Extract base class from DashDownloader

This base class will be used to extend HlsDownloader from.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=160505710

library/core/src/main/java/com/google/android/exoplayer2/source/offline/Downloader.java

+/*
+ * 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.offline;
+
+import android.support.annotation.Nullable;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.upstream.DataSink;
+import com.google.android.exoplayer2.upstream.DataSource;
+import com.google.android.exoplayer2.upstream.DummyDataSource;
+import com.google.android.exoplayer2.upstream.FileDataSource;
+import com.google.android.exoplayer2.upstream.PriorityDataSource;
+import com.google.android.exoplayer2.upstream.cache.Cache;
+import com.google.android.exoplayer2.upstream.cache.CacheDataSink;
+import com.google.android.exoplayer2.upstream.cache.CacheDataSource;
+import com.google.android.exoplayer2.util.ClosedSource;
+import com.google.android.exoplayer2.util.PriorityTaskManager;
+import java.io.IOException;
+
+/**
+ * Base class for stream downloaders.
+ *
+ * <p>All of the methods are blocking. Also they are not thread safe, except {@link
+ * #getTotalSegments()}, {@link #getDownloadedSegments()} and {@link #getDownloadedBytes()}.
+ *
+ * @param <M> The type of the manifest object.
+ * @param <K> The type of the representation key object.
+ */
+@ClosedSource(reason = "Not ready yet")
+public abstract class Downloader<M, K> {
+
+  /**
+   * Listener notified when download progresses.
+   */
+  public interface ProgressListener {
+    /**
+     * Called for the first time after the initialization and then after download of each segment.
+     * It is called on the thread which invoked {@link #downloadRepresentations(ProgressListener)}.
+     *
+     * @param downloader The reporting instance.
+     * @param totalSegments Total number of segments in the content.
+     * @param downloadedSegments Total number of downloaded segments.
+     * @param downloadedBytes Total number of downloaded bytes.
+     * @see #downloadRepresentations(ProgressListener)
+     */
+    void onDownloadProgress(Downloader<?, ?> downloader, int totalSegments,
+        int downloadedSegments, long downloadedBytes);
+  }
+
+  protected final Cache cache;
+  protected final CacheDataSource dataSource;
+  protected final CacheDataSource offlineDataSource;
+  protected final PriorityTaskManager priorityTaskManager;
+  protected final String manifestUri;
+
+  protected volatile int totalSegments;
+  protected volatile int downloadedSegments;
+  protected volatile long downloadedBytes;
+
+  /**
+   * Constructs a Downloader.
+   *
+   * @param manifestUri The URI of the manifest to be downloaded.
+   * @param cache Cache instance to be used to store downloaded data.
+   * @param upstreamDataSource A {@link DataSource} for downloading data.
+   * @param cacheReadDataSource A {@link DataSource} for reading data from the cache.
+   *     If null, a {@link FileDataSource} instance is created and used.
+   * @param cacheWriteDataSink A {@link DataSink} for writing data to the cache. If
+   *     null, a {@link CacheDataSink} instance is created and used.
+   * @param priorityTaskManager If not null it's used to check whether it is allowed to proceed with
+   *     download. Downloader priority is {@link C#PRIORITY_DOWNLOAD}.
+   */
+  public Downloader(String manifestUri, Cache cache, DataSource upstreamDataSource,
+      @Nullable DataSource cacheReadDataSource, @Nullable DataSink cacheWriteDataSink,
+      @Nullable PriorityTaskManager priorityTaskManager) {
+    if (priorityTaskManager != null) {
+      upstreamDataSource =
+          new PriorityDataSource(upstreamDataSource, priorityTaskManager, C.PRIORITY_DOWNLOAD);
+    } else {
+      priorityTaskManager = new PriorityTaskManager(); // dummy PriorityTaskManager
+    }
+    if (cacheReadDataSource == null) {
+      cacheReadDataSource = new FileDataSource();
+    }
+    if (cacheWriteDataSink == null) {
+      cacheWriteDataSink = new CacheDataSink(cache,
+          CacheDataSource.DEFAULT_MAX_CACHE_FILE_SIZE);
+    }
+
+    this.manifestUri = manifestUri;
+    this.cache = cache;
+    this.dataSource = new CacheDataSource(cache, upstreamDataSource, cacheReadDataSource,
+            cacheWriteDataSink, CacheDataSource.FLAG_BLOCK_ON_CACHE, null);
+    this.offlineDataSource = new CacheDataSource(cache, DummyDataSource.INSTANCE,
+            cacheReadDataSource, null, CacheDataSource.FLAG_BLOCK_ON_CACHE, null);
+    this.priorityTaskManager = priorityTaskManager;
+
+    resetCounters();
+  }
+
+  /**
+   * Downloads the manifest.
+   *
+   * @return The downloaded manifest.
+   * @throws IOException If an error occurs reading data from the stream.
+   */
+  public abstract M downloadManifest() throws IOException;
+
+  /**
+   * Selects multiple representations pointed to by the keys for downloading, removing or checking
+   * status. Any previous selection is cleared.
+   */
+  public abstract void selectRepresentations(K... keys);
+
+  /**
+   * Initializes the total segments, downloaded segments and downloaded bytes counters for the
+   * selected representations.
+   *
+   * @throws IOException Thrown when there is an error while reading from cache.
+   * @throws DownloaderException Thrown when a representation index is unbounded.
+   * @throws InterruptedException If the thread has been interrupted.
+   * @see #getTotalSegments()
+   * @see #getDownloadedSegments()
+   * @see #getDownloadedBytes()
+   */
+  public abstract void initStatus() throws DownloaderException, InterruptedException, IOException;
+
+  /**
+   * Downloads the content for the selected representations in sync or resumes a previously stopped
+   * download.
+   *
+   * @throws IOException Thrown when there is an error while downloading.
+   * @throws DownloaderException Thrown when no index data can be found for a representation or
+   *     the index is unbounded.
+   * @throws InterruptedException If the thread has been interrupted.
+   */
+  public abstract void downloadRepresentations(@Nullable ProgressListener listener)
+      throws IOException, DownloaderException, InterruptedException;
+
+  /**
+   * Returns the total number of segments in the representations which are selected, or {@link
+   * C#LENGTH_UNSET} if it hasn't been calculated yet.
+   *
+   * @see #initStatus()
+   */
+  public final int getTotalSegments() {
+    return totalSegments;
+  }
+
+  /**
+   * Returns the total number of downloaded segments in the representations which are selected, or
+   * {@link C#LENGTH_UNSET} if it hasn't been calculated yet.
+   *
+   * @see #initStatus()
+   */
+  public final int getDownloadedSegments() {
+    return downloadedSegments;
+  }
+
+  /**
+   * Returns the total number of downloaded bytes in the representations which are selected, or
+   * {@link C#LENGTH_UNSET} if it hasn't been calculated yet.
+   *
+   * @see #initStatus()
+   */
+  public final long getDownloadedBytes() {
+    return downloadedBytes;
+  }
+
+  /**
+   * Removes all representations declared in the manifest and the manifest itself.
+   *
+   * @throws InterruptedException Thrown if the thread was interrupted.
+   */
+  public abstract void removeAll() throws InterruptedException;
+
+  protected final void resetCounters() {
+    totalSegments = C.LENGTH_UNSET;
+    downloadedSegments = C.LENGTH_UNSET;
+    downloadedBytes = C.LENGTH_UNSET;
+  }
+
+}

library/core/src/main/java/com/google/android/exoplayer2/source/offline/DownloaderException.java

+/*
+ * 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.offline;
+
+import com.google.android.exoplayer2.util.ClosedSource;
+
+/** Thrown on an error in {@link Downloader}. */
+@ClosedSource(reason = "Not ready yet")
+public final class DownloaderException extends Exception {
+
+  public DownloaderException(String message) {
+    super(message);
+  }
+
+}