1 files changed, 580 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/cache/CacheDataSource.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/cache/CacheDataSource.java
new file mode 100644
index 0000000000..19fb8191e4
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/cache/CacheDataSource.java
@@ -0,0 +1,580 @@
+/*
+ * 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 org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.cache;
+
+import android.net.Uri;
+import androidx.annotation.IntDef;
+import androidx.annotation.Nullable;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.DataSink;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.DataSource;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.DataSourceException;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.DataSpec;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.DataSpec.HttpMethod;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.FileDataSource;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.TeeDataSource;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.TransferListener;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.cache.Cache.CacheException;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions;
+import java.io.IOException;
+import java.io.InterruptedIOException;
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * A {@link DataSource} that reads and writes a {@link Cache}. Requests are fulfilled from the cache
+ * when possible. When data is not cached it is requested from an upstream {@link DataSource} and
+ * written into the cache.
+ */
+public final class CacheDataSource implements DataSource {
+
+  /**
+   * Flags controlling the CacheDataSource's behavior. Possible flag values are {@link
+   * #FLAG_BLOCK_ON_CACHE}, {@link #FLAG_IGNORE_CACHE_ON_ERROR} and {@link
+   * #FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS}.
+   */
+  @Documented
+  @Retention(RetentionPolicy.SOURCE)
+  @IntDef(
+      flag = true,
+      value = {
+        FLAG_BLOCK_ON_CACHE,
+        FLAG_IGNORE_CACHE_ON_ERROR,
+        FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS
+      })
+  public @interface Flags {}
+  /**
+   * A flag indicating whether we will block reads if the cache key is locked. If unset then data is
+   * read from upstream if the cache key is locked, regardless of whether the data is cached.
+   */
+  public static final int FLAG_BLOCK_ON_CACHE = 1;
+
+  /**
+   * A flag indicating whether the cache is bypassed following any cache related error. If set
+   * then cache related exceptions may be thrown for one cycle of open, read and close calls.
+   * Subsequent cycles of these calls will then bypass the cache.
+   */
+  public static final int FLAG_IGNORE_CACHE_ON_ERROR = 1 << 1; // 2
+
+  /**
+   * A flag indicating that the cache should be bypassed for requests whose lengths are unset. This
+   * flag is provided for legacy reasons only.
+   */
+  public static final int FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS = 1 << 2; // 4
+
+  /**
+   * Reasons the cache may be ignored. One of {@link #CACHE_IGNORED_REASON_ERROR} or {@link
+   * #CACHE_IGNORED_REASON_UNSET_LENGTH}.
+   */
+  @Documented
+  @Retention(RetentionPolicy.SOURCE)
+  @IntDef({CACHE_IGNORED_REASON_ERROR, CACHE_IGNORED_REASON_UNSET_LENGTH})
+  public @interface CacheIgnoredReason {}
+
+  /** Cache not ignored. */
+  private static final int CACHE_NOT_IGNORED = -1;
+
+  /** Cache ignored due to a cache related error. */
+  public static final int CACHE_IGNORED_REASON_ERROR = 0;
+
+  /** Cache ignored due to a request with an unset length. */
+  public static final int CACHE_IGNORED_REASON_UNSET_LENGTH = 1;
+
+  /**
+   * Listener of {@link CacheDataSource} events.
+   */
+  public interface EventListener {
+
+    /**
+     * Called when bytes have been read from the cache.
+     *
+     * @param cacheSizeBytes Current cache size in bytes.
+     * @param cachedBytesRead Total bytes read from the cache since this method was last called.
+     */
+    void onCachedBytesRead(long cacheSizeBytes, long cachedBytesRead);
+
+    /**
+     * Called when the current request ignores cache.
+     *
+     * @param reason Reason cache is bypassed.
+     */
+    void onCacheIgnored(@CacheIgnoredReason int reason);
+  }
+
+  /** Minimum number of bytes to read before checking cache for availability. */
+  private static final long MIN_READ_BEFORE_CHECKING_CACHE = 100 * 1024;
+
+  private final Cache cache;
+  private final DataSource cacheReadDataSource;
+  @Nullable private final DataSource cacheWriteDataSource;
+  private final DataSource upstreamDataSource;
+  private final CacheKeyFactory cacheKeyFactory;
+  @Nullable private final EventListener eventListener;
+
+  private final boolean blockOnCache;
+  private final boolean ignoreCacheOnError;
+  private final boolean ignoreCacheForUnsetLengthRequests;
+
+  @Nullable private DataSource currentDataSource;
+  private boolean currentDataSpecLengthUnset;
+  @Nullable private Uri uri;
+  @Nullable private Uri actualUri;
+  @HttpMethod private int httpMethod;
+  @Nullable private byte[] httpBody;
+  private Map<String, String> httpRequestHeaders = Collections.emptyMap();
+  @DataSpec.Flags private int flags;
+  @Nullable private String key;
+  private long readPosition;
+  private long bytesRemaining;
+  @Nullable private CacheSpan currentHoleSpan;
+  private boolean seenCacheError;
+  private boolean currentRequestIgnoresCache;
+  private long totalCachedBytesRead;
+  private long checkCachePosition;
+
+  /**
+   * Constructs an instance with default {@link DataSource} and {@link DataSink} instances for
+   * reading and writing the cache.
+   *
+   * @param cache The cache.
+   * @param upstream A {@link DataSource} for reading data not in the cache.
+   */
+  public CacheDataSource(Cache cache, DataSource upstream) {
+    this(cache, upstream, /* flags= */ 0);
+  }
+
+  /**
+   * Constructs an instance with default {@link DataSource} and {@link DataSink} instances for
+   * reading and writing the cache.
+   *
+   * @param cache The cache.
+   * @param upstream A {@link DataSource} for reading data not in the cache.
+   * @param flags A combination of {@link #FLAG_BLOCK_ON_CACHE}, {@link #FLAG_IGNORE_CACHE_ON_ERROR}
+   *     and {@link #FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS}, or 0.
+   */
+  public CacheDataSource(Cache cache, DataSource upstream, @Flags int flags) {
+    this(
+        cache,
+        upstream,
+        new FileDataSource(),
+        new CacheDataSink(cache, CacheDataSink.DEFAULT_FRAGMENT_SIZE),
+        flags,
+        /* eventListener= */ null);
+  }
+
+  /**
+   * Constructs an instance with arbitrary {@link DataSource} and {@link DataSink} instances for
+   * reading and writing the cache. One use of this constructor is to allow data to be transformed
+   * before it is written to disk.
+   *
+   * @param cache The cache.
+   * @param upstream A {@link DataSource} for reading data not in the cache.
+   * @param cacheReadDataSource A {@link DataSource} for reading data from the cache.
+   * @param cacheWriteDataSink A {@link DataSink} for writing data to the cache. If null, cache is
+   *     accessed read-only.
+   * @param flags A combination of {@link #FLAG_BLOCK_ON_CACHE}, {@link #FLAG_IGNORE_CACHE_ON_ERROR}
+   *     and {@link #FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS}, or 0.
+   * @param eventListener An optional {@link EventListener} to receive events.
+   */
+  public CacheDataSource(
+      Cache cache,
+      DataSource upstream,
+      DataSource cacheReadDataSource,
+      @Nullable DataSink cacheWriteDataSink,
+      @Flags int flags,
+      @Nullable EventListener eventListener) {
+    this(
+        cache,
+        upstream,
+        cacheReadDataSource,
+        cacheWriteDataSink,
+        flags,
+        eventListener,
+        /* cacheKeyFactory= */ null);
+  }
+
+  /**
+   * Constructs an instance with arbitrary {@link DataSource} and {@link DataSink} instances for
+   * reading and writing the cache. One use of this constructor is to allow data to be transformed
+   * before it is written to disk.
+   *
+   * @param cache The cache.
+   * @param upstream A {@link DataSource} for reading data not in the cache.
+   * @param cacheReadDataSource A {@link DataSource} for reading data from the cache.
+   * @param cacheWriteDataSink A {@link DataSink} for writing data to the cache. If null, cache is
+   *     accessed read-only.
+   * @param flags A combination of {@link #FLAG_BLOCK_ON_CACHE}, {@link #FLAG_IGNORE_CACHE_ON_ERROR}
+   *     and {@link #FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS}, or 0.
+   * @param eventListener An optional {@link EventListener} to receive events.
+   * @param cacheKeyFactory An optional factory for cache keys.
+   */
+  public CacheDataSource(
+      Cache cache,
+      DataSource upstream,
+      DataSource cacheReadDataSource,
+      @Nullable DataSink cacheWriteDataSink,
+      @Flags int flags,
+      @Nullable EventListener eventListener,
+      @Nullable CacheKeyFactory cacheKeyFactory) {
+    this.cache = cache;
+    this.cacheReadDataSource = cacheReadDataSource;
+    this.cacheKeyFactory =
+        cacheKeyFactory != null ? cacheKeyFactory : CacheUtil.DEFAULT_CACHE_KEY_FACTORY;
+    this.blockOnCache = (flags & FLAG_BLOCK_ON_CACHE) != 0;
+    this.ignoreCacheOnError = (flags & FLAG_IGNORE_CACHE_ON_ERROR) != 0;
+    this.ignoreCacheForUnsetLengthRequests =
+        (flags & FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS) != 0;
+    this.upstreamDataSource = upstream;
+    if (cacheWriteDataSink != null) {
+      this.cacheWriteDataSource = new TeeDataSource(upstream, cacheWriteDataSink);
+    } else {
+      this.cacheWriteDataSource = null;
+    }
+    this.eventListener = eventListener;
+  }
+
+  @Override
+  public void addTransferListener(TransferListener transferListener) {
+    cacheReadDataSource.addTransferListener(transferListener);
+    upstreamDataSource.addTransferListener(transferListener);
+  }
+
+  @Override
+  public long open(DataSpec dataSpec) throws IOException {
+    try {
+      key = cacheKeyFactory.buildCacheKey(dataSpec);
+      uri = dataSpec.uri;
+      actualUri = getRedirectedUriOrDefault(cache, key, /* defaultUri= */ uri);
+      httpMethod = dataSpec.httpMethod;
+      httpBody = dataSpec.httpBody;
+      httpRequestHeaders = dataSpec.httpRequestHeaders;
+      flags = dataSpec.flags;
+      readPosition = dataSpec.position;
+
+      int reason = shouldIgnoreCacheForRequest(dataSpec);
+      currentRequestIgnoresCache = reason != CACHE_NOT_IGNORED;
+      if (currentRequestIgnoresCache) {
+        notifyCacheIgnored(reason);
+      }
+
+      if (dataSpec.length != C.LENGTH_UNSET || currentRequestIgnoresCache) {
+        bytesRemaining = dataSpec.length;
+      } else {
+        bytesRemaining = ContentMetadata.getContentLength(cache.getContentMetadata(key));
+        if (bytesRemaining != C.LENGTH_UNSET) {
+          bytesRemaining -= dataSpec.position;
+          if (bytesRemaining <= 0) {
+            throw new DataSourceException(DataSourceException.POSITION_OUT_OF_RANGE);
+          }
+        }
+      }
+      openNextSource(false);
+      return bytesRemaining;
+    } catch (Throwable e) {
+      handleBeforeThrow(e);
+      throw e;
+    }
+  }
+
+  @Override
+  public int read(byte[] buffer, int offset, int readLength) throws IOException {
+    if (readLength == 0) {
+      return 0;
+    }
+    if (bytesRemaining == 0) {
+      return C.RESULT_END_OF_INPUT;
+    }
+    try {
+      if (readPosition >= checkCachePosition) {
+        openNextSource(true);
+      }
+      int bytesRead = currentDataSource.read(buffer, offset, readLength);
+      if (bytesRead != C.RESULT_END_OF_INPUT) {
+        if (isReadingFromCache()) {
+          totalCachedBytesRead += bytesRead;
+        }
+        readPosition += bytesRead;
+        if (bytesRemaining != C.LENGTH_UNSET) {
+          bytesRemaining -= bytesRead;
+        }
+      } else if (currentDataSpecLengthUnset) {
+        setNoBytesRemainingAndMaybeStoreLength();
+      } else if (bytesRemaining > 0 || bytesRemaining == C.LENGTH_UNSET) {
+        closeCurrentSource();
+        openNextSource(false);
+        return read(buffer, offset, readLength);
+      }
+      return bytesRead;
+    } catch (IOException e) {
+      if (currentDataSpecLengthUnset && CacheUtil.isCausedByPositionOutOfRange(e)) {
+        setNoBytesRemainingAndMaybeStoreLength();
+        return C.RESULT_END_OF_INPUT;
+      }
+      handleBeforeThrow(e);
+      throw e;
+    } catch (Throwable e) {
+      handleBeforeThrow(e);
+      throw e;
+    }
+  }
+
+  @Override
+  @Nullable
+  public Uri getUri() {
+    return actualUri;
+  }
+
+  @Override
+  public Map<String, List<String>> getResponseHeaders() {
+    // TODO: Implement.
+    return isReadingFromUpstream()
+        ? upstreamDataSource.getResponseHeaders()
+        : Collections.emptyMap();
+  }
+
+  @Override
+  public void close() throws IOException {
+    uri = null;
+    actualUri = null;
+    httpMethod = DataSpec.HTTP_METHOD_GET;
+    httpBody = null;
+    httpRequestHeaders = Collections.emptyMap();
+    flags = 0;
+    readPosition = 0;
+    key = null;
+    notifyBytesRead();
+    try {
+      closeCurrentSource();
+    } catch (Throwable e) {
+      handleBeforeThrow(e);
+      throw e;
+    }
+  }
+
+  /**
+   * Opens the next source. If the cache contains data spanning the current read position then
+   * {@link #cacheReadDataSource} is opened to read from it. Else {@link #upstreamDataSource} is
+   * opened to read from the upstream source and write into the cache.
+   *
+   * <p>There must not be a currently open source when this method is called, except in the case
+   * that {@code checkCache} is true. If {@code checkCache} is true then there must be a currently
+   * open source, and it must be {@link #upstreamDataSource}. It will be closed and a new source
+   * opened if it's possible to switch to reading from or writing to the cache. If a switch isn't
+   * possible then the current source is left unchanged.
+   *
+   * @param checkCache If true tries to switch to reading from or writing to cache instead of
+   *     reading from {@link #upstreamDataSource}, which is the currently open source.
+   */
+  private void openNextSource(boolean checkCache) throws IOException {
+    CacheSpan nextSpan;
+    if (currentRequestIgnoresCache) {
+      nextSpan = null;
+    } else if (blockOnCache) {
+      try {
+        nextSpan = cache.startReadWrite(key, readPosition);
+      } catch (InterruptedException e) {
+        Thread.currentThread().interrupt();
+        throw new InterruptedIOException();
+      }
+    } else {
+      nextSpan = cache.startReadWriteNonBlocking(key, readPosition);
+    }
+
+    DataSpec nextDataSpec;
+    DataSource nextDataSource;
+    if (nextSpan == null) {
+      // The data is locked in the cache, or we're ignoring the cache. Bypass the cache and read
+      // from upstream.
+      nextDataSource = upstreamDataSource;
+      nextDataSpec =
+          new DataSpec(
+              uri,
+              httpMethod,
+              httpBody,
+              readPosition,
+              readPosition,
+              bytesRemaining,
+              key,
+              flags,
+              httpRequestHeaders);
+    } else if (nextSpan.isCached) {
+      // Data is cached, read from cache.
+      Uri fileUri = Uri.fromFile(nextSpan.file);
+      long filePosition = readPosition - nextSpan.position;
+      long length = nextSpan.length - filePosition;
+      if (bytesRemaining != C.LENGTH_UNSET) {
+        length = Math.min(length, bytesRemaining);
+      }
+      // Deliberately skip the HTTP-related parameters since we're reading from the cache, not
+      // making an HTTP request.
+      nextDataSpec = new DataSpec(fileUri, readPosition, filePosition, length, key, flags);
+      nextDataSource = cacheReadDataSource;
+    } else {
+      // Data is not cached, and data is not locked, read from upstream with cache backing.
+      long length;
+      if (nextSpan.isOpenEnded()) {
+        length = bytesRemaining;
+      } else {
+        length = nextSpan.length;
+        if (bytesRemaining != C.LENGTH_UNSET) {
+          length = Math.min(length, bytesRemaining);
+        }
+      }
+      nextDataSpec =
+          new DataSpec(
+              uri,
+              httpMethod,
+              httpBody,
+              readPosition,
+              readPosition,
+              length,
+              key,
+              flags,
+              httpRequestHeaders);
+      if (cacheWriteDataSource != null) {
+        nextDataSource = cacheWriteDataSource;
+      } else {
+        nextDataSource = upstreamDataSource;
+        cache.releaseHoleSpan(nextSpan);
+        nextSpan = null;
+      }
+    }
+
+    checkCachePosition =
+        !currentRequestIgnoresCache && nextDataSource == upstreamDataSource
+            ? readPosition + MIN_READ_BEFORE_CHECKING_CACHE
+            : Long.MAX_VALUE;
+    if (checkCache) {
+      Assertions.checkState(isBypassingCache());
+      if (nextDataSource == upstreamDataSource) {
+        // Continue reading from upstream.
+        return;
+      }
+      // We're switching to reading from or writing to the cache.
+      try {
+        closeCurrentSource();
+      } catch (Throwable e) {
+        if (nextSpan.isHoleSpan()) {
+          // Release the hole span before throwing, else we'll hold it forever.
+          cache.releaseHoleSpan(nextSpan);
+        }
+        throw e;
+      }
+    }
+
+    if (nextSpan != null && nextSpan.isHoleSpan()) {
+      currentHoleSpan = nextSpan;
+    }
+    currentDataSource = nextDataSource;
+    currentDataSpecLengthUnset = nextDataSpec.length == C.LENGTH_UNSET;
+    long resolvedLength = nextDataSource.open(nextDataSpec);
+
+    // Update bytesRemaining, actualUri and (if writing to cache) the cache metadata.
+    ContentMetadataMutations mutations = new ContentMetadataMutations();
+    if (currentDataSpecLengthUnset && resolvedLength != C.LENGTH_UNSET) {
+      bytesRemaining = resolvedLength;
+      ContentMetadataMutations.setContentLength(mutations, readPosition + bytesRemaining);
+    }
+    if (isReadingFromUpstream()) {
+      actualUri = currentDataSource.getUri();
+      boolean isRedirected = !uri.equals(actualUri);
+      ContentMetadataMutations.setRedirectedUri(mutations, isRedirected ? actualUri : null);
+    }
+    if (isWritingToCache()) {
+      cache.applyContentMetadataMutations(key, mutations);
+    }
+  }
+
+  private void setNoBytesRemainingAndMaybeStoreLength() throws IOException {
+    bytesRemaining = 0;
+    if (isWritingToCache()) {
+      ContentMetadataMutations mutations = new ContentMetadataMutations();
+      ContentMetadataMutations.setContentLength(mutations, readPosition);
+      cache.applyContentMetadataMutations(key, mutations);
+    }
+  }
+
+  private static Uri getRedirectedUriOrDefault(Cache cache, String key, Uri defaultUri) {
+    Uri redirectedUri = ContentMetadata.getRedirectedUri(cache.getContentMetadata(key));
+    return redirectedUri != null ? redirectedUri : defaultUri;
+  }
+
+  private boolean isReadingFromUpstream() {
+    return !isReadingFromCache();
+  }
+
+  private boolean isBypassingCache() {
+    return currentDataSource == upstreamDataSource;
+  }
+
+  private boolean isReadingFromCache() {
+    return currentDataSource == cacheReadDataSource;
+  }
+
+  private boolean isWritingToCache() {
+    return currentDataSource == cacheWriteDataSource;
+  }
+
+  private void closeCurrentSource() throws IOException {
+    if (currentDataSource == null) {
+      return;
+    }
+    try {
+      currentDataSource.close();
+    } finally {
+      currentDataSource = null;
+      currentDataSpecLengthUnset = false;
+      if (currentHoleSpan != null) {
+        cache.releaseHoleSpan(currentHoleSpan);
+        currentHoleSpan = null;
+      }
+    }
+  }
+
+  private void handleBeforeThrow(Throwable exception) {
+    if (isReadingFromCache() || exception instanceof CacheException) {
+      seenCacheError = true;
+    }
+  }
+
+  private int shouldIgnoreCacheForRequest(DataSpec dataSpec) {
+    if (ignoreCacheOnError && seenCacheError) {
+      return CACHE_IGNORED_REASON_ERROR;
+    } else if (ignoreCacheForUnsetLengthRequests && dataSpec.length == C.LENGTH_UNSET) {
+      return CACHE_IGNORED_REASON_UNSET_LENGTH;
+    } else {
+      return CACHE_NOT_IGNORED;
+    }
+  }
+
+  private void notifyCacheIgnored(@CacheIgnoredReason int reason) {
+    if (eventListener != null) {
+      eventListener.onCacheIgnored(reason);
+    }
+  }
+
+  private void notifyBytesRead() {
+    if (eventListener != null && totalCachedBytesRead > 0) {
+      eventListener.onCachedBytesRead(cache.getCacheSpace(), totalCachedBytesRead);
+      totalCachedBytesRead = 0;
+    }
+  }
+
+}