video/out/gpu/context: convert --gpu-context to use obj_settings_list

Since the list of available GPU contexts is a compile time constant,
use obj_settings_list instead of opt_string_validate for GPU contexts.
This has several advantages:

- Aligns with the existing usage of vo, ao, and filter lists.
- Allows custom probing order.
- Allows list option suffixes. (--gpu-context-append, etc.)
- Allows autocomplete in console.lua.
- Uses the standard obj_settings_list help printing, so the custom
  help printing function is no longer needed.

This also deduplicates some context creation code for ra_ctx_create
and ra_ctx_create_by_name.

player/command.c

@@ -7306,7 +7306,7 @@ void mp_option_change_callback(void *ctx, struct m_config_option *co, int flags,
     }
 
     if (opt_ptr == &opts->vo->video_driver_list ||
-        opt_ptr == &opts->ra_ctx_opts->context_name ||
+        opt_ptr == &opts->ra_ctx_opts->context_list ||
         opt_ptr == &opts->ra_ctx_opts->context_type) {
         struct track *track = mpctx->current_track[0][STREAM_VIDEO];
         uninit_video_out(mpctx);

video/out/gpu/context.c

@@ -119,6 +119,38 @@ static const struct ra_ctx_fns *no_api_contexts[] = {
 #endif
 };
 
+static bool get_desc(struct m_obj_desc *dst, int index)
+{
+    if (index >= MP_ARRAY_SIZE(contexts))
+        return false;
+    const struct ra_ctx_fns *ctx = contexts[index];
+    *dst = (struct m_obj_desc) {
+        .name = ctx->name,
+    };
+    return true;
+}
+
+static bool check_unknown_entry(const char *name)
+{
+    struct bstr param = bstr0(name);
+    if (bstr_equals0(param, "auto"))
+        return true;
+    for (int i = 0; i < MP_ARRAY_SIZE(contexts); i++) {
+        if (bstr_equals0(param, contexts[i]->name))
+            return true;
+    }
+    return false;
+}
+
+const struct m_obj_list ra_ctx_obj_list = {
+    .get_desc = get_desc,
+    .check_unknown_entry = check_unknown_entry,
+    .description = "GPU contexts",
+    .allow_trailer = true,
+    .disallow_positional_parameters = true,
+    .use_global_options = true,
+};
+
 static int ra_ctx_api_help(struct mp_log *log, const struct m_option *opt,
                            struct bstr name)
 {
@@ -142,93 +174,36 @@ static inline OPT_STRING_VALIDATE_FUNC(ra_ctx_validate_api)
     return M_OPT_INVALID;
 }
 
-static int ra_ctx_context_help(struct mp_log *log, const struct m_option *opt,
+#define OPT_BASE_STRUCT struct ra_ctx_opts
-                               struct bstr name)
+const struct m_sub_options ra_ctx_conf = {
-{
+    .opts = (const m_option_t[]) {
-    mp_info(log, "GPU contexts (APIs):\n");
+        {"gpu-context",
-    mp_info(log, "    auto (autodetect)\n");
+            OPT_SETTINGSLIST(context_list, &ra_ctx_obj_list)},
-    for (int n = 0; n < MP_ARRAY_SIZE(contexts); n++) {
+        {"gpu-api",
-        mp_info(log, "    %s (%s)\n", contexts[n]->name, contexts[n]->type);
+            OPT_STRING_VALIDATE(context_type, ra_ctx_validate_api),
-    }
+            .help = ra_ctx_api_help},
-    return M_OPT_EXIT;
+        {"gpu-debug", OPT_BOOL(debug)},
-}
+        {"gpu-sw", OPT_BOOL(allow_sw)},
-
+        {0}
-static inline OPT_STRING_VALIDATE_FUNC(ra_ctx_validate_context)
+    },
-{
+    .size = sizeof(struct ra_ctx_opts),
-    struct bstr param = bstr0(*value);
-    if (bstr_equals0(param, "auto"))
-        return 1;
-    for (int i = 0; i < MP_ARRAY_SIZE(contexts); i++) {
-        if (bstr_equals0(param, contexts[i]->name))
-            return 1;
-    }
-    return M_OPT_INVALID;
-}
-
-// Create a VO window and create a RA context on it.
-//  vo_flags: passed to the backend's create window function
-struct ra_ctx *ra_ctx_create(struct vo *vo, struct ra_ctx_opts opts)
-{
-    bool api_auto = !opts.context_type || strcmp(opts.context_type, "auto") == 0;
-    bool ctx_auto = !opts.context_name || strcmp(opts.context_name, "auto") == 0;
-
-    if (ctx_auto) {
-        MP_VERBOSE(vo, "Probing for best GPU context.\n");
-        opts.probing = true;
-    }
-
-    // Hack to silence backend (X11/Wayland/etc.) errors. Kill it once backends
-    // are separate from `struct vo`
-    bool old_probing = vo->probing;
-    vo->probing = opts.probing;
-
-    for (int i = 0; i < MP_ARRAY_SIZE(contexts); i++) {
-        if (!opts.probing && strcmp(contexts[i]->name, opts.context_name) != 0)
-            continue;
-        if (!api_auto && strcmp(contexts[i]->type, opts.context_type) != 0)
-            continue;
-
-        struct ra_ctx *ctx = talloc_ptrtype(NULL, ctx);
-        *ctx = (struct ra_ctx) {
-            .vo = vo,
-            .global = vo->global,
-            .log = mp_log_new(ctx, vo->log, contexts[i]->type),
-            .opts = opts,
-            .fns = contexts[i],
 };
 
-        MP_VERBOSE(ctx, "Initializing GPU context '%s'\n", ctx->fns->name);
+static struct ra_ctx *create_in_contexts(struct vo *vo, const char *name, bool api_auto,
-        if (contexts[i]->init(ctx)) {
-            vo->probing = old_probing;
-            vo->context_name = ctx->fns->name;
-            return ctx;
-        }
-
-        talloc_free(ctx);
-    }
-
-    vo->probing = old_probing;
-
-    // If we've reached this point, then none of the contexts matched the name
-    // requested, or the backend creation failed for all of them.
-    if (!vo->probing)
-        MP_ERR(vo, "Failed initializing any suitable GPU context!\n");
-    return NULL;
-}
-
-static struct ra_ctx *create_in_contexts(struct vo *vo, const char *name,
                                          const struct ra_ctx_fns *ctxs[],
-                                         size_t size)
+                                         size_t size, struct ra_ctx_opts opts)
 {
     for (int i = 0; i < size; i++) {
         if (strcmp(name, ctxs[i]->name) != 0)
             continue;
-
+        if (!api_auto && strcmp(ctxs[i]->type, opts.context_type) != 0)
+            continue;
         struct ra_ctx *ctx = talloc_ptrtype(NULL, ctx);
         *ctx = (struct ra_ctx) {
             .vo = vo,
             .global = vo->global,
             .log = mp_log_new(ctx, vo->log, ctxs[i]->type),
+            .opts = opts,
             .fns = ctxs[i],
         };
 
@@ -242,12 +217,64 @@ static struct ra_ctx *create_in_contexts(struct vo *vo, const char *name,
 
 struct ra_ctx *ra_ctx_create_by_name(struct vo *vo, const char *name)
 {
-    struct ra_ctx *ctx = create_in_contexts(vo, name, contexts,
+    struct ra_ctx_opts dummy = {0};
-                                            MP_ARRAY_SIZE(contexts));
+    struct ra_ctx *ctx = create_in_contexts(vo, name, true, contexts,
+                                            MP_ARRAY_SIZE(contexts), dummy);
     if (ctx)
         return ctx;
-    return create_in_contexts(vo, name, no_api_contexts,
+    return create_in_contexts(vo, name, true, no_api_contexts,
-                              MP_ARRAY_SIZE(no_api_contexts));
+                              MP_ARRAY_SIZE(no_api_contexts), dummy);
+}
+
+// Create a VO window and create a RA context on it.
+//  vo_flags: passed to the backend's create window function
+struct ra_ctx *ra_ctx_create(struct vo *vo, struct ra_ctx_opts opts)
+{
+    bool api_auto = !opts.context_type || strcmp(opts.context_type, "auto") == 0;
+    bool ctx_auto = !opts.context_list ||
+                    (opts.context_list[0].name &&
+                     strcmp(opts.context_list[0].name, "auto") == 0);
+
+    if (ctx_auto) {
+        MP_VERBOSE(vo, "Probing for best GPU context.\n");
+        opts.probing = true;
+    }
+
+    // Hack to silence backend (X11/Wayland/etc.) errors. Kill it once backends
+    // are separate from `struct vo`
+    bool old_probing = vo->probing;
+    vo->probing = opts.probing;
+
+    struct ra_ctx *ctx = NULL;
+    if (opts.probing) {
+        for (int i = 0; i < MP_ARRAY_SIZE(contexts); i++) {
+            ctx = create_in_contexts(vo, contexts[i]->name, api_auto,
+                                     contexts, MP_ARRAY_SIZE(contexts), opts);
+            if (ctx)
+                goto done;
+        }
+    }
+    for (int i = 0; opts.context_list && opts.context_list[i].name; i++) {
+        ctx = create_in_contexts(vo, opts.context_list[i].name, api_auto,
+                                 contexts, MP_ARRAY_SIZE(contexts), opts);
+        if (ctx)
+            goto done;
+    }
+
+done:
+    if (ctx) {
+        vo->probing = old_probing;
+        vo->context_name = ctx->fns->name;
+        return ctx;
+    }
+
+    vo->probing = old_probing;
+
+    // If we've reached this point, then none of the contexts matched the name
+    // requested, or the backend creation failed for all of them.
+    if (!vo->probing)
+        MP_ERR(vo, "Failed initializing any suitable GPU context!\n");
+    return NULL;
 }
 
 void ra_ctx_destroy(struct ra_ctx **ctx_ptr)
@@ -264,19 +291,3 @@ void ra_ctx_destroy(struct ra_ctx **ctx_ptr)
 
     *ctx_ptr = NULL;
 }
-
-#define OPT_BASE_STRUCT struct ra_ctx_opts
-const struct m_sub_options ra_ctx_conf = {
-    .opts = (const m_option_t[]) {
-        {"gpu-context",
-            OPT_STRING_VALIDATE(context_name, ra_ctx_validate_context),
-            .help = ra_ctx_context_help},
-        {"gpu-api",
-            OPT_STRING_VALIDATE(context_type, ra_ctx_validate_api),
-            .help = ra_ctx_api_help},
-        {"gpu-debug", OPT_BOOL(debug)},
-        {"gpu-sw", OPT_BOOL(allow_sw)},
-        {0}
-    },
-    .size = sizeof(struct ra_ctx_opts),
-};

video/out/gpu/context.h

@@ -10,7 +10,7 @@ struct ra_ctx_opts {
     bool want_alpha;      // create an alpha framebuffer if possible
     bool debug;           // enable debugging layers/callbacks etc.
     bool probing;        // the backend was auto-probed
-    char *context_name;  // filter by `ra_ctx_fns.name`
+    struct m_obj_settings *context_list; // list of `ra_ctx_fns.name` to probe
     char *context_type;  // filter by `ra_ctx_fns.type`
 };