Add release callback and reference count to java EncodedImage class

Callback set by HardwareVideoEncoder, and wired to the codec's
releaseOutputBuffer. Intention is to move call of this method to the
destructor of a corresponding C++ class in a followup cl, and
eliminate an allocation and memcpy in the process.

Bug: webrtc:9378
Change-Id: I578480b63b68e6ac7a96cdde36379b3c50f05c3f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/142160
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29283}

sdk/android/api/org/webrtc/EncodedImage.java

@@ -18,7 +18,7 @@ import java.util.concurrent.TimeUnit;
  * An encoded frame from a video stream. Used as an input for decoders and as an output for
  * encoders.
  */
-public class EncodedImage {
+public class EncodedImage implements RefCounted {
   // Must be kept in sync with common_types.h FrameType.
   public enum FrameType {
     EmptyFrame(0),
@@ -46,6 +46,8 @@ public class EncodedImage {
     }
   }
 
+  private final RefCountDelegate refCountDelegate;
+  private final boolean supportsRetain;
   public final ByteBuffer buffer;
   public final int encodedWidth;
   public final int encodedHeight;
@@ -56,8 +58,31 @@ public class EncodedImage {
   public final boolean completeFrame;
   public final @Nullable Integer qp;
 
+  // TODO(bugs.webrtc.org/9378): Use retain and release from jni code.
+  @Override
+  public void retain() {
+    refCountDelegate.retain();
+  }
+
+  @Override
+  public void release() {
+    refCountDelegate.release();
+  }
+
+  // A false return value means that the encoder expects that the buffer is no longer used after
+  // VideoEncoder.Callback.onEncodedFrame returns.
+  boolean maybeRetain() {
+    if (supportsRetain) {
+      retain();
+      return true;
+    } else {
+      return false;
+    }
+  }
+
   @CalledByNative
-  private EncodedImage(ByteBuffer buffer, int encodedWidth, int encodedHeight, long captureTimeNs,
+  private EncodedImage(ByteBuffer buffer, boolean supportsRetain,
+      @Nullable Runnable releaseCallback, int encodedWidth, int encodedHeight, long captureTimeNs,
       FrameType frameType, int rotation, boolean completeFrame, @Nullable Integer qp) {
     this.buffer = buffer;
     this.encodedWidth = encodedWidth;
@@ -68,6 +93,8 @@ public class EncodedImage {
     this.rotation = rotation;
     this.completeFrame = completeFrame;
     this.qp = qp;
+    this.supportsRetain = supportsRetain;
+    this.refCountDelegate = new RefCountDelegate(releaseCallback);
   }
 
   @CalledByNative
@@ -116,6 +143,8 @@ public class EncodedImage {
 
   public static class Builder {
     private ByteBuffer buffer;
+    private boolean supportsRetain;
+    private @Nullable Runnable releaseCallback;
     private int encodedWidth;
     private int encodedHeight;
     private long captureTimeNs;
@@ -126,8 +155,18 @@ public class EncodedImage {
 
     private Builder() {}
 
+    @Deprecated
     public Builder setBuffer(ByteBuffer buffer) {
       this.buffer = buffer;
+      this.releaseCallback = null;
+      this.supportsRetain = false;
+      return this;
+    }
+
+    public Builder setBuffer(ByteBuffer buffer, @Nullable Runnable releaseCallback) {
+      this.buffer = buffer;
+      this.releaseCallback = releaseCallback;
+      this.supportsRetain = true;
       return this;
     }
 
@@ -173,8 +212,8 @@ public class EncodedImage {
     }
 
     public EncodedImage createEncodedImage() {
-      return new EncodedImage(buffer, encodedWidth, encodedHeight, captureTimeNs, frameType,
-          rotation, completeFrame, qp);
+      return new EncodedImage(buffer, supportsRetain, releaseCallback, encodedWidth, encodedHeight,
+          captureTimeNs, frameType, rotation, completeFrame, qp);
     }
   }
 }