Refactor DisplayEventReceiver read loop. (bec0a868) · Commits · e / os / android_frameworks_base

core/jni/android_view_DisplayEventReceiver.cpp

+29 −28

Original line number	Diff line number	Diff line
		@@ -49,7 +49,6 @@ public:

		status_t initialize();
		status_t scheduleVsync();
		static int handleReceiveCallback(int receiveFd, int events, void* data);

		protected:
		virtual ~NativeDisplayEventReceiver();
		@@ -59,6 +58,9 @@ private:
		sp<Looper> mLooper;
		DisplayEventReceiver mReceiver;
		bool mWaitingForVsync;

		static int handleReceiveCallback(int receiveFd, int events, void* data);
		bool readLastVsyncMessage(nsecs_t* outTimestamp, uint32_t* outCount);
		};


		@@ -100,16 +102,9 @@ status_t NativeDisplayEventReceiver::scheduleVsync() {
		ALOGV("receiver %p ~ Scheduling vsync.", this);

		// Drain all pending events.
		DisplayEventReceiver::Event buf[EVENT_BUFFER_SIZE];
		ssize_t n;
		while ((n = mReceiver.getEvents(buf, EVENT_BUFFER_SIZE)) > 0) {
		ALOGV("receiver %p ~ Drained %d events.", this, int(n));
		}

		if (n < 0) {
		ALOGW("Failed to drain events from display event receiver, status=%d", status_t(n));
		return status_t(n);
		}
		nsecs_t vsyncTimestamp;
		uint32_t vsyncCount;
		readLastVsyncMessage(&vsyncTimestamp, &vsyncCount);

		status_t status = mReceiver.requestNextVsync();
		if (status) {
		@@ -138,23 +133,9 @@ int NativeDisplayEventReceiver::handleReceiveCallback(int receiveFd, int events,
		}

		// Drain all pending events, keep the last vsync.
		nsecs_t vsyncTimestamp = -1;
		uint32_t vsyncCount = 0;

		DisplayEventReceiver::Event buf[EVENT_BUFFER_SIZE];
		ssize_t n;
		while ((n = r->mReceiver.getEvents(buf, EVENT_BUFFER_SIZE)) > 0) {
		ALOGV("receiver %p ~ Read %d events.", data, int(n));
		while (n-- > 0) {
		if (buf[n].header.type == DisplayEventReceiver::DISPLAY_EVENT_VSYNC) {
		vsyncTimestamp = buf[n].header.timestamp;
		vsyncCount = buf[n].vsync.count;
		break; // stop at last vsync in the buffer
		}
		}
		}

		if (vsyncTimestamp < 0) {
		nsecs_t vsyncTimestamp;
		uint32_t vsyncCount;
		if (!r->readLastVsyncMessage(&vsyncTimestamp, &vsyncCount)) {
		ALOGV("receiver %p ~ Woke up but there was no vsync pulse!", data);
		return 1; // keep the callback, did not obtain a vsync pulse
		}
		@@ -179,6 +160,26 @@ int NativeDisplayEventReceiver::handleReceiveCallback(int receiveFd, int events,
		return 1; // keep the callback
		}

		bool NativeDisplayEventReceiver::readLastVsyncMessage(
		nsecs_t* outTimestamp, uint32_t* outCount) {
		DisplayEventReceiver::Event buf[EVENT_BUFFER_SIZE];
		ssize_t n;
		while ((n = mReceiver.getEvents(buf, EVENT_BUFFER_SIZE)) > 0) {
		ALOGV("receiver %p ~ Read %d events.", this, int(n));
		while (n-- > 0) {
		if (buf[n].header.type == DisplayEventReceiver::DISPLAY_EVENT_VSYNC) {
		*outTimestamp = buf[n].header.timestamp;
		*outCount = buf[n].vsync.count;
		return true; // stop at last vsync in the buffer
		}
		}
		}
		if (n < 0) {
		ALOGW("Failed to get events from display event receiver, status=%d", status_t(n));
		}
		return false;
		}


		static jint nativeInit(JNIEnv* env, jclass clazz, jobject receiverObj,
		jobject messageQueueObj) {