Add DashDownloader helper class to download dash streams

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=151456161

library/core/src/main/java/com/google/android/exoplayer2/C.java

@@ -541,9 +541,18 @@ public final class C {
 
   /**
    * Priority for media playback.
+   *
+   * <p>Larger values indicate higher priorities.
    */
   public static final int PRIORITY_PLAYBACK = 0;
 
+  /**
+   * Priority for media downloading.
+   *
+   * <p>Larger values indicate higher priorities.
+   */
+  public static final int PRIORITY_DOWNLOAD = PRIORITY_PLAYBACK - 1000;
+
   /**
    * Converts a time in microseconds to the corresponding time in milliseconds, preserving
    * {@link #TIME_UNSET} values.

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CacheDataSource.java

@@ -108,6 +108,15 @@ public final class CacheDataSource implements DataSource {
   private boolean currentRequestIgnoresCache;
   private long totalCachedBytesRead;
 
+  /**
+   * Generates a cache key out of the given {@link Uri}.
+   *
+   * @param uri Uri of a content which the requested key is for.
+   */
+  public static String generateKey(Uri uri) {
+    return uri.toString();
+  }
+
   /**
    * Constructs an instance with default {@link DataSource} and {@link DataSink} instances for
    * reading and writing the cache and with {@link #DEFAULT_MAX_CACHE_FILE_SIZE}.
@@ -171,7 +180,7 @@ public final class CacheDataSource implements DataSource {
     try {
       uri = dataSpec.uri;
       flags = dataSpec.flags;
-      key = dataSpec.key != null ? dataSpec.key : uri.toString();
+      key = dataSpec.key != null ? dataSpec.key : generateKey(dataSpec.uri);
       readPosition = dataSpec.position;
       currentRequestIgnoresCache = (ignoreCacheOnError && seenCacheError)
           || (dataSpec.length == C.LENGTH_UNSET && ignoreCacheForUnsetLengthRequests);

library/core/src/main/java/com/google/android/exoplayer2/util/PriorityTaskManager.java

@@ -54,7 +54,7 @@ public final class PriorityTaskManager {
   /**
    * Register a new task. The task must call {@link #remove(int)} when done.
    *
-   * @param priority The priority of the task.
+   * @param priority The priority of the task. Larger values indicate higher priorities.
    */
   public void add(int priority) {
     synchronized (lock) {

library/dash/src/androidTest/java/com/google/android/exoplayer2/source/dash/offline/DashDownloaderTest.java

@@ -0,0 +1,420 @@
+/*
+ * Copyright (C) 2017 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.dash.offline;
+
+import android.net.Uri;
+import android.test.InstrumentationTestCase;
+import android.test.MoreAsserts;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.source.dash.manifest.DashManifest;
+import com.google.android.exoplayer2.source.dash.manifest.RepresentationKey;
+import com.google.android.exoplayer2.source.dash.offline.DashDownloader.ProgressListener;
+import com.google.android.exoplayer2.testutil.FakeDataSource;
+import com.google.android.exoplayer2.testutil.FakeDataSource.FakeData;
+import com.google.android.exoplayer2.testutil.FakeDataSource.FakeDataSet;
+import com.google.android.exoplayer2.testutil.TestUtil;
+import com.google.android.exoplayer2.upstream.DataSourceInputStream;
+import com.google.android.exoplayer2.upstream.DataSpec;
+import com.google.android.exoplayer2.upstream.DummyDataSource;
+import com.google.android.exoplayer2.upstream.cache.CacheDataSource;
+import com.google.android.exoplayer2.upstream.cache.NoOpCacheEvictor;
+import com.google.android.exoplayer2.upstream.cache.SimpleCache;
+import com.google.android.exoplayer2.util.ClosedSource;
+import com.google.android.exoplayer2.util.Util;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.util.Arrays;
+
+/**
+ * Unit tests for {@link DashDownloader}.
+ */
+@ClosedSource(reason = "Not ready yet")
+public class DashDownloaderTest extends InstrumentationTestCase {
+
+  private static final byte[] TEST_MPD =
+      ("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+          + "<MPD xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n"
+          + "    type=\"dynamic\">\n"
+          + "    <Period start=\"PT6462826.784S\" >\n"
+          + "        <SegmentList\n"
+          + "            presentationTimeOffset=\"34740095\"\n"
+          + "            timescale=\"1000\" >\n"
+          + "            <SegmentTimeline>\n"
+          + "                <S d=\"4804\" />\n"
+          + "                <S d=\"5338\" />\n"
+          + "                <S d=\"4938\" />\n"
+          + "            </SegmentTimeline>\n"
+          + "        </SegmentList>\n"
+          + "        <AdaptationSet>\n"
+          + "            <Representation>\n"
+          + "                <SegmentList>\n"
+          // Bounded range data
+          + "                    <Initialization range=\"0-9\" sourceURL=\"audio_init_data\" />\n"
+          // Unbounded range data
+          + "                    <SegmentURL media=\"audio_segment_1\" />\n"
+          + "                    <SegmentURL media=\"audio_segment_2\" />\n"
+          + "                    <SegmentURL media=\"audio_segment_3\" />\n"
+          + "                </SegmentList>\n"
+          + "            </Representation>\n"
+          + "        </AdaptationSet>\n"
+          + "        <AdaptationSet>\n"
+          + "            <Representation>\n"
+          + "                <SegmentList>\n"
+          + "                    <SegmentURL media=\"text_segment_1\" />\n"
+          + "                    <SegmentURL media=\"text_segment_2\" />\n"
+          + "                    <SegmentURL media=\"text_segment_3\" />\n"
+          + "                </SegmentList>\n"
+          + "            </Representation>\n"
+          + "        </AdaptationSet>\n"
+          + "    </Period>\n"
+          + "</MPD>").getBytes();
+
+  private static final byte[] TEST_MPD_NO_INDEX =
+      ("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+          + "<MPD xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" type=\"dynamic\">\n"
+          + "    <Period start=\"PT6462826.784S\" >\n"
+          + "        <AdaptationSet>\n"
+          + "            <Representation>\n"
+          + "                <SegmentBase indexRange='0-10'/>\n"
+          + "            </Representation>\n"
+          + "        </AdaptationSet>\n"
+          + "    </Period>\n"
+          + "</MPD>").getBytes();
+
+  private File tempFolder;
+  private SimpleCache cache;
+
+  @Override
+  public void setUp() throws Exception {
+    super.setUp();
+    tempFolder = Util.createTempDirectory(getInstrumentation().getContext(), "ExoPlayerTest");
+    cache = new SimpleCache(tempFolder, new NoOpCacheEvictor());
+  }
+
+  @Override
+  public void tearDown() throws Exception {
+    Util.recursiveDelete(tempFolder);
+  }
+
+  public void testDownloadManifest() throws Exception {
+    FakeDataSet fakeDataSet = new FakeDataSet()
+        .setData("test.mpd", TEST_MPD);
+    DashDownloader dashDownloader =
+        new DashDownloader("test.mpd", cache, new FakeDataSource(fakeDataSet));
+
+    DashManifest manifest = dashDownloader.downloadManifest();
+
+    assertNotNull(manifest);
+    assertCachedData(fakeDataSet);
+  }
+
+  public void testDownloadManifestFailure() throws Exception {
+    byte[] testMpdFirstPart = Arrays.copyOf(TEST_MPD, 10);
+    byte[] testMpdSecondPart = Arrays.copyOfRange(TEST_MPD, 10, TEST_MPD.length);
+    FakeDataSet fakeDataSet = new FakeDataSet()
+        .newData("test.mpd")
+        .appendReadData(testMpdFirstPart)
+        .appendReadError(new IOException())
+        .appendReadData(testMpdSecondPart)
+        .endData();
+    DashDownloader dashDownloader =
+        new DashDownloader("test.mpd", cache, new FakeDataSource(fakeDataSet));
+
+    // downloadManifest fails on the first try
+    try {
+      dashDownloader.downloadManifest();
+      fail();
+    } catch (IOException e) {
+      // ignore
+    }
+    assertCachedData("test.mpd", testMpdFirstPart);
+
+    // on the second try it downloads the rest of the data
+    DashManifest manifest = dashDownloader.downloadManifest();
+
+    assertNotNull(manifest);
+    assertCachedData(fakeDataSet);
+  }
+
+  public void testDownloadRepresentation() throws Exception {
+    FakeDataSet fakeDataSet = new FakeDataSet()
+        .setData("test.mpd", TEST_MPD)
+        .setData("audio_init_data", TestUtil.buildTestData(10))
+        .setData("audio_segment_1", TestUtil.buildTestData(4))
+        .setData("audio_segment_2", TestUtil.buildTestData(5))
+        .setData("audio_segment_3", TestUtil.buildTestData(6));
+    DashDownloader dashDownloader =
+        new DashDownloader("test.mpd", cache, new FakeDataSource(fakeDataSet));
+    dashDownloader.downloadManifest();
+
+    dashDownloader.selectRepresentations(new RepresentationKey(0, 0, 0));
+    dashDownloader.downloadRepresentations(null);
+
+    assertCachedData(fakeDataSet);
+  }
+
+  public void testDownloadRepresentationInSmallParts() throws Exception {
+    FakeDataSet fakeDataSet = new FakeDataSet()
+        .setData("test.mpd", TEST_MPD)
+        .setData("audio_init_data", TestUtil.buildTestData(10))
+        .newData("audio_segment_1")
+        .appendReadData(TestUtil.buildTestData(10))
+        .appendReadData(TestUtil.buildTestData(10))
+        .appendReadData(TestUtil.buildTestData(10))
+        .endData()
+        .setData("audio_segment_2", TestUtil.buildTestData(5))
+        .setData("audio_segment_3", TestUtil.buildTestData(6));
+    DashDownloader dashDownloader =
+        new DashDownloader("test.mpd", cache, new FakeDataSource(fakeDataSet));
+    dashDownloader.downloadManifest();
+
+    dashDownloader.selectRepresentations(new RepresentationKey(0, 0, 0));
+    dashDownloader.downloadRepresentations(null);
+
+    assertCachedData(fakeDataSet);
+  }
+
+  public void testDownloadRepresentations() throws Exception {
+    FakeDataSet fakeDataSet = new FakeDataSet()
+        .setData("test.mpd", TEST_MPD)
+        .setData("audio_init_data", TestUtil.buildTestData(10))
+        .setData("audio_segment_1", TestUtil.buildTestData(4))
+        .setData("audio_segment_2", TestUtil.buildTestData(5))
+        .setData("audio_segment_3", TestUtil.buildTestData(6))
+        .setData("text_segment_1", TestUtil.buildTestData(1))
+        .setData("text_segment_2", TestUtil.buildTestData(2))
+        .setData("text_segment_3", TestUtil.buildTestData(3));
+    DashDownloader dashDownloader =
+        new DashDownloader("test.mpd", cache, new FakeDataSource(fakeDataSet));
+    dashDownloader.downloadManifest();
+
+    dashDownloader.selectRepresentations(
+        new RepresentationKey(0, 0, 0),
+        new RepresentationKey(0, 1, 0));
+    dashDownloader.downloadRepresentations(null);
+
+    assertCachedData(fakeDataSet);
+  }
+
+  public void testDownloadRepresentationFailure() throws Exception {
+    FakeDataSet fakeDataSet = new FakeDataSet()
+        .setData("test.mpd", TEST_MPD)
+        .setData("audio_init_data", TestUtil.buildTestData(10))
+        .setData("audio_segment_1", TestUtil.buildTestData(4))
+        .newData("audio_segment_2")
+        .appendReadData(TestUtil.buildTestData(2))
+        .appendReadError(new IOException())
+        .appendReadData(TestUtil.buildTestData(3))
+        .endData()
+        .setData("audio_segment_3", TestUtil.buildTestData(6));
+    DashDownloader dashDownloader =
+        new DashDownloader("test.mpd", cache, new FakeDataSource(fakeDataSet));
+    dashDownloader.downloadManifest();
+
+    dashDownloader.selectRepresentations(new RepresentationKey(0, 0, 0));
+    // downloadRepresentations fails on the first try
+    try {
+      dashDownloader.downloadRepresentations(null);
+      fail();
+    } catch (IOException e) {
+      // ignore
+    }
+    dashDownloader.downloadRepresentations(null);
+
+    assertCachedData(fakeDataSet);
+  }
+
+  public void testCounters() throws Exception {
+    FakeDataSet fakeDataSet = new FakeDataSet()
+        .setData("test.mpd", TEST_MPD)
+        .setData("audio_init_data", TestUtil.buildTestData(10))
+        .setData("audio_segment_1", TestUtil.buildTestData(4))
+        .newData("audio_segment_2")
+        .appendReadData(TestUtil.buildTestData(2))
+        .appendReadError(new IOException())
+        .appendReadData(TestUtil.buildTestData(3))
+        .endData()
+        .setData("audio_segment_3", TestUtil.buildTestData(6));
+    DashDownloader dashDownloader =
+        new DashDownloader("test.mpd", cache, new FakeDataSource(fakeDataSet));
+    dashDownloader.downloadManifest();
+
+    assertCounters(dashDownloader, C.LENGTH_UNSET, C.LENGTH_UNSET, C.LENGTH_UNSET);
+
+    dashDownloader.selectRepresentations(new RepresentationKey(0, 0, 0));
+    dashDownloader.initStatus();
+    assertCounters(dashDownloader, 3, 0, 0);
+
+    // downloadRepresentations fails after downloading init data, segment 1 and 2 bytes in segment 2
+    try {
+      dashDownloader.downloadRepresentations(null);
+      fail();
+    } catch (IOException e) {
+      // ignore
+    }
+    dashDownloader.initStatus();
+    assertCounters(dashDownloader, 3, 1, 10 + 4 + 2);
+
+    dashDownloader.downloadRepresentations(null);
+
+    assertCounters(dashDownloader, 3, 3, 10 + 4 + 5 + 6);
+  }
+
+  public void testListener() throws Exception {
+    FakeDataSet fakeDataSet = new FakeDataSet()
+        .setData("test.mpd", TEST_MPD)
+        .setData("audio_init_data", TestUtil.buildTestData(10))
+        .setData("audio_segment_1", TestUtil.buildTestData(4))
+        .setData("audio_segment_2", TestUtil.buildTestData(5))
+        .setData("audio_segment_3", TestUtil.buildTestData(6));
+    DashDownloader dashDownloader =
+        new DashDownloader("test.mpd", cache, new FakeDataSource(fakeDataSet));
+    dashDownloader.downloadManifest();
+
+    dashDownloader.selectRepresentations(new RepresentationKey(0, 0, 0));
+    dashDownloader.downloadRepresentations(new ProgressListener() {
+      private int counter = 0;
+      @Override
+      public void onDownloadProgress(DashDownloader dashDownloader, int totalSegments,
+          int downloadedSegments,
+          long downloadedBytes) {
+        switch (counter++) {
+          case 0:
+            assertTrue(totalSegments == 3 && downloadedSegments == 0 && downloadedBytes == 10);
+            break;
+          case 1:
+            assertTrue(totalSegments == 3 && downloadedSegments == 1 && downloadedBytes == 14);
+            break;
+          case 2:
+            assertTrue(totalSegments == 3 && downloadedSegments == 2 && downloadedBytes == 19);
+            break;
+          case 3:
+            assertTrue(totalSegments == 3 && downloadedSegments == 3 && downloadedBytes == 25);
+            break;
+          default:
+            fail();
+        }
+      }
+    });
+  }
+
+  public void testRemoveAll() throws Exception {
+    FakeDataSet fakeDataSet = new FakeDataSet()
+        .setData("test.mpd", TEST_MPD)
+        .setData("audio_init_data", TestUtil.buildTestData(10))
+        .setData("audio_segment_1", TestUtil.buildTestData(4))
+        .setData("audio_segment_2", TestUtil.buildTestData(5))
+        .setData("audio_segment_3", TestUtil.buildTestData(6))
+        .setData("text_segment_1", TestUtil.buildTestData(1))
+        .setData("text_segment_2", TestUtil.buildTestData(2))
+        .setData("text_segment_3", TestUtil.buildTestData(3));
+    DashDownloader dashDownloader =
+        new DashDownloader("test.mpd", cache, new FakeDataSource(fakeDataSet));
+    dashDownloader.downloadManifest();
+    dashDownloader.selectRepresentations(
+        new RepresentationKey(0, 0, 0),
+        new RepresentationKey(0, 1, 0));
+    dashDownloader.downloadRepresentations(null);
+
+    dashDownloader.removeAll();
+
+    assertEquals(0, cache.getCacheSpace());
+  }
+
+  public void testRemoveRepresentations() throws Exception {
+    FakeDataSet fakeDataSet = new FakeDataSet()
+        .setData("test.mpd", TEST_MPD)
+        .setData("audio_init_data", TestUtil.buildTestData(10))
+        .setData("audio_segment_1", TestUtil.buildTestData(4))
+        .setData("audio_segment_2", TestUtil.buildTestData(5))
+        .setData("audio_segment_3", TestUtil.buildTestData(6))
+        .setData("text_segment_1", TestUtil.buildTestData(1))
+        .setData("text_segment_2", TestUtil.buildTestData(2))
+        .setData("text_segment_3", TestUtil.buildTestData(3));
+    DashDownloader dashDownloader =
+        new DashDownloader("test.mpd", cache, new FakeDataSource(fakeDataSet));
+    dashDownloader.downloadManifest();
+    dashDownloader.selectRepresentations(
+        new RepresentationKey(0, 0, 0),
+        new RepresentationKey(0, 1, 0));
+    dashDownloader.downloadRepresentations(null);
+
+    dashDownloader.removeRepresentations();
+
+    assertEquals(TEST_MPD.length, cache.getCacheSpace());
+    assertCachedData("test.mpd", TEST_MPD);
+  }
+
+  public void testMpdNoIndex() throws Exception {
+    FakeDataSet fakeDataSet = new FakeDataSet()
+        .setData("test.mpd", TEST_MPD_NO_INDEX)
+        .setData("test_segment_1", TestUtil.buildTestData(4));
+    DashDownloader dashDownloader =
+        new DashDownloader("test.mpd", cache, new FakeDataSource(fakeDataSet));
+    dashDownloader.downloadManifest();
+
+    dashDownloader.selectRepresentations(new RepresentationKey(0, 0, 0));
+    dashDownloader.initStatus();
+    try {
+      dashDownloader.downloadRepresentations(null);
+      fail();
+    } catch (DashDownloaderException e) {
+      // expected interrupt.
+    }
+    dashDownloader.removeAll();
+
+    assertEquals(0, cache.getCacheSpace());
+  }
+
+  private void assertCachedData(FakeDataSet fakeDataSet) throws IOException {
+    int totalLength = 0;
+    for (FakeData fakeData : fakeDataSet.getAllData()) {
+      byte[] data = fakeData.getData();
+      assertCachedData(fakeData.uri, data);
+      totalLength += data.length;
+    }
+    assertEquals(totalLength, cache.getCacheSpace());
+  }
+
+  private void assertCachedData(String uriString, byte[] expected) throws IOException {
+    CacheDataSource dataSource = new CacheDataSource(cache, DummyDataSource.INSTANCE, 0);
+    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+    DataSourceInputStream inputStream = new DataSourceInputStream(dataSource,
+        new DataSpec(Uri.parse(uriString), DataSpec.FLAG_ALLOW_CACHING_UNKNOWN_LENGTH));
+    try {
+      inputStream.open();
+      byte[] buffer = new byte[1024];
+      int bytesRead;
+      while ((bytesRead = inputStream.read(buffer)) != -1) {
+        outputStream.write(buffer, 0, bytesRead);
+      }
+    } catch (IOException e) {
+      // Ignore
+    } finally {
+      inputStream.close();
+    }
+    MoreAsserts.assertEquals(expected, outputStream.toByteArray());
+  }
+
+  private static void assertCounters(DashDownloader dashDownloader, int totalSegments,
+      int downloadedSegments, int downloadedBytes) {
+    assertEquals(totalSegments, dashDownloader.getTotalSegments());
+    assertEquals(downloadedSegments, dashDownloader.getDownloadedSegments());
+    assertEquals(downloadedBytes, dashDownloader.getDownloadedBytes());
+  }
+
+}

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

@@ -48,14 +48,14 @@ public final class DashUtil {
    * Loads a DASH manifest.
    *
    * @param dataSource The {@link HttpDataSource} from which the manifest should be read.
-   * @param manifestUriString The URI of the manifest to be read.
+   * @param manifestUri The URI of the manifest to be read.
    * @return An instance of {@link DashManifest}.
    * @throws IOException Thrown when there is an error while loading.
    */
-  public static DashManifest loadManifest(DataSource dataSource, String manifestUriString)
+  public static DashManifest loadManifest(DataSource dataSource, String manifestUri)
       throws IOException {
     DataSourceInputStream inputStream = new DataSourceInputStream(dataSource,
-        new DataSpec(Uri.parse(manifestUriString), DataSpec.FLAG_ALLOW_CACHING_UNKNOWN_LENGTH));
+        new DataSpec(Uri.parse(manifestUri), DataSpec.FLAG_ALLOW_CACHING_UNKNOWN_LENGTH));
     try {
       inputStream.open();
       DashManifestParser parser = new DashManifestParser();

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

@@ -22,7 +22,7 @@ import com.google.android.exoplayer2.source.dash.manifest.RangedUri;
  * An implementation of {@link DashSegmentIndex} that wraps a {@link ChunkIndex} parsed from a
  * media stream.
  */
-/* package */ final class DashWrappingSegmentIndex implements DashSegmentIndex {
+public final class DashWrappingSegmentIndex implements DashSegmentIndex {
 
   private final ChunkIndex chunkIndex;
 

playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/gts/DashStreamingTest.java

@@ -28,9 +28,9 @@ import com.google.android.exoplayer2.util.Util;
 /**
  * Tests DASH playbacks using {@link ExoPlayer}.
  */
-public final class DashTest extends ActivityInstrumentationTestCase2<HostActivity> {
+public final class DashStreamingTest extends ActivityInstrumentationTestCase2<HostActivity> {
 
-  private static final String TAG = "DashTest";
+  private static final String TAG = "DashStreamingTest";
 
   private static final ActionSchedule SEEKING_SCHEDULE = new ActionSchedule.Builder(TAG)
       .delay(10000).seek(15000)
@@ -72,7 +72,7 @@ public final class DashTest extends ActivityInstrumentationTestCase2<HostActivit
   
   private DashTestRunner testRunner;
 
-  public DashTest() {
+  public DashStreamingTest() {
     super(HostActivity.class);
   }
 

playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/gts/DashTestData.java

@@ -18,7 +18,7 @@ package com.google.android.exoplayer2.playbacktests.gts;
 import com.google.android.exoplayer2.util.Util;
 
 /**
- * Test data for {@link DashTest} and {@link DashWidevineOfflineTest).
+ * Test data for DASH tests.
  */
 public final class DashTestData {