Fix content length calculation for gzipped files

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=134011959

extensions/cronet/src/androidTest/java/com/google/android/exoplayer2/ext/cronet/CronetDataSourceTest.java

@@ -109,7 +109,7 @@ public final class CronetDataSourceTest {
   @Mock
   private Predicate<String> mockContentTypePredicate;
   @Mock
-  private TransferListener mockTransferListener;
+  private TransferListener<CronetDataSource> mockTransferListener;
   @Mock
   private Clock mockClock;
   @Mock
@@ -172,8 +172,8 @@ public final class CronetDataSourceTest {
   }
 
   @Test(expected = IllegalStateException.class)
-  public void testOpeningTwiceThrows() throws HttpDataSourceException, IllegalStateException {
-    mockResponesStartSuccess();
+  public void testOpeningTwiceThrows() throws HttpDataSourceException {
+    mockResponseStartSuccess();
 
     assertConnectionState(CronetDataSource.IDLE_CONNECTION);
     dataSourceUnderTest.open(testDataSpec);
@@ -183,7 +183,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testCallbackFromPreviousRequest() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
 
     dataSourceUnderTest.open(testDataSpec);
     dataSourceUnderTest.close();
@@ -217,7 +217,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testRequestStartCalled() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
 
     dataSourceUnderTest.open(testDataSpec);
     verify(mockCronetEngine).createRequest(
@@ -234,7 +234,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testRequestHeadersSet() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
 
     testDataSpec = new DataSpec(Uri.parse(TEST_URL), 1000, 5000, null);
     testResponseHeader.put("Content-Length", Long.toString(5000L));
@@ -252,13 +252,29 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testRequestOpen() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
 
     assertEquals(TEST_CONTENT_LENGTH, dataSourceUnderTest.open(testDataSpec));
     assertConnectionState(CronetDataSource.OPEN_CONNECTION);
     verify(mockTransferListener).onTransferStart(dataSourceUnderTest, testDataSpec);
   }
 
+
+  @Test
+  public void testRequestOpenGzippedCompressedReturnsDataSpecLength()
+      throws HttpDataSourceException {
+    testResponseHeader.put("Content-Encoding", "gzip");
+    testUrlResponseInfo = createUrlResponseInfo(200); // statusCode
+    mockResponseStartSuccess();
+
+    // Data spec's requested length, 5000. Test response's length, 16,000.
+    testDataSpec = new DataSpec(Uri.parse(TEST_URL), 1000, 5000, null);
+
+    assertEquals(5000 /* contentLength */, dataSourceUnderTest.open(testDataSpec));
+    assertConnectionState(CronetDataSource.OPEN_CONNECTION);
+    verify(mockTransferListener).onTransferStart(dataSourceUnderTest, testDataSpec);
+  }
+
   @Test
   public void testRequestOpenFail() {
     mockResponseStartFailure();
@@ -295,7 +311,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testRequestOpenValidatesStatusCode() {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
     testUrlResponseInfo = createUrlResponseInfo(500); // statusCode
 
     try {
@@ -312,7 +328,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testRequestOpenValidatesContentTypePredicate() {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
     when(mockContentTypePredicate.evaluate(anyString())).thenReturn(false);
 
     try {
@@ -329,7 +345,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testRequestOpenValidatesContentLength() {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
 
     // Data spec's requested length, 5000. Test response's length, 16,000.
     testDataSpec = new DataSpec(Uri.parse(TEST_URL), 1000, 5000, null);
@@ -348,7 +364,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testPostRequestOpen() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
 
     dataSourceUnderTest.setRequestProperty("Content-Type", TEST_CONTENT_TYPE);
     assertEquals(TEST_CONTENT_LENGTH, dataSourceUnderTest.open(testPostDataSpec));
@@ -358,7 +374,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testPostRequestOpenValidatesContentType() {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
 
     try {
       dataSourceUnderTest.open(testPostDataSpec);
@@ -370,7 +386,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testPostRequestOpenRejects307Redirects() {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
     mockResponseStartRedirect();
 
     try {
@@ -384,7 +400,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testRequestReadTwice() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
     mockReadSuccess();
 
     dataSourceUnderTest.open(testDataSpec);
@@ -406,7 +422,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testSecondRequestNoContentLength() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
     mockReadSuccess();
 
     byte[] returnedBuffer = new byte[8];
@@ -437,7 +453,23 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testReadWithOffset() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
+    mockReadSuccess();
+
+    dataSourceUnderTest.open(testDataSpec);
+
+    byte[] returnedBuffer = new byte[16];
+    int bytesRead = dataSourceUnderTest.read(returnedBuffer, 8, 8);
+    assertArrayEquals(prefixZeros(buildTestDataArray(0, 8), 16), returnedBuffer);
+    assertEquals(8, bytesRead);
+    verify(mockTransferListener).onBytesTransferred(dataSourceUnderTest, 8);
+  }
+
+  @Test
+  public void testReadWithUnsetLength() throws HttpDataSourceException {
+    testResponseHeader.remove("Content-Length");
+    testUrlResponseInfo = createUrlResponseInfo(200); // statusCode
+    mockResponseStartSuccess();
     mockReadSuccess();
 
     dataSourceUnderTest.open(testDataSpec);
@@ -451,7 +483,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testReadReturnsWhatItCan() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
     mockReadSuccess();
 
     dataSourceUnderTest.open(testDataSpec);
@@ -465,7 +497,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testClosedMeansClosed() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
     mockReadSuccess();
 
     int bytesRead = 0;
@@ -493,7 +525,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testOverread() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
     mockReadSuccess();
 
     // Ask for 16 bytes
@@ -680,7 +712,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testExceptionFromTransferListener() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
 
     // Make mockTransferListener throw an exception in CronetDataSource.close(). Ensure that
     // the subsequent open() call succeeds.
@@ -699,7 +731,7 @@ public final class CronetDataSourceTest {
 
   @Test
   public void testReadFailure() throws HttpDataSourceException {
-    mockResponesStartSuccess();
+    mockResponseStartSuccess();
     mockReadFailure();
 
     dataSourceUnderTest.open(testDataSpec);
@@ -726,7 +758,7 @@ public final class CronetDataSourceTest {
     }).when(mockUrlRequest).getStatus(any(UrlRequest.StatusListener.class));
   }
 
-  private void mockResponesStartSuccess() {
+  private void mockResponseStartSuccess() {
     doAnswer(new Answer<Object>() {
       @Override
       public Object answer(InvocationOnMock invocation) throws Throwable {

extensions/cronet/src/main/java/com/google/android/exoplayer2/ext/cronet/CronetDataSource.java

@@ -300,15 +300,20 @@ public class CronetDataSource extends UrlRequest.Callback implements HttpDataSou
     try {
       validateResponse(info);
       responseInfo = info;
-      // Check content length.
-      contentLength = getContentLength(info.getAllHeaders());
-      // If a specific length is requested and a specific length is returned but the 2 don't match
-      // it's an error.
-      if (currentDataSpec.length != C.LENGTH_UNSET
-          && contentLength != C.LENGTH_UNSET
-          && currentDataSpec.length != contentLength) {
-        throw new OpenException("Content length did not match requested length", currentDataSpec,
-            getCurrentRequestStatus());
+
+      if (isCompressed(info)) {
+        contentLength = currentDataSpec.length;
+      } else {
+        // Check content length.
+        contentLength = getContentLength(info.getAllHeaders());
+        // If a specific length is requested and a specific length is returned but the 2 don't match
+        // it's an error.
+        if (currentDataSpec.length != C.LENGTH_UNSET
+            && contentLength != C.LENGTH_UNSET
+            && currentDataSpec.length != contentLength) {
+          throw new OpenException("Content length did not match requested length", currentDataSpec,
+              getCurrentRequestStatus());
+        }
       }
 
       if (contentLength > 0) {
@@ -326,6 +331,23 @@ public class CronetDataSource extends UrlRequest.Callback implements HttpDataSou
     }
   }
 
+  /**
+   * Returns {@code true} iff the content is compressed.
+   *
+   * <p>If {@code true}, clients cannot use the value of content length from the request headers to
+   * read the data, since Cronet returns the uncompressed data and this content length reflects the
+   * compressed content length.
+   */
+  private boolean isCompressed(UrlResponseInfo info) {
+    for (Map.Entry<String, String> entry : info.getAllHeadersAsList()) {
+      if (entry.getKey().equalsIgnoreCase("Content-Encoding")) {
+        return !entry.getValue().equalsIgnoreCase("identity");
+      }
+    }
+
+    return false;
+  }
+
   private void validateResponse(UrlResponseInfo info) throws HttpDataSourceException {
     // Check for a valid response code.
     int responseCode = info.getHttpStatusCode();