1 files changed, 195 insertions, 138 deletions

diff --git a/core/io/resource_loader.cpp b/core/io/resource_loader.cpp
index c9ed4e27d9..d2c4668d12 100644
--- a/core/io/resource_loader.cpp
+++ b/core/io/resource_loader.cpp
@@ -207,34 +207,53 @@ void ResourceFormatLoader::_bind_methods() {
 
 ///////////////////////////////////
 
+// These are used before and after a wait for a WorkerThreadPool task
+// because that can lead to another load started in the same thread,
+// something we must treat as a different stack for the purposes
+// of tracking nesting.
+
+#define PREPARE_FOR_WTP_WAIT                                                   \
+	int load_nesting_backup = ResourceLoader::load_nesting;                    \
+	Vector<String> load_paths_stack_backup = ResourceLoader::load_paths_stack; \
+	ResourceLoader::load_nesting = 0;                                          \
+	ResourceLoader::load_paths_stack.clear();
+
+#define RESTORE_AFTER_WTP_WAIT                                  \
+	DEV_ASSERT(ResourceLoader::load_nesting == 0);              \
+	DEV_ASSERT(ResourceLoader::load_paths_stack.is_empty());    \
+	ResourceLoader::load_nesting = load_nesting_backup;         \
+	ResourceLoader::load_paths_stack = load_paths_stack_backup; \
+	load_paths_stack_backup.clear();
+
 // This should be robust enough to be called redundantly without issues.
 void ResourceLoader::LoadToken::clear() {
 	thread_load_mutex.lock();
 
 	WorkerThreadPool::TaskID task_to_await = 0;
 
+	// User-facing tokens shouldn't be deleted until completely claimed.
+	DEV_ASSERT(user_rc == 0 && user_path.is_empty());
+
 	if (!local_path.is_empty()) { // Empty is used for the special case where the load task is not registered.
 		DEV_ASSERT(thread_load_tasks.has(local_path));
 		ThreadLoadTask &load_task = thread_load_tasks[local_path];
-		if (!load_task.awaited) {
+		if (load_task.task_id && !load_task.awaited) {
 			task_to_await = load_task.task_id;
-			load_task.awaited = true;
 		}
+		// Removing a task which is still in progress would be catastrophic.
+		// Tokens must be alive until the task thread function is done.
+		DEV_ASSERT(load_task.status == THREAD_LOAD_FAILED || load_task.status == THREAD_LOAD_LOADED);
 		thread_load_tasks.erase(local_path);
 		local_path.clear();
 	}
 
-	if (!user_path.is_empty()) {
-		DEV_ASSERT(user_load_tokens.has(user_path));
-		user_load_tokens.erase(user_path);
-		user_path.clear();
-	}
-
 	thread_load_mutex.unlock();
 
 	// If task is unused, await it here, locally, now the token data is consistent.
 	if (task_to_await) {
+		PREPARE_FOR_WTP_WAIT
 		WorkerThreadPool::get_singleton()->wait_for_task_completion(task_to_await);
+		RESTORE_AFTER_WTP_WAIT
 	}
 }
 
@@ -295,11 +314,11 @@ Ref<Resource> ResourceLoader::_load(const String &p_path, const String &p_origin
 	ERR_FAIL_V_MSG(Ref<Resource>(), vformat("No loader found for resource: %s (expected type: %s)", p_path, p_type_hint));
 }
 
-void ResourceLoader::_thread_load_function(void *p_userdata) {
+// This implementation must allow re-entrancy for a task that started awaiting in a deeper stack frame.
+void ResourceLoader::_run_load_task(void *p_userdata) {
 	ThreadLoadTask &load_task = *(ThreadLoadTask *)p_userdata;
 
 	thread_load_mutex.lock();
-	caller_task_id = load_task.task_id;
 	if (cleaning_tasks) {
 		load_task.status = THREAD_LOAD_FAILED;
 		thread_load_mutex.unlock();
@@ -322,8 +341,10 @@ void ResourceLoader::_thread_load_function(void *p_userdata) {
 	}
 	// --
 
+	bool xl_remapped = false;
+	const String &remapped_path = _path_remap(load_task.local_path, &xl_remapped);
 	Error load_err = OK;
-	Ref<Resource> res = _load(load_task.remapped_path, load_task.remapped_path != load_task.local_path ? load_task.local_path : String(), load_task.type_hint, load_task.cache_mode, &load_err, load_task.use_sub_threads, &load_task.progress);
+	Ref<Resource> res = _load(remapped_path, remapped_path != load_task.local_path ? load_task.local_path : String(), load_task.type_hint, load_task.cache_mode, &load_err, load_task.use_sub_threads, &load_task.progress);
 	if (MessageQueue::get_singleton() != MessageQueue::get_main_singleton()) {
 		MessageQueue::get_singleton()->flush();
 	}
@@ -356,27 +377,40 @@ void ResourceLoader::_thread_load_function(void *p_userdata) {
 		unlock_pending = false;
 
 		if (!ignoring) {
-			if (replacing) {
-				Ref<Resource> old_res = ResourceCache::get_ref(load_task.local_path);
-				if (old_res.is_valid() && old_res != load_task.resource) {
-					// If resource is already loaded, only replace its data, to avoid existing invalidating instances.
-					old_res->copy_from(load_task.resource);
+			ResourceCache::lock.lock(); // Check and operations must happen atomically.
+			bool pending_unlock = true;
+			Ref<Resource> old_res = ResourceCache::get_ref(load_task.local_path);
+			if (old_res.is_valid()) {
+				if (old_res != load_task.resource) {
+					// Resource can already exists at this point for two reasons:
+					// a) The load uses replace mode.
+					// b) There were more than one load in flight for the same path because of deadlock prevention.
+					// Either case, we want to keep the resource that was already there.
+					ResourceCache::lock.unlock();
+					pending_unlock = false;
+					if (replacing) {
+						old_res->copy_from(load_task.resource);
+					}
 					load_task.resource = old_res;
 				}
+			} else {
+				load_task.resource->set_path(load_task.local_path);
+			}
+			if (pending_unlock) {
+				ResourceCache::lock.unlock();
 			}
-			load_task.resource->set_path(load_task.local_path, replacing);
 		} else {
 			load_task.resource->set_path_cache(load_task.local_path);
 		}
 
-		if (load_task.xl_remapped) {
+		if (xl_remapped) {
 			load_task.resource->set_as_translation_remapped(true);
 		}
 
 #ifdef TOOLS_ENABLED
 		load_task.resource->set_edited(false);
 		if (timestamp_on_load) {
-			uint64_t mt = FileAccess::get_modified_time(load_task.remapped_path);
+			uint64_t mt = FileAccess::get_modified_time(remapped_path);
 			//printf("mt %s: %lli\n",remapped_path.utf8().get_data(),mt);
 			load_task.resource->set_last_modified_time(mt);
 		}
@@ -426,36 +460,44 @@ static String _validate_local_path(const String &p_path) {
 }
 
 Error ResourceLoader::load_threaded_request(const String &p_path, const String &p_type_hint, bool p_use_sub_threads, ResourceFormatLoader::CacheMode p_cache_mode) {
-	thread_load_mutex.lock();
-	if (user_load_tokens.has(p_path)) {
-		print_verbose("load_threaded_request(): Another threaded load for resource path '" + p_path + "' has been initiated. Not an error.");
-		user_load_tokens[p_path]->reference(); // Additional request.
-		thread_load_mutex.unlock();
-		return OK;
-	}
-	user_load_tokens[p_path] = nullptr;
-	thread_load_mutex.unlock();
+	Ref<ResourceLoader::LoadToken> token = _load_start(p_path, p_type_hint, p_use_sub_threads ? LOAD_THREAD_DISTRIBUTE : LOAD_THREAD_SPAWN_SINGLE, p_cache_mode, true);
+	return token.is_valid() ? OK : FAILED;
+}
 
-	Ref<ResourceLoader::LoadToken> token = _load_start(p_path, p_type_hint, p_use_sub_threads ? LOAD_THREAD_DISTRIBUTE : LOAD_THREAD_SPAWN_SINGLE, p_cache_mode);
-	if (token.is_valid()) {
-		thread_load_mutex.lock();
-		token->user_path = p_path;
-		token->reference(); // First request.
-		user_load_tokens[p_path] = token.ptr();
-		print_lt("REQUEST: user load tokens: " + itos(user_load_tokens.size()));
-		thread_load_mutex.unlock();
-		return OK;
+ResourceLoader::LoadToken *ResourceLoader::_load_threaded_request_reuse_user_token(const String &p_path) {
+	HashMap<String, LoadToken *>::Iterator E = user_load_tokens.find(p_path);
+	if (E) {
+		print_verbose("load_threaded_request(): Another threaded load for resource path '" + p_path + "' has been initiated. Not an error.");
+		LoadToken *token = E->value;
+		token->user_rc++;
+		return token;
 	} else {
-		return FAILED;
+		return nullptr;
 	}
 }
 
+void ResourceLoader::_load_threaded_request_setup_user_token(LoadToken *p_token, const String &p_path) {
+	p_token->user_path = p_path;
+	p_token->reference(); // Extra RC until all user requests have been gotten.
+	p_token->user_rc = 1;
+	user_load_tokens[p_path] = p_token;
+	print_lt("REQUEST: user load tokens: " + itos(user_load_tokens.size()));
+}
+
 Ref<Resource> ResourceLoader::load(const String &p_path, const String &p_type_hint, ResourceFormatLoader::CacheMode p_cache_mode, Error *r_error) {
 	if (r_error) {
 		*r_error = OK;
 	}
 
-	Ref<LoadToken> load_token = _load_start(p_path, p_type_hint, LOAD_THREAD_FROM_CURRENT, p_cache_mode);
+	LoadThreadMode thread_mode = LOAD_THREAD_FROM_CURRENT;
+	if (WorkerThreadPool::get_singleton()->get_caller_task_id() != WorkerThreadPool::INVALID_TASK_ID) {
+		// If user is initiating a single-threaded load from a WorkerThreadPool task,
+		// we instead spawn a new task so there's a precondition that a load in a pool task
+		// is always initiated by the engine. That makes certain aspects simpler, such as
+		// cyclic load detection and awaiting.
+		thread_mode = LOAD_THREAD_SPAWN_SINGLE;
+	}
+	Ref<LoadToken> load_token = _load_start(p_path, p_type_hint, thread_mode, p_cache_mode);
 	if (!load_token.is_valid()) {
 		if (r_error) {
 			*r_error = FAILED;
@@ -467,7 +509,7 @@ Ref<Resource> ResourceLoader::load(const String &p_path, const String &p_type_hi
 	return res;
 }
 
-Ref<ResourceLoader::LoadToken> ResourceLoader::_load_start(const String &p_path, const String &p_type_hint, LoadThreadMode p_thread_mode, ResourceFormatLoader::CacheMode p_cache_mode) {
+Ref<ResourceLoader::LoadToken> ResourceLoader::_load_start(const String &p_path, const String &p_type_hint, LoadThreadMode p_thread_mode, ResourceFormatLoader::CacheMode p_cache_mode, bool p_for_user) {
 	String local_path = _validate_local_path(p_path);
 
 	bool ignoring_cache = p_cache_mode == ResourceFormatLoader::CACHE_MODE_IGNORE || p_cache_mode == ResourceFormatLoader::CACHE_MODE_IGNORE_DEEP;
@@ -480,6 +522,13 @@ Ref<ResourceLoader::LoadToken> ResourceLoader::_load_start(const String &p_path,
 	{
 		MutexLock thread_load_lock(thread_load_mutex);
 
+		if (p_for_user) {
+			LoadToken *existing_token = _load_threaded_request_reuse_user_token(p_path);
+			if (existing_token) {
+				return Ref<LoadToken>(existing_token);
+			}
+		}
+
 		if (!ignoring_cache && thread_load_tasks.has(local_path)) {
 			load_token = Ref<LoadToken>(thread_load_tasks[local_path].load_token);
 			if (load_token.is_valid()) {
@@ -493,12 +542,14 @@ Ref<ResourceLoader::LoadToken> ResourceLoader::_load_start(const String &p_path,
 
 		load_token.instantiate();
 		load_token->local_path = local_path;
+		if (p_for_user) {
+			_load_threaded_request_setup_user_token(load_token.ptr(), p_path);
+		}
 
 		//create load task
 		{
 			ThreadLoadTask load_task;
 
-			load_task.remapped_path = _path_remap(local_path, &load_task.xl_remapped);
 			load_task.load_token = load_token.ptr();
 			load_task.local_path = local_path;
 			load_task.type_hint = p_type_hint;
@@ -511,6 +562,7 @@ Ref<ResourceLoader::LoadToken> ResourceLoader::_load_start(const String &p_path,
 					load_task.resource = existing;
 					load_task.status = THREAD_LOAD_LOADED;
 					load_task.progress = 1.0;
+					DEV_ASSERT(!thread_load_tasks.has(local_path));
 					thread_load_tasks[local_path] = load_task;
 					return load_token;
 				}
@@ -532,14 +584,20 @@ Ref<ResourceLoader::LoadToken> ResourceLoader::_load_start(const String &p_path,
 		run_on_current_thread = must_not_register || p_thread_mode == LOAD_THREAD_FROM_CURRENT;
 
 		if (run_on_current_thread) {
-			load_task_ptr->thread_id = Thread::get_caller_id();
+			// The current thread may happen to be a thread from the pool.
+			WorkerThreadPool::TaskID tid = WorkerThreadPool::get_singleton()->get_caller_task_id();
+			if (tid != WorkerThreadPool::INVALID_TASK_ID) {
+				load_task_ptr->task_id = tid;
+			} else {
+				load_task_ptr->thread_id = Thread::get_caller_id();
+			}
 		} else {
-			load_task_ptr->task_id = WorkerThreadPool::get_singleton()->add_native_task(&ResourceLoader::_thread_load_function, load_task_ptr);
+			load_task_ptr->task_id = WorkerThreadPool::get_singleton()->add_native_task(&ResourceLoader::_run_load_task, load_task_ptr);
 		}
-	}
+	} // MutexLock(thread_load_mutex).
 
 	if (run_on_current_thread) {
-		_thread_load_function(load_task_ptr);
+		_run_load_task(load_task_ptr);
 		if (must_not_register) {
 			load_token->res_if_unregistered = load_task_ptr->resource;
 		}
@@ -626,22 +684,16 @@ Ref<Resource> ResourceLoader::load_threaded_get(const String &p_path, Error *r_e
 		}
 
 		LoadToken *load_token = user_load_tokens[p_path];
-		if (!load_token) {
-			// This happens if requested from one thread and rapidly querying from another.
-			if (r_error) {
-				*r_error = ERR_BUSY;
-			}
-			return Ref<Resource>();
-		}
+		DEV_ASSERT(load_token->user_rc >= 1);
 
 		// Support userland requesting on the main thread before the load is reported to be complete.
 		if (Thread::is_main_thread() && !load_token->local_path.is_empty()) {
 			const ThreadLoadTask &load_task = thread_load_tasks[load_token->local_path];
 			while (load_task.status == THREAD_LOAD_IN_PROGRESS) {
-				thread_load_lock.~MutexLock();
+				thread_load_lock.temp_unlock();
 				bool exit = !_ensure_load_progress();
 				OS::get_singleton()->delay_usec(1000);
-				new (&thread_load_lock) MutexLock(thread_load_mutex);
+				thread_load_lock.temp_relock();
 				if (exit) {
 					break;
 				}
@@ -649,8 +701,15 @@ Ref<Resource> ResourceLoader::load_threaded_get(const String &p_path, Error *r_e
 		}
 
 		res = _load_complete_inner(*load_token, r_error, thread_load_lock);
-		if (load_token->unreference()) {
-			memdelete(load_token);
+
+		load_token->user_rc--;
+		if (load_token->user_rc == 0) {
+			load_token->user_path.clear();
+			user_load_tokens.erase(p_path);
+			if (load_token->unreference()) {
+				memdelete(load_token);
+				load_token = nullptr;
+			}
 		}
 	}
 
@@ -682,7 +741,7 @@ Ref<Resource> ResourceLoader::_load_complete_inner(LoadToken &p_load_token, Erro
 		if (load_task.status == THREAD_LOAD_IN_PROGRESS) {
 			DEV_ASSERT((load_task.task_id == 0) != (load_task.thread_id == 0));
 
-			if ((load_task.task_id != 0 && load_task.task_id == caller_task_id) ||
+			if ((load_task.task_id != 0 && load_task.task_id == WorkerThreadPool::get_singleton()->get_caller_task_id()) ||
 					(load_task.thread_id != 0 && load_task.thread_id == Thread::get_caller_id())) {
 				// Load is in progress, but it's precisely this thread the one in charge.
 				// That means this is a cyclic load.
@@ -693,55 +752,45 @@ Ref<Resource> ResourceLoader::_load_complete_inner(LoadToken &p_load_token, Erro
 			}
 
 			bool loader_is_wtp = load_task.task_id != 0;
-			Error wtp_task_err = FAILED;
 			if (loader_is_wtp) {
 				// Loading thread is in the worker pool.
+				p_thread_load_lock.temp_unlock();
+
+				PREPARE_FOR_WTP_WAIT
+				Error wait_err = WorkerThreadPool::get_singleton()->wait_for_task_completion(load_task.task_id);
+				RESTORE_AFTER_WTP_WAIT
+
+				DEV_ASSERT(!wait_err || wait_err == ERR_BUSY);
+				if (wait_err == ERR_BUSY) {
+					// The WorkerThreadPool has reported that the current task wants to await on an older one.
+					// That't not allowed for safety, to avoid deadlocks. Fortunately, though, in the context of
+					// resource loading that means that the task to wait for can be restarted here to break the
+					// cycle, with as much recursion into this process as needed.
+					// When the stack is eventually unrolled, the original load will have been notified to go on.
+					_run_load_task(&load_task);
+				}
+
+				p_thread_load_lock.temp_relock();
 				load_task.awaited = true;
-				thread_load_mutex.unlock();
-				wtp_task_err = WorkerThreadPool::get_singleton()->wait_for_task_completion(load_task.task_id);
-			}
 
-			if (load_task.status == THREAD_LOAD_IN_PROGRESS) { // If early errored, awaiting would deadlock.
-				if (loader_is_wtp) {
-					if (wtp_task_err == ERR_BUSY) {
-						// The WorkerThreadPool has reported that the current task wants to await on an older one.
-						// That't not allowed for safety, to avoid deadlocks. Fortunately, though, in the context of
-						// resource loading that means that the task to wait for can be restarted here to break the
-						// cycle, with as much recursion into this process as needed.
-						// When the stack is eventually unrolled, the original load will have been notified to go on.
-						// CACHE_MODE_IGNORE is needed because, otherwise, the new request would just see there's
-						// an ongoing load for that resource and wait for it again. This value forces a new load.
-						Ref<ResourceLoader::LoadToken> token = _load_start(load_task.local_path, load_task.type_hint, LOAD_THREAD_DISTRIBUTE, ResourceFormatLoader::CACHE_MODE_IGNORE);
-						Ref<Resource> resource = _load_complete(*token.ptr(), &wtp_task_err);
-						if (r_error) {
-							*r_error = wtp_task_err;
-						}
-						thread_load_mutex.lock();
-						return resource;
-					} else {
-						DEV_ASSERT(wtp_task_err == OK);
-						thread_load_mutex.lock();
-					}
-				} else if (load_task.need_wait) {
-					// Loading thread is main or user thread.
-					if (!load_task.cond_var) {
-						load_task.cond_var = memnew(ConditionVariable);
-					}
-					load_task.awaiters_count++;
-					do {
-						load_task.cond_var->wait(p_thread_load_lock);
-						DEV_ASSERT(thread_load_tasks.has(p_load_token.local_path) && p_load_token.get_reference_count());
-					} while (load_task.need_wait);
-					load_task.awaiters_count--;
-					if (load_task.awaiters_count == 0) {
-						memdelete(load_task.cond_var);
-						load_task.cond_var = nullptr;
-					}
+				DEV_ASSERT(load_task.status == THREAD_LOAD_FAILED || load_task.status == THREAD_LOAD_LOADED);
+			} else if (load_task.need_wait) {
+				// Loading thread is main or user thread.
+				if (!load_task.cond_var) {
+					load_task.cond_var = memnew(ConditionVariable);
 				}
-			} else {
-				if (loader_is_wtp) {
-					thread_load_mutex.lock();
+				load_task.awaiters_count++;
+				do {
+					load_task.cond_var->wait(p_thread_load_lock);
+					DEV_ASSERT(thread_load_tasks.has(p_load_token.local_path) && p_load_token.get_reference_count());
+				} while (load_task.need_wait);
+				load_task.awaiters_count--;
+				if (load_task.awaiters_count == 0) {
+					memdelete(load_task.cond_var);
+					load_task.cond_var = nullptr;
 				}
+
+				DEV_ASSERT(load_task.status == THREAD_LOAD_FAILED || load_task.status == THREAD_LOAD_LOADED);
 			}
 		}
 
@@ -1055,36 +1104,39 @@ String ResourceLoader::_path_remap(const String &p_path, bool *r_translation_rem
 		new_path = path_remaps[new_path];
 	} else {
 		// Try file remap.
-		Error err;
-		Ref<FileAccess> f = FileAccess::open(new_path + ".remap", FileAccess::READ, &err);
-		if (f.is_valid()) {
-			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, nullptr, true);
-				if (err == ERR_FILE_EOF) {
-					break;
-				} else if (err != OK) {
-					ERR_PRINT("Parse error: " + p_path + ".remap:" + itos(lines) + " error: " + error_text + ".");
-					break;
-				}
+		// Usually, there's no remap file and FileAccess::exists() is faster than FileAccess::open().
+		if (FileAccess::exists(new_path + ".remap")) {
+			Error err;
+			Ref<FileAccess> f = FileAccess::open(new_path + ".remap", FileAccess::READ, &err);
+			if (f.is_valid()) {
+				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, nullptr, true);
+					if (err == ERR_FILE_EOF) {
+						break;
+					} else if (err != OK) {
+						ERR_PRINT("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;
+					if (assign == "path") {
+						new_path = value;
+						break;
+					} else if (next_tag.name != "remap") {
+						break;
+					}
 				}
 			}
 		}
@@ -1156,7 +1208,7 @@ void ResourceLoader::clear_translation_remaps() {
 void ResourceLoader::clear_thread_load_tasks() {
 	// Bring the thing down as quickly as possible without causing deadlocks or leaks.
 
-	thread_load_mutex.lock();
+	MutexLock thread_load_lock(thread_load_mutex);
 	cleaning_tasks = true;
 
 	while (true) {
@@ -1175,21 +1227,23 @@ void ResourceLoader::clear_thread_load_tasks() {
 		if (none_running) {
 			break;
 		}
-		thread_load_mutex.unlock();
+		thread_load_lock.temp_unlock();
 		OS::get_singleton()->delay_usec(1000);
-		thread_load_mutex.lock();
+		thread_load_lock.temp_relock();
 	}
 
 	while (user_load_tokens.begin()) {
-		// User load tokens remove themselves from the map on destruction.
-		memdelete(user_load_tokens.begin()->value);
+		LoadToken *user_token = user_load_tokens.begin()->value;
+		user_load_tokens.remove(user_load_tokens.begin());
+		DEV_ASSERT(user_token->user_rc > 0 && !user_token->user_path.is_empty());
+		user_token->user_path.clear();
+		user_token->user_rc = 0;
+		user_token->unreference();
 	}
-	user_load_tokens.clear();
 
 	thread_load_tasks.clear();
 
 	cleaning_tasks = false;
-	thread_load_mutex.unlock();
 }
 
 void ResourceLoader::load_path_remaps() {
@@ -1302,12 +1356,15 @@ bool ResourceLoader::abort_on_missing_resource = true;
 bool ResourceLoader::timestamp_on_load = false;
 
 thread_local int ResourceLoader::load_nesting = 0;
-thread_local WorkerThreadPool::TaskID ResourceLoader::caller_task_id = 0;
 thread_local Vector<String> ResourceLoader::load_paths_stack;
 thread_local HashMap<int, HashMap<String, Ref<Resource>>> ResourceLoader::res_ref_overrides;
 
+SafeBinaryMutex<ResourceLoader::BINARY_MUTEX_TAG> &_get_res_loader_mutex() {
+	return ResourceLoader::thread_load_mutex;
+}
+
 template <>
-thread_local uint32_t SafeBinaryMutex<ResourceLoader::BINARY_MUTEX_TAG>::count = 0;
+thread_local SafeBinaryMutex<ResourceLoader::BINARY_MUTEX_TAG>::TLSData SafeBinaryMutex<ResourceLoader::BINARY_MUTEX_TAG>::tls_data(_get_res_loader_mutex());
 SafeBinaryMutex<ResourceLoader::BINARY_MUTEX_TAG> ResourceLoader::thread_load_mutex;
 HashMap<String, ResourceLoader::ThreadLoadTask> ResourceLoader::thread_load_tasks;
 bool ResourceLoader::cleaning_tasks = false;