Add ISO-8859-1 awareness to IcyDecoder

Also change IcyInfo.rawMetatadata from String to byte[]

ICY doesn't specify the character encoding, and there are streams
not using UTF-8 (issue:#6753). It seems the default of at least one
server is ISO-8859-1 so let's support that as a fallback:
https://github.com/savonet/liquidsoap/issues/411#issuecomment-288759200

Also update IcyDecoder to skip strings it doesn't recognise at all
instead of decoding invalid characters.

The feed from issue:#6753 now decodes accents correctly:
EventLogger:   ICY: title="D Pai - Le temps de la rentrée", url="null"
PiperOrigin-RevId: 285388522

RELEASENOTES.md

@@ -26,6 +26,10 @@
   (e.g. subtitles).
 * Add `Player.getCurrentLiveOffset` to conveniently return the live offset.
 * Propagate HTTP request headers through `CacheDataSource`.
+* Update `IcyDecoder` to try ISO-8859-1 decoding if UTF-8 decoding fails.
+  Also change `IcyInfo.rawMetadata` from `String` to `byte[]` to allow
+  developers to handle data that's neither UTF-8 nor ISO-8859-1
+  ([#6753](https://github.com/google/ExoPlayer/issues/6753)).
 
 ### 2.11.0 (2019-12-11) ###
 

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

@@ -95,14 +95,16 @@ public final class C {
    * The name of the ASCII charset.
    */
   public static final String ASCII_NAME = "US-ASCII";
+
   /**
    * The name of the UTF-8 charset.
    */
   public static final String UTF8_NAME = "UTF-8";
 
-  /**
+  /** The name of the ISO-8859-1 charset. */
-   * The name of the UTF-16 charset.
+  public static final String ISO88591_NAME = "ISO-8859-1";
-   */
+
+  /** The name of the UTF-16 charset. */
   public static final String UTF16_NAME = "UTF-16";
 
   /** The name of the UTF-16 little-endian charset. */

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

@@ -16,13 +16,16 @@
 package com.google.android.exoplayer2.metadata.icy;
 
 import androidx.annotation.Nullable;
-import androidx.annotation.VisibleForTesting;
+import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.MetadataDecoder;
 import com.google.android.exoplayer2.metadata.MetadataInputBuffer;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Util;
 import java.nio.ByteBuffer;
+import java.nio.charset.CharacterCodingException;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -33,24 +36,33 @@ public final class IcyDecoder implements MetadataDecoder {
   private static final String STREAM_KEY_NAME = "streamtitle";
   private static final String STREAM_KEY_URL = "streamurl";
 
+  private final CharsetDecoder utf8Decoder;
+  private final CharsetDecoder iso88591Decoder;
+
+  public IcyDecoder() {
+    utf8Decoder = Charset.forName(C.UTF8_NAME).newDecoder();
+    iso88591Decoder = Charset.forName(C.ISO88591_NAME).newDecoder();
+  }
+
   @Override
   @SuppressWarnings("ByteBufferBackingArray")
   public Metadata decode(MetadataInputBuffer inputBuffer) {
     ByteBuffer buffer = Assertions.checkNotNull(inputBuffer.data);
-    byte[] data = buffer.array();
+    @Nullable String icyString = decodeToString(buffer);
-    int length = buffer.limit();
+    byte[] icyBytes = new byte[buffer.limit()];
-    return decode(Util.fromUtf8Bytes(data, 0, length));
+    buffer.get(icyBytes);
-  }
+
+    if (icyString == null) {
+      return new Metadata(new IcyInfo(icyBytes, /* title= */ null, /* url= */ null));
+    }
 
-  @VisibleForTesting
-  /* package */ Metadata decode(String metadata) {
     @Nullable String name = null;
     @Nullable String url = null;
     int index = 0;
-    Matcher matcher = METADATA_ELEMENT.matcher(metadata);
+    Matcher matcher = METADATA_ELEMENT.matcher(icyString);
     while (matcher.find(index)) {
-      String key = Util.toLowerInvariant(matcher.group(1));
+      @Nullable String key = Util.toLowerInvariant(matcher.group(1));
-      String value = matcher.group(2);
+      @Nullable String value = matcher.group(2);
       switch (key) {
         case STREAM_KEY_NAME:
           name = value;
@@ -61,6 +73,29 @@ public final class IcyDecoder implements MetadataDecoder {
       }
       index = matcher.end();
     }
-    return new Metadata(new IcyInfo(metadata, name, url));
+    return new Metadata(new IcyInfo(icyBytes, name, url));
+  }
+
+  // The ICY spec doesn't specify a character encoding, and there's no way to communicate one
+  // either. So try decoding UTF-8 first, then fall back to ISO-8859-1.
+  // https://github.com/google/ExoPlayer/issues/6753
+  @Nullable
+  private String decodeToString(ByteBuffer data) {
+    try {
+      return utf8Decoder.decode(data).toString();
+    } catch (CharacterCodingException e) {
+      // Fall through to try ISO-8859-1 decoding.
+    } finally {
+      utf8Decoder.reset();
+      data.rewind();
+    }
+    try {
+      return iso88591Decoder.decode(data).toString();
+    } catch (CharacterCodingException e) {
+      return null;
+    } finally {
+      iso88591Decoder.reset();
+      data.rewind();
+    }
   }
 }

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

@@ -20,34 +20,34 @@ import android.os.Parcelable;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.util.Assertions;
-import com.google.android.exoplayer2.util.Util;
+import java.util.Arrays;
 
 /** ICY in-stream information. */
 public final class IcyInfo implements Metadata.Entry {
 
-  /** The complete metadata string used to construct this IcyInfo. */
+  /** The complete metadata bytes used to construct this IcyInfo. */
-  public final String rawMetadata;
+  public final byte[] rawMetadata;
-  /** The stream title if present, or {@code null}. */
+  /** The stream title if present and decodable, or {@code null}. */
   @Nullable public final String title;
-  /** The stream URL if present, or {@code null}. */
+  /** The stream URL if present and decodable, or {@code null}. */
   @Nullable public final String url;
 
   /**
-   * Construct a new IcyInfo from the source metadata string, and optionally a StreamTitle and
+   * Construct a new IcyInfo from the source metadata, and optionally a StreamTitle and StreamUrl
-   * StreamUrl that have been extracted.
+   * that have been extracted.
    *
    * @param rawMetadata See {@link #rawMetadata}.
    * @param title See {@link #title}.
    * @param url See {@link #url}.
    */
-  public IcyInfo(String rawMetadata, @Nullable String title, @Nullable String url) {
+  public IcyInfo(byte[] rawMetadata, @Nullable String title, @Nullable String url) {
     this.rawMetadata = rawMetadata;
     this.title = title;
     this.url = url;
   }
 
   /* package */ IcyInfo(Parcel in) {
-    rawMetadata = Assertions.checkNotNull(in.readString());
+    rawMetadata = Assertions.checkNotNull(in.createByteArray());
     title = in.readString();
     url = in.readString();
   }
@@ -62,26 +62,26 @@ public final class IcyInfo implements Metadata.Entry {
     }
     IcyInfo other = (IcyInfo) obj;
     // title & url are derived from rawMetadata, so no need to include them in the comparison.
-    return Util.areEqual(rawMetadata, other.rawMetadata);
+    return Arrays.equals(rawMetadata, other.rawMetadata);
   }
 
   @Override
   public int hashCode() {
     // title & url are derived from rawMetadata, so no need to include them in the hash.
-    return rawMetadata.hashCode();
+    return Arrays.hashCode(rawMetadata);
   }
 
   @Override
   public String toString() {
     return String.format(
-        "ICY: title=\"%s\", url=\"%s\", rawMetadata=\"%s\"", title, url, rawMetadata);
+        "ICY: title=\"%s\", url=\"%s\", rawMetadata.length=\"%s\"", title, url, rawMetadata.length);
   }
 
   // Parcelable implementation.
 
   @Override
   public void writeToParcel(Parcel dest, int flags) {
-    dest.writeString(rawMetadata);
+    dest.writeByteArray(rawMetadata);
     dest.writeString(title);
     dest.writeString(url);
   }

library/core/src/test/java/com/google/android/exoplayer2/metadata/icy/IcyDecoderTest.java

@@ -16,9 +16,15 @@
 package com.google.android.exoplayer2.metadata.icy;
 
 import static com.google.common.truth.Truth.assertThat;
+import static java.nio.charset.StandardCharsets.ISO_8859_1;
+import static java.nio.charset.StandardCharsets.UTF_16;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.metadata.Metadata;
+import com.google.android.exoplayer2.metadata.MetadataInputBuffer;
+import com.google.android.exoplayer2.testutil.TestUtil;
+import java.nio.ByteBuffer;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -26,11 +32,13 @@ import org.junit.runner.RunWith;
 @RunWith(AndroidJUnit4.class)
 public final class IcyDecoderTest {
 
+  private final IcyDecoder decoder = new IcyDecoder();
+
   @Test
   public void decode() {
-    IcyDecoder decoder = new IcyDecoder();
+    byte[] icyContent = "StreamTitle='test title';StreamURL='test_url';".getBytes(UTF_8);
-    String icyContent = "StreamTitle='test title';StreamURL='test_url';";
+
-    Metadata metadata = decoder.decode(icyContent);
+    Metadata metadata = decoder.decode(createMetadataInputBuffer(icyContent));
 
     assertThat(metadata.length()).isEqualTo(1);
     IcyInfo streamInfo = (IcyInfo) metadata.get(0);
@@ -39,11 +47,29 @@ public final class IcyDecoderTest {
     assertThat(streamInfo.url).isEqualTo("test_url");
   }
 
+  @Test
+  // Check the decoder is reading MetadataInputBuffer.data.limit() correctly.
+  public void decode_respectsLimit() {
+    byte[] icyTitle = "StreamTitle='test title';".getBytes(UTF_8);
+    byte[] icyUrl = "StreamURL='test_url';".getBytes(UTF_8);
+    byte[] paddedRawBytes = TestUtil.joinByteArrays(icyTitle, icyUrl);
+    MetadataInputBuffer metadataBuffer = createMetadataInputBuffer(paddedRawBytes);
+    // Stop before the stream URL.
+    metadataBuffer.data.limit(icyTitle.length);
+    Metadata metadata = decoder.decode(metadataBuffer);
+
+    assertThat(metadata.length()).isEqualTo(1);
+    IcyInfo streamInfo = (IcyInfo) metadata.get(0);
+    assertThat(streamInfo.rawMetadata).isEqualTo(icyTitle);
+    assertThat(streamInfo.title).isEqualTo("test title");
+    assertThat(streamInfo.url).isNull();
+  }
+
   @Test
   public void decode_titleOnly() {
-    IcyDecoder decoder = new IcyDecoder();
+    byte[] icyContent = "StreamTitle='test title';".getBytes(UTF_8);
-    String icyContent = "StreamTitle='test title';";
+
-    Metadata metadata = decoder.decode(icyContent);
+    Metadata metadata = decoder.decode(createMetadataInputBuffer(icyContent));
 
     assertThat(metadata.length()).isEqualTo(1);
     IcyInfo streamInfo = (IcyInfo) metadata.get(0);
@@ -54,10 +80,11 @@ public final class IcyDecoderTest {
 
   @Test
   public void decode_extraTags() {
-    String icyContent =
+    byte[] icyContent =
-        "StreamTitle='test title';StreamURL='test_url';CustomTag|withWeirdSeparator";
+        "StreamTitle='test title';StreamURL='test_url';CustomTag|withWeirdSeparator"
-    IcyDecoder decoder = new IcyDecoder();
+            .getBytes(UTF_8);
-    Metadata metadata = decoder.decode(icyContent);
+
+    Metadata metadata = decoder.decode(createMetadataInputBuffer(icyContent));
 
     assertThat(metadata.length()).isEqualTo(1);
     IcyInfo streamInfo = (IcyInfo) metadata.get(0);
@@ -68,9 +95,9 @@ public final class IcyDecoderTest {
 
   @Test
   public void decode_emptyTitle() {
-    IcyDecoder decoder = new IcyDecoder();
+    byte[] icyContent = "StreamTitle='';StreamURL='test_url';".getBytes(UTF_8);
-    String icyContent = "StreamTitle='';StreamURL='test_url';";
+
-    Metadata metadata = decoder.decode(icyContent);
+    Metadata metadata = decoder.decode(createMetadataInputBuffer(icyContent));
 
     assertThat(metadata.length()).isEqualTo(1);
     IcyInfo streamInfo = (IcyInfo) metadata.get(0);
@@ -81,9 +108,9 @@ public final class IcyDecoderTest {
 
   @Test
   public void decode_semiColonInTitle() {
-    IcyDecoder decoder = new IcyDecoder();
+    byte[] icyContent = "StreamTitle='test; title';StreamURL='test_url';".getBytes(UTF_8);
-    String icyContent = "StreamTitle='test; title';StreamURL='test_url';";
+
-    Metadata metadata = decoder.decode(icyContent);
+    Metadata metadata = decoder.decode(createMetadataInputBuffer(icyContent));
 
     assertThat(metadata.length()).isEqualTo(1);
     IcyInfo streamInfo = (IcyInfo) metadata.get(0);
@@ -94,9 +121,9 @@ public final class IcyDecoderTest {
 
   @Test
   public void decode_quoteInTitle() {
-    IcyDecoder decoder = new IcyDecoder();
+    byte[] icyContent = "StreamTitle='test' title';StreamURL='test_url';".getBytes(UTF_8);
-    String icyContent = "StreamTitle='test' title';StreamURL='test_url';";
+
-    Metadata metadata = decoder.decode(icyContent);
+    Metadata metadata = decoder.decode(createMetadataInputBuffer(icyContent));
 
     assertThat(metadata.length()).isEqualTo(1);
     IcyInfo streamInfo = (IcyInfo) metadata.get(0);
@@ -107,9 +134,9 @@ public final class IcyDecoderTest {
 
   @Test
   public void decode_lineTerminatorInTitle() {
-    IcyDecoder decoder = new IcyDecoder();
+    byte[] icyContent = "StreamTitle='test\r\ntitle';StreamURL='test_url';".getBytes(UTF_8);
-    String icyContent = "StreamTitle='test\r\ntitle';StreamURL='test_url';";
+
-    Metadata metadata = decoder.decode(icyContent);
+    Metadata metadata = decoder.decode(createMetadataInputBuffer(icyContent));
 
     assertThat(metadata.length()).isEqualTo(1);
     IcyInfo streamInfo = (IcyInfo) metadata.get(0);
@@ -119,14 +146,50 @@ public final class IcyDecoderTest {
   }
 
   @Test
-  public void decode_noReconisedHeaders() {
+  public void decode_iso885911() {
-    IcyDecoder decoder = new IcyDecoder();
+    // Create an invalid UTF-8 string by using 'é'.
-    Metadata metadata = decoder.decode("NotIcyData");
+    byte[] icyContent = "StreamTitle='tést';StreamURL='tést_url';".getBytes(ISO_8859_1);
+
+    Metadata metadata = decoder.decode(createMetadataInputBuffer(icyContent));
 
     assertThat(metadata.length()).isEqualTo(1);
     IcyInfo streamInfo = (IcyInfo) metadata.get(0);
-    assertThat(streamInfo.rawMetadata).isEqualTo("NotIcyData");
+    assertThat(streamInfo.rawMetadata).isEqualTo(icyContent);
+    assertThat(streamInfo.title).isEqualTo("tést");
+    assertThat(streamInfo.url).isEqualTo("tést_url");
+  }
+
+  @Test
+  public void decode_unrecognisedEncoding() {
+    // Create an invalid UTF-8 and ISO-88591-1 string by using 'é'.
+    byte[] icyContent = "StreamTitle='tést';StreamURL='tést_url';".getBytes(UTF_16);
+
+    Metadata metadata = decoder.decode(createMetadataInputBuffer(icyContent));
+
+    assertThat(metadata.length()).isEqualTo(1);
+    IcyInfo streamInfo = (IcyInfo) metadata.get(0);
+    assertThat(streamInfo.rawMetadata).isEqualTo(icyContent);
     assertThat(streamInfo.title).isNull();
     assertThat(streamInfo.url).isNull();
   }
+
+  @Test
+  public void decode_noRecognisedHeaders() {
+    byte[] icyContent = "NotIcyData".getBytes(UTF_8);
+
+    Metadata metadata = decoder.decode(createMetadataInputBuffer(icyContent));
+
+    assertThat(metadata.length()).isEqualTo(1);
+    IcyInfo streamInfo = (IcyInfo) metadata.get(0);
+    assertThat(streamInfo.rawMetadata).isEqualTo(icyContent);
+    assertThat(streamInfo.title).isNull();
+    assertThat(streamInfo.url).isNull();
+  }
+
+  private static MetadataInputBuffer createMetadataInputBuffer(byte[] data) {
+    MetadataInputBuffer metadataInputBuffer = new MetadataInputBuffer();
+    metadataInputBuffer.data = ByteBuffer.allocate(data.length).put(data);
+    metadataInputBuffer.data.flip();
+    return metadataInputBuffer;
+  }
 }

library/core/src/test/java/com/google/android/exoplayer2/metadata/icy/IcyInfoTest.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.metadata.icy;
 
 import static com.google.common.truth.Truth.assertThat;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import android.os.Parcel;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
@@ -28,7 +29,8 @@ public final class IcyInfoTest {
 
   @Test
   public void parcelEquals() {
-    IcyInfo streamInfo = new IcyInfo("StreamName='name';StreamUrl='url'", "name", "url");
+    IcyInfo streamInfo =
+        new IcyInfo("StreamName='name';StreamUrl='url'".getBytes(UTF_8), "name", "url");
     // Write to parcel.
     Parcel parcel = Parcel.obtain();
     streamInfo.writeToParcel(parcel, 0);