single buffer mode for BufferQueue

Bug: 9891035
Change-Id: Id1ab5f911a6dc4c1d8235e65775b3d3635231ad4

2 files changed, 25 insertions, 2 deletions

diff --git a/include/gui/BufferQueue.h b/include/gui/BufferQueue.h
index 628678f..cfce40d 100644
--- a/include/gui/BufferQueue.h
+++ b/include/gui/BufferQueue.h
@@ -340,6 +340,13 @@ public:
     // The count must be between 2 and NUM_BUFFER_SLOTS, inclusive.
     status_t setDefaultMaxBufferCount(int bufferCount);
 
+    // disableAsyncBuffer disables the extra buffer used in async mode
+    // (when both producer and consumer have set their "isControlledByApp"
+    // flag) and has dequeueBuffer() return WOULD_BLOCK instead.
+    //
+    // This can only be called before consumerConnect().
+    status_t disableAsyncBuffer();
+
     // setMaxAcquiredBufferCount sets the maximum number of buffers that can
     // be acquired by the consumer at one time (default 1).  This call will
     // fail if a producer is connected to the BufferQueue.
@@ -364,6 +371,7 @@ public:
     // NATIVE_WINDOW_TRANSFORM_ROT_90.  The default is 0 (no transform).
     status_t setTransformHint(uint32_t hint);
 
+
 private:
     // freeBufferLocked frees the GraphicBuffer and sync resources for the
     // given slot.
@@ -559,10 +567,14 @@ private:
     bool mConsumerControlledByApp;
 
     // mDequeueBufferCannotBlock whether dequeueBuffer() isn't allowed to block.
-    // this flag is set durring connect() when both consumer and producer are controlled
+    // this flag is set during connect() when both consumer and producer are controlled
     // by the application.
     bool mDequeueBufferCannotBlock;
 
+    // mUseAsyncBuffer whether an extra buffer is used in async mode to prevent
+    // dequeueBuffer() from ever blocking.
+    bool mUseAsyncBuffer;
+
     // mConnectedApi indicates the producer API that is currently connected
     // to this BufferQueue.  It defaults to NO_CONNECTED_API (= 0), and gets
     // updated by the connect and disconnect methods.
diff --git a/include/gui/GLConsumer.h b/include/gui/GLConsumer.h
index 1df5b42..ac4a832 100644
--- a/include/gui/GLConsumer.h
+++ b/include/gui/GLConsumer.h
@@ -98,6 +98,13 @@ public:
     // This calls doGLFenceWait to ensure proper synchronization.
     status_t updateTexImage();
 
+    // releaseTexImage releases the texture acquired in updateTexImage().
+    // This is intended to be used in single buffer mode.
+    //
+    // This call may only be made while the OpenGL ES context to which the
+    // target texture belongs is bound to the calling thread.
+    status_t releaseTexImage();
+
     // setReleaseFence stores a fence that will signal when the current buffer
     // is no longer being read. This fence will be returned to the producer
     // when the current buffer is released by updateTexImage(). Multiple
@@ -251,7 +258,7 @@ protected:
     // This releases the buffer in the slot referenced by mCurrentTexture,
     // then updates state to refer to the BufferItem, which must be a
     // newly-acquired buffer.
-    status_t releaseAndUpdateLocked(const BufferQueue::BufferItem& item);
+    status_t updateAndReleaseLocked(const BufferQueue::BufferItem& item);
 
     // Binds mTexName and the current buffer to mTexTarget.  Uses
     // mCurrentTexture if it's set, mCurrentTextureBuf if not.  If the
@@ -416,6 +423,10 @@ private:
     // It is set to false by detachFromContext, and then set to true again by
     // attachToContext.
     bool mAttached;
+
+    // mReleasedTexImageBuffer is a dummy buffer used when in single buffer
+    // mode and releaseTexImage() has been called
+    sp<GraphicBuffer> mReleasedTexImageBuffer;
 };
 
 // ----------------------------------------------------------------------------