SurfaceTexture can now force the client to request a buffer

SurfaceTexture now has the concept of default size a new method,
setDefaultBufferSize() to set it. When the default size is
changed, dequeueBuffer() will return a value telling the
client that it must ask for a new buffer.

The above only applies if the client has not
overriden the buffer size with setGeometry.

Change-Id: I520dc40363054b7e37fdb67d6a2e7bce70326e81

2 files changed, 27 insertions, 0 deletions

diff --git a/include/gui/ISurfaceTexture.h b/include/gui/ISurfaceTexture.h
index 6ed3c6f..d2d3bb8 100644
--- a/include/gui/ISurfaceTexture.h
+++ b/include/gui/ISurfaceTexture.h
@@ -36,6 +36,8 @@ class ISurfaceTexture : public IInterface
 public:
     DECLARE_META_INTERFACE(SurfaceTexture);
 
+    enum { BUFFER_NEEDS_REALLOCATION = 1 };
+
     // requestBuffer requests a new buffer for the given index. The server (i.e.
     // the ISurfaceTexture implementation) assigns the newly created buffer to
     // the given slot index, and the client is expected to mirror the
@@ -56,6 +58,8 @@ public:
     // should call requestBuffer to assign a new buffer to that slot. The client
     // is expected to either call cancelBuffer on the dequeued slot or to fill
     // in the contents of its associated buffer contents and call queueBuffer.
+    // If dequeueBuffer return BUFFER_NEEDS_REALLOCATION, the client is
+    // expected to call requestBuffer immediately.
     virtual status_t dequeueBuffer(int *slot) = 0;
 
     // queueBuffer indicates that the client has finished filling in the
diff --git a/include/gui/SurfaceTexture.h b/include/gui/SurfaceTexture.h
index afa64d3..585d288 100644
--- a/include/gui/SurfaceTexture.h
+++ b/include/gui/SurfaceTexture.h
@@ -121,6 +121,12 @@ public:
     // buffers before the client is done with them.
     sp<IBinder> getAllocator();
 
+    // setDefaultBufferSize is used to set the size of buffers returned by
+    // requestBuffers when a with and height of zero is requested.
+    // A call to setDefaultBufferSize() may trigger requestBuffers() to
+    // be called from the client.
+    status_t setDefaultBufferSize(uint32_t w, uint32_t h);
+
 private:
 
     // freeAllBuffers frees the resources (both GraphicBuffer and EGLImage) for
@@ -158,6 +164,23 @@ private:
     // for a slot when requestBuffer is called with that slot's index.
     BufferSlot mSlots[NUM_BUFFER_SLOTS];
 
+    // mDefaultWidth holds the default width of allocated buffers. It is used
+    // in requestBuffers() if a width and height of zero is specified.
+    uint32_t mDefaultWidth;
+
+    // mDefaultHeight holds the default height of allocated buffers. It is used
+    // in requestBuffers() if a width and height of zero is specified.
+    uint32_t mDefaultHeight;
+
+    // mPixelFormat holds the pixel format of allocated buffers. It is used
+    // in requestBuffers() if a format of zero is specified.
+    uint32_t mPixelFormat;
+
+    // mUseDefaultSize indicates whether or not the default size should be used
+    // that is, if the last requestBuffer has been called with both width
+    // and height null.
+    bool mUseDefaultSize;
+
     // mBufferCount is the number of buffer slots that the client and server
     // must maintain. It defaults to MIN_BUFFER_SLOTS and can be changed by
     // calling setBufferCount.