Add a BufferItem parameter to onFrameAvailable

Passes the BufferItem for the queued buffer to the onFrameAvailable
callback so the consumer can track the BufferQueue's contents. Also
adds an onFrameReplaced callback, which is necessary if the consumer
wants to do anything more than simple queue length tracking.

Bug: 18111837
Change-Id: If9d07229c9b586c668e5f99074e9b63b0468feb0

6 files changed, 32 insertions, 6 deletions

diff --git a/include/gui/BufferItem.h b/include/gui/BufferItem.h
index 5effd10..01b6ff4 100644
--- a/include/gui/BufferItem.h
+++ b/include/gui/BufferItem.h
@@ -44,6 +44,7 @@ class BufferItem : public Flattenable<BufferItem> {
     // The default value of mBuf, used to indicate this doesn't correspond to a slot.
     enum { INVALID_BUFFER_SLOT = -1 };
     BufferItem();
+    ~BufferItem();
     operator IGraphicBufferConsumer::BufferItem() const;
 
     static const char* scalingModeName(uint32_t scalingMode);
diff --git a/include/gui/BufferQueue.h b/include/gui/BufferQueue.h
index 3297b10..1188837 100644
--- a/include/gui/BufferQueue.h
+++ b/include/gui/BufferQueue.h
@@ -62,7 +62,7 @@ public:
     public:
         ProxyConsumerListener(const wp<ConsumerListener>& consumerListener);
         virtual ~ProxyConsumerListener();
-        virtual void onFrameAvailable();
+        virtual void onFrameAvailable(const android::BufferItem& item);
         virtual void onBuffersReleased();
         virtual void onSidebandStreamChanged();
     private:
diff --git a/include/gui/BufferQueueProducer.h b/include/gui/BufferQueueProducer.h
index c619a11..ed1056a 100644
--- a/include/gui/BufferQueueProducer.h
+++ b/include/gui/BufferQueueProducer.h
@@ -203,6 +203,16 @@ private:
     // since the previous buffer might have already been acquired.
     sp<Fence> mLastQueueBufferFence;
 
+    // Take-a-ticket system for ensuring that onFrame* callbacks are called in
+    // the order that frames are queued. While the BufferQueue lock
+    // (mCore->mMutex) is held, a ticket is retained by the producer. After
+    // dropping the BufferQueue lock, the producer must wait on the condition
+    // variable until the current callback ticket matches its retained ticket.
+    Mutex mCallbackMutex;
+    int mNextCallbackTicket; // Protected by mCore->mMutex
+    int mCurrentCallbackTicket; // Protected by mCallbackMutex
+    Condition mCallbackCondition;
+
 }; // class BufferQueueProducer
 
 } // namespace android
diff --git a/include/gui/ConsumerBase.h b/include/gui/ConsumerBase.h
index 100bb26..f7ab5ac 100644
--- a/include/gui/ConsumerBase.h
+++ b/include/gui/ConsumerBase.h
@@ -46,7 +46,7 @@ public:
         //
         // This is called without any lock held and can be called concurrently
         // by multiple threads.
-        virtual void onFrameAvailable() = 0;
+        virtual void onFrameAvailable(const BufferItem& item) = 0;
     };
 
     virtual ~ConsumerBase();
@@ -106,7 +106,7 @@ protected:
     // the ConsumerBase implementation must be called from the derived class.
     // The ConsumerBase version of onSidebandStreamChanged does nothing and can
     // be overriden by derived classes if they want the notification.
-    virtual void onFrameAvailable();
+    virtual void onFrameAvailable(const BufferItem& item);
     virtual void onBuffersReleased();
     virtual void onSidebandStreamChanged();
 
diff --git a/include/gui/IConsumerListener.h b/include/gui/IConsumerListener.h
index 260099e..2ef7c4d 100644
--- a/include/gui/IConsumerListener.h
+++ b/include/gui/IConsumerListener.h
@@ -28,6 +28,8 @@
 namespace android {
 // ----------------------------------------------------------------------------
 
+class BufferItem;
+
 // ConsumerListener is the interface through which the BufferQueue notifies
 // the consumer of events that the consumer may wish to react to.  Because
 // the consumer will generally have a mutex that is locked during calls from
@@ -43,11 +45,24 @@ public:
     // frame becomes available for consumption. This means that frames that
     // are queued while in asynchronous mode only trigger the callback if no
     // previous frames are pending. Frames queued while in synchronous mode
-    // always trigger the callback.
+    // always trigger the callback. The item passed to the callback will contain
+    // all of the information about the queued frame except for its
+    // GraphicBuffer pointer, which will always be null.
+    //
+    // This is called without any lock held and can be called concurrently
+    // by multiple threads.
+    virtual void onFrameAvailable(const BufferItem& item) = 0; /* Asynchronous */
+
+    // onFrameReplaced is called from queueBuffer if the frame being queued is
+    // replacing an existing slot in the queue. Any call to queueBuffer that
+    // doesn't call onFrameAvailable will call this callback instead. The item
+    // passed to the callback will contain all of the information about the
+    // queued frame except for its GraphicBuffer pointer, which will always be
+    // null.
     //
     // This is called without any lock held and can be called concurrently
     // by multiple threads.
-    virtual void onFrameAvailable() = 0; /* Asynchronous */
+    virtual void onFrameReplaced(const BufferItem& item) {} /* Asynchronous */
 
     // onBuffersReleased is called to notify the buffer consumer that the
     // BufferQueue has released its references to one or more GraphicBuffers
diff --git a/include/gui/StreamSplitter.h b/include/gui/StreamSplitter.h
index f927953..8f47eb4 100644
--- a/include/gui/StreamSplitter.h
+++ b/include/gui/StreamSplitter.h
@@ -74,7 +74,7 @@ private:
     // can block if there are too many outstanding buffers. If it blocks, it
     // will resume when onBufferReleasedByOutput releases a buffer back to the
     // input.
-    virtual void onFrameAvailable();
+    virtual void onFrameAvailable(const BufferItem& item);
 
     // From IConsumerListener
     // We don't care about released buffers because we detach each buffer as