Add flags to DataSpec. Support GZIP option.

Also remove uriIsFullStream. It's not doing anything particularly
useful, so I think it makes sense to remove it from the public API;
it's unlikely anyone is using it.

Issue: #329

library/src/main/java/com/google/android/exoplayer/hls/HlsChunkSource.java

@@ -438,13 +438,14 @@ public class HlsChunkSource {
 
   private MediaPlaylistChunk newMediaPlaylistChunk(int variantIndex) {
     Uri mediaPlaylistUri = Util.getMergedUri(baseUri, enabledVariants[variantIndex].url);
-    DataSpec dataSpec = new DataSpec(mediaPlaylistUri, 0, C.LENGTH_UNBOUNDED, null);
+    DataSpec dataSpec = new DataSpec(mediaPlaylistUri, 0, C.LENGTH_UNBOUNDED, null,
+        DataSpec.FLAG_ALLOW_GZIP);
     return new MediaPlaylistChunk(variantIndex, upstreamDataSource, dataSpec,
         mediaPlaylistUri.toString());
   }
 
   private EncryptionKeyChunk newEncryptionKeyChunk(Uri keyUri, String iv) {
-    DataSpec dataSpec = new DataSpec(keyUri, 0, C.LENGTH_UNBOUNDED, null);
+    DataSpec dataSpec = new DataSpec(keyUri, 0, C.LENGTH_UNBOUNDED, null, DataSpec.FLAG_ALLOW_GZIP);
     return new EncryptionKeyChunk(upstreamDataSource, dataSpec, iv);
   }
 

library/src/main/java/com/google/android/exoplayer/upstream/DataSourceStream.java

@@ -230,7 +230,7 @@ public final class DataSourceStream implements Loadable, NonBlockingInputStream
         long remainingLength = resolvedLength != C.LENGTH_UNBOUNDED
             ? resolvedLength - loadPosition : C.LENGTH_UNBOUNDED;
         loadDataSpec = new DataSpec(dataSpec.uri, dataSpec.position + loadPosition,
-            remainingLength, dataSpec.key);
+            remainingLength, dataSpec.key, dataSpec.flags);
         dataSource.open(loadDataSpec);
       }
 

library/src/main/java/com/google/android/exoplayer/upstream/DataSpec.java

@@ -25,22 +25,32 @@ import android.net.Uri;
  */
 public final class DataSpec {
 
+  /**
+   * Permits an underlying network stack to request that the server use gzip compression.
+   * <p>
+   * Should not typically be set if the data being requested is already compressed (e.g. most audio
+   * and video requests). May be set when requesting other data.
+   * <p>
+   * When a {@link DataSource} is used to request data with this flag set, and if the
+   * {@link DataSource} does make a network request, then the value returned from
+   * {@link DataSource#open(DataSpec)} will typically be {@link C#LENGTH_UNBOUNDED}. The data read
+   * from {@link DataSource#read(byte[], int, int)} will be the decompressed data.
+   */
+  public static final int FLAG_ALLOW_GZIP = 1;
+
   /**
    * Identifies the source from which data should be read.
    */
   public final Uri uri;
-  /**
-   * True if the data at {@link #uri} is the full stream. False otherwise. An example where this
-   * may be false is if {@link #uri} defines the location of a cached part of the stream.
-   */
-  public final boolean uriIsFullStream;
   /**
    * The absolute position of the data in the full stream.
    */
   public final long absoluteStreamPosition;
   /**
-   * The position of the data when read from {@link #uri}. Always equal to
-   * {@link #absoluteStreamPosition} if {@link #uriIsFullStream}.
+   * The position of the data when read from {@link #uri}.
+   * <p>
+   * Always equal to {@link #absoluteStreamPosition} unless the {@link #uri} defines the location
+   * of a subset of the underyling data.
    */
   public final long position;
   /**
@@ -52,6 +62,10 @@ public final class DataSpec {
    * {@link DataSpec} is not intended to be used in conjunction with a cache.
    */
   public final String key;
+  /**
+   * Request flags. Currently {@link #FLAG_ALLOW_GZIP} is the only supported flag.
+   */
+  public final int flags;
 
   /**
    * Construct a {@link DataSpec} for the given uri and with {@link #key} set to null.
@@ -59,11 +73,21 @@ public final class DataSpec {
    * @param uri {@link #uri}.
    */
   public DataSpec(Uri uri) {
-    this(uri, 0, C.LENGTH_UNBOUNDED, null);
+    this(uri, 0);
   }
 
   /**
-   * Construct a {@link DataSpec} for which {@link #uriIsFullStream} is true.
+   * Construct a {@link DataSpec} for the given uri and with {@link #key} set to null.
+   *
+   * @param uri {@link #uri}.
+   * @param flags {@link #flags}.
+   */
+  public DataSpec(Uri uri, int flags) {
+    this(uri, 0, C.LENGTH_UNBOUNDED, null, flags);
+  }
+
+  /**
+   * Construct a {@link DataSpec} where {@link #position} equals {@link #absoluteStreamPosition}.
    *
    * @param uri {@link #uri}.
    * @param absoluteStreamPosition {@link #absoluteStreamPosition}, equal to {@link #position}.
@@ -71,50 +95,50 @@ public final class DataSpec {
    * @param key {@link #key}.
    */
   public DataSpec(Uri uri, long absoluteStreamPosition, long length, String key) {
-    this(uri, absoluteStreamPosition, length, key, absoluteStreamPosition, true);
+    this(uri, absoluteStreamPosition, absoluteStreamPosition, length, key, 0);
   }
 
   /**
-   * Construct a {@link DataSpec} for which {@link #uriIsFullStream} is false.
+   * Construct a {@link DataSpec} where {@link #position} equals {@link #absoluteStreamPosition}.
    *
    * @param uri {@link #uri}.
-   * @param absoluteStreamPosition {@link #absoluteStreamPosition}.
+   * @param absoluteStreamPosition {@link #absoluteStreamPosition}, equal to {@link #position}.
    * @param length {@link #length}.
    * @param key {@link #key}.
-   * @param position {@link #position}.
+   * @param flags {@link #flags}.
    */
-  public DataSpec(Uri uri, long absoluteStreamPosition, long length, String key, long position) {
-    this(uri, absoluteStreamPosition, length, key, position, false);
+  public DataSpec(Uri uri, long absoluteStreamPosition, long length, String key, int flags) {
+    this(uri, absoluteStreamPosition, absoluteStreamPosition, length, key, flags);
   }
 
   /**
-   * Construct a {@link DataSpec}.
+   * Construct a {@link DataSpec} where {@link #position} may differ from
+   * {@link #absoluteStreamPosition}.
    *
    * @param uri {@link #uri}.
    * @param absoluteStreamPosition {@link #absoluteStreamPosition}.
+   * @param position {@link #position}.
    * @param length {@link #length}.
    * @param key {@link #key}.
-   * @param position {@link #position}.
-   * @param uriIsFullStream {@link #uriIsFullStream}.
+   * @param flags {@link #flags}.
    */
-  public DataSpec(Uri uri, long absoluteStreamPosition, long length, String key, long position,
-      boolean uriIsFullStream) {
+  public DataSpec(Uri uri, long absoluteStreamPosition, long position, long length, String key,
+      int flags) {
     Assertions.checkArgument(absoluteStreamPosition >= 0);
     Assertions.checkArgument(position >= 0);
     Assertions.checkArgument(length > 0 || length == C.LENGTH_UNBOUNDED);
-    Assertions.checkArgument(absoluteStreamPosition == position || !uriIsFullStream);
     this.uri = uri;
-    this.uriIsFullStream = uriIsFullStream;
     this.absoluteStreamPosition = absoluteStreamPosition;
     this.position = position;
     this.length = length;
     this.key = key;
+    this.flags = flags;
   }
 
   @Override
   public String toString() {
-    return "DataSpec[" + uri + ", " + uriIsFullStream + ", " + absoluteStreamPosition + ", " +
-        position + ", " + length + ", " + key + "]";
+    return "DataSpec[" + uri + ", " + ", " + absoluteStreamPosition + ", " +
+        position + ", " + length + ", " + key + ", " + flags + "]";
   }
 
 }

library/src/main/java/com/google/android/exoplayer/upstream/DefaultHttpDataSource.java

@@ -132,19 +132,6 @@ public class DefaultHttpDataSource implements HttpDataSource {
     }
   }
 
-  /*
-   * TODO: If the server uses gzip compression when serving the response, this may end up returning
-   * the size of the compressed response, where-as it should be returning the decompressed size or
-   * -1. See: developer.android.com/reference/java/net/HttpURLConnection.html
-   *
-   * To fix this we should:
-   *
-   * 1. Explicitly require no compression for media requests (since media should be compressed
-   *    already) by setting the Accept-Encoding header to "identity"
-   * 2. In other cases, for example when requesting manifests, we don't want to disable compression.
-   *    For these cases we should ensure that we return -1 here (and avoid performing any sanity
-   *    checks on the content length).
-   */
   @Override
   public long open(DataSpec dataSpec) throws HttpDataSourceException {
     this.dataSpec = dataSpec;
@@ -177,16 +164,23 @@ public class DefaultHttpDataSource implements HttpDataSource {
       throw new InvalidContentTypeException(contentType, dataSpec);
     }
 
-    long contentLength = getContentLength(connection);
-    dataLength = dataSpec.length == C.LENGTH_UNBOUNDED ? contentLength : dataSpec.length;
-
-    if (dataSpec.length != C.LENGTH_UNBOUNDED && contentLength != C.LENGTH_UNBOUNDED
-        && contentLength != dataSpec.length) {
-      // The DataSpec specified a length and we resolved a length from the response headers, but
-      // the two lengths do not match.
-      closeConnection();
-      throw new HttpDataSourceException(
-          new UnexpectedLengthException(dataSpec.length, contentLength), dataSpec);
+    if ((dataSpec.flags & DataSpec.FLAG_ALLOW_GZIP) == 0) {
+      long contentLength = getContentLength(connection);
+      dataLength = dataSpec.length == C.LENGTH_UNBOUNDED ? contentLength : dataSpec.length;
+      if (dataSpec.length != C.LENGTH_UNBOUNDED && contentLength != C.LENGTH_UNBOUNDED
+          && contentLength != dataSpec.length) {
+        // The DataSpec specified a length and we resolved a length from the response headers, but
+        // the two lengths do not match.
+        closeConnection();
+        throw new HttpDataSourceException(
+            new UnexpectedLengthException(dataSpec.length, contentLength), dataSpec);
+      }
+    } else {
+      // Gzip is enabled. If the server opts to use gzip then the content length in the response
+      // will be that of the compressed data, which isn't what we want. Furthermore, there isn't a
+      // reliable way to determine whether the gzip was used or not. Hence we always treat the
+      // length as unknown.
+      dataLength = C.LENGTH_UNBOUNDED;
     }
 
     try {
@@ -301,6 +295,9 @@ public class DefaultHttpDataSource implements HttpDataSource {
     }
     setRangeHeader(connection, dataSpec);
     connection.setRequestProperty("User-Agent", userAgent);
+    if ((dataSpec.flags & DataSpec.FLAG_ALLOW_GZIP) == 0) {
+      connection.setRequestProperty("Accept-Encoding", "identity");
+    }
     connection.connect();
     return connection;
   }

library/src/main/java/com/google/android/exoplayer/upstream/NetworkLoadable.java

@@ -63,7 +63,7 @@ public final class NetworkLoadable<T> implements Loadable {
   public NetworkLoadable(String url, HttpDataSource httpDataSource, Parser<T> parser) {
     this.httpDataSource = httpDataSource;
     this.parser = parser;
-    dataSpec = new DataSpec(Uri.parse(url));
+    dataSpec = new DataSpec(Uri.parse(url), DataSpec.FLAG_ALLOW_GZIP);
   }
 
   /**

library/src/main/java/com/google/android/exoplayer/upstream/TeeDataSource.java

@@ -42,8 +42,8 @@ public final class TeeDataSource implements DataSource {
     long dataLength = upstream.open(dataSpec);
     if (dataSpec.length == C.LENGTH_UNBOUNDED && dataLength != C.LENGTH_UNBOUNDED) {
       // Reconstruct dataSpec in order to provide the resolved length to the sink.
-      dataSpec = new DataSpec(dataSpec.uri, dataSpec.absoluteStreamPosition, dataLength,
-          dataSpec.key, dataSpec.position, dataSpec.uriIsFullStream);
+      dataSpec = new DataSpec(dataSpec.uri, dataSpec.absoluteStreamPosition, dataSpec.position,
+          dataLength, dataSpec.key, dataSpec.flags);
     }
     dataSink.open(dataSpec);
     return dataLength;

library/src/main/java/com/google/android/exoplayer/upstream/cache/CacheDataSource.java

@@ -22,7 +22,6 @@ import com.google.android.exoplayer.upstream.DataSpec;
 import com.google.android.exoplayer.upstream.FileDataSource;
 import com.google.android.exoplayer.upstream.TeeDataSource;
 import com.google.android.exoplayer.upstream.cache.CacheDataSink.CacheDataSinkException;
-import com.google.android.exoplayer.util.Assertions;
 
 import android.net.Uri;
 import android.util.Log;
@@ -64,6 +63,7 @@ public final class CacheDataSource implements DataSource {
 
   private DataSource currentDataSource;
   private Uri uri;
+  private int flags;
   private String key;
   private long readPosition;
   private long bytesRemaining;
@@ -125,9 +125,9 @@ public final class CacheDataSource implements DataSource {
 
   @Override
   public long open(DataSpec dataSpec) throws IOException {
-    Assertions.checkState(dataSpec.uriIsFullStream);
     try {
       uri = dataSpec.uri;
+      flags = dataSpec.flags;
       key = dataSpec.key;
       readPosition = dataSpec.position;
       bytesRemaining = dataSpec.length;
@@ -201,19 +201,19 @@ public final class CacheDataSource implements DataSource {
         // The data is locked in the cache, or we're ignoring the cache. Bypass the cache and read
         // from upstream.
         currentDataSource = upstreamDataSource;
-        dataSpec = new DataSpec(uri, readPosition, bytesRemaining, key);
+        dataSpec = new DataSpec(uri, readPosition, bytesRemaining, key, flags);
       } else if (span.isCached) {
         // Data is cached, read from cache.
         Uri fileUri = Uri.fromFile(span.file);
         long filePosition = readPosition - span.position;
         long length = Math.min(span.length - filePosition, bytesRemaining);
-        dataSpec = new DataSpec(fileUri, readPosition, length, key, filePosition);
+        dataSpec = new DataSpec(fileUri, readPosition, filePosition, length, key, flags);
         currentDataSource = cacheReadDataSource;
       } else {
         // Data is not cached, and data is not locked, read from upstream with cache backing.
         lockedSpan = span;
         long length = span.isOpenEnded() ? bytesRemaining : Math.min(span.length, bytesRemaining);
-        dataSpec = new DataSpec(uri, readPosition, length, key);
+        dataSpec = new DataSpec(uri, readPosition, length, key, flags);
         currentDataSource = cacheWriteDataSource != null ? cacheWriteDataSource
             : upstreamDataSource;
       }