js: require: directory-scripts: first look at <dir>/modules/

Also, add the function mp.get_script_directory() to let scripts know if
they're loaded as a directory and where.

DOCS/interface-changes.rst

@@ -28,6 +28,8 @@ Interface changes
     - directories in ~/.mpv/scripts/ (or equivalent) now have special semantics
       (see mpv Lua scripting docs)
     - names starting with "." in ~/.mpv/scripts/ (or equivalent) are now ignored
+    - js modules: ~~/scripts/modules.js/ is no longer used, global paths can be
+      set with custom init (see docs), dir-scripts first look at <dir>/modules/
  --- mpv 0.32.0 ---
     - change behavior when using legacy option syntax with options that start
       with two dashes (``--`` instead of a ``-``). Now, using the recommended

DOCS/man/javascript.rst

@@ -139,6 +139,8 @@ success, ``fn`` is called always a-sync, ``error`` is empty string on success.
 
 ``mp.get_script_name()``
 
+``mp.get_script_directory()``
+
 ``mp.osd_message(text [,duration])``
 
 ``mp.get_wakeup_pipe()``
@@ -309,7 +311,8 @@ or ``~/x``. Otherwise it's considered a global module id and searched according
 load ``x.js`` at one of the array paths, and id ``foo/x`` tries to load ``x.js``
 inside dir ``foo`` at one of the paths.
 
-The ``mp.module_paths`` array is empty by default.
+The ``mp.module_paths`` array is empty by default except for scripts which are
+loaded as a directory where it contains one item - ``<directory>/modules/``.
 ``mp.module_paths`` may be updated from a script (preferably via custom init -
 see below) which will affect future calls to ``require`` for global module id's
 which are not already loaded/cached.

player/javascript.c

@@ -59,6 +59,7 @@ static const char *const builtin_files[][3] = {
 // Represents a loaded script. Each has its own js state.
 struct script_ctx {
     const char *filename;
+    const char *path; // NULL if single file
     struct mpv_handle *client;
     struct MPContext *mpctx;
     struct mp_log *log;
@@ -477,6 +478,7 @@ static int s_load_javascript(struct mp_script_args *args)
         .log = args->log,
         .last_error_str = talloc_strdup(ctx, "Cannot initialize JavaScript"),
         .filename = args->filename,
+        .path = args->path,
     };
 
     int r = -1;
@@ -1281,6 +1283,11 @@ static void add_functions(js_State *J, struct script_ctx *ctx)
     js_pushstring(J, ctx->filename);
     js_setproperty(J, -2, "script_file");
 
+    if (ctx->path) {
+        js_pushstring(J, ctx->path);
+        js_setproperty(J, -2, "script_path");
+    }
+
     js_pop(J, 2);  // leave the stack as we got it
 }
 

player/javascript/defaults.js

@@ -463,6 +463,8 @@ function process_timers() {
  *********************************************************************/
 
 mp.module_paths = [];  // global modules search paths
+if (mp.script_path !== undefined)  // loaded as a directory
+    mp.module_paths.push(mp.utils.join_path(mp.script_path, "modules"));
 
 // Internal meta top-dirs. Users should not rely on these names.
 var MODULES_META = "~~modules",
@@ -645,6 +647,7 @@ mp.options = { read_options: read_options };
 g.print = mp.msg.info;  // convenient alias
 mp.get_script_name = function() { return mp.script_name };
 mp.get_script_file = function() { return mp.script_file };
+mp.get_script_directory = function() { return mp.script_path };
 mp.get_time = function() { return mp.get_time_ms() / 1000 };
 mp.utils.getcwd = function() { return mp.get_property("working-directory") };
 mp.dispatch_event = dispatch_event;