[libcamera-devel] [RFC PATCH 5/6] android: camera_device: Add thread safety annotation

[Hirokazu Honda]

This applies clang thread safety annotation to CameraDevice.
Mutex and MutexLocker there are replaced with Mutex2 and
MutexLocer2.

Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
---
 src/android/camera_device.cpp | 26 ++++++++++++++------------
 src/android/camera_device.h   | 18 +++++++++---------
 2 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
index f2e0bdbd..e05b5767 100644
--- a/src/android/camera_device.cpp
+++ b/src/android/camera_device.cpp
@@ -14,7 +14,6 @@
 #include <vector>
 
 #include <libcamera/base/log.h>
-#include <libcamera/base/thread.h>
 #include <libcamera/base/utils.h>
 
 #include <libcamera/control_ids.h>
@@ -399,7 +398,7 @@ void CameraDevice::close()
 void CameraDevice::flush()
 {
 	{
-		MutexLocker stateLock(stateMutex_);
+		MutexLocker2 stateLock(stateMutex_);
 		if (state_ != State::Running)
 			return;
 
@@ -409,20 +408,23 @@ void CameraDevice::flush()
 	worker_.stop();
 	camera_->stop();
 
-	MutexLocker stateLock(stateMutex_);
+	MutexLocker2 stateLock(stateMutex_);
 	state_ = State::Stopped;
 }
 
 void CameraDevice::stop()
 {
-	MutexLocker stateLock(stateMutex_);
+	MutexLocker2 stateLock(stateMutex_);
 	if (state_ == State::Stopped)
 		return;
 
 	worker_.stop();
 	camera_->stop();
 
-	descriptors_ = {};
+	{
+		MutexLocker2 descriptorsLock(descriptorsMutex_);
+		descriptors_ = {};
+	}
 	streams_.clear();
 
 	state_ = State::Stopped;
@@ -919,6 +921,7 @@ int CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
 		 */
 		FrameBuffer *frameBuffer = nullptr;
 		int acquireFence = -1;
+		MutexLocker2 lock(descriptor->streamsProcessMutex_);
 		switch (cameraStream->type()) {
 		case CameraStream::Type::Mapped:
 			/*
@@ -926,7 +929,6 @@ int CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
 			 * Request.
 			 */
 			LOG(HAL, Debug) << ss.str() << " (mapped)";
-
 			descriptor->pendingStreamsToProcess_.insert(
 				{ cameraStream, &buffer });
 			continue;
@@ -986,12 +988,12 @@ int CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
 	 * on the queue to be later completed. If the camera has been stopped we
 	 * have to re-start it to be able to process the request.
 	 */
-	MutexLocker stateLock(stateMutex_);
+	MutexLocker2 stateLock(stateMutex_);
 
 	if (state_ == State::Flushing) {
 		Camera3RequestDescriptor *rawDescriptor = descriptor.get();
 		{
-			MutexLocker descriptorsLock(descriptorsMutex_);
+			MutexLocker2 descriptorsLock(descriptorsMutex_);
 			descriptors_.push(std::move(descriptor));
 		}
 		abortRequest(rawDescriptor);
@@ -1016,7 +1018,7 @@ int CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
 	CaptureRequest *request = descriptor->request_.get();
 
 	{
-		MutexLocker descriptorsLock(descriptorsMutex_);
+		MutexLocker2 descriptorsLock(descriptorsMutex_);
 		descriptors_.push(std::move(descriptor));
 	}
 
@@ -1103,7 +1105,7 @@ void CameraDevice::requestComplete(Request *request)
 	}
 
 	/* Handle post-processing. */
-	MutexLocker locker(descriptor->streamsProcessMutex_);
+	MutexLocker2 locker(descriptor->streamsProcessMutex_);
 
 	/*
 	 * Queue all the post-processing streams request at once. The completion
@@ -1149,7 +1151,7 @@ void CameraDevice::requestComplete(Request *request)
 
 void CameraDevice::completeDescriptor(Camera3RequestDescriptor *descriptor)
 {
-	MutexLocker lock(descriptorsMutex_);
+	MutexLocker2 lock(descriptorsMutex_);
 	descriptor->complete_ = true;
 
 	sendCaptureResults();
@@ -1229,7 +1231,7 @@ void CameraDevice::streamProcessingComplete(Camera3RequestDescriptor::StreamBuff
 	Camera3RequestDescriptor *request = streamBuffer->request;
 
 	{
-		MutexLocker locker(request->streamsProcessMutex_);
+		MutexLocker2 locker(request->streamsProcessMutex_);
 
 		request->pendingStreamsToProcess_.erase(streamBuffer->stream);
 		if (!request->pendingStreamsToProcess_.empty())
diff --git a/src/android/camera_device.h b/src/android/camera_device.h
index 2a414020..9feb287e 100644
--- a/src/android/camera_device.h
+++ b/src/android/camera_device.h
@@ -9,7 +9,6 @@
 
 #include <map>
 #include <memory>
-#include <mutex>
 #include <queue>
 #include <vector>
 
@@ -18,7 +17,8 @@
 #include <libcamera/base/class.h>
 #include <libcamera/base/log.h>
 #include <libcamera/base/message.h>
-#include <libcamera/base/thread.h>
+#include <libcamera/base/mutex.h>
+#include <libcamera/base/thread_annotations.h>
 
 #include <libcamera/camera.h>
 #include <libcamera/framebuffer.h>
@@ -83,7 +83,7 @@ private:
 		Running,
 	};
 
-	void stop();
+	void stop() EXCLUDES(stateMutex_);
 
 	std::unique_ptr<libcamera::FrameBuffer>
 	createFrameBuffer(const buffer_handle_t camera3buffer,
@@ -95,8 +95,8 @@ private:
 	void notifyError(uint32_t frameNumber, camera3_stream_t *stream,
 			 camera3_error_msg_code code) const;
 	int processControls(Camera3RequestDescriptor *descriptor);
-	void completeDescriptor(Camera3RequestDescriptor *descriptor);
-	void sendCaptureResults();
+	void completeDescriptor(Camera3RequestDescriptor *descriptor) EXCLUDES(descriptorsMutex_);
+	void sendCaptureResults() REQUIRES(descriptorsMutex_);
 	void setBufferStatus(Camera3RequestDescriptor::StreamBuffer &buffer,
 			     Camera3RequestDescriptor::Status status);
 	std::unique_ptr<CameraMetadata> getResultMetadata(
@@ -107,8 +107,8 @@ private:
 
 	CameraWorker worker_;
 
-	libcamera::Mutex stateMutex_; /* Protects access to the camera state. */
-	State state_;
+	libcamera::Mutex2 stateMutex_; /* Protects access to the camera state. */
+	State state_ GUARDED_BY(stateMutex_);
 
 	std::shared_ptr<libcamera::Camera> camera_;
 	std::unique_ptr<libcamera::CameraConfiguration> config_;
@@ -119,8 +119,8 @@ private:
 
 	std::vector<CameraStream> streams_;
 
-	libcamera::Mutex descriptorsMutex_; /* Protects descriptors_. */
-	std::queue<std::unique_ptr<Camera3RequestDescriptor>> descriptors_;
+	libcamera::Mutex2 descriptorsMutex_ ACQUIRED_AFTER(stateMutex_);
+	std::queue<std::unique_ptr<Camera3RequestDescriptor>> descriptors_ GUARDED_BY(descriptorsMutex_);
 
 	std::string maker_;
 	std::string model_;
-- 
2.33.1.1089.g2158813163f-goog