diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index ca3a0f40de..243bf9dfa7 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -25,6 +25,10 @@
gather bandwidth information.
* Pass `TransferListener` to `MediaSource`s to listen to media data transfers.
Always null at the moment.
+ * Add method to `DataSource` to add `TransferListener`s. Custom `DataSource`s
+ directly reading data should implement `BaseDataSource` to handle the
+ registration correctly. Custom `DataSource`'s forwarding to other sources
+ should forward all calls to `addTransferListener`.
* Error handling:
* Allow configuration of the Loader retry delay
([#3370](https://github.com/google/ExoPlayer/issues/3370)).
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/upstream/BaseDataSource.java b/library/core/src/main/java/com/google/android/exoplayer2/upstream/BaseDataSource.java
new file mode 100644
index 0000000000..915f67c065
--- /dev/null
+++ b/library/core/src/main/java/com/google/android/exoplayer2/upstream/BaseDataSource.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2018 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 com.google.android.exoplayer2.upstream;
+
+import java.util.ArrayList;
+
+/**
+ * Base {@link DataSource} implementation to keep a list of {@link TransferListener}s.
+ *
+ *
Subclasses must call {@link #transferStarted(DataSpec)}, {@link #bytesTransferred(int)}, and
+ * {@link #transferEnded()} to inform listeners of data transfers.
+ */
+public abstract class BaseDataSource implements DataSource {
+
+ private final @DataSource.Type int type;
+ private final ArrayList> listeners;
+
+ /**
+ * Creates base data source for a data source of the specified type.
+ *
+ * @param type The {@link DataSource.Type} of the data source.
+ */
+ protected BaseDataSource(@DataSource.Type int type) {
+ this.type = type;
+ this.listeners = new ArrayList<>(/* initialCapacity= */ 1);
+ }
+
+ @Override
+ public final void addTransferListener(TransferListener super DataSource> transferListener) {
+ listeners.add(transferListener);
+ }
+
+ /**
+ * Notifies listeners that data transfer for the specified {@link DataSpec} started.
+ *
+ * @param dataSpec {@link DataSpec} describing the data being transferred.
+ */
+ protected final void transferStarted(DataSpec dataSpec) {
+ for (int i = 0; i < listeners.size(); i++) {
+ listeners.get(i).onTransferStart(/* source= */ this, dataSpec);
+ }
+ }
+
+ /**
+ * Notifies listeners that bytes were transferred.
+ *
+ * @param bytesTransferred The number of bytes transferred since the previous call to this method
+ * (or if the first call, since the transfer was started).
+ */
+ protected final void bytesTransferred(int bytesTransferred) {
+ for (int i = 0; i < listeners.size(); i++) {
+ listeners.get(i).onBytesTransferred(/* source= */ this, bytesTransferred);
+ }
+ }
+
+ /** Notifies listeners that a transfer ended. */
+ protected final void transferEnded() {
+ for (int i = 0; i < listeners.size(); i++) {
+ listeners.get(i).onTransferEnd(/* source= */ this);
+ }
+ }
+}
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/upstream/DataSource.java b/library/core/src/main/java/com/google/android/exoplayer2/upstream/DataSource.java
index 835ced3f0f..cdcdba305b 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/upstream/DataSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/upstream/DataSource.java
@@ -16,9 +16,12 @@
package com.google.android.exoplayer2.upstream;
import android.net.Uri;
+import android.support.annotation.IntDef;
import android.support.annotation.Nullable;
import com.google.android.exoplayer2.C;
import java.io.IOException;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
import java.util.Collections;
import java.util.List;
import java.util.Map;
@@ -28,6 +31,15 @@ import java.util.Map;
*/
public interface DataSource {
+ /** Type of a data source. */
+ @Retention(RetentionPolicy.SOURCE)
+ @IntDef({TYPE_REMOTE, TYPE_LOCAL})
+ public @interface Type {}
+ /** Data source which loads data from a remote (network) source. */
+ int TYPE_REMOTE = 0;
+ /** Data source which loads data from a local (on-device) source. */
+ int TYPE_LOCAL = 1;
+
/**
* A factory for {@link DataSource} instances.
*/
@@ -37,7 +49,16 @@ public interface DataSource {
* Creates a {@link DataSource} instance.
*/
DataSource createDataSource();
+ }
+ /**
+ * Adds a {@link TransferListener} to listen to data transfers. Must be called before the first
+ * call to {@link #open(DataSpec)}.
+ *
+ * @param transferListener A {@link TransferListener}.
+ */
+ default void addTransferListener(TransferListener super DataSource> transferListener) {
+ // TODO: Make non-default once all DataSources implement this method.
}
/**
@@ -102,5 +123,4 @@ public interface DataSource {
* @throws IOException If an error occurs closing the source.
*/
void close() throws IOException;
-
}
diff --git a/library/core/src/test/java/com/google/android/exoplayer2/upstream/BaseDataSourceTest.java b/library/core/src/test/java/com/google/android/exoplayer2/upstream/BaseDataSourceTest.java
new file mode 100644
index 0000000000..2b1f6246d3
--- /dev/null
+++ b/library/core/src/test/java/com/google/android/exoplayer2/upstream/BaseDataSourceTest.java
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2018 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 com.google.android.exoplayer2.upstream;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.net.Uri;
+import android.support.annotation.Nullable;
+import com.google.android.exoplayer2.C;
+import java.io.IOException;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Unit test for {@link BaseDataSource}. */
+@RunWith(RobolectricTestRunner.class)
+public class BaseDataSourceTest {
+
+ @Test
+ public void dataTransfer_withLocalSource_isReported() throws IOException {
+ TestSource testSource = new TestSource(DataSource.TYPE_LOCAL);
+ TestTransferListener transferListener = new TestTransferListener();
+ testSource.addTransferListener(transferListener);
+
+ DataSpec dataSpec = new DataSpec(Uri.EMPTY);
+ testSource.open(dataSpec);
+ testSource.read(/* buffer= */ null, /* offset= */ 0, /* readLength= */ 100);
+ testSource.close();
+
+ assertThat(transferListener.lastTransferStartSource).isSameAs(testSource);
+ assertThat(transferListener.lastBytesTransferredSource).isSameAs(testSource);
+ assertThat(transferListener.lastTransferEndSource).isSameAs(testSource);
+ assertThat(transferListener.lastTransferStartDataSpec).isEqualTo(dataSpec);
+ assertThat(transferListener.lastBytesTransferred).isEqualTo(100);
+ }
+
+ @Test
+ public void dataTransfer_withRemoteSource_isReported() throws IOException {
+ TestSource testSource = new TestSource(DataSource.TYPE_REMOTE);
+ TestTransferListener transferListener = new TestTransferListener();
+ testSource.addTransferListener(transferListener);
+
+ DataSpec dataSpec = new DataSpec(Uri.EMPTY);
+ testSource.open(dataSpec);
+ testSource.read(/* buffer= */ null, /* offset= */ 0, /* readLength= */ 100);
+ testSource.close();
+
+ assertThat(transferListener.lastTransferStartSource).isSameAs(testSource);
+ assertThat(transferListener.lastBytesTransferredSource).isSameAs(testSource);
+ assertThat(transferListener.lastTransferEndSource).isSameAs(testSource);
+ assertThat(transferListener.lastTransferStartDataSpec).isEqualTo(dataSpec);
+ assertThat(transferListener.lastBytesTransferred).isEqualTo(100);
+ }
+
+ private static final class TestSource extends BaseDataSource {
+
+ public TestSource(@DataSource.Type int type) {
+ super(type);
+ }
+
+ @Override
+ public long open(DataSpec dataSpec) throws IOException {
+ transferStarted(dataSpec);
+ return C.LENGTH_UNSET;
+ }
+
+ @Override
+ public int read(byte[] buffer, int offset, int readLength) throws IOException {
+ bytesTransferred(readLength);
+ return readLength;
+ }
+
+ @Override
+ public @Nullable Uri getUri() {
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ public void close() throws IOException {
+ transferEnded();
+ }
+ }
+
+ private static final class TestTransferListener implements TransferListener {
+
+ public Object lastTransferStartSource;
+ public DataSpec lastTransferStartDataSpec;
+ public Object lastBytesTransferredSource;
+ public int lastBytesTransferred;
+ public Object lastTransferEndSource;
+
+ @Override
+ public void onTransferStart(DataSource source, DataSpec dataSpec) {
+ lastTransferStartSource = source;
+ lastTransferStartDataSpec = dataSpec;
+ }
+
+ @Override
+ public void onBytesTransferred(DataSource source, int bytesTransferred) {
+ lastBytesTransferredSource = source;
+ lastBytesTransferred = bytesTransferred;
+ }
+
+ @Override
+ public void onTransferEnd(DataSource source) {
+ lastTransferEndSource = source;
+ }
+ }
+}