player: make --osc/--ytdl settable during playback

Setting the osc or ytdl properties will now load/unload the associated
scripts. (For ytdl this does not mean the currently played URL will be
reloaded.)

Also add a changelog entry for this, which also covers the preceding
work for --terminal.

DOCS/interface-changes.rst

@@ -86,6 +86,10 @@ Interface changes
       has been added to the manpage describing some conflicting behavior
       between options and properties)
     - implement changing sub-speed during playback
+    - make many previously fixed options changeable at runtime (for example
+      --terminal, --osc, --ytdl, can all be enable/disabled after
+      mpv_initialize() - this can be extended to other still fixed options
+      on user requests)
  --- mpv 0.20.0 ---
     - add --image-display-duration option - this also means that image duration
       is not influenced by --mf-fps anymore in the general case (this is an

options/m_option.h

@@ -385,7 +385,8 @@ struct m_option {
 #define UPDATE_RENDERER         (1 << 15) // mainly vo_opengl options
 #define UPDATE_VIDEOPOS         (1 << 16) // video position (panscan etc.)
 #define UPDATE_OSD              (1 << 17) // related to OSD rendering
-#define UPDATE_OPT_LAST         (1 << 17)
+#define UPDATE_BUILTIN_SCRIPTS  (1 << 18) // osc/ytdl
+#define UPDATE_OPT_LAST         (1 << 18)
 
 // All bits between _FIRST and _LAST (inclusive)
 #define UPDATE_OPTS_MASK \

options/options.c

@@ -282,8 +282,8 @@ const m_option_t mp_opts[] = {
 #if HAVE_LUA
     OPT_STRINGLIST("script", script_files, CONF_GLOBAL | M_OPT_FILE),
     OPT_KEYVALUELIST("script-opts", script_opts, 0),
-    OPT_FLAG("osc", lua_load_osc, CONF_GLOBAL),
-    OPT_FLAG("ytdl", lua_load_ytdl, CONF_GLOBAL),
+    OPT_FLAG("osc", lua_load_osc, UPDATE_BUILTIN_SCRIPTS),
+    OPT_FLAG("ytdl", lua_load_ytdl, UPDATE_BUILTIN_SCRIPTS),
     OPT_STRING("ytdl-format", lua_ytdl_format, 0),
     OPT_KEYVALUELIST("ytdl-raw-options", lua_ytdl_raw_options, 0),
     OPT_FLAG("load-scripts", auto_load_scripts, CONF_GLOBAL),

player/command.c

@@ -5603,6 +5603,9 @@ void mp_option_change_callback(void *ctx, struct m_config_option *co, int flags)
         osd_changed(mpctx->osd);
         mp_wakeup_core(mpctx);
     }
+
+    if (flags & UPDATE_BUILTIN_SCRIPTS)
+        mp_load_builtin_scripts(mpctx);
 }
 
 void mp_notify_property(struct MPContext *mpctx, const char *property)

player/core.h

@@ -549,6 +549,7 @@ struct mp_scripting {
     int (*load)(struct mpv_handle *client, const char *filename);
 };
 void mp_load_scripts(struct MPContext *mpctx);
+void mp_load_builtin_scripts(struct MPContext *mpctx);
 
 // sub.c
 void reset_subtitle_state(struct MPContext *mpctx);

player/scripting.c

@@ -176,13 +176,41 @@ static char **list_script_files(void *talloc_ctx, char *path)
     return files;
 }
 
+static void load_builtin_script(struct MPContext *mpctx, bool enable,
+                                const char *fname)
+{
+    void *tmp = talloc_new(NULL);
+    // (The name doesn't have to match if there were conflicts with other
+    // scripts, so this is on best-effort basis.)
+    char *name = script_name_from_filename(tmp, fname);
+    if (enable != mp_client_exists(mpctx, name)) {
+        if (enable) {
+            mp_load_script(mpctx, fname);
+        } else {
+            // Try to unload it by sending a shutdown event. Wait until it has
+            // terminated, or re-enabling the script could be racy (because it'd
+            // recognize a still-terminating script as "loaded").
+            while (mp_client_exists(mpctx, name)) {
+                if (mp_client_send_event(mpctx, name, MPV_EVENT_SHUTDOWN, NULL) < 0)
+                    break;
+                mp_idle(mpctx);
+            }
+            mp_wakeup_core(mpctx); // avoid lost wakeups during waiting
+        }
+    }
+    talloc_free(tmp);
+}
+
+void mp_load_builtin_scripts(struct MPContext *mpctx)
+{
+    load_builtin_script(mpctx, mpctx->opts->lua_load_osc, "@osc.lua");
+    load_builtin_script(mpctx, mpctx->opts->lua_load_ytdl, "@ytdl_hook.lua");
+}
+
 void mp_load_scripts(struct MPContext *mpctx)
 {
     // Load scripts from options
-    if (mpctx->opts->lua_load_osc)
-        mp_load_script(mpctx, "@osc.lua");
-    if (mpctx->opts->lua_load_ytdl)
-        mp_load_script(mpctx, "@ytdl_hook.lua");
+    mp_load_builtin_scripts(mpctx);
     char **files = mpctx->opts->script_files;
     for (int n = 0; files && files[n]; n++) {
         if (files[n][0])