Added Forwarding classes for Extractor and ExtractorOutput

libraries/extractor/src/main/java/androidx/media3/extractor/ForwardingExtractor.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2020 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.
+ */
+package androidx.media3.extractor;
+
+import androidx.media3.common.util.UnstableApi;
+import java.io.IOException;
+
+/** An overridable {@link Extractor} implementation forwarding all methods to an underlying Extractor. */
+@UnstableApi
+public class ForwardingExtractor implements Extractor {
+  private final Extractor delegate;
+
+  public ForwardingExtractor(Extractor delegate) {
+    this.delegate = delegate;
+  }
+
+  @Override
+  public boolean sniff(ExtractorInput input) throws IOException {
+    return delegate.sniff(input);
+  }
+
+  @Override
+  public void init(ExtractorOutput output) {
+    delegate.init(output);
+  }
+
+  @Override
+  public @ReadResult int read(ExtractorInput input, PositionHolder seekPosition)
+      throws IOException {
+    return delegate.read(input, seekPosition);
+  }
+
+  @Override
+  public void seek(long position, long timeUs) {
+    delegate.seek(position, timeUs);
+  }
+
+  @Override
+  public void release() {
+    delegate.release();
+  }
+}

libraries/extractor/src/main/java/androidx/media3/extractor/ForwardingExtractorOutput.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2020 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.
+ */
+package androidx.media3.extractor;
+
+import androidx.media3.common.C;
+import androidx.media3.common.util.UnstableApi;
+
+/** An overridable {@link ExtractorOutput} implementation forwarding all methods to another input. */
+@UnstableApi
+public class ForwardingExtractorOutput implements ExtractorOutput {
+  private final ExtractorOutput output;
+
+  public ForwardingExtractorOutput(ExtractorOutput output) {
+    this.output = output;
+  }
+
+  @Override
+  public TrackOutput track(int id, @C.TrackType int type) {
+    return output.track(id, type);
+  }
+
+  @Override
+  public void endTracks() {
+    output.endTracks();
+  }
+
+  @Override
+  public void seekMap(SeekMap seekMap) {
+    output.seekMap(seekMap);
+  }
+}