Add MediaChunkIterator for FakeAdaptiveDataSet.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=203102464

library/core/src/main/java/com/google/android/exoplayer2/source/chunk/BaseMediaChunkIterator.java

@@ -0,0 +1,69 @@
+/*
+ * 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.source.chunk;
+
+import java.util.NoSuchElementException;
+
+/**
+ * Base class for {@link MediaChunkIterator}s. Handles {@link #next()} and {@link #isEnded()}, and
+ * provides a bounds check for child classes.
+ */
+public abstract class BaseMediaChunkIterator implements MediaChunkIterator {
+
+  private final long fromIndex;
+  private final long toIndex;
+
+  private long currentIndex;
+
+  /**
+   * Creates base iterator.
+   *
+   * @param fromIndex The index at which the iterator will start.
+   * @param toIndex The last available index.
+   */
+  public BaseMediaChunkIterator(long fromIndex, long toIndex) {
+    this.fromIndex = fromIndex;
+    this.toIndex = toIndex;
+    currentIndex = fromIndex - 1;
+  }
+
+  @Override
+  public boolean isEnded() {
+    return currentIndex > toIndex;
+  }
+
+  @Override
+  public boolean next() {
+    currentIndex++;
+    return !isEnded();
+  }
+
+  /**
+   * Verifies that the iterator points to a valid element.
+   *
+   * @throws NoSuchElementException If the iterator does not point to a valid element.
+   */
+  protected void checkInBounds() {
+    if (currentIndex < fromIndex || currentIndex > toIndex) {
+      throw new NoSuchElementException();
+    }
+  }
+
+  /** Returns the current index this iterator is pointing to. */
+  protected long getCurrentIndex() {
+    return currentIndex;
+  }
+}

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DefaultDashChunkSource.java

@@ -30,6 +30,7 @@ import com.google.android.exoplayer2.extractor.mkv.MatroskaExtractor;
 import com.google.android.exoplayer2.extractor.mp4.FragmentedMp4Extractor;
 import com.google.android.exoplayer2.extractor.rawcc.RawCcExtractor;
 import com.google.android.exoplayer2.source.BehindLiveWindowException;
+import com.google.android.exoplayer2.source.chunk.BaseMediaChunkIterator;
 import com.google.android.exoplayer2.source.chunk.Chunk;
 import com.google.android.exoplayer2.source.chunk.ChunkExtractorWrapper;
 import com.google.android.exoplayer2.source.chunk.ChunkHolder;
@@ -55,7 +56,6 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
-import java.util.NoSuchElementException;
 
 /**
  * A default {@link DashChunkSource} implementation.
@@ -509,13 +509,9 @@ public class DefaultDashChunkSource implements DashChunkSource {
   // Protected classes.
 
   /** {@link MediaChunkIterator} wrapping a {@link RepresentationHolder}. */
-  protected static final class RepresentationSegmentIterator implements MediaChunkIterator {
+  protected static final class RepresentationSegmentIterator extends BaseMediaChunkIterator {
 
     private final RepresentationHolder representationHolder;
-    private final long firstSegmentNum;
-    private final long lastAvailableSegmentNum;
-
-    private long segmentNum;
 
     /**
      * Creates iterator.
@@ -526,28 +522,15 @@ public class DefaultDashChunkSource implements DashChunkSource {
      */
     public RepresentationSegmentIterator(
         RepresentationHolder representation, long segmentNum, long lastAvailableSegmentNum) {
+      super(/* fromIndex= */ segmentNum, /* toIndex= */ lastAvailableSegmentNum);
       this.representationHolder = representation;
-      this.firstSegmentNum = segmentNum;
-      this.segmentNum = segmentNum - 1;
-      this.lastAvailableSegmentNum = lastAvailableSegmentNum;
     }
 
     @Override
-    public boolean isEnded() {
+    public DataSpec getDataSpec() {
-      return segmentNum > lastAvailableSegmentNum;
-    }
-
-    @Override
-    public boolean next() {
-      segmentNum++;
-      return segmentNum <= lastAvailableSegmentNum;
-    }
-
-    @Override
-    public @Nullable DataSpec getDataSpec() {
       checkInBounds();
       Representation representation = representationHolder.representation;
-      RangedUri segmentUri = representationHolder.getSegmentUrl(segmentNum);
+      RangedUri segmentUri = representationHolder.getSegmentUrl(getCurrentIndex());
       Uri resolvedUri = segmentUri.resolveUri(representation.baseUrl);
       String cacheKey = representation.getCacheKey();
       return new DataSpec(resolvedUri, segmentUri.start, segmentUri.length, cacheKey);
@@ -556,19 +539,13 @@ public class DefaultDashChunkSource implements DashChunkSource {
     @Override
     public long getChunkStartTimeUs() {
       checkInBounds();
-      return representationHolder.getSegmentStartTimeUs(segmentNum);
+      return representationHolder.getSegmentStartTimeUs(getCurrentIndex());
     }
 
     @Override
     public long getChunkEndTimeUs() {
       checkInBounds();
-      return representationHolder.getSegmentEndTimeUs(segmentNum);
+      return representationHolder.getSegmentEndTimeUs(getCurrentIndex());
-    }
-
-    private void checkInBounds() {
-      if (segmentNum < firstSegmentNum || segmentNum > lastAvailableSegmentNum) {
-        throw new NoSuchElementException();
-      }
     }
   }
 

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeAdaptiveDataSet.java

@@ -15,9 +15,14 @@
  */
 package com.google.android.exoplayer2.testutil;
 
+import android.net.Uri;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.source.TrackGroup;
+import com.google.android.exoplayer2.source.chunk.BaseMediaChunkIterator;
+import com.google.android.exoplayer2.source.chunk.MediaChunkIterator;
+import com.google.android.exoplayer2.testutil.FakeDataSet.FakeData.Segment;
+import com.google.android.exoplayer2.upstream.DataSpec;
 import java.util.Random;
 
 /**
@@ -63,6 +68,49 @@ public final class FakeAdaptiveDataSet extends FakeDataSet {
 
   }
 
+  /** {@link MediaChunkIterator} for the chunks defined by a fake adaptive data set. */
+  public static final class Iterator extends BaseMediaChunkIterator {
+
+    private final FakeAdaptiveDataSet dataSet;
+    private final int trackGroupIndex;
+
+    /**
+     * Create iterator.
+     *
+     * @param dataSet The data set to iterate over.
+     * @param trackGroupIndex The index of the track group to iterate over.
+     * @param chunkIndex The chunk index to which the iterator points initially.
+     */
+    public Iterator(FakeAdaptiveDataSet dataSet, int trackGroupIndex, int chunkIndex) {
+      super(/* fromIndex= */ chunkIndex, /* toIndex= */ dataSet.getChunkCount() - 1);
+      this.dataSet = dataSet;
+      this.trackGroupIndex = trackGroupIndex;
+    }
+
+    @Override
+    public DataSpec getDataSpec() {
+      checkInBounds();
+      String uri = dataSet.getUri(trackGroupIndex);
+      int chunkIndex = (int) getCurrentIndex();
+      Segment fakeDataChunk = dataSet.getData(uri).getSegments().get(chunkIndex);
+      return new DataSpec(
+          Uri.parse(uri), fakeDataChunk.byteOffset, fakeDataChunk.length, /* key= */ null);
+    }
+
+    @Override
+    public long getChunkStartTimeUs() {
+      checkInBounds();
+      return dataSet.getStartTime((int) getCurrentIndex());
+    }
+
+    @Override
+    public long getChunkEndTimeUs() {
+      checkInBounds();
+      int chunkIndex = (int) getCurrentIndex();
+      return dataSet.getStartTime(chunkIndex) + dataSet.getChunkDuration(chunkIndex);
+    }
+  }
+
   private final int chunkCount;
   private final long chunkDurationUs;
   private final long lastChunkDurationUs;
@@ -124,5 +172,4 @@ public final class FakeAdaptiveDataSet extends FakeDataSet {
   public int getChunkIndexByPosition(long positionUs) {
     return (int) (positionUs / chunkDurationUs);
   }
-
 }