Add WritableDownloadIndex interface

One goal we forgot about a little bit was to allow applications
to provide their own index implementation. This requires the
writable side to also be defined by an interface.

PiperOrigin-RevId: 243979660

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

@@ -38,7 +38,7 @@ import java.util.List;
  * <p class="caution">Database access may take a long time, do not call methods of this class from
  * the application main thread.
  */
-public final class DefaultDownloadIndex implements DownloadIndex {
+public final class DefaultDownloadIndex implements WritableDownloadIndex {
 
   private static final String TABLE_NAME = DatabaseProvider.TABLE_PREFIX + "Downloads";
 
@@ -185,12 +185,7 @@ public final class DefaultDownloadIndex implements DownloadIndex {
     return new DownloadCursorImpl(cursor);
   }
 
-  /**
-   * Adds or replaces a {@link Download}.
-   *
-   * @param download The {@link Download} to be added.
-   * @throws DatabaseIOException If an error occurs setting the state.
-   */
+  @Override
   public void putDownload(Download download) throws DatabaseIOException {
     ensureInitialized();
     ContentValues values = new ContentValues();
@@ -218,12 +213,7 @@ public final class DefaultDownloadIndex implements DownloadIndex {
     }
   }
 
-  /**
-   * Removes the {@link Download} with the given {@code id}.
-   *
-   * @param id ID of a {@link Download}.
-   * @throws DatabaseIOException If an error occurs removing the state.
-   */
+  @Override
   public void removeDownload(String id) throws DatabaseIOException {
     ensureInitialized();
     try {
@@ -233,13 +223,7 @@ public final class DefaultDownloadIndex implements DownloadIndex {
     }
   }
 
-  /**
-   * Sets the manual stop reason of the downloads in a terminal state ({@link
-   * Download#STATE_COMPLETED}, {@link Download#STATE_FAILED}).
-   *
-   * @param manualStopReason The manual stop reason.
-   * @throws DatabaseIOException If an error occurs updating the state.
-   */
+  @Override
   public void setManualStopReason(int manualStopReason) throws DatabaseIOException {
     ensureInitialized();
     try {
@@ -252,17 +236,7 @@ public final class DefaultDownloadIndex implements DownloadIndex {
     }
   }
 
-  /**
-   * Sets the manual stop reason of the download with the given {@code id} in a terminal state
-   * ({@link Download#STATE_COMPLETED}, {@link Download#STATE_FAILED}).
-   *
-   * <p>If there's no {@link Download} with the given {@code id} or it isn't in a terminal state,
-   * then nothing happens.
-   *
-   * @param id ID of a {@link Download}.
-   * @param manualStopReason The manual stop reason.
-   * @throws DatabaseIOException If an error occurs updating the state.
-   */
+  @Override
   public void setManualStopReason(String id, int manualStopReason) throws DatabaseIOException {
     ensureInitialized();
     try {

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

@@ -18,7 +18,7 @@ package com.google.android.exoplayer2.offline;
 import androidx.annotation.Nullable;
 import java.io.IOException;
 
-/** Persists {@link Download}s. */
+/** An index of {@link Download Downloads}. */
 public interface DownloadIndex {
 
   /**

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

@@ -34,7 +34,6 @@ import android.os.Message;
 import androidx.annotation.IntDef;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
-import com.google.android.exoplayer2.database.DatabaseIOException;
 import com.google.android.exoplayer2.database.DatabaseProvider;
 import com.google.android.exoplayer2.scheduler.Requirements;
 import com.google.android.exoplayer2.scheduler.RequirementsWatcher;
@@ -155,7 +154,7 @@ public final class DownloadManager {
   private final int maxSimultaneousDownloads;
   private final int minRetryCount;
   private final Context context;
-  private final DefaultDownloadIndex downloadIndex;
+  private final WritableDownloadIndex downloadIndex;
   private final DownloaderFactory downloaderFactory;
   private final Handler mainHandler;
   private final HandlerThread internalThread;
@@ -231,7 +230,7 @@ public final class DownloadManager {
    * Constructs a {@link DownloadManager}.
    *
    * @param context Any context.
-   * @param downloadIndex The {@link DefaultDownloadIndex} that holds the downloads.
+   * @param downloadIndex The download index used to hold the download information.
    * @param downloaderFactory A factory for creating {@link Downloader}s.
    * @param maxSimultaneousDownloads The maximum number of simultaneous downloads.
    * @param minRetryCount The minimum number of times a download must be retried before failing.
@@ -239,7 +238,7 @@ public final class DownloadManager {
    */
   public DownloadManager(
       Context context,
-      DefaultDownloadIndex downloadIndex,
+      WritableDownloadIndex downloadIndex,
       DownloaderFactory downloaderFactory,
       int maxSimultaneousDownloads,
       int minRetryCount,
@@ -651,7 +650,7 @@ public final class DownloadManager {
       } else {
         downloadIndex.setManualStopReason(manualStopReason);
       }
-    } catch (DatabaseIOException e) {
+    } catch (IOException e) {
       Log.e(TAG, "setManualStopReason failed", e);
     }
   }
@@ -734,7 +733,7 @@ public final class DownloadManager {
     logd("Download state is changed", downloadInternal);
     try {
       downloadIndex.putDownload(download);
-    } catch (DatabaseIOException e) {
+    } catch (IOException e) {
       Log.e(TAG, "Failed to update index", e);
     }
     if (downloadInternal.state == STATE_COMPLETED || downloadInternal.state == STATE_FAILED) {
@@ -747,7 +746,7 @@ public final class DownloadManager {
     logd("Download is removed", downloadInternal);
     try {
       downloadIndex.removeDownload(download.request.id);
-    } catch (DatabaseIOException e) {
+    } catch (IOException e) {
       Log.e(TAG, "Failed to remove from index", e);
     }
     downloadInternals.remove(downloadInternal);
@@ -805,7 +804,7 @@ public final class DownloadManager {
   private Download loadDownload(String id) {
     try {
       return downloadIndex.getDownload(id);
-    } catch (DatabaseIOException e) {
+    } catch (IOException e) {
       Log.e(TAG, "loadDownload failed", e);
     }
     return null;

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

+/*
+ * Copyright (C) 2019 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.offline;
+
+import java.io.IOException;
+
+/** An writable index of {@link Download Downloads}. */
+public interface WritableDownloadIndex extends DownloadIndex {
+
+  /**
+   * Adds or replaces a {@link Download}.
+   *
+   * @param download The {@link Download} to be added.
+   * @throws throws IOException If an error occurs setting the state.
+   */
+  void putDownload(Download download) throws IOException;
+
+  /**
+   * Removes the {@link Download} with the given {@code id}.
+   *
+   * @param id ID of a {@link Download}.
+   * @throws throws IOException If an error occurs removing the state.
+   */
+  void removeDownload(String id) throws IOException;
+  /**
+   * Sets the manual stop reason of the downloads in a terminal state ({@link
+   * Download#STATE_COMPLETED}, {@link Download#STATE_FAILED}).
+   *
+   * @param manualStopReason The manual stop reason.
+   * @throws throws IOException If an error occurs updating the state.
+   */
+  void setManualStopReason(int manualStopReason) throws IOException;
+
+  /**
+   * Sets the manual stop reason of the download with the given {@code id} in a terminal state
+   * ({@link Download#STATE_COMPLETED}, {@link Download#STATE_FAILED}).
+   *
+   * <p>If there's no {@link Download} with the given {@code id} or it isn't in a terminal state,
+   * then nothing happens.
+   *
+   * @param id ID of a {@link Download}.
+   * @param manualStopReason The manual stop reason.
+   * @throws throws IOException If an error occurs updating the state.
+   */
+  void setManualStopReason(String id, int manualStopReason) throws IOException;
+}