client API: create core thread at an earlier time

Create the core thread right in mpv_create(), and reduce what
mpv_initialize() does further. This is simpler, and allows the API user
to do more before calling mpv_initialize(). The latter is not the real
goal, rather we'd like mpv_intialize() reduced to do almost nothing. It
still does a lot, but nothing truly special anymore that is absolutely
required for basic mpv workings.

One thing we want the user to be able to do is changing properties
before mpv_initialize() to reduce the special status of
mpv_set_option().

DOCS/client-api-changes.rst

@@ -35,6 +35,8 @@ API changes
  --- mpv 0.21.0 ---
  1.23   - deprecate setting "no-" options via mpv_set_option*(). For example,
           instead of "no-video=" you should set "video=no".
+        - be much more permissive what API calls are allowed before
+          mpv_initialize().
  --- mpv 0.19.0 ---
  1.22   - add stream_cb API for custom protocols
  --- mpv 0.18.1 ---

libmpv/client.h

@@ -370,7 +370,7 @@ const char *mpv_client_name(mpv_handle *ctx);
  * and needs to be initialized to be actually used with most other API
  * functions.
  *
- * Most API functions will return MPV_ERROR_UNINITIALIZED in the uninitialized
+ * Some API functions will return MPV_ERROR_UNINITIALIZED in the uninitialized
  * state. You can call mpv_set_option() (or mpv_set_option_string() and other
  * variants) to set initial options. After this, call mpv_initialize() to start
  * the player, and then use e.g. mpv_command() to start playback of a file.

player/client.c

@@ -364,14 +364,12 @@ void mp_resume_all(mpv_handle *ctx)
 
 static void lock_core(mpv_handle *ctx)
 {
-    if (ctx->mpctx->initialized)
+    mp_dispatch_lock(ctx->mpctx->dispatch);
-        mp_dispatch_lock(ctx->mpctx->dispatch);
 }
 
 static void unlock_core(mpv_handle *ctx)
 {
-    if (ctx->mpctx->initialized)
+    mp_dispatch_unlock(ctx->mpctx->dispatch);
-        mp_dispatch_unlock(ctx->mpctx->dispatch);
 }
 
 void mpv_wait_async_requests(mpv_handle *ctx)
@@ -438,7 +436,7 @@ void mpv_terminate_destroy(mpv_handle *ctx)
 
     mpv_command(ctx, (const char*[]){"quit", NULL});
 
-    if (!ctx->owner || !ctx->mpctx->initialized) {
+    if (!ctx->owner) {
         mpv_detach_destroy(ctx);
         return;
     }
@@ -458,6 +456,26 @@ void mpv_terminate_destroy(mpv_handle *ctx)
     pthread_join(playthread, NULL);
 }
 
+static void *playback_thread(void *p)
+{
+    struct MPContext *mpctx = p;
+    mpctx->autodetach = true;
+
+    mpthread_set_name("mpv core");
+
+    while (!mpctx->initialized && mpctx->stop_play != PT_QUIT)
+        mp_idle(mpctx);
+
+    if (mpctx->initialized)
+        mp_play_files(mpctx);
+
+    // This actually waits until all clients are gone before actually
+    // destroying mpctx.
+    mp_destroy(mpctx);
+
+    return NULL;
+}
+
 // We mostly care about LC_NUMERIC, and how "." vs. "," is treated,
 // Other locale stuff might break too, but probably isn't too bad.
 static bool check_locale(void)
@@ -484,6 +502,13 @@ mpv_handle *mpv_create(void)
     } else {
         mp_destroy(mpctx);
     }
+
+    pthread_t thread;
+    if (pthread_create(&thread, NULL, playback_thread, ctx->mpctx) != 0) {
+        mpv_terminate_destroy(ctx);
+        return NULL;
+    }
+
     return ctx;
 }
 
@@ -491,40 +516,25 @@ mpv_handle *mpv_create_client(mpv_handle *ctx, const char *name)
 {
     if (!ctx)
         return mpv_create();
-    if (!ctx->mpctx->initialized)
-        return NULL;
     mpv_handle *new = mp_new_client(ctx->mpctx->clients, name);
     if (new)
         mpv_wait_event(new, 0); // set fuzzy_initialized
     return new;
 }
 
-static void *playback_thread(void *p)
+static void doinit(void *ctx)
 {
-    struct MPContext *mpctx = p;
+    void **args = ctx;
-    mpctx->autodetach = true;
 
-    mpthread_set_name("playback core");
+    *(int *)args[1] = mp_initialize(args[0], NULL);
-
-    mp_play_files(mpctx);
-
-    // This actually waits until all clients are gone before actually
-    // destroying mpctx.
-    mp_destroy(mpctx);
-
-    return NULL;
 }
 
 int mpv_initialize(mpv_handle *ctx)
 {
-    if (mp_initialize(ctx->mpctx, NULL) < 0)
+    int res = 0;
-        return MPV_ERROR_INVALID_PARAMETER;
+    void *args[2] = {ctx->mpctx, &res};
-
+    mp_dispatch_run(ctx->mpctx->dispatch, doinit, args);
-    pthread_t thread;
+    return res < 0 ? MPV_ERROR_INVALID_PARAMETER : 0;
-    if (pthread_create(&thread, NULL, playback_thread, ctx->mpctx) != 0)
-        return MPV_ERROR_NOMEM;
-
-    return 0;
 }
 
 // set ev->data to a new copy of the original data
@@ -979,8 +989,6 @@ static void cmd_fn(void *data)
 
 static int run_client_command(mpv_handle *ctx, struct mp_cmd *cmd, mpv_node *res)
 {
-    if (!ctx->mpctx->initialized)
-        return MPV_ERROR_UNINITIALIZED;
     if (!cmd)
         return MPV_ERROR_INVALID_PARAMETER;
 
@@ -1020,8 +1028,6 @@ int mpv_command_string(mpv_handle *ctx, const char *args)
 
 static int run_cmd_async(mpv_handle *ctx, uint64_t ud, struct mp_cmd *cmd)
 {
-    if (!ctx->mpctx->initialized)
-        return MPV_ERROR_UNINITIALIZED;
     if (!cmd)
         return MPV_ERROR_INVALID_PARAMETER;
 
@@ -1099,8 +1105,6 @@ static void setproperty_fn(void *arg)
 int mpv_set_property(mpv_handle *ctx, const char *name, mpv_format format,
                      void *data)
 {
-    if (!ctx->mpctx->initialized)
-        return MPV_ERROR_UNINITIALIZED;
     if (!get_mp_type(format))
         return MPV_ERROR_PROPERTY_FORMAT;
 
@@ -1130,8 +1134,6 @@ int mpv_set_property_async(mpv_handle *ctx, uint64_t ud, const char *name,
                            mpv_format format, void *data)
 {
     const struct m_option *type = get_mp_type(format);
-    if (!ctx->mpctx->initialized)
-        return MPV_ERROR_UNINITIALIZED;
     if (!type)
         return MPV_ERROR_PROPERTY_FORMAT;
 
@@ -1244,8 +1246,6 @@ static void getproperty_fn(void *arg)
 int mpv_get_property(mpv_handle *ctx, const char *name, mpv_format format,
                      void *data)
 {
-    if (!ctx->mpctx->initialized)
-        return MPV_ERROR_UNINITIALIZED;
     if (!data)
         return MPV_ERROR_INVALID_PARAMETER;
     if (!get_mp_type_get(format))
@@ -1278,8 +1278,6 @@ char *mpv_get_property_osd_string(mpv_handle *ctx, const char *name)
 int mpv_get_property_async(mpv_handle *ctx, uint64_t ud, const char *name,
                            mpv_format format)
 {
-    if (!ctx->mpctx->initialized)
-        return MPV_ERROR_UNINITIALIZED;
     if (!get_mp_type_get(format))
         return MPV_ERROR_PROPERTY_FORMAT;
 
@@ -1448,8 +1446,6 @@ static void update_prop(void *p)
 // outstanding property.
 static bool gen_property_change_event(struct mpv_handle *ctx)
 {
-    if (!ctx->mpctx->initialized)
-        return false;
     int start = ctx->lowest_changed;
     ctx->lowest_changed = ctx->num_properties;
     for (int n = start; n < ctx->num_properties; n++) {
@@ -1715,8 +1711,6 @@ int mpv_opengl_cb_render(mpv_opengl_cb_context *ctx, int fbo, int vp[4])
 
 void *mpv_get_sub_api(mpv_handle *ctx, mpv_sub_api sub_api)
 {
-    if (!ctx->mpctx->initialized)
-        return NULL;
     void *res = NULL;
     lock_core(ctx);
     switch (sub_api) {

player/main.c

@@ -323,6 +323,12 @@ static int cfg_include(void *ctx, char *filename, int flags)
     return r;
 }
 
+void wakeup_playloop(void *ctx)
+{
+    struct MPContext *mpctx = ctx;
+    mp_input_wakeup(mpctx->input);
+}
+
 struct MPContext *mp_create(void)
 {
     mp_time_init();
@@ -366,18 +372,16 @@ struct MPContext *mp_create(void)
     command_init(mpctx);
     init_libav(mpctx->global);
     mp_clients_init(mpctx);
+    mpctx->osd = osd_create(mpctx->global);
 
 #if HAVE_COCOA
     cocoa_set_input_context(mpctx->input);
 #endif
 
-    return mpctx;
+    mp_input_set_cancel(mpctx->input, mpctx->playback_abort);
-}
+    mp_dispatch_set_wakeup_fn(mpctx->dispatch, wakeup_playloop, mpctx);
 
-void wakeup_playloop(void *ctx)
+    return mpctx;
-{
-    struct MPContext *mpctx = ctx;
-    mp_input_wakeup(mpctx->input);
 }
 
 // Finish mpctx initialization. This must be done after setting up all options.
@@ -442,9 +446,6 @@ int mp_initialize(struct MPContext *mpctx, char **options)
         return -3;
 
     mp_input_load(mpctx->input);
-    mp_input_set_cancel(mpctx->input, mpctx->playback_abort);
-
-    mp_dispatch_set_wakeup_fn(mpctx->dispatch, wakeup_playloop, mpctx);
 
 #if HAVE_ENCODING
     if (opts->encode_opts->file && opts->encode_opts->file[0]) {
@@ -464,8 +465,6 @@ int mp_initialize(struct MPContext *mpctx, char **options)
     MP_WARN(mpctx, "There will be no OSD and no text subtitles.\n");
 #endif
 
-    mpctx->osd = osd_create(mpctx->global);
-
     // From this point on, all mpctx members are initialized.
     mpctx->initialized = true;