camera2: Add support for secondary surface for stream

- Enhance OutputConfiguration to contain multiple surfaces for one
  underlying stream.
- Create Camera3SharedOutputStream to handle streams with multiple
  surfaces.
- Create Camera3StreamSplitter to handle buffer flows between camera and
  multiple consumers.

Test: cts, and manually test camera preview/snapshot/recording
Bug: 33777818
Change-Id: Ia010c3cc9d9b4bd5b9ea03cc42fe4e0a0d8033f1
diff --git a/services/camera/libcameraservice/device3/Camera3StreamSplitter.h b/services/camera/libcameraservice/device3/Camera3StreamSplitter.h
new file mode 100644
index 0000000..5a25712
--- /dev/null
+++ b/services/camera/libcameraservice/device3/Camera3StreamSplitter.h
@@ -0,0 +1,209 @@
+/*
+ * Copyright 2014,2016 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.
+ */
+
+#ifndef ANDROID_SERVERS_STREAMSPLITTER_H
+#define ANDROID_SERVERS_STREAMSPLITTER_H
+
+#include <gui/IConsumerListener.h>
+#include <gui/IProducerListener.h>
+#include <gui/BufferItemConsumer.h>
+
+#include <utils/Condition.h>
+#include <utils/Mutex.h>
+#include <utils/StrongPointer.h>
+#include <utils/Timers.h>
+
+namespace android {
+
+class GraphicBuffer;
+class IGraphicBufferConsumer;
+class IGraphicBufferProducer;
+
+// Camera3StreamSplitter is an autonomous class that manages one input BufferQueue
+// and multiple output BufferQueues. By using the buffer attach and detach logic
+// in BufferQueue, it is able to present the illusion of a single split
+// BufferQueue, where each buffer queued to the input is available to be
+// acquired by each of the outputs, and is able to be dequeued by the input
+// again only once all of the outputs have released it.
+class Camera3StreamSplitter : public BnConsumerListener {
+public:
+
+    // Constructor
+    Camera3StreamSplitter() = default;
+
+    // Connect to the stream splitter by creating buffer queue and connecting it
+    // with output surfaces.
+    status_t connect(const std::vector<sp<Surface> >& surfaces,
+            uint32_t consumerUsage, size_t hal_max_buffers,
+            sp<Surface>& consumer);
+
+    // addOutput adds an output BufferQueue to the splitter. The splitter
+    // connects to outputQueue as a CPU producer, and any buffers queued
+    // to the input will be queued to each output. It is assumed that all of the
+    // outputs are added before any buffers are queued on the input. If any
+    // output is abandoned by its consumer, the splitter will abandon its input
+    // queue (see onAbandoned).
+    //
+    // A return value other than NO_ERROR means that an error has occurred and
+    // outputQueue has not been added to the splitter. BAD_VALUE is returned if
+    // outputQueue is NULL. See IGraphicBufferProducer::connect for explanations
+    // of other error codes.
+    status_t addOutput(sp<Surface>& outputQueue, size_t hal_max_buffers);
+
+    // Request surfaces for a particular frame number. The requested surfaces
+    // are stored in a FIFO queue. And when the buffer becomes available from the
+    // input queue, the registered surfaces are used to decide which output is
+    // the buffer sent to.
+    status_t notifyRequestedSurfaces(const std::vector<size_t>& surfaces);
+
+    // Disconnect the buffer queue from output surfaces.
+    void disconnect();
+
+private:
+    // From IConsumerListener
+    //
+    // During this callback, we store some tracking information, detach the
+    // buffer from the input, and attach it to each of the outputs. This call
+    // can block if there are too many outstanding buffers. If it blocks, it
+    // will resume when onBufferReleasedByOutput releases a buffer back to the
+    // input.
+    void onFrameAvailable(const BufferItem& item) override;
+
+    // From IConsumerListener
+    // We don't care about released buffers because we detach each buffer as
+    // soon as we acquire it. See the comment for onBufferReleased below for
+    // some clarifying notes about the name.
+    void onBuffersReleased() override {}
+
+    // From IConsumerListener
+    // We don't care about sideband streams, since we won't be splitting them
+    void onSidebandStreamChanged() override {}
+
+    // This is the implementation of the onBufferReleased callback from
+    // IProducerListener. It gets called from an OutputListener (see below), and
+    // 'from' is which producer interface from which the callback was received.
+    //
+    // During this callback, we detach the buffer from the output queue that
+    // generated the callback, update our state tracking to see if this is the
+    // last output releasing the buffer, and if so, release it to the input.
+    // If we release the buffer to the input, we allow a blocked
+    // onFrameAvailable call to proceed.
+    void onBufferReleasedByOutput(const sp<IGraphicBufferProducer>& from);
+
+    // When this is called, the splitter disconnects from (i.e., abandons) its
+    // input queue and signals any waiting onFrameAvailable calls to wake up.
+    // It still processes callbacks from other outputs, but only detaches their
+    // buffers so they can continue operating until they run out of buffers to
+    // acquire. This must be called with mMutex locked.
+    void onAbandonedLocked();
+
+    // This is a thin wrapper class that lets us determine which BufferQueue
+    // the IProducerListener::onBufferReleased callback is associated with. We
+    // create one of these per output BufferQueue, and then pass the producer
+    // into onBufferReleasedByOutput above.
+    class OutputListener : public BnProducerListener,
+                           public IBinder::DeathRecipient {
+    public:
+        OutputListener(wp<Camera3StreamSplitter> splitter,
+                wp<IGraphicBufferProducer> output);
+        virtual ~OutputListener() = default;
+
+        // From IProducerListener
+        void onBufferReleased() override;
+
+        // From IBinder::DeathRecipient
+        void binderDied(const wp<IBinder>& who) override;
+
+    private:
+        wp<Camera3StreamSplitter> mSplitter;
+        wp<IGraphicBufferProducer> mOutput;
+    };
+
+    class BufferTracker {
+    public:
+        BufferTracker(const sp<GraphicBuffer>& buffer, size_t referenceCount);
+        ~BufferTracker() = default;
+
+        const sp<GraphicBuffer>& getBuffer() const { return mBuffer; }
+        const sp<Fence>& getMergedFence() const { return mMergedFence; }
+
+        void mergeFence(const sp<Fence>& with);
+
+        // Returns the new value
+        // Only called while mMutex is held
+        size_t decrementReferenceCountLocked();
+
+    private:
+
+        // Disallow copying
+        BufferTracker(const BufferTracker& other);
+        BufferTracker& operator=(const BufferTracker& other);
+
+        sp<GraphicBuffer> mBuffer; // One instance that holds this native handle
+        sp<Fence> mMergedFence;
+        size_t mReferenceCount;
+    };
+
+    // A deferred output is an output being added to the splitter after
+    // connect() call, whereas a non deferred output is added within connect()
+    // call.
+    enum class OutputType { NonDeferred, Deferred };
+
+    // Must be accessed through RefBase
+    virtual ~Camera3StreamSplitter();
+
+    status_t addOutputLocked(const sp<Surface>& outputQueue,
+                             size_t hal_max_buffers, OutputType outputType);
+
+    // Get unique name for the buffer queue consumer
+    static String8 getUniqueConsumerName();
+
+    // Max consumer side buffers for deferred surface. This will be used as a
+    // lower bound for overall consumer side max buffers.
+    static const int MAX_BUFFERS_DEFERRED_OUTPUT = 2;
+    int mMaxConsumerBuffers = MAX_BUFFERS_DEFERRED_OUTPUT;
+
+    static const nsecs_t kDequeueBufferTimeout   = s2ns(1); // 1 sec
+
+    // mIsAbandoned is set to true when an output dies. Once the Camera3StreamSplitter
+    // has been abandoned, it will continue to detach buffers from other
+    // outputs, but it will disconnect from the input and not attempt to
+    // communicate with it further.
+    bool mIsAbandoned = false;
+
+    Mutex mMutex;
+    Condition mReleaseCondition;
+    int mOutstandingBuffers = 0;
+
+    sp<IGraphicBufferProducer> mProducer;
+    sp<IGraphicBufferConsumer> mConsumer;
+    sp<BufferItemConsumer> mBufferItemConsumer;
+    sp<Surface> mSurface;
+
+    std::vector<sp<IGraphicBufferProducer> > mOutputs;
+    // Tracking which outputs should the buffer be attached and queued
+    // to for each input buffer.
+    std::vector<std::vector<size_t> > mRequestedSurfaces;
+
+    // Map of GraphicBuffer IDs (GraphicBuffer::getId()) to buffer tracking
+    // objects (which are mostly for counting how many outputs have released the
+    // buffer, but also contain merged release fences).
+    std::unordered_map<uint64_t, std::unique_ptr<BufferTracker> > mBuffers;
+};
+
+} // namespace android
+
+#endif