Pass the IGraphicBufferAlloc to SurfaceTextureClient.

This change passes a reference to the IGraphicBufferAlloc binder object
to SurfaceTextureClient objects.  When STC objects are created they
query their associated ISurfaceTexture object for the
IGraphicBufferAlloc that the SurfaceTexture uses to allocate buffers.
Having the SurfaceTextureClient hold this reference prevents the
GraphicBufferAlloc in SurfaceFlinger from freeing the allocated buffers
before the SurfaceTextureClient is done with them.

Change-Id: Ib8e30e8b37fdd60438cbb4cb7e9174d0ba6d661c
related-bug: 3362519

include/gui/ISurfaceTexture.h

@@ -72,6 +72,12 @@ public:
 
     virtual status_t setCrop(const Rect& reg) = 0;
     virtual status_t setTransform(uint32_t transform) = 0;
+
+    // getAllocator retrieves the binder object that must be referenced as long
+    // as the GraphicBuffers dequeued from this ISurfaceTexture are referenced.
+    // Holding this binder reference prevents SurfaceFlinger from freeing the
+    // buffers before the client is done with them.
+    virtual sp<IBinder> getAllocator() = 0;
 };
 
 // ----------------------------------------------------------------------------

include/gui/SurfaceTexture.h

@@ -101,6 +101,12 @@ public:
     // when a new frame becomes available.
     void setFrameAvailableListener(const sp<FrameAvailableListener>& l);
 
+    // getAllocator retrieves the binder object that must be referenced as long
+    // as the GraphicBuffers dequeued from this SurfaceTexture are referenced.
+    // Holding this binder reference prevents SurfaceFlinger from freeing the
+    // buffers before the client is done with them.
+    sp<IBinder> getAllocator();
+
 private:
 
     // freeAllBuffers frees the resources (both GraphicBuffer and EGLImage) for

include/gui/SurfaceTextureClient.h

@@ -83,6 +83,10 @@ private:
     // interactions with the server using this interface.
     sp<ISurfaceTexture> mSurfaceTexture;
 
+    // mAllocator is the binder object that is referenced to prevent the
+    // dequeued buffers from being freed prematurely.
+    sp<IBinder> mAllocator;
+
     // mSlots stores the buffers that have been allocated for each buffer slot.
     // It is initialized to null pointers, and gets filled in with the result of
     // ISurfaceTexture::requestBuffer when the client dequeues a buffer from a

libs/gui/ISurfaceTexture.cpp

@@ -38,6 +38,7 @@ enum {
     CANCEL_BUFFER,
     SET_CROP,
     SET_TRANSFORM,
+    GET_ALLOCATOR,
 };
 
 
@@ -123,6 +124,13 @@ public:
         status_t result = reply.readInt32();
         return result;
     }
+
+    virtual sp<IBinder> getAllocator() {
+        Parcel data, reply;
+        data.writeInterfaceToken(ISurfaceTexture::getInterfaceDescriptor());
+        remote()->transact(GET_ALLOCATOR, data, &reply);
+        return reply.readStrongBinder();
+    }
 };
 
 IMPLEMENT_META_INTERFACE(SurfaceTexture, "android.gui.SurfaceTexture");
@@ -195,6 +203,12 @@ status_t BnSurfaceTexture::onTransact(
             reply->writeInt32(result);
             return NO_ERROR;
         } break;
+        case GET_ALLOCATOR: {
+            CHECK_INTERFACE(ISurfaceTexture, data, reply);
+            sp<IBinder> result = getAllocator();
+            reply->writeStrongBinder(result);
+            return NO_ERROR;
+        } break;
     }
     return BBinder::onTransact(code, data, reply, flags);
 }

libs/gui/SurfaceTexture.cpp

@@ -304,6 +304,11 @@ void SurfaceTexture::setFrameAvailableListener(
     mFrameAvailableListener = l;
 }
 
+sp<IBinder> SurfaceTexture::getAllocator() {
+    LOGV("SurfaceTexture::getAllocator");
+    return mGraphicBufferAlloc->asBinder();
+}
+
 void SurfaceTexture::freeAllBuffers() {
     for (int i = 0; i < NUM_BUFFER_SLOTS; i++) {
         mSlots[i].mGraphicBuffer = 0;

libs/gui/SurfaceTextureClient.cpp

@@ -25,8 +25,8 @@ namespace android {
 
 SurfaceTextureClient::SurfaceTextureClient(
         const sp<ISurfaceTexture>& surfaceTexture):
-        mSurfaceTexture(surfaceTexture), mReqWidth(1), mReqHeight(1),
-        mReqFormat(DEFAULT_FORMAT), mReqUsage(0), mMutex() {
+        mSurfaceTexture(surfaceTexture), mAllocator(0), mReqWidth(1),
+        mReqHeight(1), mReqFormat(DEFAULT_FORMAT), mReqUsage(0), mMutex() {
     // Initialize the ANativeWindow function pointers.
     ANativeWindow::setSwapInterval  = setSwapInterval;
     ANativeWindow::dequeueBuffer    = dequeueBuffer;
@@ -35,6 +35,9 @@ SurfaceTextureClient::SurfaceTextureClient(
     ANativeWindow::queueBuffer      = queueBuffer;
     ANativeWindow::query            = query;
     ANativeWindow::perform          = perform;
+
+    // Get a reference to the allocator.
+    mAllocator = mSurfaceTexture->getAllocator();
 }
 
 int SurfaceTextureClient::setSwapInterval(ANativeWindow* window, int interval) {