libobs: Add post-load module callback

This allows the ability for certain types of modules (particularly
scripting-related modules) to initialize extra data when all other
modules have loaded.  Because front-ends may wish to have custom
handling for loading modules, the front-end must manually call
obs_post_load_modules after it has completed loading all plug-in
modules.

Closes jp9000/obs-studio#965

UI/window-basic-main.cpp

@@ -1317,6 +1317,8 @@ void OBSBasic::OBSInit()
 	obs_load_all_modules();
 	blog(LOG_INFO, "---------------------------------");
 	obs_log_loaded_modules();
+	blog(LOG_INFO, "---------------------------------");
+	obs_post_load_modules();
 
 	blog(LOG_INFO, STARTUP_SEPARATOR);
 

libobs/obs-internal.h

@@ -82,6 +82,7 @@ struct obs_module {
 
 	bool        (*load)(void);
 	void        (*unload)(void);
+	void        (*post_load)(void);
 	void        (*set_locale)(const char *locale);
 	void        (*free_locale)(void);
 	uint32_t    (*ver)(void);

libobs/obs-module.c

@@ -48,6 +48,7 @@ static int load_module_exports(struct obs_module *mod, const char *path)
 
 	/* optional exports */
 	mod->unload      = os_dlsym(mod->module, "obs_module_unload");
+	mod->post_load   = os_dlsym(mod->module, "obs_module_post_load");
 	mod->set_locale  = os_dlsym(mod->module, "obs_module_set_locale");
 	mod->free_locale = os_dlsym(mod->module, "obs_module_free_locale");
 	mod->name        = os_dlsym(mod->module, "obs_module_name");
@@ -254,6 +255,13 @@ void obs_load_all_modules(void)
 	profile_end(obs_load_all_modules_name);
 }
 
+void obs_post_load_modules(void)
+{
+	for (obs_module_t *mod = obs->first_module; !!mod; mod = mod->next)
+		if (mod->post_load)
+			mod->post_load();
+}
+
 static inline void make_data_dir(struct dstr *parsed_data_dir,
 		const char *data_dir, const char *name)
 {

libobs/obs-module.h

@@ -97,6 +97,9 @@ MODULE_EXPORT bool obs_module_load(void);
 /** Optional: Called when the module is unloaded.  */
 MODULE_EXPORT void obs_module_unload(void);
 
+/** Optional: Called when all modules have finished loading */
+MODULE_EXPORT void obs_module_post_load(void);
+
 /** Called to set the current locale data for the module.  */
 MODULE_EXPORT void obs_module_set_locale(const char *locale);
 

libobs/obs.h

@@ -374,6 +374,10 @@ EXPORT void obs_add_module_path(const char *bin, const char *data);
 /** Automatically loads all modules from module paths (convenience function) */
 EXPORT void obs_load_all_modules(void);
 
+/** Notifies modules that all modules have been loaded.  This function should
+ * be called after all modules have been loaded. */
+EXPORT void obs_post_load_modules(void);
+
 struct obs_module_info {
 	const char *bin_path;
 	const char *data_path;