Move deserialization code to a more natural location

- Add DownloadAction.fromByteArray for symmetry with toByteArray
- Make DownloadService call fromByteArray, for symmetry with calls
  to toByteArray

PiperOrigin-RevId: 222801703

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

@@ -19,6 +19,7 @@ import android.net.Uri;
 import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Util;
+import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.DataInputStream;
 import java.io.DataOutputStream;
@@ -44,6 +45,18 @@ public final class DownloadAction {
 
   private static final int VERSION = 2;
 
+  /**
+   * Deserializes an action from the {@code data}.
+   *
+   * @param data The action data to deserialize.
+   * @return The deserialized action.
+   * @throws IOException If the data could not be deserialized.
+   */
+  public static DownloadAction fromByteArray(byte[] data) throws IOException {
+    ByteArrayInputStream input = new ByteArrayInputStream(data);
+    return deserializeFromStream(input);
+  }
+
   /**
    * Deserializes one action that was serialized with {@link #serializeToStream(OutputStream)} from
    * the {@code input}.
@@ -52,8 +65,8 @@ public final class DownloadAction {
    *
    * @param input The stream from which to read.
    * @return The deserialized action.
-   * @throws IOException If there is an IO error reading from {@code input}, or if the action type
-   *     isn't supported by any of the {@code deserializers}.
+   * @throws IOException If there is an IO error reading from {@code input}, or if the data could
+   *     not be deserialized.
    */
   public static DownloadAction deserializeFromStream(InputStream input) throws IOException {
     return readFromStream(new DataInputStream(input));

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

@@ -31,7 +31,6 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Log;
 import com.google.android.exoplayer2.util.Util;
-import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.IOException;
 import java.lang.annotation.Documented;
@@ -187,21 +186,6 @@ public final class DownloadManager {
     }
   }
 
-  /**
-   * Deserializes an action from {@code actionData}, and calls {@link
-   * #handleAction(DownloadAction)}.
-   *
-   * @param actionData Serialized version of the action to be executed.
-   * @return The id of the newly created task.
-   * @throws IOException If an error occurs deserializing the action.
-   */
-  public int handleAction(byte[] actionData) throws IOException {
-    Assertions.checkState(!released);
-    ByteArrayInputStream input = new ByteArrayInputStream(actionData);
-    DownloadAction action = DownloadAction.deserializeFromStream(input);
-    return handleAction(action);
-  }
-
   /**
    * Handles the given action. A task is created and added to the task queue. If it's a remove
    * action then any download tasks for the same media are immediately canceled.

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

@@ -259,7 +259,7 @@ public abstract class DownloadService extends Service {
           Log.e(TAG, "Ignoring ADD action with no action data");
         } else {
           try {
-            downloadManager.handleAction(actionData);
+            downloadManager.handleAction(DownloadAction.fromByteArray(actionData));
           } catch (IOException e) {
             Log.e(TAG, "Failed to handle ADD action", e);
           }

library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadActionTest.java

@@ -19,6 +19,7 @@ import static com.google.android.exoplayer2.offline.DownloadAction.TYPE_DASH;
 import static com.google.android.exoplayer2.offline.DownloadAction.TYPE_HLS;
 import static com.google.android.exoplayer2.offline.DownloadAction.TYPE_PROGRESSIVE;
 import static com.google.android.exoplayer2.offline.DownloadAction.TYPE_SS;
+import static com.google.android.exoplayer2.offline.DownloadAction.fromByteArray;
 import static com.google.common.truth.Truth.assertThat;
 
 import android.net.Uri;
@@ -142,15 +143,28 @@ public class DownloadActionTest {
   }
 
   @Test
-  public void testSerializerWriteRead() throws Exception {
-    assertSerializationRoundTrip(
+  public void testStreamSerialization() throws Exception {
+    assertStreamSerializationRoundTrip(
         DownloadAction.createDownloadAction(
             TYPE_DASH,
             uri1,
             toList(new StreamKey(0, 1, 2), new StreamKey(3, 4, 5)),
             "key123",
             data));
-    assertSerializationRoundTrip(
+    assertStreamSerializationRoundTrip(
+        DownloadAction.createRemoveAction(TYPE_DASH, uri1, "key123", data));
+  }
+
+  @Test
+  public void testArraySerialization() throws Exception {
+    assertArraySerializationRoundTrip(
+        DownloadAction.createDownloadAction(
+            TYPE_DASH,
+            uri1,
+            toList(new StreamKey(0, 1, 2), new StreamKey(3, 4, 5)),
+            "key123",
+            data));
+    assertArraySerializationRoundTrip(
         DownloadAction.createRemoveAction(TYPE_DASH, uri1, "key123", data));
   }
 
@@ -259,7 +273,7 @@ public class DownloadActionTest {
     assertThat(action2).isEqualTo(action1);
   }
 
-  private static void assertSerializationRoundTrip(DownloadAction action) throws IOException {
+  private static void assertStreamSerializationRoundTrip(DownloadAction action) throws IOException {
     ByteArrayOutputStream out = new ByteArrayOutputStream();
     DataOutputStream output = new DataOutputStream(out);
     action.serializeToStream(output);
@@ -267,6 +281,10 @@ public class DownloadActionTest {
     assertEqual(action, deserializeActionFromStream(out));
   }
 
+  private static void assertArraySerializationRoundTrip(DownloadAction action) throws IOException {
+    assertEqual(action, fromByteArray(action.toByteArray()));
+  }
+
   // TODO: Remove this method and add assets for legacy serialized actions.
   private static void assertLegacySerializationRoundTrip(DownloadAction action, int version)
       throws IOException {