[sf] Implement addSamplingListener
Implements ISurfaceComposer::addSamplingListener, which allows a client
to receive streaming median luma updates for a given region of the
screen.
Bug: 119639245
Test: Manual using SamplingDemo in libgui
Test: Automated libgui_test in Ic85a97f475a3414a79d3719bbd0b2b648bbccfb0
Change-Id: Ic52359aeab884e734a806372be0eb4e327c45298
diff --git a/services/surfaceflinger/RegionSamplingThread.h b/services/surfaceflinger/RegionSamplingThread.h
new file mode 100644
index 0000000..bf59007
--- /dev/null
+++ b/services/surfaceflinger/RegionSamplingThread.h
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <condition_variable>
+#include <mutex>
+#include <thread>
+#include <unordered_map>
+
+#include <android-base/thread_annotations.h>
+#include <binder/IBinder.h>
+#include <ui/Rect.h>
+#include <utils/StrongPointer.h>
+
+namespace android {
+
+class GraphicBuffer;
+class IRegionSamplingListener;
+class Layer;
+class SurfaceFlinger;
+
+class RegionSamplingThread : public IBinder::DeathRecipient {
+public:
+ explicit RegionSamplingThread(SurfaceFlinger& flinger);
+ ~RegionSamplingThread();
+
+ void addListener(const Rect& samplingArea, const sp<IBinder>& stopLayerHandle,
+ const sp<IRegionSamplingListener>& listener);
+ void removeListener(const sp<IRegionSamplingListener>& listener);
+ void sampleNow();
+
+ struct Descriptor {
+ Rect area = Rect::EMPTY_RECT;
+ wp<Layer> stopLayer;
+ sp<IRegionSamplingListener> listener;
+ };
+
+ struct WpHash {
+ size_t operator()(const wp<IBinder>& p) const {
+ return std::hash<IBinder*>()(p.unsafe_get());
+ }
+ };
+
+private:
+ void binderDied(const wp<IBinder>& who) override;
+
+ void captureSample() REQUIRES(mMutex);
+ void threadMain();
+
+ SurfaceFlinger& mFlinger;
+
+ std::mutex mThreadMutex;
+ std::thread mThread GUARDED_BY(mThreadMutex);
+
+ std::mutex mMutex;
+ std::condition_variable_any mCondition;
+ bool mRunning GUARDED_BY(mMutex) = true;
+ bool mSampleRequested GUARDED_BY(mMutex) = false;
+
+ std::unordered_map<wp<IBinder>, Descriptor, WpHash> mDescriptors GUARDED_BY(mMutex);
+};
+
+} // namespace android