Add JSON asset list parser

PiperOrigin-RevId: 697966021

libraries/exoplayer_hls/src/main/java/androidx/media3/exoplayer/hls/AssetListParser.java

@@ -0,0 +1,208 @@
+/*
+ * Copyright 2024 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 androidx.media3.exoplayer.hls;
+
+import android.net.Uri;
+import android.util.JsonReader;
+import android.util.JsonToken;
+import androidx.annotation.Nullable;
+import androidx.media3.common.C;
+import androidx.media3.exoplayer.upstream.ParsingLoadable;
+import com.google.common.collect.ImmutableList;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.Objects;
+
+/** Parses a X-ASSET-LIST JSON object. */
+/* package */ final class AssetListParser
+    implements ParsingLoadable.Parser<AssetListParser.AssetList> {
+
+  /** Holds assets. */
+  public static final class AssetList {
+
+    private static final AssetList EMPTY = new AssetList(ImmutableList.of(), ImmutableList.of());
+
+    /** The list of assets. */
+    public final ImmutableList<Asset> assets;
+
+    /** The list of string attributes of the asset list JSON object. */
+    public final ImmutableList<StringAttribute> stringAttributes;
+
+    /** Creates an instance. */
+    public AssetList(ImmutableList<Asset> assets, ImmutableList<StringAttribute> stringAttributes) {
+      this.assets = assets;
+      this.stringAttributes = stringAttributes;
+    }
+
+    @Override
+    public boolean equals(@Nullable Object o) {
+      if (this == o) {
+        return true;
+      }
+      if (!(o instanceof AssetList)) {
+        return false;
+      }
+      AssetList assetList = (AssetList) o;
+      return Objects.equals(assets, assetList.assets)
+          && Objects.equals(stringAttributes, assetList.stringAttributes);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(assets, stringAttributes);
+    }
+  }
+
+  /**
+   * An asset with a URI and a duration.
+   *
+   * <p>See RFC 8216bis, appendix D.2, X-ASSET-LIST.
+   */
+  public static final class Asset {
+
+    /** A uri to an HLS source. */
+    public final Uri uri;
+
+    /** The duration, in microseconds. */
+    public final long durationUs;
+
+    /** Creates an instance. */
+    public Asset(Uri uri, long durationUs) {
+      this.uri = uri;
+      this.durationUs = durationUs;
+    }
+
+    @Override
+    public boolean equals(@Nullable Object o) {
+      if (this == o) {
+        return true;
+      }
+      if (!(o instanceof Asset)) {
+        return false;
+      }
+      Asset asset = (Asset) o;
+      return durationUs == asset.durationUs && Objects.equals(uri, asset.uri);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(uri, durationUs);
+    }
+  }
+
+  /** A string attribute with its name and value. */
+  public static final class StringAttribute {
+
+    /** The name of the attribute. */
+    public final String name;
+
+    /** The value of the attribute. */
+    public final String value;
+
+    /** Creates an instance. */
+    public StringAttribute(String name, String value) {
+      this.name = name;
+      this.value = value;
+    }
+
+    @Override
+    public boolean equals(@Nullable Object o) {
+      if (this == o) {
+        return true;
+      }
+      if (!(o instanceof StringAttribute)) {
+        return false;
+      }
+      StringAttribute that = (StringAttribute) o;
+      return Objects.equals(name, that.name) && Objects.equals(value, that.value);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(name, value);
+    }
+  }
+
+  /** The asset name of the assets array in a X-ASSET-LIST JSON object. */
+  private static final String ASSET_LIST_JSON_NAME_ASSET_ARRAY = "ASSETS";
+
+  /** The asset URI name in a X-ASSET-LIST JSON object. */
+  private static final String ASSET_LIST_JSON_NAME_URI = "URI";
+
+  /** The asset duration name in a X-ASSET-LIST JSON object. */
+  private static final String ASSET_LIST_JSON_NAME_DURATION = "DURATION";
+
+  @Override
+  public AssetList parse(Uri uri, InputStream inputStream) throws IOException {
+    try (JsonReader reader = new JsonReader(new InputStreamReader(inputStream))) {
+      if (reader.peek() != JsonToken.BEGIN_OBJECT) {
+        return AssetList.EMPTY;
+      }
+      ImmutableList.Builder<Asset> assets = new ImmutableList.Builder<>();
+      ImmutableList.Builder<StringAttribute> stringAttributes = new ImmutableList.Builder<>();
+      reader.beginObject();
+      while (reader.hasNext()) {
+        JsonToken token = reader.peek();
+        if (token.equals(JsonToken.NAME)) {
+          String name = reader.nextName();
+          if (name.equals(ASSET_LIST_JSON_NAME_ASSET_ARRAY)
+              && reader.peek() == JsonToken.BEGIN_ARRAY) {
+            parseAssetArray(reader, assets);
+          } else if (reader.peek() == JsonToken.STRING) {
+            stringAttributes.add(new StringAttribute(name, reader.nextString()));
+          } else {
+            reader.skipValue();
+          }
+        }
+      }
+      return new AssetList(assets.build(), stringAttributes.build());
+    }
+  }
+
+  private static void parseAssetArray(JsonReader reader, ImmutableList.Builder<Asset> assets)
+      throws IOException {
+    reader.beginArray();
+    while (reader.hasNext()) {
+      if (reader.peek() == JsonToken.BEGIN_OBJECT) {
+        parseAssetObject(reader, assets);
+      }
+    }
+    reader.endArray();
+  }
+
+  private static void parseAssetObject(JsonReader reader, ImmutableList.Builder<Asset> assets)
+      throws IOException {
+    reader.beginObject();
+    String uri = null;
+    long duration = C.TIME_UNSET;
+    String name;
+    while (reader.hasNext()) {
+      name = reader.nextName();
+      if (name.equals(ASSET_LIST_JSON_NAME_URI) && reader.peek() == JsonToken.STRING) {
+        uri = reader.nextString();
+      } else if (name.equals(ASSET_LIST_JSON_NAME_DURATION) && reader.peek() == JsonToken.NUMBER) {
+        duration = (long) (reader.nextDouble() * C.MICROS_PER_SECOND);
+      } else {
+        reader.skipValue();
+      }
+    }
+    if (uri != null && duration != C.TIME_UNSET) {
+      assets.add(new Asset(Uri.parse(uri), duration));
+    }
+    reader.endObject();
+  }
+}

libraries/exoplayer_hls/src/test/java/androidx/media3/exoplayer/hls/AssetListParserTest.java

@@ -0,0 +1,119 @@
+/*
+ * Copyright 2024 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 androidx.media3.exoplayer.hls;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.assertThrows;
+
+import android.net.Uri;
+import androidx.media3.common.C;
+import androidx.media3.datasource.ByteArrayDataSource;
+import androidx.media3.exoplayer.hls.AssetListParser.Asset;
+import androidx.media3.exoplayer.upstream.ParsingLoadable;
+import androidx.media3.test.utils.TestUtil;
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import java.io.EOFException;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+public class AssetListParserTest {
+
+  @Test
+  public void load() throws IOException {
+    byte[] assetListBytes =
+        ("{\"ASSETS\": [ "
+                + "{\"URI\": \"http://1\", \"DURATION\":1.23},"
+                + "{\"URI\": \"http://2\", \"DURATION\":2.34}"
+                + "] }")
+            .getBytes(Charset.defaultCharset());
+    ParsingLoadable<AssetListParser.AssetList> parsingLoadable =
+        new ParsingLoadable<>(
+            new ByteArrayDataSource(assetListBytes),
+            Uri.EMPTY,
+            C.DATA_TYPE_AD,
+            new AssetListParser());
+
+    parsingLoadable.load();
+
+    assertThat(parsingLoadable.getResult().assets)
+        .containsExactly(
+            new Asset(Uri.parse("http://1"), /* durationUs= */ 1_230_000L),
+            new Asset(Uri.parse("http://2"), /* durationUs= */ 2_340_000L))
+        .inOrder();
+  }
+
+  @Test
+  public void load_fileWithDisturbingJsonJunk_parsesCorrectly() throws IOException {
+    byte[] assetListBytes =
+        TestUtil.getByteArray(
+            ApplicationProvider.getApplicationContext(),
+            "media/hls/interstitials/x_asset_list_mixed_elements.json");
+    ParsingLoadable<AssetListParser.AssetList> parsingLoadable =
+        new ParsingLoadable<>(
+            new ByteArrayDataSource(assetListBytes),
+            Uri.EMPTY,
+            C.DATA_TYPE_AD,
+            new AssetListParser());
+
+    parsingLoadable.load();
+
+    assertThat(parsingLoadable.getResult().assets)
+        .containsExactly(
+            new Asset(Uri.parse("http://1"), 12_123_000L),
+            new Asset(Uri.parse("http://2"), 22_123_000L),
+            new Asset(Uri.parse("http://3"), 32_122_999L),
+            new Asset(Uri.parse("http://4"), 42_123_000L))
+        .inOrder();
+    assertThat(parsingLoadable.getResult().stringAttributes)
+        .containsExactly(
+            new AssetListParser.StringAttribute("foo", "foo"),
+            new AssetListParser.StringAttribute("fooBar", "fooBar"),
+            new AssetListParser.StringAttribute("ASSETS", "stringValue"))
+        .inOrder();
+  }
+
+  @Test
+  public void load_withJsonArrayAsRoot_emptyResult() throws IOException {
+    byte[] assetListBytes = "[]".getBytes(Charset.defaultCharset());
+    ParsingLoadable<AssetListParser.AssetList> parsingLoadable =
+        new ParsingLoadable<>(
+            new ByteArrayDataSource(assetListBytes),
+            Uri.EMPTY,
+            C.DATA_TYPE_AD,
+            new AssetListParser());
+
+    parsingLoadable.load();
+
+    assertThat(parsingLoadable.getResult().assets).isEmpty();
+    assertThat(parsingLoadable.getResult().stringAttributes).isEmpty();
+  }
+
+  @Test
+  public void load_emptyInputStream_throwsEOFException() throws IOException {
+    ParsingLoadable<AssetListParser.AssetList> parsingLoadable =
+        new ParsingLoadable<>(
+            new ByteArrayDataSource(" ".getBytes(Charset.defaultCharset())),
+            Uri.EMPTY,
+            C.DATA_TYPE_AD,
+            new AssetListParser());
+
+    assertThrows(EOFException.class, parsingLoadable::load);
+  }
+}

libraries/test_data/src/test/assets/media/hls/interstitials/x_asset_list_mixed_elements.json

@@ -0,0 +1,112 @@
+{
+  "bar": [
+    {},
+    {
+      "foo": [
+        {
+          "URI": "http://1",
+          "DURATION": 12.123
+        },
+        {
+          "URI": "http://2",
+          "DURATION": 22.123
+        },
+        {
+          "URI": "http://3",
+          "DURATION": 32.123
+        }
+      ]
+    }
+  ],
+  "foo": "foo",
+  "fooObject": {
+    "attr1": "",
+    "attr2": 2.0
+  },
+  "ASSETS": [
+    {
+      "URI": "http://1",
+      "DURATION": 12.123,
+      "foo": 12,
+      "fooBar": "text",
+      "booleanFoo": true,
+      "fooObject": {
+        "id": 23
+      },
+      "fooEmpty": {},
+      "fooArray": [
+        {
+          "id": "1"
+        },
+        {
+          "id": "2"
+        }
+      ]
+    },
+    {
+      "URI": null,
+      "DURATION": 12.123
+    },
+    {
+      "URI": 1.2,
+      "DURATION": 12.123
+    },
+    {},
+    {
+      "URI": true,
+      "DURATION": 12.123
+    },
+    {
+      "DURATION": 12.123
+    },
+    {
+      "URI": "http://2",
+      "DURATION": 22.123
+    },
+    {
+      "URI": "http://2",
+      "DURATION": null
+    },
+    {
+      "URI": "http://2",
+      "DURATION": "12.0"
+    },
+    {
+      "URI": "http://2",
+      "DURATION": "twelve"
+    },
+    {
+      "URI": "http://2",
+      "DURATION": false
+    },
+    {
+      "URI": "http://2"
+    },
+    {
+      "foo": 12,
+      "fooBar": "text",
+      "fooObject": {
+        "id": 23
+      },
+      "fooEmpty": {},
+      "fooArray": [
+        {
+          "id": "1"
+        }
+      ],
+      "URI": "http://3",
+      "DURATION": 32.123
+    }
+  ],
+  "fooBar": "fooBar",
+  "barFoo": 12.00,
+  "nullFoo": null,
+  "ASSETS": "stringValue",
+  "ASSETS": [
+    {
+      "URI": "http://4",
+      "DURATION": 42.123
+    }
+  ],
+  "booleanFoo": true
+}