Modernize atomics

- Based on C++11's `atomic`
- Reworked `SafeRefCount` (based on the rewrite by @hpvb)
- Replaced free atomic functions by the new `SafeNumeric<T>`
- Replaced wrong cases of `volatile bool` by the new `SafeFlag`
- Platform-specific implementations no longer needed

Co-authored-by: Hein-Pieter van Braam-Stewart <hp@tmm.cx>

4 files changed, 11 insertions, 8 deletions

diff --git a/modules/cvtt/image_compress_cvtt.cpp b/modules/cvtt/image_compress_cvtt.cpp
index dbd6d9e9f9..3beca3d12a 100644
--- a/modules/cvtt/image_compress_cvtt.cpp
+++ b/modules/cvtt/image_compress_cvtt.cpp
@@ -33,6 +33,7 @@
 #include "core/os/os.h"
 #include "core/os/thread.h"
 #include "core/string/print_string.h"
+#include "core/templates/safe_refcount.h"
 
 #include <ConvectionKernels.h>
 
@@ -56,7 +57,7 @@ struct CVTTCompressionJobQueue {
 	CVTTCompressionJobParams job_params;
 	const CVTTCompressionRowTask *job_tasks;
 	uint32_t num_tasks = 0;
-	uint32_t current_task = 0;
+	SafeNumeric<uint32_t> current_task;
 };
 
 static void _digest_row_task(const CVTTCompressionJobParams &p_job_params, const CVTTCompressionRowTask &p_row_task) {
@@ -131,7 +132,7 @@ static void _digest_row_task(const CVTTCompressionJobParams &p_job_params, const
 static void _digest_job_queue(void *p_job_queue) {
 	CVTTCompressionJobQueue *job_queue = static_cast<CVTTCompressionJobQueue *>(p_job_queue);
 
-	for (uint32_t next_task = atomic_increment(&job_queue->current_task); next_task <= job_queue->num_tasks; next_task = atomic_increment(&job_queue->current_task)) {
+	for (uint32_t next_task = job_queue->current_task.increment(); next_task <= job_queue->num_tasks; next_task = job_queue->current_task.increment()) {
 		_digest_row_task(job_queue->job_params, job_queue->job_tasks[next_task - 1]);
 	}
 }
@@ -263,7 +264,7 @@ void image_compress_cvtt(Image *p_image, float p_lossy_quality, Image::UsedChann
 		const CVTTCompressionRowTask *tasks_rb = tasks.ptr();
 
 		job_queue.job_tasks = &tasks_rb[0];
-		job_queue.current_task = 0;
+		job_queue.current_task.set(0);
 		job_queue.num_tasks = static_cast<uint32_t>(tasks.size());
 
 		for (int i = 0; i < num_job_threads; i++) {
diff --git a/modules/gdnative/nativescript/nativescript.cpp b/modules/gdnative/nativescript/nativescript.cpp
index 64fb8ee9c7..1bdbb0b03b 100644
--- a/modules/gdnative/nativescript/nativescript.cpp
+++ b/modules/gdnative/nativescript/nativescript.cpp
@@ -1670,7 +1670,7 @@ void NativeScriptLanguage::defer_init_library(Ref<GDNativeLibrary> lib, NativeSc
 	MutexLock lock(mutex);
 	libs_to_init.insert(lib);
 	scripts_to_register.insert(script);
-	has_objects_to_register = true;
+	has_objects_to_register.set();
 }
 #endif
 
@@ -1759,7 +1759,7 @@ void NativeScriptLanguage::call_libraries_cb(const StringName &name) {
 
 void NativeScriptLanguage::frame() {
 #ifndef NO_THREADS
-	if (has_objects_to_register) {
+	if (has_objects_to_register.is_set()) {
 		MutexLock lock(mutex);
 		for (Set<Ref<GDNativeLibrary>>::Element *L = libs_to_init.front(); L; L = L->next()) {
 			init_library(L->get());
@@ -1769,7 +1769,7 @@ void NativeScriptLanguage::frame() {
 			register_script(S->get());
 		}
 		scripts_to_register.clear();
-		has_objects_to_register = false;
+		has_objects_to_register.clear();
 	}
 #endif
 
diff --git a/modules/gdnative/nativescript/nativescript.h b/modules/gdnative/nativescript/nativescript.h
index 81a158d09b..d6ba2bbec1 100644
--- a/modules/gdnative/nativescript/nativescript.h
+++ b/modules/gdnative/nativescript/nativescript.h
@@ -40,6 +40,7 @@
 #include "core/os/thread_safe.h"
 #include "core/templates/oa_hash_map.h"
 #include "core/templates/ordered_hash_map.h"
+#include "core/templates/safe_refcount.h"
 #include "core/templates/self_list.h"
 #include "scene/main/node.h"
 
@@ -262,7 +263,7 @@ private:
 #ifndef NO_THREADS
 	Set<Ref<GDNativeLibrary>> libs_to_init;
 	Set<NativeScript *> scripts_to_register;
-	volatile bool has_objects_to_register = false; // so that we don't lock mutex every frame - it's rarely needed
+	SafeFlag has_objects_to_register; // so that we don't lock mutex every frame - it's rarely needed
 	void defer_init_library(Ref<GDNativeLibrary> lib, NativeScript *script);
 #endif
 
diff --git a/modules/theora/video_stream_theora.h b/modules/theora/video_stream_theora.h
index f92fe2340e..2685a8a013 100644
--- a/modules/theora/video_stream_theora.h
+++ b/modules/theora/video_stream_theora.h
@@ -36,6 +36,7 @@
 #include "core/os/semaphore.h"
 #include "core/os/thread.h"
 #include "core/templates/ring_buffer.h"
+#include "core/templates/safe_refcount.h"
 #include "scene/resources/video_stream.h"
 #include "servers/audio_server.h"
 
@@ -113,7 +114,7 @@ class VideoStreamPlaybackTheora : public VideoStreamPlayback {
 	bool thread_eof = false;
 	Semaphore *thread_sem;
 	Thread thread;
-	volatile bool thread_exit = false;
+	SafeFlag thread_exit;
 
 	static void _streaming_thread(void *ud);