Java 类com.google.android.exoplayer2.upstream.cache.Cache 实例源码

/**
 * Sets a {@link CachingCounters} to contain the number of bytes already downloaded and the
 * length for the content defined by a {@code dataSpec}. {@link CachingCounters#newlyCachedBytes}
 * is reset to 0.
 *
 * @param dataSpec Defines the data to be checked.
 * @param cache    A {@link Cache} which has the data.
 * @param counters The {@link CachingCounters} to update.
 */
public static void getCached(DataSpec dataSpec, Cache cache, CachingCounters counters) {
    String key = getKey(dataSpec);
    long start = dataSpec.absoluteStreamPosition;
    long left = dataSpec.length != C.LENGTH_UNSET ? dataSpec.length : cache.getContentLength(key);
    counters.contentLength = left;
    counters.alreadyCachedBytes = 0;
    counters.newlyCachedBytes = 0;
    while (left != 0) {
        long blockLength = cache.getCachedBytes(key, start,
                left != C.LENGTH_UNSET ? left : Long.MAX_VALUE);
        if (blockLength > 0) {
            counters.alreadyCachedBytes += blockLength;
        } else {
            blockLength = -blockLength;
            if (blockLength == Long.MAX_VALUE) {
                return;
            }
        }
        start += blockLength;
        left -= left == C.LENGTH_UNSET ? 0 : blockLength;
    }
}

private void configureExoMedia() {
    // Registers the media sources to use the OkHttp client instead of the standard Apache one
    // Note: the OkHttpDataSourceFactory can be found in the ExoPlayer extension library `extension-okhttp`
    ExoMedia.setDataSourceFactoryProvider(new ExoMedia.DataSourceFactoryProvider() {
        @NonNull
        @Override
        public DataSource.Factory provide(@NonNull String userAgent, @Nullable TransferListener<? super DataSource> listener) {
            // Updates the network data source to use the OKHttp implementation
            DataSource.Factory upstreamFactory = new OkHttpDataSourceFactory(new OkHttpClient(), userAgent, listener);

            // Adds a cache around the upstreamFactory
            Cache cache = new SimpleCache(getCacheDir(), new LeastRecentlyUsedCacheEvictor(50 * 1024 * 1024));
            return new CacheDataSourceFactory(cache, upstreamFactory, CacheDataSource.FLAG_IGNORE_CACHE_ON_ERROR);
        }
    });
}

/** Asserts that the cache contains the given data for {@code uriString}. */
public static void assertDataCached(Cache cache, Uri uri, byte[] expected) throws IOException {
  CacheDataSource dataSource = new CacheDataSource(cache, DummyDataSource.INSTANCE, 0);
  ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
  DataSourceInputStream inputStream = new DataSourceInputStream(dataSource,
      new DataSpec(uri, DataSpec.FLAG_ALLOW_CACHING_UNKNOWN_LENGTH));
  try {
    inputStream.open();
    byte[] buffer = new byte[1024];
    int bytesRead;
    while ((bytesRead = inputStream.read(buffer)) != -1) {
      outputStream.write(buffer, 0, bytesRead);
    }
  } catch (IOException e) {
    // Ignore
  } finally {
    inputStream.close();
  }
  MoreAsserts.assertEquals("Cached data doesn't match expected for '" + uri + "',",
      expected, outputStream.toByteArray());
}

/**
 * 删除所有的数据  {@code cache} pointed by the {@code key}.
 *
 * @param cache cache  cache
 * @param key   key    缓存文件 key
 */
public static void remove(Cache cache, String key) {
    NavigableSet<CacheSpan> cachedSpans = cache.getCachedSpans(key);
    if (cachedSpans == null) {
        return;
    }
    for (CacheSpan cachedSpan : cachedSpans) {
        try {
            cache.removeSpan(cachedSpan);
        } catch (Cache.CacheException e) {
            // do nothing
        }
    }
}

@Override
public void onCreate() {
    super.onCreate();

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        NotificationChannel notificationChannel = new NotificationChannel(NOTIFICATION_DEFAULT_CHANNEL_ID, getString(R.string.notification_channel_name), NotificationManagerCompat.IMPORTANCE_DEFAULT);
        NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        notificationManager.createNotificationChannel(notificationChannel);

        AudioAttributes audioAttributes = new AudioAttributes.Builder()
                .setUsage(AudioAttributes.USAGE_MEDIA)
                .setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
                .build();
        audioFocusRequest = new AudioFocusRequest.Builder(AudioManager.AUDIOFOCUS_GAIN)
                .setOnAudioFocusChangeListener(audioFocusChangeListener)
                .setAcceptsDelayedFocusGain(false)
                .setWillPauseWhenDucked(true)
                .setAudioAttributes(audioAttributes)
                .build();
    }

    audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);

    mediaSession = new MediaSessionCompat(this, "PlayerService");
    mediaSession.setFlags(MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS | MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS);
    mediaSession.setCallback(mediaSessionCallback);

    Context appContext = getApplicationContext();

    Intent activityIntent = new Intent(appContext, MainActivity.class);
    mediaSession.setSessionActivity(PendingIntent.getActivity(appContext, 0, activityIntent, 0));

    Intent mediaButtonIntent = new Intent(Intent.ACTION_MEDIA_BUTTON, null, appContext, MediaButtonReceiver.class);
    mediaSession.setMediaButtonReceiver(PendingIntent.getBroadcast(appContext, 0, mediaButtonIntent, 0));

    exoPlayer = ExoPlayerFactory.newSimpleInstance(new DefaultRenderersFactory(this), new DefaultTrackSelector(), new DefaultLoadControl());
    exoPlayer.addListener(exoPlayerListener);
    DataSource.Factory httpDataSourceFactory = new OkHttpDataSourceFactory(new OkHttpClient(), Util.getUserAgent(this, getString(R.string.app_name)), null);
    Cache cache = new SimpleCache(new File(this.getCacheDir().getAbsolutePath() + "/exoplayer"), new LeastRecentlyUsedCacheEvictor(1024 * 1024 * 100)); // 100 Mb max
    this.dataSourceFactory = new CacheDataSourceFactory(cache, httpDataSourceFactory, CacheDataSource.FLAG_BLOCK_ON_CACHE | CacheDataSource.FLAG_IGNORE_CACHE_ON_ERROR);
    this.extractorsFactory = new DefaultExtractorsFactory();
}

/** Asserts that the cache content is equal to the data in the {@code fakeDataSet}. */
public static void assertCachedData(Cache cache, FakeDataSet fakeDataSet) throws IOException {
  ArrayList<FakeData> allData = fakeDataSet.getAllData();
  Uri[] uris = new Uri[allData.size()];
  for (int i = 0; i < allData.size(); i++) {
    uris[i] = allData.get(i).uri;
  }
  assertCachedData(cache, fakeDataSet, uris);
}

/**
 * Asserts that the cache content is equal to the given subset of data in the {@code fakeDataSet}.
 */
public static void assertCachedData(Cache cache, FakeDataSet fakeDataSet, String... uriStrings)
    throws IOException {
  Uri[] uris = new Uri[uriStrings.length];
  for (int i = 0; i < uriStrings.length; i++) {
    uris[i] = Uri.parse(uriStrings[i]);
  }
  assertCachedData(cache, fakeDataSet, uris);
}

/**
 * Asserts that the cache content is equal to the given subset of data in the {@code fakeDataSet}.
 */
public static void assertCachedData(Cache cache, FakeDataSet fakeDataSet, Uri... uris)
    throws IOException {
  int totalLength = 0;
  for (Uri uri : uris) {
    byte[] data = fakeDataSet.getData(uri).getData();
    assertDataCached(cache, uri, data);
    totalLength += data.length;
  }
  assertEquals(totalLength, cache.getCacheSpace());
}

/** Asserts that the cache contains the given subset of data in the {@code fakeDataSet}. */
public static void assertDataCached(Cache cache, FakeDataSet fakeDataSet, Uri... uris)
    throws IOException {
  for (Uri uri : uris) {
    assertDataCached(cache, uri, fakeDataSet.getData(uri).getData());
  }
}

/** Asserts that there is no cache content for the given {@code uriStrings}. */
public static void assertDataNotCached(Cache cache, String... uriStrings) {
  for (String uriString : uriStrings) {
    Assert.assertNull("There is cached data for '" + uriString + "',",
        cache.getCachedSpans(CacheUtil.generateKey(Uri.parse(uriString))));
  }
}

/**
 * @param cache Cache instance to be used to store downloaded data.
 * @param upstreamDataSourceFactory A {@link Factory} for downloading data.
 * @param cacheReadDataSourceFactory A {@link Factory} for reading data from the cache.
 *     If null, null is passed to {@link Downloader} constructor.
 * @param cacheWriteDataSinkFactory A {@link DataSink.Factory} for writing data to the cache. If
 *     null, null is passed to {@link Downloader} constructor.
 * @param priorityTaskManager If one is given then the download priority is set lower than
 *     loading. If null, null is passed to {@link Downloader} constructor.
 */
public DownloaderConstructorHelper(Cache cache, Factory upstreamDataSourceFactory,
    @Nullable Factory cacheReadDataSourceFactory,
    @Nullable DataSink.Factory cacheWriteDataSinkFactory,
    @Nullable PriorityTaskManager priorityTaskManager) {
  Assertions.checkNotNull(upstreamDataSourceFactory);
  this.cache = cache;
  this.upstreamDataSourceFactory = upstreamDataSourceFactory;
  this.cacheReadDataSourceFactory = cacheReadDataSourceFactory;
  this.cacheWriteDataSinkFactory = cacheWriteDataSinkFactory;
  this.priorityTaskManager = priorityTaskManager;
}

/** Asserts that the cache is empty. */
public static void assertCacheEmpty(Cache cache) {
  assertEquals(0, cache.getCacheSpace());
}

/** Returns the {@link Cache} instance. */
public Cache getCache() {
  return cache;
}

/**
 * Sets cache.
 *
 * @param cache 缓存文件实例
 * @return Builder cache
 */
public Builder setCache(@NonNull Cache cache) {
    this.simpleCache = cache;
    return this;
}

/**
 * @param cache Cache instance to be used to store downloaded data.
 * @param upstreamDataSourceFactory A {@link Factory} for downloading data.
 */
public DownloaderConstructorHelper(Cache cache, Factory upstreamDataSourceFactory) {
  this(cache, upstreamDataSourceFactory, null, null, null);
}