Nullness fixes for emsg and id3 metadata classes

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=205972857

library/core/src/main/java/com/google/android/exoplayer2/metadata/MetadataDecoder.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata;
 
+import android.support.annotation.Nullable;
+
 /**
  * Decodes metadata from binary data.
  */
@@ -24,9 +26,8 @@ public interface MetadataDecoder {
    * Decodes a {@link Metadata} element from the provided input buffer.
    *
    * @param inputBuffer The input buffer to decode.
-   * @return The decoded metadata object.
+   * @return The decoded metadata object, or null if the metadata could not be decoded.
-   * @throws MetadataDecoderException If a problem occurred decoding the data.
    */
-  Metadata decode(MetadataInputBuffer inputBuffer) throws MetadataDecoderException;
+  @Nullable
-
+  Metadata decode(MetadataInputBuffer inputBuffer);
 }

library/core/src/main/java/com/google/android/exoplayer2/metadata/MetadataDecoderException.java

@@ -1,38 +0,0 @@
-/*
- * Copyright (C) 2016 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.metadata;
-
-/**
- * Thrown when an error occurs decoding metadata.
- */
-public class MetadataDecoderException extends Exception {
-
-  /**
-   * @param message The detail message for this exception.
-   */
-  public MetadataDecoderException(String message) {
-    super(message);
-  }
-
-  /**
-   * @param message The detail message for this exception.
-   * @param cause The cause of this exception.
-   */
-  public MetadataDecoderException(String message, Throwable cause) {
-    super(message, cause);
-  }
-
-}

library/core/src/main/java/com/google/android/exoplayer2/metadata/MetadataRenderer.java

@@ -128,14 +128,10 @@ public final class MetadataRenderer extends BaseRenderer implements Callback {
         } else {
           buffer.subsampleOffsetUs = formatHolder.format.subsampleOffsetUs;
           buffer.flip();
-          try {
           int index = (pendingMetadataIndex + pendingMetadataCount) % MAX_PENDING_METADATA_COUNT;
           pendingMetadata[index] = decoder.decode(buffer);
           pendingMetadataTimestamps[index] = buffer.timeUs;
           pendingMetadataCount++;
-          } catch (MetadataDecoderException e) {
-            throw ExoPlaybackException.createForRenderer(e, getIndex());
-          }
         }
       }
     }

library/core/src/main/java/com/google/android/exoplayer2/metadata/emsg/EventMessage.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata.emsg;
 
+import static org.checkerframework.checker.nullness.NullnessUtil.castNonNull;
+
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.support.annotation.Nullable;
@@ -81,12 +83,12 @@ public final class EventMessage implements Metadata.Entry {
   }
 
   /* package */ EventMessage(Parcel in) {
-    schemeIdUri = in.readString();
+    schemeIdUri = castNonNull(in.readString());
-    value = in.readString();
+    value = castNonNull(in.readString());
     presentationTimeUs = in.readLong();
     durationMs = in.readLong();
     id = in.readLong();
-    messageData = in.createByteArray();
+    messageData = castNonNull(in.createByteArray());
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/ApicFrame.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata.id3;
 
+import static org.checkerframework.checker.nullness.NullnessUtil.castNonNull;
+
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.support.annotation.Nullable;
@@ -44,10 +46,10 @@ public final class ApicFrame extends Id3Frame {
 
   /* package */ ApicFrame(Parcel in) {
     super(ID);
-    mimeType = in.readString();
+    mimeType = castNonNull(in.readString());
-    description = in.readString();
+    description = castNonNull(in.readString());
     pictureType = in.readInt();
-    pictureData = in.createByteArray();
+    pictureData = castNonNull(in.createByteArray());
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/BinaryFrame.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata.id3;
 
+import static org.checkerframework.checker.nullness.NullnessUtil.castNonNull;
+
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.support.annotation.Nullable;
@@ -33,8 +35,8 @@ public final class BinaryFrame extends Id3Frame {
   }
 
   /* package */ BinaryFrame(Parcel in) {
-    super(in.readString());
+    super(castNonNull(in.readString()));
-    data = in.createByteArray();
+    data = castNonNull(in.createByteArray());
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/ChapterFrame.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata.id3;
 
+import static org.checkerframework.checker.nullness.NullnessUtil.castNonNull;
+
 import android.os.Parcel;
 import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
@@ -54,7 +56,7 @@ public final class ChapterFrame extends Id3Frame {
 
   /* package */ ChapterFrame(Parcel in) {
     super(ID);
-    this.chapterId = in.readString();
+    this.chapterId = castNonNull(in.readString());
     this.startTimeMs = in.readInt();
     this.endTimeMs = in.readInt();
     this.startOffset = in.readLong();

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/ChapterTocFrame.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata.id3;
 
+import static org.checkerframework.checker.nullness.NullnessUtil.castNonNull;
+
 import android.os.Parcel;
 import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.util.Util;
@@ -45,7 +47,7 @@ public final class ChapterTocFrame extends Id3Frame {
 
   /* package */ ChapterTocFrame(Parcel in) {
     super(ID);
-    this.elementId = in.readString();
+    this.elementId = castNonNull(in.readString());
     this.isRoot = in.readByte() != 0;
     this.isOrdered = in.readByte() != 0;
     this.children = in.createStringArray();

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/CommentFrame.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata.id3;
 
+import static org.checkerframework.checker.nullness.NullnessUtil.castNonNull;
+
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.support.annotation.Nullable;
@@ -40,9 +42,9 @@ public final class CommentFrame extends Id3Frame {
 
   /* package */ CommentFrame(Parcel in) {
     super(ID);
-    language = in.readString();
+    language = castNonNull(in.readString());
-    description = in.readString();
+    description = castNonNull(in.readString());
-    text = in.readString();
+    text = castNonNull(in.readString());
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/GeobFrame.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata.id3;
 
+import static org.checkerframework.checker.nullness.NullnessUtil.castNonNull;
+
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.support.annotation.Nullable;
@@ -43,10 +45,10 @@ public final class GeobFrame extends Id3Frame {
 
   /* package */ GeobFrame(Parcel in) {
     super(ID);
-    mimeType = in.readString();
+    mimeType = castNonNull(in.readString());
-    filename = in.readString();
+    filename = castNonNull(in.readString());
-    description = in.readString();
+    description = castNonNull(in.readString());
-    data = in.createByteArray();
+    data = castNonNull(in.createByteArray());
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/Id3Decoder.java

@@ -103,7 +103,7 @@ public final class Id3Decoder implements MetadataDecoder {
   }
 
   @Override
-  public Metadata decode(MetadataInputBuffer inputBuffer) {
+  public @Nullable Metadata decode(MetadataInputBuffer inputBuffer) {
     ByteBuffer buffer = inputBuffer.data;
     return decode(buffer.array(), buffer.limit());
   }
@@ -113,9 +113,10 @@ public final class Id3Decoder implements MetadataDecoder {
    *
    * @param data The bytes to decode ID3 tags from.
    * @param size Amount of bytes in {@code data} to read.
-   * @return A {@link Metadata} object containing the decoded ID3 tags.
+   * @return A {@link Metadata} object containing the decoded ID3 tags, or null if the data could
+   *     not be decoded.
    */
-  public Metadata decode(byte[] data, int size) {
+  public @Nullable Metadata decode(byte[] data, int size) {
     List<Id3Frame> id3Frames = new ArrayList<>();
     ParsableByteArray id3Data = new ParsableByteArray(data, size);
 
@@ -157,7 +158,7 @@ public final class Id3Decoder implements MetadataDecoder {
    * @param data A {@link ParsableByteArray} from which the header should be read.
    * @return The parsed header, or null if the ID3 tag is unsupported.
    */
-  private static Id3Header decodeHeader(ParsableByteArray data) {
+  private static @Nullable Id3Header decodeHeader(ParsableByteArray data) {
     if (data.bytesLeft() < ID3_HEADER_LENGTH) {
       Log.w(TAG, "Data too short to be an ID3 tag");
       return null;
@@ -271,7 +272,7 @@ public final class Id3Decoder implements MetadataDecoder {
     }
   }
 
-  private static Id3Frame decodeFrame(
+  private static @Nullable Id3Frame decodeFrame(
       int majorVersion,
       ParsableByteArray id3Data,
       boolean unsignedIntFrameSizeHack,
@@ -404,8 +405,8 @@ public final class Id3Decoder implements MetadataDecoder {
     }
   }
 
-  private static TextInformationFrame decodeTxxxFrame(ParsableByteArray id3Data, int frameSize)
+  private static @Nullable TextInformationFrame decodeTxxxFrame(
-      throws UnsupportedEncodingException {
+      ParsableByteArray id3Data, int frameSize) throws UnsupportedEncodingException {
     if (frameSize < 1) {
       // Frame is malformed.
       return null;
@@ -427,8 +428,8 @@ public final class Id3Decoder implements MetadataDecoder {
     return new TextInformationFrame("TXXX", description, value);
   }
 
-  private static TextInformationFrame decodeTextInformationFrame(ParsableByteArray id3Data,
+  private static @Nullable TextInformationFrame decodeTextInformationFrame(
-      int frameSize, String id) throws UnsupportedEncodingException {
+      ParsableByteArray id3Data, int frameSize, String id) throws UnsupportedEncodingException {
     if (frameSize < 1) {
       // Frame is malformed.
       return null;
@@ -446,7 +447,7 @@ public final class Id3Decoder implements MetadataDecoder {
     return new TextInformationFrame(id, null, value);
   }
 
-  private static UrlLinkFrame decodeWxxxFrame(ParsableByteArray id3Data, int frameSize)
+  private static @Nullable UrlLinkFrame decodeWxxxFrame(ParsableByteArray id3Data, int frameSize)
       throws UnsupportedEncodingException {
     if (frameSize < 1) {
       // Frame is malformed.
@@ -557,7 +558,7 @@ public final class Id3Decoder implements MetadataDecoder {
     return new ApicFrame(mimeType, description, pictureType, pictureData);
   }
 
-  private static CommentFrame decodeCommentFrame(ParsableByteArray id3Data, int frameSize)
+  private static @Nullable CommentFrame decodeCommentFrame(ParsableByteArray id3Data, int frameSize)
       throws UnsupportedEncodingException {
     if (frameSize < 4) {
       // Frame is malformed.

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/Id3Frame.java

@@ -16,7 +16,6 @@
 package com.google.android.exoplayer2.metadata.id3;
 
 import com.google.android.exoplayer2.metadata.Metadata;
-import com.google.android.exoplayer2.util.Assertions;
 
 /**
  * Base class for ID3 frames.
@@ -29,7 +28,7 @@ public abstract class Id3Frame implements Metadata.Entry {
   public final String id;
 
   public Id3Frame(String id) {
-    this.id = Assertions.checkNotNull(id);
+    this.id = id;
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/InternalFrame.java

@@ -15,9 +15,10 @@
  */
 package com.google.android.exoplayer2.metadata.id3;
 
+import static org.checkerframework.checker.nullness.NullnessUtil.castNonNull;
+
 import android.os.Parcel;
 import android.support.annotation.Nullable;
-import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Util;
 
 /** Internal ID3 frame that is intended for use by the player. */
@@ -38,9 +39,9 @@ public final class InternalFrame extends Id3Frame {
 
   /* package */ InternalFrame(Parcel in) {
     super(ID);
-    domain = Assertions.checkNotNull(in.readString());
+    domain = castNonNull(in.readString());
-    description = Assertions.checkNotNull(in.readString());
+    description = castNonNull(in.readString());
-    text = Assertions.checkNotNull(in.readString());
+    text = castNonNull(in.readString());
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/PrivFrame.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata.id3;
 
+import static org.checkerframework.checker.nullness.NullnessUtil.castNonNull;
+
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.support.annotation.Nullable;
@@ -39,8 +41,8 @@ public final class PrivFrame extends Id3Frame {
 
   /* package */ PrivFrame(Parcel in) {
     super(ID);
-    owner = in.readString();
+    owner = castNonNull(in.readString());
-    privateData = in.createByteArray();
+    privateData = castNonNull(in.createByteArray());
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/TextInformationFrame.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata.id3;
 
+import static org.checkerframework.checker.nullness.NullnessUtil.castNonNull;
+
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.support.annotation.Nullable;
@@ -35,9 +37,9 @@ public final class TextInformationFrame extends Id3Frame {
   }
 
   /* package */ TextInformationFrame(Parcel in) {
-    super(in.readString());
+    super(castNonNull(in.readString()));
     description = in.readString();
-    value = in.readString();
+    value = castNonNull(in.readString());
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/metadata/id3/UrlLinkFrame.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.metadata.id3;
 
+import static org.checkerframework.checker.nullness.NullnessUtil.castNonNull;
+
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.support.annotation.Nullable;
@@ -25,19 +27,19 @@ import com.google.android.exoplayer2.util.Util;
  */
 public final class UrlLinkFrame extends Id3Frame {
 
-  public final String description;
+  public final @Nullable String description;
   public final String url;
 
-  public UrlLinkFrame(String id, String description, String url) {
+  public UrlLinkFrame(String id, @Nullable String description, String url) {
     super(id);
     this.description = description;
     this.url = url;
   }
 
   /* package */ UrlLinkFrame(Parcel in) {
-    super(in.readString());
+    super(castNonNull(in.readString()));
     description = in.readString();
-    url = in.readString();
+    url = castNonNull(in.readString());
   }
 
   @Override

library/core/src/main/java/com/google/android/exoplayer2/metadata/scte35/SpliceInfoDecoder.java

@@ -17,7 +17,6 @@ package com.google.android.exoplayer2.metadata.scte35;
 
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.MetadataDecoder;
-import com.google.android.exoplayer2.metadata.MetadataDecoderException;
 import com.google.android.exoplayer2.metadata.MetadataInputBuffer;
 import com.google.android.exoplayer2.util.ParsableBitArray;
 import com.google.android.exoplayer2.util.ParsableByteArray;
@@ -46,7 +45,7 @@ public final class SpliceInfoDecoder implements MetadataDecoder {
   }
 
   @Override
-  public Metadata decode(MetadataInputBuffer inputBuffer) throws MetadataDecoderException {
+  public Metadata decode(MetadataInputBuffer inputBuffer) {
     // Internal timestamps adjustment.
     if (timestampAdjuster == null
         || inputBuffer.subsampleOffsetUs != timestampAdjuster.getTimestampOffsetUs()) {

library/core/src/test/java/com/google/android/exoplayer2/metadata/id3/Id3DecoderTest.java

@@ -19,7 +19,6 @@ import static com.google.common.truth.Truth.assertThat;
 
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.metadata.Metadata;
-import com.google.android.exoplayer2.metadata.MetadataDecoderException;
 import com.google.android.exoplayer2.util.Assertions;
 import java.nio.charset.Charset;
 import java.util.Arrays;
@@ -38,7 +37,7 @@ public final class Id3DecoderTest {
   private static final int ID3_TEXT_ENCODING_UTF_8 = 3;
 
   @Test
-  public void testDecodeTxxxFrame() throws MetadataDecoderException {
+  public void testDecodeTxxxFrame() {
     byte[] rawId3 = buildSingleFrameTag("TXXX", new byte[] {3, 0, 109, 100, 105, 97, 108, 111, 103,
         95, 86, 73, 78, 68, 73, 67, 79, 49, 53, 50, 55, 54, 54, 52, 95, 115, 116, 97, 114, 116, 0});
     Id3Decoder decoder = new Id3Decoder();
@@ -65,7 +64,7 @@ public final class Id3DecoderTest {
   }
 
   @Test
-  public void testDecodeTextInformationFrame() throws MetadataDecoderException {
+  public void testDecodeTextInformationFrame() {
     byte[] rawId3 = buildSingleFrameTag("TIT2", new byte[] {3, 72, 101, 108, 108, 111, 32, 87, 111,
         114, 108, 100, 0});
     Id3Decoder decoder = new Id3Decoder();
@@ -92,7 +91,7 @@ public final class Id3DecoderTest {
   }
 
   @Test
-  public void testDecodeWxxxFrame() throws MetadataDecoderException {
+  public void testDecodeWxxxFrame() {
     byte[] rawId3 = buildSingleFrameTag("WXXX", new byte[] {ID3_TEXT_ENCODING_UTF_8, 116, 101, 115,
         116, 0, 104, 116, 116, 112, 115, 58, 47, 47, 116, 101, 115, 116, 46, 99, 111, 109, 47, 97,
         98, 99, 63, 100, 101, 102});
@@ -120,7 +119,7 @@ public final class Id3DecoderTest {
   }
 
   @Test
-  public void testDecodeUrlLinkFrame() throws MetadataDecoderException {
+  public void testDecodeUrlLinkFrame() {
     byte[] rawId3 = buildSingleFrameTag("WCOM", new byte[] {104, 116, 116, 112, 115, 58, 47, 47,
         116, 101, 115, 116, 46, 99, 111, 109, 47, 97, 98, 99, 63, 100, 101, 102});
     Id3Decoder decoder = new Id3Decoder();
@@ -142,7 +141,7 @@ public final class Id3DecoderTest {
   }
 
   @Test
-  public void testDecodePrivFrame() throws MetadataDecoderException {
+  public void testDecodePrivFrame() {
     byte[] rawId3 = buildSingleFrameTag("PRIV", new byte[] {116, 101, 115, 116, 0, 1, 2, 3, 4});
     Id3Decoder decoder = new Id3Decoder();
     Metadata metadata = decoder.decode(rawId3, rawId3.length);
@@ -161,7 +160,7 @@ public final class Id3DecoderTest {
   }
 
   @Test
-  public void testDecodeApicFrame() throws MetadataDecoderException {
+  public void testDecodeApicFrame() {
     byte[] rawId3 = buildSingleFrameTag("APIC", new byte[] {3, 105, 109, 97, 103, 101, 47, 106, 112,
         101, 103, 0, 16, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 0, 1, 2, 3, 4, 5, 6, 7,
         8, 9, 0});
@@ -177,7 +176,7 @@ public final class Id3DecoderTest {
   }
 
   @Test
-  public void testDecodeCommentFrame() throws MetadataDecoderException {
+  public void testDecodeCommentFrame() {
     byte[] rawId3 = buildSingleFrameTag("COMM", new byte[] {ID3_TEXT_ENCODING_UTF_8, 101, 110, 103,
         100, 101, 115, 99, 114, 105, 112, 116, 105, 111, 110, 0, 116, 101, 120, 116, 0});
     Id3Decoder decoder = new Id3Decoder();
@@ -204,7 +203,7 @@ public final class Id3DecoderTest {
   }
 
   @Test
-  public void testDecodeMultiFrames() throws MetadataDecoderException {
+  public void testDecodeMultiFrames() {
     byte[] rawId3 =
         buildMultiFramesTag(
             new FrameSpec(

library/core/src/test/java/com/google/android/exoplayer2/metadata/scte35/SpliceInfoDecoderTest.java

@@ -19,7 +19,6 @@ import static com.google.android.exoplayer2.C.TIME_UNSET;
 import static com.google.common.truth.Truth.assertThat;
 
 import com.google.android.exoplayer2.metadata.Metadata;
-import com.google.android.exoplayer2.metadata.MetadataDecoderException;
 import com.google.android.exoplayer2.metadata.MetadataInputBuffer;
 import com.google.android.exoplayer2.util.TimestampAdjuster;
 import java.nio.ByteBuffer;
@@ -45,7 +44,7 @@ public final class SpliceInfoDecoderTest {
   }
 
   @Test
-  public void testWrappedAroundTimeSignalCommand() throws MetadataDecoderException {
+  public void testWrappedAroundTimeSignalCommand() {
     byte[] rawTimeSignalSection = new byte[] {
         0, // table_id.
         (byte) 0x80, // section_syntax_indicator, private_indicator, reserved, section_length(4).
@@ -72,7 +71,7 @@ public final class SpliceInfoDecoderTest {
   }
 
   @Test
-  public void test2SpliceInsertCommands() throws MetadataDecoderException {
+  public void test2SpliceInsertCommands() {
     byte[] rawSpliceInsertCommand1 = new byte[] {
         0, // table_id.
         (byte) 0x80, // section_syntax_indicator, private_indicator, reserved, section_length(4).
@@ -165,8 +164,7 @@ public final class SpliceInfoDecoderTest {
     assertThat(command.availsExpected).isEqualTo(2);
   }
 
-  private Metadata feedInputBuffer(byte[] data, long timeUs, long subsampleOffset)
+  private Metadata feedInputBuffer(byte[] data, long timeUs, long subsampleOffset) {
-      throws MetadataDecoderException{
     inputBuffer.clear();
     inputBuffer.data = ByteBuffer.allocate(data.length).put(data);
     inputBuffer.timeUs = timeUs;