godot/core/io/resource_loader.cpp

/*************************************************************************/
/*  resource_loader.cpp                                                  */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
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/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/

#include "resource_loader.h"

#include "core/io/resource_importer.h"
#include "core/os/file_access.h"
#include "core/os/os.h"
#include "core/path_remap.h"
#include "core/print_string.h"
#include "core/project_settings.h"
#include "core/translation.h"
#include "core/variant_parser.h"

Ref<ResourceFormatLoader> ResourceLoader::loader[ResourceLoader::MAX_LOADERS];

int ResourceLoader::loader_count = 0;

Error ResourceInteractiveLoader::wait() {

	Error err = poll();
	while (err == OK) {
		err = poll();
	}

	return err;
}

ResourceInteractiveLoader::~ResourceInteractiveLoader() {
	if (path_loading != String()) {
		ResourceLoader::_remove_from_loading_map(path_loading);
	}
}

bool ResourceFormatLoader::recognize_path(const String &p_path, const String &p_for_type) const {

	String extension = p_path.get_extension();

	List<String> extensions;
	if (p_for_type == String()) {
		get_recognized_extensions(&extensions);
	} else {
		get_recognized_extensions_for_type(p_for_type, &extensions);
	}

	for (List<String>::Element *E = extensions.front(); E; E = E->next()) {

		if (E->get().nocasecmp_to(extension) == 0)
			return true;
	}

	return false;
}

bool ResourceFormatLoader::handles_type(const String &p_type) const {

	if (get_script_instance() && get_script_instance()->has_method("handles_type")) {
		// I guess custom loaders for custom resources should use "Resource"
		return get_script_instance()->call("handles_type", p_type);
	}

	return false;
}

String ResourceFormatLoader::get_resource_type(const String &p_path) const {

	if (get_script_instance() && get_script_instance()->has_method("get_resource_type")) {
		return get_script_instance()->call("get_resource_type", p_path);
	}

	return "";
}

void ResourceFormatLoader::get_recognized_extensions_for_type(const String &p_type, List<String> *p_extensions) const {

	if (p_type == "" || handles_type(p_type))
		get_recognized_extensions(p_extensions);
}

void ResourceLoader::get_recognized_extensions_for_type(const String &p_type, List<String> *p_extensions) {

	for (int i = 0; i < loader_count; i++) {
		loader[i]->get_recognized_extensions_for_type(p_type, p_extensions);
	}
}

void ResourceInteractiveLoader::_bind_methods() {

	ClassDB::bind_method(D_METHOD("get_resource"), &ResourceInteractiveLoader::get_resource);
	ClassDB::bind_method(D_METHOD("poll"), &ResourceInteractiveLoader::poll);
	ClassDB::bind_method(D_METHOD("wait"), &ResourceInteractiveLoader::wait);
	ClassDB::bind_method(D_METHOD("get_stage"), &ResourceInteractiveLoader::get_stage);
	ClassDB::bind_method(D_METHOD("get_stage_count"), &ResourceInteractiveLoader::get_stage_count);
}

class ResourceInteractiveLoaderDefault : public ResourceInteractiveLoader {

	GDCLASS(ResourceInteractiveLoaderDefault, ResourceInteractiveLoader);

public:
	Ref<Resource> resource;

	virtual void set_local_path(const String &p_local_path) { /*scene->set_filename(p_local_path);*/
	}
	virtual Ref<Resource> get_resource() { return resource; }
	virtual Error poll() { return ERR_FILE_EOF; }
	virtual int get_stage() const { return 1; }
	virtual int get_stage_count() const { return 1; }
	virtual void set_translation_remapped(bool p_remapped) { resource->set_as_translation_remapped(p_remapped); }

	ResourceInteractiveLoaderDefault() {}
};

Ref<ResourceInteractiveLoader> ResourceFormatLoader::load_interactive(const String &p_path, const String &p_original_path, Error *r_error) {

	//either this
	Ref<Resource> res = load(p_path, p_original_path, r_error);
	if (res.is_null())
		return Ref<ResourceInteractiveLoader>();

	Ref<ResourceInteractiveLoaderDefault> ril = Ref<ResourceInteractiveLoaderDefault>(memnew(ResourceInteractiveLoaderDefault));
	ril->resource = res;
	return ril;
}

bool ResourceFormatLoader::exists(const String &p_path) const {
	return FileAccess::exists(p_path); //by default just check file
}

void ResourceFormatLoader::get_recognized_extensions(List<String> *p_extensions) const {

	if (get_script_instance() && get_script_instance()->has_method("get_recognized_extensions")) {
		PoolStringArray exts = get_script_instance()->call("get_recognized_extensions");

		{
			PoolStringArray::Read r = exts.read();
			for (int i = 0; i < exts.size(); ++i) {
				p_extensions->push_back(r[i]);
			}
		}
	}
}

RES ResourceFormatLoader::load(const String &p_path, const String &p_original_path, Error *r_error) {

	if (get_script_instance() && get_script_instance()->has_method("load")) {
		Variant res = get_script_instance()->call("load", p_path, p_original_path);

		if (res.get_type() == Variant::INT) {

			if (r_error)
				*r_error = (Error)res.operator int64_t();

		} else {

			if (r_error)
				*r_error = OK;
			return res;
		}
	}

	//or this must be implemented
	Ref<ResourceInteractiveLoader> ril = load_interactive(p_path, p_original_path, r_error);
	if (!ril.is_valid())
		return RES();
	ril->set_local_path(p_original_path);

	while (true) {

		Error err = ril->poll();

		if (err == ERR_FILE_EOF) {
			if (r_error)
				*r_error = OK;
			return ril->get_resource();
		}

		if (r_error)
			*r_error = err;

		ERR_FAIL_COND_V(err != OK, RES());
	}

	return RES();
}

void ResourceFormatLoader::get_dependencies(const String &p_path, List<String> *p_dependencies, bool p_add_types) {

	if (get_script_instance() && get_script_instance()->has_method("get_dependencies")) {
		PoolStringArray deps = get_script_instance()->call("get_dependencies", p_path, p_add_types);

		{
			PoolStringArray::Read r = deps.read();
			for (int i = 0; i < deps.size(); ++i) {
				p_dependencies->push_back(r[i]);
			}
		}
	}
}

Error ResourceFormatLoader::rename_dependencies(const String &p_path, const Map<String, String> &p_map) {

	if (get_script_instance() && get_script_instance()->has_method("rename_dependencies")) {

		Dictionary deps_dict;
		for (Map<String, String>::Element *E = p_map.front(); E; E = E->next()) {
			deps_dict[E->key()] = E->value();
		}

		int64_t res = get_script_instance()->call("rename_dependencies", deps_dict);
		return (Error)res;
	}

	return OK;
}

void ResourceFormatLoader::_bind_methods() {

	{
		MethodInfo info = MethodInfo(Variant::NIL, "load", PropertyInfo(Variant::STRING, "path"), PropertyInfo(Variant::STRING, "original_path"));
		info.return_val.usage |= PROPERTY_USAGE_NIL_IS_VARIANT;
		ClassDB::add_virtual_method(get_class_static(), info);
	}

	ClassDB::add_virtual_method(get_class_static(), MethodInfo(Variant::POOL_STRING_ARRAY, "get_recognized_extensions"));
	ClassDB::add_virtual_method(get_class_static(), MethodInfo(Variant::BOOL, "handles_type", PropertyInfo(Variant::STRING, "typename")));
	ClassDB::add_virtual_method(get_class_static(), MethodInfo(Variant::STRING, "get_resource_type", PropertyInfo(Variant::STRING, "path")));
	ClassDB::add_virtual_method(get_class_static(), MethodInfo("get_dependencies", PropertyInfo(Variant::STRING, "path"), PropertyInfo(Variant::STRING, "add_types")));
	ClassDB::add_virtual_method(get_class_static(), MethodInfo(Variant::INT, "rename_dependencies", PropertyInfo(Variant::STRING, "path"), PropertyInfo(Variant::STRING, "renames")));
}

///////////////////////////////////

RES ResourceLoader::_load(const String &p_path, const String &p_original_path, const String &p_type_hint, bool p_no_cache, Error *r_error) {

	bool found = false;

	// Try all loaders and pick the first match for the type hint
	for (int i = 0; i < loader_count; i++) {

		if (!loader[i]->recognize_path(p_path, p_type_hint)) {
			continue;
		}
		found = true;
		RES res = loader[i]->load(p_path, p_original_path != String() ? p_original_path : p_path, r_error);
		if (res.is_null()) {
			continue;
		}

		return res;
	}

	if (found) {
		ERR_EXPLAIN("Failed loading resource: " + p_path);
	} else {
		ERR_EXPLAIN("No loader found for resource: " + p_path);
	}
	ERR_FAIL_V(RES());
	return RES();
}

bool ResourceLoader::_add_to_loading_map(const String &p_path) {

	bool success;
	if (loading_map_mutex) {
		loading_map_mutex->lock();
	}

	if (loading_map.has(p_path)) {
		success = false;
	} else {
		loading_map[p_path] = true;
		success = true;
	}

	if (loading_map_mutex) {
		loading_map_mutex->unlock();
	}

	return success;
}

void ResourceLoader::_remove_from_loading_map(const String &p_path) {
	if (loading_map_mutex) {
		loading_map_mutex->lock();
	}

	loading_map.erase(p_path);

	if (loading_map_mutex) {
		loading_map_mutex->unlock();
	}
}

RES ResourceLoader::load(const String &p_path, const String &p_type_hint, bool p_no_cache, Error *r_error) {

	if (r_error)
		*r_error = ERR_CANT_OPEN;

	String local_path;
	if (p_path.is_rel_path())
		local_path = "res://" + p_path;
	else
		local_path = ProjectSettings::get_singleton()->localize_path(p_path);

	if (!p_no_cache) {

		{
			bool success = _add_to_loading_map(local_path);
			if (!success) {
				ERR_EXPLAIN("Resource: '" + local_path + "' is already being loaded. Cyclic reference?");
				ERR_FAIL_V(RES());
			}
		}

		//lock first if possible
		if (ResourceCache::lock) {
			ResourceCache::lock->read_lock();
		}

		//get ptr
		Resource **rptr = ResourceCache::resources.getptr(local_path);

		if (rptr) {
			RES res(*rptr);
			//it is possible this resource was just freed in a thread. If so, this referencing will not work and resource is considered not cached
			if (res.is_valid()) {
				//referencing is fine
				if (r_error)
					*r_error = OK;
				if (ResourceCache::lock) {
					ResourceCache::lock->read_unlock();
				}
				_remove_from_loading_map(local_path);
				return res;
			}
		}
		if (ResourceCache::lock) {
			ResourceCache::lock->read_unlock();
		}
	}

	bool xl_remapped = false;
	String path = _path_remap(local_path, &xl_remapped);

	if (path == "") {
		if (!p_no_cache) {
			_remove_from_loading_map(local_path);
		}
		ERR_EXPLAIN("Remapping '" + local_path + "'failed.");
		ERR_FAIL_V(RES());
	}

	print_verbose("Loading resource: " + path);
	RES res = _load(path, local_path, p_type_hint, p_no_cache, r_error);

	if (res.is_null()) {
		if (!p_no_cache) {
			_remove_from_loading_map(local_path);
		}
		return RES();
	}
	if (!p_no_cache)
		res->set_path(local_path);

	if (xl_remapped)
		res->set_as_translation_remapped(true);

#ifdef TOOLS_ENABLED

	res->set_edited(false);
	if (timestamp_on_load) {
		uint64_t mt = FileAccess::get_modified_time(path);
		//printf("mt %s: %lli\n",remapped_path.utf8().get_data(),mt);
		res->set_last_modified_time(mt);
	}
#endif

	if (!p_no_cache) {
		_remove_from_loading_map(local_path);
	}

	if (_loaded_callback) {
		_loaded_callback(res, p_path);
	}

	return res;
}

bool ResourceLoader::exists(const String &p_path, const String &p_type_hint) {

	String local_path;
	if (p_path.is_rel_path())
		local_path = "res://" + p_path;
	else
		local_path = ProjectSettings::get_singleton()->localize_path(p_path);

	if (ResourceCache::has(local_path)) {

		return true; // If cached, it probably exists
	}

	bool xl_remapped = false;
	String path = _path_remap(local_path, &xl_remapped);

	// Try all loaders and pick the first match for the type hint
	for (int i = 0; i < loader_count; i++) {

		if (!loader[i]->recognize_path(path, p_type_hint)) {
			continue;
		}

		if (loader[i]->exists(path))
			return true;
	}

	return false;
}

Ref<ResourceInteractiveLoader> ResourceLoader::load_interactive(const String &p_path, const String &p_type_hint, bool p_no_cache, Error *r_error) {

	if (r_error)
		*r_error = ERR_CANT_OPEN;

	String local_path;
	if (p_path.is_rel_path())
		local_path = "res://" + p_path;
	else
		local_path = ProjectSettings::get_singleton()->localize_path(p_path);

	if (!p_no_cache) {

		bool success = _add_to_loading_map(local_path);
		if (!success) {
			ERR_EXPLAIN("Resource: '" + local_path + "' is already being loaded. Cyclic reference?");
			ERR_FAIL_V(RES());
		}

		if (ResourceCache::has(local_path)) {

			print_verbose("Loading resource: " + local_path + " (cached)");
			Ref<Resource> res_cached = ResourceCache::get(local_path);
			Ref<ResourceInteractiveLoaderDefault> ril = Ref<ResourceInteractiveLoaderDefault>(memnew(ResourceInteractiveLoaderDefault));

			ril->resource = res_cached;
			ril->path_loading = local_path;
			return ril;
		}
	}

	bool xl_remapped = false;
	String path = _path_remap(local_path, &xl_remapped);
	if (path == "") {
		if (!p_no_cache) {
			_remove_from_loading_map(local_path);
		}
		ERR_EXPLAIN("Remapping '" + local_path + "'failed.");
		ERR_FAIL_V(RES());
	}

	print_verbose("Loading resource: " + path);

	bool found = false;
	for (int i = 0; i < loader_count; i++) {

		if (!loader[i]->recognize_path(path, p_type_hint))
			continue;
		found = true;
		Ref<ResourceInteractiveLoader> ril = loader[i]->load_interactive(path, local_path, r_error);
		if (ril.is_null())
			continue;
		if (!p_no_cache) {
			ril->set_local_path(local_path);
			ril->path_loading = local_path;
		}

		if (xl_remapped)
			ril->set_translation_remapped(true);

		return ril;
	}

	if (!p_no_cache) {
		_remove_from_loading_map(local_path);
	}

	if (found) {
		ERR_EXPLAIN("Failed loading resource: " + path);
	} else {
		ERR_EXPLAIN("No loader found for resource: " + path);
	}
	ERR_FAIL_V(Ref<ResourceInteractiveLoader>());
	return Ref<ResourceInteractiveLoader>();
}

void ResourceLoader::add_resource_format_loader(Ref<ResourceFormatLoader> p_format_loader, bool p_at_front) {

	ERR_FAIL_COND(p_format_loader.is_null());
	ERR_FAIL_COND(loader_count >= MAX_LOADERS);

	if (p_at_front) {
		for (int i = loader_count; i > 0; i--) {
			loader[i] = loader[i - 1];
		}
		loader[0] = p_format_loader;
		loader_count++;
	} else {
		loader[loader_count++] = p_format_loader;
	}
}

void ResourceLoader::remove_resource_format_loader(Ref<ResourceFormatLoader> p_format_loader) {

	ERR_FAIL_COND(p_format_loader.is_null());

	// Find loader
	int i = 0;
	for (; i < loader_count; ++i) {
		if (loader[i] == p_format_loader)
			break;
	}

	ERR_FAIL_COND(i >= loader_count); // Not found

	// Shift next loaders up
	for (; i < loader_count - 1; ++i) {
		loader[i] = loader[i + 1];
	}
	loader[loader_count - 1].unref();
	--loader_count;
}

int ResourceLoader::get_import_order(const String &p_path) {

	String path = _path_remap(p_path);

	String local_path;
	if (path.is_rel_path())
		local_path = "res://" + path;
	else
		local_path = ProjectSettings::get_singleton()->localize_path(path);

	for (int i = 0; i < loader_count; i++) {

		if (!loader[i]->recognize_path(local_path))
			continue;
		/*
		if (p_type_hint!="" && !loader[i]->handles_type(p_type_hint))
			continue;
		*/

		return loader[i]->get_import_order(p_path);
	}

	return 0;
}

bool ResourceLoader::is_import_valid(const String &p_path) {

	String path = _path_remap(p_path);

	String local_path;
	if (path.is_rel_path())
		local_path = "res://" + path;
	else
		local_path = ProjectSettings::get_singleton()->localize_path(path);

	for (int i = 0; i < loader_count; i++) {

		if (!loader[i]->recognize_path(local_path))
			continue;
		/*
		if (p_type_hint!="" && !loader[i]->handles_type(p_type_hint))
			continue;
		*/

		return loader[i]->is_import_valid(p_path);
	}

	return false; //not found
}

void ResourceLoader::get_dependencies(const String &p_path, List<String> *p_dependencies, bool p_add_types) {

	String path = _path_remap(p_path);

	String local_path;
	if (path.is_rel_path())
		local_path = "res://" + path;
	else
		local_path = ProjectSettings::get_singleton()->localize_path(path);

	for (int i = 0; i < loader_count; i++) {

		if (!loader[i]->recognize_path(local_path))
			continue;
		/*
		if (p_type_hint!="" && !loader[i]->handles_type(p_type_hint))
			continue;
		*/

		loader[i]->get_dependencies(local_path, p_dependencies, p_add_types);
	}
}

Error ResourceLoader::rename_dependencies(const String &p_path, const Map<String, String> &p_map) {

	String path = _path_remap(p_path);

	String local_path;
	if (path.is_rel_path())
		local_path = "res://" + path;
	else
		local_path = ProjectSettings::get_singleton()->localize_path(path);

	for (int i = 0; i < loader_count; i++) {

		if (!loader[i]->recognize_path(local_path))
			continue;
		/*
		if (p_type_hint!="" && !loader[i]->handles_type(p_type_hint))
			continue;
		*/

		return loader[i]->rename_dependencies(local_path, p_map);
	}

	return OK; // ??
}

String ResourceLoader::get_resource_type(const String &p_path) {

	String local_path;
	if (p_path.is_rel_path())
		local_path = "res://" + p_path;
	else
		local_path = ProjectSettings::get_singleton()->localize_path(p_path);

	for (int i = 0; i < loader_count; i++) {

		String result = loader[i]->get_resource_type(local_path);
		if (result != "")
			return result;
	}

	return "";
}

String ResourceLoader::_path_remap(const String &p_path, bool *r_translation_remapped) {

	String new_path = p_path;

	if (translation_remaps.has(new_path)) {

		Vector<String> &v = *translation_remaps.getptr(new_path);
		String locale = TranslationServer::get_singleton()->get_locale();
		if (r_translation_remapped) {
			*r_translation_remapped = true;
		}
		for (int i = 0; i < v.size(); i++) {

			int split = v[i].find_last(":");
			if (split == -1)
				continue;
			String l = v[i].right(split + 1).strip_edges();
			if (l == String())
				continue;

			if (l.begins_with(locale)) {
				new_path = v[i].left(split);
				break;
			}
		}
	}

	if (path_remaps.has(new_path)) {
		new_path = path_remaps[new_path];
	}

	if (new_path == p_path) { //did not remap
		//try file remap
		Error err;
		FileAccess *f = FileAccess::open(p_path + ".remap", FileAccess::READ, &err);

		if (f) {

			VariantParser::StreamFile stream;
			stream.f = f;

			String assign;
			Variant value;
			VariantParser::Tag next_tag;

			int lines = 0;
			String error_text;
			while (true) {

				assign = Variant();
				next_tag.fields.clear();
				next_tag.name = String();

				err = VariantParser::parse_tag_assign_eof(&stream, lines, error_text, next_tag, assign, value, NULL, true);
				if (err == ERR_FILE_EOF) {
					break;
				} else if (err != OK) {
					ERR_PRINTS("Parse error: " + p_path + ".remap:" + itos(lines) + " error: " + error_text);
					break;
				}

				if (assign == "path") {
					new_path = value;
					break;
				} else if (next_tag.name != "remap") {
					break;
				}
			}

			memdelete(f);
		}
	}

	return new_path;
}

String ResourceLoader::import_remap(const String &p_path) {

	if (ResourceFormatImporter::get_singleton()->recognize_path(p_path)) {

		return ResourceFormatImporter::get_singleton()->get_internal_resource_path(p_path);
	}

	return p_path;
}

String ResourceLoader::path_remap(const String &p_path) {
	return _path_remap(p_path);
}

void ResourceLoader::reload_translation_remaps() {

	if (ResourceCache::lock) {
		ResourceCache::lock->read_lock();
	}

	List<Resource *> to_reload;
	SelfList<Resource> *E = remapped_list.first();

	while (E) {
		to_reload.push_back(E->self());
		E = E->next();
	}

	if (ResourceCache::lock) {
		ResourceCache::lock->read_unlock();
	}

	//now just make sure to not delete any of these resources while changing locale..
	while (to_reload.front()) {
		to_reload.front()->get()->reload_from_file();
		to_reload.pop_front();
	}
}

void ResourceLoader::load_translation_remaps() {

	if (!ProjectSettings::get_singleton()->has_setting("locale/translation_remaps"))
		return;

	Dictionary remaps = ProjectSettings::get_singleton()->get("locale/translation_remaps");
	List<Variant> keys;
	remaps.get_key_list(&keys);
	for (List<Variant>::Element *E = keys.front(); E; E = E->next()) {

		Array langs = remaps[E->get()];
		Vector<String> lang_remaps;
		lang_remaps.resize(langs.size());
		for (int i = 0; i < langs.size(); i++) {
			lang_remaps.write[i] = langs[i];
		}

		translation_remaps[String(E->get())] = lang_remaps;
	}
}

void ResourceLoader::clear_translation_remaps() {
	translation_remaps.clear();
}

void ResourceLoader::load_path_remaps() {

	if (!ProjectSettings::get_singleton()->has_setting("path_remap/remapped_paths"))
		return;

	PoolVector<String> remaps = ProjectSettings::get_singleton()->get("path_remap/remapped_paths");
	int rc = remaps.size();
	ERR_FAIL_COND(rc & 1); //must be even
	PoolVector<String>::Read r = remaps.read();

	for (int i = 0; i < rc; i += 2) {

		path_remaps[r[i]] = r[i + 1];
	}
}

void ResourceLoader::clear_path_remaps() {

	path_remaps.clear();
}

void ResourceLoader::set_load_callback(ResourceLoadedCallback p_callback) {
	_loaded_callback = p_callback;
}

ResourceLoadedCallback ResourceLoader::_loaded_callback = NULL;

Ref<ResourceFormatLoader> ResourceLoader::_find_custom_resource_format_loader(String path) {
	for (int i = 0; i < loader_count; ++i) {
		if (loader[i]->get_script_instance() && loader[i]->get_script_instance()->get_script()->get_path() == path) {
			return loader[i];
		}
	}
	return Ref<ResourceFormatLoader>();
}

bool ResourceLoader::add_custom_resource_format_loader(String script_path) {

	if (_find_custom_resource_format_loader(script_path).is_valid())
		return false;

	Ref<Resource> res = ResourceLoader::load(script_path);
	ERR_FAIL_COND_V(res.is_null(), false);
	ERR_FAIL_COND_V(!res->is_class("Script"), false);

	Ref<Script> s = res;
	StringName ibt = s->get_instance_base_type();
	bool valid_type = ClassDB::is_parent_class(ibt, "ResourceFormatLoader");
	ERR_EXPLAIN("Script does not inherit a CustomResourceLoader: " + script_path);
	ERR_FAIL_COND_V(!valid_type, false);

	Object *obj = ClassDB::instance(ibt);

	ERR_EXPLAIN("Cannot instance script as custom resource loader, expected 'ResourceFormatLoader' inheritance, got: " + String(ibt));
	ERR_FAIL_COND_V(obj == NULL, false);

	ResourceFormatLoader *crl = NULL;
	crl = Object::cast_to<ResourceFormatLoader>(obj);
	crl->set_script(s.get_ref_ptr());
	ResourceLoader::add_resource_format_loader(crl);

	return true;
}

void ResourceLoader::remove_custom_resource_format_loader(String script_path) {

	Ref<ResourceFormatLoader> loader = _find_custom_resource_format_loader(script_path);
	if (loader.is_valid())
		remove_resource_format_loader(loader);
}

void ResourceLoader::add_custom_loaders() {
	// Custom loaders registration exploits global class names

	String custom_loader_base_class = ResourceFormatLoader::get_class_static();

	List<StringName> global_classes;
	ScriptServer::get_global_class_list(&global_classes);

	for (List<StringName>::Element *E = global_classes.front(); E; E = E->next()) {

		StringName class_name = E->get();
		StringName base_class = ScriptServer::get_global_class_base(class_name);

		if (base_class == custom_loader_base_class) {
			String path = ScriptServer::get_global_class_path(class_name);
			add_custom_resource_format_loader(path);
		}
	}
}

void ResourceLoader::remove_custom_loaders() {

	Vector<Ref<ResourceFormatLoader> > custom_loaders;
	for (int i = 0; i < loader_count; ++i) {
		if (loader[i]->get_script_instance()) {
			custom_loaders.push_back(loader[i]);
		}
	}

	for (int i = 0; i < custom_loaders.size(); ++i) {
		remove_resource_format_loader(custom_loaders[i]);
	}
}

Mutex *ResourceLoader::loading_map_mutex = NULL;
HashMap<String, int> ResourceLoader::loading_map;

void ResourceLoader::initialize() {
#ifndef NO_THREADS
	loading_map_mutex = Mutex::create();
#endif
}

void ResourceLoader::finalize() {
#ifndef NO_THREADS
	const String *K = NULL;
	while ((K = loading_map.next(K))) {
		ERR_PRINTS("Exited while resource is being loaded: " + *K);
	}
	loading_map.clear();
	memdelete(loading_map_mutex);
	loading_map_mutex = NULL;
#endif
}

ResourceLoadErrorNotify ResourceLoader::err_notify = NULL;
void *ResourceLoader::err_notify_ud = NULL;

DependencyErrorNotify ResourceLoader::dep_err_notify = NULL;
void *ResourceLoader::dep_err_notify_ud = NULL;

bool ResourceLoader::abort_on_missing_resource = true;
bool ResourceLoader::timestamp_on_load = false;

SelfList<Resource>::List ResourceLoader::remapped_list;
HashMap<String, Vector<String> > ResourceLoader::translation_remaps;
HashMap<String, String> ResourceLoader::path_remaps;

ResourceLoaderImport ResourceLoader::import = NULL;