m_config: remove extra default_data field

Just wastes memory (a few KB, because there are so many options).

options/m_config.c

@@ -220,12 +220,12 @@ static void alloc_group(struct m_config_data *data, int group_index,
         if (co->opt->offset < 0 || co->opt->type->size == 0)
             continue;
 
-        const void *defptr = co->default_data;
+        void *dst = gdata->udata + co->opt->offset;
+        const void *defptr = co->opt->defval ? co->opt->defval : dst;
         if (copy_src)
             defptr = copy_src + co->opt->offset;
 
-        if (defptr)
-            init_opt_inplace(co->opt, gdata->udata + co->opt->offset, defptr);
+        init_opt_inplace(co->opt, dst, defptr);
     }
 
     // If there's a parent, update its pointer to the new struct.
@@ -529,8 +529,6 @@ static void add_sub_group(struct m_config *config, const char *name_prefix,
         .co_index = config->num_opts,
     };
 
-    const void *optstruct_def = subopts->defaults;
-
     if (subopts->prefix && subopts->prefix[0])
         name_prefix = subopts->prefix;
     if (!name_prefix)
@@ -546,16 +544,9 @@ static void add_sub_group(struct m_config *config, const char *name_prefix,
             .name = concat_name(config, name_prefix, opt->name),
             .opt = opt,
             .group_index = group_index,
-            .default_data = &default_value,
             .is_hidden = !!opt->deprecation_message,
         };
 
-        if (opt->offset >= 0 && optstruct_def)
-            co.default_data = (char *)optstruct_def + opt->offset;
-
-        if (opt->defval)
-            co.default_data = opt->defval;
-
         if (opt->type != &m_option_type_subconfig)
             MP_TARRAY_APPEND(config, config->opts, config->num_opts, co);
     }
@@ -571,8 +562,8 @@ static void add_sub_group(struct m_config *config, const char *name_prefix,
             const struct m_sub_options *new_subopts = opt->priv;
 
             // Providing default structs in-place is not allowed.
-            if (opt->offset >= 0 && optstruct_def) {
-                void *ptr = (char *)optstruct_def + opt->offset;
+            if (opt->offset >= 0 && subopts->defaults) {
+                void *ptr = (char *)subopts->defaults + opt->offset;
                 assert(!substruct_read_ptr(ptr));
             }
 
@@ -672,6 +663,19 @@ struct m_config_option *m_config_get_co_index(struct m_config *config, int index
     return &config->opts[index];
 }
 
+const void *m_config_get_co_default(const struct m_config *config,
+                                    struct m_config_option *co)
+{
+    if (co->opt->defval)
+        return co->opt->defval;
+
+    const struct m_sub_options *subopt = config->groups[co->group_index].group;
+    if (co->opt->offset >= 0 && subopt->defaults)
+        return (char *)subopt->defaults + co->opt->offset;
+
+    return NULL;
+}
+
 const char *m_config_get_positional_option(const struct m_config *config, int p)
 {
     int pos = 0;
@@ -1077,8 +1081,11 @@ void m_config_print_option_list(const struct m_config *config, const char *name)
             MP_INFO(config, " (%s to %s)", min, max);
         }
         char *def = NULL;
-        if (co->default_data)
-            def = m_option_pretty_print(opt, co->default_data);
+        const void *defptr = m_config_get_co_default(config, co);
+        if (!defptr)
+            defptr = &default_value;
+        if (defptr)
+            def = m_option_pretty_print(opt, defptr);
         if (def) {
             MP_INFO(config, " (default: %s)", def);
             talloc_free(def);

options/m_config.h

@@ -47,7 +47,6 @@ struct m_config_option {
     const char *name;               // Full name (ie option-subopt)
     const struct m_option *opt;     // Option description
     void *data;                     // Raw value of the option
-    const void *default_data;       // Raw default value
 };
 
 // Config object
@@ -179,6 +178,8 @@ struct m_config_option *m_config_get_co(const struct m_config *config,
 
 int m_config_get_co_count(struct m_config *config);
 struct m_config_option *m_config_get_co_index(struct m_config *config, int index);
+const void *m_config_get_co_default(const struct m_config *config,
+                                    struct m_config_option *co);
 
 // Return the n-th option by position. n==0 is the first option. If there are
 // less than (n + 1) options, return NULL.

player/command.c

@@ -3732,12 +3732,13 @@ static int mp_property_option_info(void *ctx, struct m_property *prop,
         struct m_config_option *co = m_config_get_co(mpctx->mconfig, key);
         if (!co)
             return M_PROPERTY_UNKNOWN;
+        const struct m_option *opt = co->opt;
 
         union m_option_value def = {0};
-        if (co->default_data)
-            memcpy(&def, co->default_data, co->opt->type->size);
+        const void *def_ptr = m_config_get_co_default(mpctx->mconfig, co);
+        if (def_ptr && opt->type->size > 0)
+            memcpy(&def, def_ptr, opt->type->size);
 
-        const struct m_option *opt = co->opt;
         bool has_minmax =
             opt->type == &m_option_type_int ||
             opt->type == &m_option_type_int64 ||