Java VideoRenderer.Callbacks: Make renderFrame() interface asynchronous

talk/app/webrtc/java/src/org/webrtc/VideoRenderer.java

Index: talk/app/webrtc/java/src/org/webrtc/VideoRenderer.java
diff --git a/talk/app/webrtc/java/src/org/webrtc/VideoRenderer.java b/talk/app/webrtc/java/src/org/webrtc/VideoRenderer.java
index b496f3ebccf64ee50a4f5880e69d5fc40a12166b..a7b88ba939c9523e4fc08227166e2ba5c1ddaec0 100644
--- a/talk/app/webrtc/java/src/org/webrtc/VideoRenderer.java
+++ b/talk/app/webrtc/java/src/org/webrtc/VideoRenderer.java
@@ -42,10 +42,12 @@ public class VideoRenderer {
     public final int width;
     public final int height;
     public final int[] yuvStrides;
-    public final ByteBuffer[] yuvPlanes;
+    public ByteBuffer[] yuvPlanes;
     public final boolean yuvFrame;
     public Object textureObject;
     public int textureId;
+    // If |nativeFramePointer| is non-zero, the memory is allocated on the C++ side.
+    private long nativeFramePointer;
 
     // rotationDegree is the degree that the frame must be rotated clockwisely
     // to be rendered correctly.
@@ -58,7 +60,7 @@ public class VideoRenderer {
      */
     public I420Frame(
         int width, int height, int rotationDegree,
-        int[] yuvStrides, ByteBuffer[] yuvPlanes) {
+        int[] yuvStrides, ByteBuffer[] yuvPlanes, long nativeFramePointer) {
       this.width = width;
       this.height = height;
       this.yuvStrides = yuvStrides;
@@ -71,6 +73,7 @@ public class VideoRenderer {
       this.yuvPlanes = yuvPlanes;
       this.yuvFrame = true;
       this.rotationDegree = rotationDegree;
+      this.nativeFramePointer = nativeFramePointer;
       if (rotationDegree % 90 != 0) {
         throw new IllegalArgumentException("Rotation degree not multiple of 90: " + rotationDegree);
       }
@@ -81,7 +84,7 @@ public class VideoRenderer {
      */
     public I420Frame(
         int width, int height, int rotationDegree,
-        Object textureObject, int textureId) {
+        Object textureObject, int textureId, long nativeFramePointer) {
       this.width = width;
       this.height = height;
       this.yuvStrides = null;
@@ -90,6 +93,7 @@ public class VideoRenderer {
       this.textureId = textureId;
       this.yuvFrame = false;
       this.rotationDegree = rotationDegree;
+      this.nativeFramePointer = nativeFramePointer;
       if (rotationDegree % 90 != 0) {
         throw new IllegalArgumentException("Rotation degree not multiple of 90: " + rotationDegree);
       }
@@ -109,6 +113,13 @@ public class VideoRenderer {
      * error and will likely crash.
      */
     public I420Frame copyFrom(I420Frame source) {
+      // |nativeFramePointer| is not copied from |source|, because resources in this object are
+      // still allocated in Java. After copyFrom() is done, this object should not hold any
+      // references to |source|. This is violated for texture frames however, because |textureId|
+      // is copied without making a deep copy.
+      if (this.nativeFramePointer != 0) {
+        throw new RuntimeException("Trying to overwrite a frame allocated in C++");
+      }
       if (source.yuvFrame && yuvFrame) {
         if (width != source.width || height != source.height) {
           throw new RuntimeException("Mismatched dimensions!  Source: " +
@@ -170,10 +181,25 @@ public class VideoRenderer {
   /** The real meat of VideoRendererInterface. */
   public static interface Callbacks {
     // |frame| might have pending rotation and implementation of Callbacks
-    // should handle that by applying rotation during rendering.
+    // should handle that by applying rotation during rendering. The callee
+    // is responsible for signaling when it is done with |frame| by calling
+    // renderFrameDone(frame).
     public void renderFrame(I420Frame frame);
   }
 
+   /**
+    * This must be called after every renderFrame() to release the frame.
+    */
+   public static void renderFrameDone(I420Frame frame) {
+     frame.yuvPlanes = null;
+     frame.textureObject = null;
+     frame.textureId = 0;
+     if (frame.nativeFramePointer != 0) {
+       releaseNativeFrame(frame.nativeFramePointer);
+       frame.nativeFramePointer = 0;
+     }
+   }
+
   // |this| either wraps a native (GUI) renderer or a client-supplied Callbacks
   // (Java) implementation; this is indicated by |isWrappedVideoRenderer|.
   long nativeVideoRenderer;
@@ -215,4 +241,6 @@ public class VideoRenderer {
 
   private static native void freeGuiVideoRenderer(long nativeVideoRenderer);
   private static native void freeWrappedVideoRenderer(long nativeVideoRenderer);
+
+  private static native void releaseNativeFrame(long nativeFramePointer);
 }