Merge pull request #45618 from RandomShaper/modernize_mt_3.2

Backport of all the multi-threading modernization (3.2)

editor/audio_stream_preview.cpp

@@ -158,7 +158,7 @@ void AudioStreamPreviewGenerator::_preview_thread(void *p_preview) {
 
 	preview->playback->stop();
 
-	preview->generating = false;
+	preview->generating.clear();
 }
 
 Ref<AudioStreamPreview> AudioStreamPreviewGenerator::generate_preview(const Ref<AudioStream> &p_stream) {
@@ -175,7 +175,7 @@ Ref<AudioStreamPreview> AudioStreamPreviewGenerator::generate_preview(const Ref<
 	Preview *preview = &previews[p_stream->get_instance_id()];
 	preview->base_stream = p_stream;
 	preview->playback = preview->base_stream->instance_playback();
-	preview->generating = true;
+	preview->generating.set();
 	preview->id = p_stream->get_instance_id();
 
 	float len_s = preview->base_stream->get_length();
@@ -199,8 +199,10 @@ Ref<AudioStreamPreview> AudioStreamPreviewGenerator::generate_preview(const Ref<
 	preview->preview->preview = maxmin;
 	preview->preview->length = len_s;
 
-	if (preview->playback.is_valid())
-		preview->thread = Thread::create(_preview_thread, preview);
+	if (preview->playback.is_valid()) {
+		preview->thread = memnew(Thread);
+		preview->thread->start(_preview_thread, preview);
+	}
 
 	return preview->preview;
 }
@@ -218,9 +220,10 @@ void AudioStreamPreviewGenerator::_notification(int p_what) {
 	if (p_what == NOTIFICATION_PROCESS) {
 		List<ObjectID> to_erase;
 		for (Map<ObjectID, Preview>::Element *E = previews.front(); E; E = E->next()) {
-			if (!E->get().generating) {
+			if (!E->get().generating.is_set()) {
 				if (E->get().thread) {
-					Thread::wait_to_finish(E->get().thread);
+					E->get().thread->wait_to_finish();
+					memdelete(E->get().thread);
 					E->get().thread = NULL;
 				}
 				if (!ObjectDB::get_instance(E->key())) { //no longer in use, get rid of preview

editor/audio_stream_preview.h

@@ -32,6 +32,7 @@
 #define AUDIO_STREAM_PREVIEW_H
 
 #include "core/os/thread.h"
+#include "core/safe_refcount.h"
 #include "scene/main/node.h"
 #include "servers/audio/audio_stream.h"
 
@@ -60,9 +61,20 @@ class AudioStreamPreviewGenerator : public Node {
 		Ref<AudioStreamPreview> preview;
 		Ref<AudioStream> base_stream;
 		Ref<AudioStreamPlayback> playback;
-		volatile bool generating;
+		SafeFlag generating;
 		ObjectID id;
 		Thread *thread;
+
+		// Needed for the bookkeeping of the Map
+		Preview &operator=(const Preview &p_rhs) {
+			preview = p_rhs.preview;
+			base_stream = p_rhs.base_stream;
+			playback = p_rhs.playback;
+			generating.set_to(generating.is_set());
+			id = p_rhs.id;
+			thread = p_rhs.thread;
+			return *this;
+		}
 	};
 
 	Map<ObjectID, Preview> previews;

editor/editor_file_system.cpp

@@ -609,7 +609,7 @@ void EditorFileSystem::scan() {
 	if (false /*&& bool(Globals::get_singleton()->get("debug/disable_scan"))*/)
 		return;
 
-	if (scanning || scanning_changes || thread)
+	if (scanning || scanning_changes || thread.is_started())
 		return;
 
 	_update_extensions();
@@ -632,13 +632,13 @@ void EditorFileSystem::scan() {
 		first_scan = false;
 	} else {
 
-		ERR_FAIL_COND(thread);
+		ERR_FAIL_COND(thread.is_started());
 		set_process(true);
 		Thread::Settings s;
 		scanning = true;
 		scan_total = 0;
 		s.priority = Thread::PRIORITY_LOW;
-		thread = Thread::create(_thread_func, this, s);
+		thread.start(_thread_func, this, s);
 		//tree->hide();
 		//progress->show();
 	}
@@ -1067,7 +1067,7 @@ void EditorFileSystem::get_changed_sources(List<String> *r_changed) {
 void EditorFileSystem::scan_changes() {
 
 	if (first_scan || // Prevent a premature changes scan from inhibiting the first full scan
-			scanning || scanning_changes || thread) {
+			scanning || scanning_changes || thread.is_started()) {
 		scan_changes_pending = true;
 		set_process(true);
 		return;
@@ -1097,12 +1097,12 @@ void EditorFileSystem::scan_changes() {
 		emit_signal("sources_changed", sources_changed.size() > 0);
 	} else {
 
-		ERR_FAIL_COND(thread_sources);
+		ERR_FAIL_COND(thread_sources.is_started());
 		set_process(true);
 		scan_total = 0;
 		Thread::Settings s;
 		s.priority = Thread::PRIORITY_LOW;
-		thread_sources = Thread::create(_thread_func_sources, this, s);
+		thread_sources.start(_thread_func_sources, this, s);
 	}
 }
 
@@ -1116,17 +1116,14 @@ void EditorFileSystem::_notification(int p_what) {
 
 		} break;
 		case NOTIFICATION_EXIT_TREE: {
-			Thread *active_thread = thread ? thread : thread_sources;
-			if (use_threads && active_thread) {
+			Thread &active_thread = thread.is_started() ? thread : thread_sources;
+			if (use_threads && active_thread.is_started()) {
 				//abort thread if in progress
 				abort_scan = true;
 				while (scanning) {
 					OS::get_singleton()->delay_usec(1000);
 				}
-				Thread::wait_to_finish(active_thread);
-				memdelete(active_thread);
-				thread = NULL;
-				thread_sources = NULL;
+				active_thread.wait_to_finish();
 				WARN_PRINT("Scan thread aborted...");
 				set_process(false);
 			}
@@ -1151,9 +1148,7 @@ void EditorFileSystem::_notification(int p_what) {
 
 						set_process(false);
 
-						Thread::wait_to_finish(thread_sources);
-						memdelete(thread_sources);
-						thread_sources = NULL;
+						thread_sources.wait_to_finish();
 						if (_update_scan_actions())
 							emit_signal("filesystem_changed");
 						emit_signal("sources_changed", sources_changed.size() > 0);
@@ -1168,9 +1163,7 @@ void EditorFileSystem::_notification(int p_what) {
 						memdelete(filesystem);
 					filesystem = new_filesystem;
 					new_filesystem = NULL;
-					Thread::wait_to_finish(thread);
-					memdelete(thread);
-					thread = NULL;
+					thread.wait_to_finish();
 					_update_scan_actions();
 					emit_signal("filesystem_changed");
 					emit_signal("sources_changed", sources_changed.size() > 0);
@@ -1452,10 +1445,10 @@ void EditorFileSystem::_scan_script_classes(EditorFileSystemDirectory *p_dir) {
 
 void EditorFileSystem::update_script_classes() {
 
-	if (!update_script_classes_queued)
+	if (!update_script_classes_queued.is_set())
 		return;
 
-	update_script_classes_queued = false;
+	update_script_classes_queued.clear();
 	ScriptServer::global_classes_clear();
 	if (get_filesystem()) {
 		_scan_script_classes(get_filesystem());
@@ -1474,11 +1467,11 @@ void EditorFileSystem::update_script_classes() {
 }
 
 void EditorFileSystem::_queue_update_script_classes() {
-	if (update_script_classes_queued) {
+	if (update_script_classes_queued.is_set()) {
 		return;
 	}
 
-	update_script_classes_queued = true;
+	update_script_classes_queued.set();
 	call_deferred("update_script_classes");
 }
 
@@ -2135,11 +2128,9 @@ EditorFileSystem::EditorFileSystem() {
 	filesystem = memnew(EditorFileSystemDirectory); //like, empty
 	filesystem->parent = NULL;
 
-	thread = NULL;
 	scanning = false;
 	importing = false;
 	use_threads = true;
-	thread_sources = NULL;
 	new_filesystem = NULL;
 
 	abort_scan = false;
@@ -2155,7 +2146,7 @@ EditorFileSystem::EditorFileSystem() {
 	memdelete(da);
 
 	scan_total = 0;
-	update_script_classes_queued = false;
+	update_script_classes_queued.clear();
 	first_scan = true;
 	scan_changes_pending = false;
 	revalidate_import_files = false;

editor/editor_file_system.h

@@ -34,8 +34,10 @@
 #include "core/os/dir_access.h"
 #include "core/os/thread.h"
 #include "core/os/thread_safe.h"
+#include "core/safe_refcount.h"
 #include "core/set.h"
 #include "scene/main/node.h"
+
 class FileAccess;
 
 struct EditorProgressBG;
@@ -136,7 +138,7 @@ class EditorFileSystem : public Node {
 	};
 
 	bool use_threads;
-	Thread *thread;
+	Thread thread;
 	static void _thread_func(void *_userdata);
 
 	EditorFileSystemDirectory *new_filesystem;
@@ -200,7 +202,7 @@ class EditorFileSystem : public Node {
 
 	void _scan_new_dir(EditorFileSystemDirectory *p_dir, DirAccess *da, const ScanProgress &p_progress);
 
-	Thread *thread_sources;
+	Thread thread_sources;
 	bool scanning_changes;
 	bool scanning_changes_done;
 
@@ -231,7 +233,7 @@ class EditorFileSystem : public Node {
 	};
 
 	void _scan_script_classes(EditorFileSystemDirectory *p_dir);
-	volatile bool update_script_classes_queued;
+	SafeFlag update_script_classes_queued;
 	void _queue_update_script_classes();
 
 	String _get_global_script_class(const String &p_type, const String &p_path, String *r_extends, String *r_icon_path) const;

editor/editor_node.cpp

@@ -5735,13 +5735,13 @@ void EditorNode::_print_handler(void *p_this, const String &p_string, bool p_err
 static void _execute_thread(void *p_ud) {
 
 	EditorNode::ExecuteThreadArgs *eta = (EditorNode::ExecuteThreadArgs *)p_ud;
-	Error err = OS::get_singleton()->execute(eta->path, eta->args, true, NULL, &eta->output, &eta->exitcode, true, eta->execute_output_mutex);
+	Error err = OS::get_singleton()->execute(eta->path, eta->args, true, NULL, &eta->output, &eta->exitcode, true, &eta->execute_output_mutex);
 	print_verbose("Thread exit status: " + itos(eta->exitcode));
 	if (err != OK) {
 		eta->exitcode = err;
 	}
 
-	eta->done = true;
+	eta->done.set();
 }
 
 int EditorNode::execute_and_show_output(const String &p_title, const String &p_path, const List<String> &p_arguments, bool p_close_on_ok, bool p_close_on_errors) {
@@ -5755,31 +5755,25 @@ int EditorNode::execute_and_show_output(const String &p_title, const String &p_p
 	ExecuteThreadArgs eta;
 	eta.path = p_path;
 	eta.args = p_arguments;
-	eta.execute_output_mutex = Mutex::create();
 	eta.exitcode = 255;
-	eta.done = false;
 
 	int prev_len = 0;
 
-	eta.execute_output_thread = Thread::create(_execute_thread, &eta);
+	eta.execute_output_thread.start(_execute_thread, &eta);
 
-	ERR_FAIL_COND_V(!eta.execute_output_thread, 0);
-
-	while (!eta.done) {
-		eta.execute_output_mutex->lock();
+	while (!eta.done.is_set()) {
+		eta.execute_output_mutex.lock();
 		if (prev_len != eta.output.length()) {
 			String to_add = eta.output.substr(prev_len, eta.output.length());
 			prev_len = eta.output.length();
 			execute_outputs->add_text(to_add);
 			Main::iteration();
 		}
-		eta.execute_output_mutex->unlock();
+		eta.execute_output_mutex.unlock();
 		OS::get_singleton()->delay_usec(1000);
 	}
 
-	Thread::wait_to_finish(eta.execute_output_thread);
-	memdelete(eta.execute_output_thread);
-	memdelete(eta.execute_output_mutex);
+	eta.execute_output_thread.wait_to_finish();
 	execute_outputs->add_text("\nExit Code: " + itos(eta.exitcode));
 
 	if (p_close_on_errors && eta.exitcode != 0) {

editor/editor_node.h

@@ -31,6 +31,7 @@
 #ifndef EDITOR_NODE_H
 #define EDITOR_NODE_H
 
+#include "core/safe_refcount.h"
 #include "editor/editor_data.h"
 #include "editor/editor_folding.h"
 #include "editor/editor_run.h"
@@ -106,10 +107,10 @@ public:
 		String path;
 		List<String> args;
 		String output;
-		Thread *execute_output_thread;
-		Mutex *execute_output_mutex;
+		Thread execute_output_thread;
+		Mutex execute_output_mutex;
 		int exitcode;
-		volatile bool done;
+		SafeFlag done;
 	};
 
 private:

editor/editor_resource_preview.cpp

@@ -109,7 +109,7 @@ void EditorResourcePreview::_thread_func(void *ud) {
 
 void EditorResourcePreview::_preview_ready(const String &p_str, const Ref<Texture> &p_texture, const Ref<Texture> &p_small_texture, ObjectID id, const StringName &p_func, const Variant &p_ud) {
 
-	preview_mutex->lock();
+	preview_mutex.lock();
 
 	String path = p_str;
 	uint32_t hash = 0;
@@ -131,7 +131,7 @@ void EditorResourcePreview::_preview_ready(const String &p_str, const Ref<Textur
 
 	cache[path] = item;
 
-	preview_mutex->unlock();
+	preview_mutex.unlock();
 
 	MessageQueue::get_singleton()->push_call(id, p_func, path, p_texture, p_small_texture, p_ud);
 }
@@ -217,11 +217,11 @@ void EditorResourcePreview::_generate_preview(Ref<ImageTexture> &r_texture, Ref<
 
 void EditorResourcePreview::_thread() {
 
-	exited = false;
-	while (!exit) {
+	exited.clear();
+	while (!exit.is_set()) {
 
-		preview_sem->wait();
-		preview_mutex->lock();
+		preview_sem.wait();
+		preview_mutex.lock();
 
 		if (queue.size()) {
 
@@ -237,10 +237,10 @@ void EditorResourcePreview::_thread() {
 
 				_preview_ready(path, cache[item.path].preview, cache[item.path].small_preview, item.id, item.function, item.userdata);
 
-				preview_mutex->unlock();
+				preview_mutex.unlock();
 			} else {
 
-				preview_mutex->unlock();
+				preview_mutex.unlock();
 
 				Ref<ImageTexture> texture;
 				Ref<ImageTexture> small_texture;
@@ -347,10 +347,10 @@ void EditorResourcePreview::_thread() {
 			}
 
 		} else {
-			preview_mutex->unlock();
+			preview_mutex.unlock();
 		}
 	}
-	exited = true;
+	exited.set();
 }
 
 void EditorResourcePreview::queue_edited_resource_preview(const Ref<Resource> &p_res, Object *p_receiver, const StringName &p_receiver_func, const Variant &p_userdata) {
@@ -358,7 +358,7 @@ void EditorResourcePreview::queue_edited_resource_preview(const Ref<Resource> &p
 	ERR_FAIL_NULL(p_receiver);
 	ERR_FAIL_COND(!p_res.is_valid());
 
-	preview_mutex->lock();
+	preview_mutex.lock();
 
 	String path_id = "ID:" + itos(p_res->get_instance_id());
 
@@ -366,7 +366,7 @@ void EditorResourcePreview::queue_edited_resource_preview(const Ref<Resource> &p
 
 		cache[path_id].order = order++;
 		p_receiver->call(p_receiver_func, path_id, cache[path_id].preview, cache[path_id].small_preview, p_userdata);
-		preview_mutex->unlock();
+		preview_mutex.unlock();
 		return;
 	}
 
@@ -380,18 +380,18 @@ void EditorResourcePreview::queue_edited_resource_preview(const Ref<Resource> &p
 	item.userdata = p_userdata;
 
 	queue.push_back(item);
-	preview_mutex->unlock();
-	preview_sem->post();
+	preview_mutex.unlock();
+	preview_sem.post();
 }
 
 void EditorResourcePreview::queue_resource_preview(const String &p_path, Object *p_receiver, const StringName &p_receiver_func, const Variant &p_userdata) {
 
 	ERR_FAIL_NULL(p_receiver);
-	preview_mutex->lock();
+	preview_mutex.lock();
 	if (cache.has(p_path)) {
 		cache[p_path].order = order++;
 		p_receiver->call(p_receiver_func, p_path, cache[p_path].preview, cache[p_path].small_preview, p_userdata);
-		preview_mutex->unlock();
+		preview_mutex.unlock();
 		return;
 	}
 
@@ -402,8 +402,8 @@ void EditorResourcePreview::queue_resource_preview(const String &p_path, Object
 	item.userdata = p_userdata;
 
 	queue.push_back(item);
-	preview_mutex->unlock();
-	preview_sem->post();
+	preview_mutex.unlock();
+	preview_sem.post();
 }
 
 void EditorResourcePreview::add_preview_generator(const Ref<EditorResourcePreviewGenerator> &p_generator) {
@@ -436,7 +436,7 @@ void EditorResourcePreview::_bind_methods() {
 
 void EditorResourcePreview::check_for_invalidation(const String &p_path) {
 
-	preview_mutex->lock();
+	preview_mutex.lock();
 
 	bool call_invalidated = false;
 	if (cache.has(p_path)) {
@@ -448,7 +448,7 @@ void EditorResourcePreview::check_for_invalidation(const String &p_path) {
 		}
 	}
 
-	preview_mutex->unlock();
+	preview_mutex.unlock();
 
 	if (call_invalidated) { //do outside mutex
 		call_deferred("emit_signal", "preview_invalidated", p_path);
@@ -456,37 +456,28 @@ void EditorResourcePreview::check_for_invalidation(const String &p_path) {
 }
 
 void EditorResourcePreview::start() {
-	ERR_FAIL_COND_MSG(thread, "Thread already started.");
-	thread = Thread::create(_thread_func, this);
+	ERR_FAIL_COND_MSG(thread.is_started(), "Thread already started.");
+	thread.start(_thread_func, this);
 }
 
 void EditorResourcePreview::stop() {
-	if (thread) {
-		exit = true;
-		preview_sem->post();
-		while (!exited) {
+	if (thread.is_started()) {
+		exit.set();
+		preview_sem.post();
+		while (!exited.is_set()) {
 			OS::get_singleton()->delay_usec(10000);
 			VisualServer::get_singleton()->sync(); //sync pending stuff, as thread may be blocked on visual server
 		}
-		Thread::wait_to_finish(thread);
-		memdelete(thread);
-		thread = NULL;
+		thread.wait_to_finish();
 	}
 }
 
 EditorResourcePreview::EditorResourcePreview() {
-	thread = NULL;
 	singleton = this;
-	preview_mutex = Mutex::create();
-	preview_sem = Semaphore::create();
 	order = 0;
-	exit = false;
-	exited = false;
 }
 
 EditorResourcePreview::~EditorResourcePreview() {
 
 	stop();
-	memdelete(preview_mutex);
-	memdelete(preview_sem);
 }

editor/editor_resource_preview.h

@@ -33,6 +33,7 @@
 
 #include "core/os/semaphore.h"
 #include "core/os/thread.h"
+#include "core/safe_refcount.h"
 #include "scene/main/node.h"
 #include "scene/resources/texture.h"
 
@@ -70,11 +71,11 @@ class EditorResourcePreview : public Node {
 
 	List<QueueItem> queue;
 
-	Mutex *preview_mutex;
-	Semaphore *preview_sem;
-	Thread *thread;
-	volatile bool exit;
-	volatile bool exited;
+	Mutex preview_mutex;
+	Semaphore preview_sem;
+	Thread thread;
+	SafeFlag exit;
+	SafeFlag exited;
 
 	struct Item {
 		Ref<Texture> preview;

editor/fileserver/editor_file_server.cpp

@@ -42,9 +42,9 @@
 void EditorFileServer::_close_client(ClientData *cd) {
 
 	cd->connection->disconnect_from_host();
-	cd->efs->wait_mutex->lock();
-	cd->efs->to_wait.insert(cd->thread);
-	cd->efs->wait_mutex->unlock();
+	cd->efs->wait_mutex.lock();
+	cd->efs->to_wait.insert(&cd->thread);
+	cd->efs->wait_mutex.unlock();
 	while (cd->files.size()) {
 		memdelete(cd->files.front()->get());
 		cd->files.erase(cd->files.front());
@@ -291,20 +291,19 @@ void EditorFileServer::_thread_start(void *s) {
 				cd->connection = self->server->take_connection();
 				cd->efs = self;
 				cd->quit = false;
-				cd->thread = Thread::create(_subthread_start, cd);
+				cd->thread.start(_subthread_start, cd);
 			}
 		}
 
-		self->wait_mutex->lock();
+		self->wait_mutex.lock();
 		while (self->to_wait.size()) {
 			Thread *w = self->to_wait.front()->get();
 			self->to_wait.erase(w);
-			self->wait_mutex->unlock();
-			Thread::wait_to_finish(w);
-			memdelete(w);
-			self->wait_mutex->lock();
+			self->wait_mutex.unlock();
+			w->wait_to_finish();
+			self->wait_mutex.lock();
 		}
-		self->wait_mutex->unlock();
+		self->wait_mutex.unlock();
 
 		OS::get_singleton()->delay_usec(100000);
 	}
@@ -331,11 +330,10 @@ void EditorFileServer::stop() {
 EditorFileServer::EditorFileServer() {
 
 	server.instance();
-	wait_mutex = Mutex::create();
 	quit = false;
 	active = false;
 	cmd = CMD_NONE;
-	thread = Thread::create(_thread_start, this);
+	thread.start(_thread_start, this);
 
 	EDITOR_DEF("filesystem/file_server/port", 6010);
 	EDITOR_DEF("filesystem/file_server/password", "");
@@ -344,7 +342,5 @@ EditorFileServer::EditorFileServer() {
 EditorFileServer::~EditorFileServer() {
 
 	quit = true;
-	Thread::wait_to_finish(thread);
-	memdelete(thread);
-	memdelete(wait_mutex);
+	thread.wait_to_finish();
 }

editor/fileserver/editor_file_server.h

@@ -49,7 +49,7 @@ class EditorFileServer : public Object {
 
 	struct ClientData {
 
-		Thread *thread;
+		Thread thread;
 		Ref<StreamPeerTCP> connection;
 		Map<int, FileAccess *> files;
 		EditorFileServer *efs;
@@ -62,8 +62,8 @@ class EditorFileServer : public Object {
 	static void _close_client(ClientData *cd);
 	static void _subthread_start(void *s);
 
-	Mutex *wait_mutex;
-	Thread *thread;
+	Mutex wait_mutex;
+	Thread thread;
 	static void _thread_start(void *);
 	bool quit;
 	Command cmd;

editor/import/resource_importer_texture.cpp

@@ -38,7 +38,7 @@
 
 void ResourceImporterTexture::_texture_reimport_srgb(const Ref<StreamTexture> &p_tex) {
 
-	singleton->mutex->lock();
+	singleton->mutex.lock();
 	StringName path = p_tex->get_path();
 
 	if (!singleton->make_flags.has(path)) {
@@ -47,12 +47,12 @@ void ResourceImporterTexture::_texture_reimport_srgb(const Ref<StreamTexture> &p
 
 	singleton->make_flags[path] |= MAKE_SRGB_FLAG;
 
-	singleton->mutex->unlock();
+	singleton->mutex.unlock();
 }
 
 void ResourceImporterTexture::_texture_reimport_3d(const Ref<StreamTexture> &p_tex) {
 
-	singleton->mutex->lock();
+	singleton->mutex.lock();
 	StringName path = p_tex->get_path();
 
 	if (!singleton->make_flags.has(path)) {
@@ -61,12 +61,12 @@ void ResourceImporterTexture::_texture_reimport_3d(const Ref<StreamTexture> &p_t
 
 	singleton->make_flags[path] |= MAKE_3D_FLAG;
 
-	singleton->mutex->unlock();
+	singleton->mutex.unlock();
 }
 
 void ResourceImporterTexture::_texture_reimport_normal(const Ref<StreamTexture> &p_tex) {
 
-	singleton->mutex->lock();
+	singleton->mutex.lock();
 	StringName path = p_tex->get_path();
 
 	if (!singleton->make_flags.has(path)) {
@@ -75,7 +75,7 @@ void ResourceImporterTexture::_texture_reimport_normal(const Ref<StreamTexture>
 
 	singleton->make_flags[path] |= MAKE_NORMAL_FLAG;
 
-	singleton->mutex->unlock();
+	singleton->mutex.unlock();
 }
 
 void ResourceImporterTexture::update_imports() {
@@ -83,10 +83,10 @@ void ResourceImporterTexture::update_imports() {
 	if (EditorFileSystem::get_singleton()->is_scanning() || EditorFileSystem::get_singleton()->is_importing()) {
 		return; // do nothing for now
 	}
-	mutex->lock();
+	mutex.lock();
 
 	if (make_flags.empty()) {
-		mutex->unlock();
+		mutex.unlock();
 		return;
 	}
 
@@ -128,7 +128,7 @@ void ResourceImporterTexture::update_imports() {
 
 	make_flags.clear();
 
-	mutex->unlock();
+	mutex.unlock();
 
 	if (to_reimport.size()) {
 		EditorFileSystem::get_singleton()->reimport_files(to_reimport);
@@ -611,10 +611,4 @@ ResourceImporterTexture::ResourceImporterTexture() {
 	StreamTexture::request_3d_callback = _texture_reimport_3d;
 	StreamTexture::request_srgb_callback = _texture_reimport_srgb;
 	StreamTexture::request_normal_callback = _texture_reimport_normal;
-	mutex = Mutex::create();
-}
-
-ResourceImporterTexture::~ResourceImporterTexture() {
-
-	memdelete(mutex);
 }

editor/import/resource_importer_texture.h

@@ -46,7 +46,7 @@ protected:
 		MAKE_NORMAL_FLAG = 4
 	};
 
-	Mutex *mutex;
+	Mutex mutex;
 	Map<StringName, int> make_flags;
 
 	static void _texture_reimport_srgb(const Ref<StreamTexture> &p_tex);
@@ -94,7 +94,6 @@ public:
 	virtual String get_import_settings_string() const;
 
 	ResourceImporterTexture();
-	~ResourceImporterTexture();
 };
 
 #endif // RESOURCEIMPORTTEXTURE_H

editor/plugins/editor_preview_plugins.cpp

@@ -308,7 +308,7 @@ EditorPackedScenePreviewPlugin::EditorPackedScenePreviewPlugin() {
 
 void EditorMaterialPreviewPlugin::_preview_done(const Variant &p_udata) {
 
-	preview_done = true;
+	preview_done.set();
 }
 
 void EditorMaterialPreviewPlugin::_bind_methods() {
@@ -336,10 +336,10 @@ Ref<Texture> EditorMaterialPreviewPlugin::generate(const RES &p_from, const Size
 
 		VS::get_singleton()->viewport_set_update_mode(viewport, VS::VIEWPORT_UPDATE_ONCE); //once used for capture
 
-		preview_done = false;
+		preview_done.clear();
 		VS::get_singleton()->request_frame_drawn_callback(const_cast<EditorMaterialPreviewPlugin *>(this), "_preview_done", Variant());
 
-		while (!preview_done) {
+		while (!preview_done.is_set()) {
 			OS::get_singleton()->delay_usec(10);
 		}
 
@@ -699,7 +699,7 @@ EditorAudioStreamPreviewPlugin::EditorAudioStreamPreviewPlugin() {
 
 void EditorMeshPreviewPlugin::_preview_done(const Variant &p_udata) {
 
-	preview_done = true;
+	preview_done.set();
 }
 
 void EditorMeshPreviewPlugin::_bind_methods() {
@@ -737,10 +737,10 @@ Ref<Texture> EditorMeshPreviewPlugin::generate(const RES &p_from, const Size2 &p
 
 	VS::get_singleton()->viewport_set_update_mode(viewport, VS::VIEWPORT_UPDATE_ONCE); //once used for capture
 
-	preview_done = false;
+	preview_done.clear();
 	VS::get_singleton()->request_frame_drawn_callback(const_cast<EditorMeshPreviewPlugin *>(this), "_preview_done", Variant());
 
-	while (!preview_done) {
+	while (!preview_done.is_set()) {
 		OS::get_singleton()->delay_usec(10);
 	}
 
@@ -819,7 +819,7 @@ EditorMeshPreviewPlugin::~EditorMeshPreviewPlugin() {
 
 void EditorFontPreviewPlugin::_preview_done(const Variant &p_udata) {
 
-	preview_done = true;
+	preview_done.set();
 }
 
 void EditorFontPreviewPlugin::_bind_methods() {
@@ -861,11 +861,11 @@ Ref<Texture> EditorFontPreviewPlugin::generate_from_path(const String &p_path, c
 
 	font->draw(canvas_item, pos, sampled_text);
 
-	preview_done = false;
+	preview_done.clear();
 	VS::get_singleton()->viewport_set_update_mode(viewport, VS::VIEWPORT_UPDATE_ONCE); //once used for capture
 	VS::get_singleton()->request_frame_drawn_callback(const_cast<EditorFontPreviewPlugin *>(this), "_preview_done", Variant());
 
-	while (!preview_done) {
+	while (!preview_done.is_set()) {
 		OS::get_singleton()->delay_usec(10);
 	}
 

editor/plugins/editor_preview_plugins.h

@@ -33,6 +33,8 @@
 
 #include "editor/editor_resource_preview.h"
 
+#include "core/safe_refcount.h"
+
 void post_process_preview(Ref<Image> p_image);
 
 class EditorTexturePreviewPlugin : public EditorResourcePreviewGenerator {
@@ -92,7 +94,7 @@ class EditorMaterialPreviewPlugin : public EditorResourcePreviewGenerator {
 	RID light2;
 	RID light_instance2;
 	RID camera;
-	mutable volatile bool preview_done;
+	mutable SafeFlag preview_done;
 
 	void _preview_done(const Variant &p_udata);
 
@@ -137,7 +139,7 @@ class EditorMeshPreviewPlugin : public EditorResourcePreviewGenerator {
 	RID light2;
 	RID light_instance2;
 	RID camera;
-	mutable volatile bool preview_done;
+	mutable SafeFlag preview_done;
 
 	void _preview_done(const Variant &p_udata);
 
@@ -160,7 +162,7 @@ class EditorFontPreviewPlugin : public EditorResourcePreviewGenerator {
 	RID viewport_texture;
 	RID canvas;
 	RID canvas_item;
-	mutable volatile bool preview_done;
+	mutable SafeFlag preview_done;
 
 	void _preview_done(const Variant &p_udata);