Fix remote GraphicBuffer allocation in SurfaceFlinger.

This change fixes a horrible hack that I did to allow application
processes to create GraphicBuffer objects by making a binder call to
SurfaceFlinger.  This change introduces a new binder interface
specifically for doing this, and does it in such a way that
SurfaceFlinger will maintain a reference to the buffers until the app is
done with them.

Change-Id: Icb240397c6c206d7f69124c1497a829f051cb49b
diff --git a/libs/surfaceflinger_client/IGraphicBufferAlloc.cpp b/libs/surfaceflinger_client/IGraphicBufferAlloc.cpp
new file mode 100644
index 0000000..e05da72
--- /dev/null
+++ b/libs/surfaceflinger_client/IGraphicBufferAlloc.cpp
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2011 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.
+ */
+
+// tag as surfaceflinger
+#define LOG_TAG "SurfaceFlinger"
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <binder/Parcel.h>
+
+#include <ui/GraphicBuffer.h>
+
+#include <surfaceflinger/IGraphicBufferAlloc.h>
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+
+enum {
+    CREATE_GRAPHIC_BUFFER = IBinder::FIRST_CALL_TRANSACTION,
+    FREE_ALL_GRAPHIC_BUFFERS_EXCEPT,
+};
+
+class BpGraphicBufferAlloc : public BpInterface<IGraphicBufferAlloc>
+{
+public:
+    BpGraphicBufferAlloc(const sp<IBinder>& impl)
+        : BpInterface<IGraphicBufferAlloc>(impl)
+    {
+    }
+
+    virtual sp<GraphicBuffer> createGraphicBuffer(uint32_t w, uint32_t h,
+            PixelFormat format, uint32_t usage) {
+        Parcel data, reply;
+        data.writeInterfaceToken(
+                IGraphicBufferAlloc::getInterfaceDescriptor());
+        data.writeInt32(w);
+        data.writeInt32(h);
+        data.writeInt32(format);
+        data.writeInt32(usage);
+        remote()->transact(CREATE_GRAPHIC_BUFFER, data, &reply);
+        sp<GraphicBuffer> graphicBuffer;
+        bool nonNull = (bool)reply.readInt32();
+        if (nonNull) {
+            graphicBuffer = new GraphicBuffer();
+            reply.read(*graphicBuffer);
+        }
+        return graphicBuffer;
+    }
+
+    virtual void freeAllGraphicBuffersExcept(int bufIdx) {
+        Parcel data, reply;
+        data.writeInterfaceToken(
+                IGraphicBufferAlloc::getInterfaceDescriptor());
+        data.writeInt32(bufIdx);
+        remote()->transact(FREE_ALL_GRAPHIC_BUFFERS_EXCEPT, data, &reply);
+    }
+};
+
+IMPLEMENT_META_INTERFACE(GraphicBufferAlloc, "android.ui.IGraphicBufferAlloc");
+
+// ----------------------------------------------------------------------
+
+status_t BnGraphicBufferAlloc::onTransact(
+    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
+{
+    // codes that don't require permission check
+
+    switch(code) {
+        case CREATE_GRAPHIC_BUFFER: {
+            CHECK_INTERFACE(IGraphicBufferAlloc, data, reply);
+            uint32_t w = data.readInt32();
+            uint32_t h = data.readInt32();
+            PixelFormat format = data.readInt32();
+            uint32_t usage = data.readInt32();
+            sp<GraphicBuffer> result(createGraphicBuffer(w, h, format, usage));
+            reply->writeInt32(result != 0);
+            if (result != 0) {
+                reply->write(*result);
+            }
+            return NO_ERROR;
+        } break;
+        case FREE_ALL_GRAPHIC_BUFFERS_EXCEPT: {
+            CHECK_INTERFACE(IGraphicBufferAlloc, data, reply);
+            int bufIdx = data.readInt32();
+            freeAllGraphicBuffersExcept(bufIdx);
+            return NO_ERROR;
+        } break;
+        default:
+            return BBinder::onTransact(code, data, reply, flags);
+    }
+}
+
+}; // namespace android