock);
+        talloc_free(mpctx->demuxer_cancel);
+        mpctx->demuxer_cancel = NULL;
+        pthread_mutex_unlock(&mpctx->lock);
     }
     talloc_free(args.url);
 }
@@ -1170,7 +1193,7 @@ terminate_playback:
     if (mpctx->step_frames)
         opts->pause = 1;
 
-    mp_cancel_trigger(mpctx->playback_abort);
+    mp_abort_playback_async(mpctx);
 
     // time to uninit all, except global stuff:
     uninit_complex_filters(mpctx);

player/main.c

@@ -311,6 +311,12 @@ static int cfg_include(void *ctx, char *filename, int flags)
     return r;
 }
 
+static void abort_playback_cb(void *ctx)
+{
+    struct MPContext *mpctx = ctx;
+    mp_abort_playback_async(mpctx);
+}
+
 struct MPContext *mp_create(void)
 {
     char *enable_talloc = getenv("MPV_LEAK_REPORT");
@@ -361,7 +367,7 @@ struct MPContext *mp_create(void)
     cocoa_set_input_context(mpctx->input);
 #endif
 
-    mp_input_set_cancel(mpctx->input, mpctx->playback_abort);
+    mp_input_set_cancel(mpctx->input, abort_playback_cb, mpctx);
 
     char *verbose_env = getenv("MPV_VERBOSE");
     if (verbose_env)

player/misc.c

@@ -287,7 +287,7 @@ int mpctx_run_reentrant(struct MPContext *mpctx, void (*thread_fn)(void *arg),
         mp_idle(mpctx);
 
         if (mpctx->stop_play)
-            mp_cancel_trigger(mpctx->playback_abort);
+            mp_abort_playback_async(mpctx);
 
         pthread_mutex_lock(&args.mutex);
         success |= args.done;