Expose new non-discarding SampleQueue read/skip methods

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=159555748

library/core/src/androidTest/java/com/google/android/exoplayer2/source/SampleQueueTest.java

@@ -133,6 +133,9 @@ public class SampleQueueTest extends TestCase {
     assertReadFormat(true, TEST_FORMAT_1);
     // Otherwise should read the sample.
     assertSampleRead(1000, true, TEST_DATA, 0, ALLOCATION_SIZE);
+    // Allocation should still be held.
+    assertAllocationCount(1);
+    sampleQueue.discardToRead();
     // The allocation should have been released.
     assertAllocationCount(0);
 
@@ -147,6 +150,9 @@ public class SampleQueueTest extends TestCase {
     assertReadFormat(true, TEST_FORMAT_1);
     // Read the sample.
     assertSampleRead(2000, false, TEST_DATA, 0, ALLOCATION_SIZE - 1);
+    // Allocation should still be held.
+    assertAllocationCount(1);
+    sampleQueue.discardToRead();
     // The last byte written to the sample queue may belong to a sample whose metadata has yet to be
     // written, so an allocation should still be held.
     assertAllocationCount(1);
@@ -158,6 +164,9 @@ public class SampleQueueTest extends TestCase {
     assertReadFormat(true, TEST_FORMAT_1);
     // Read the sample.
     assertSampleRead(3000, false, TEST_DATA, ALLOCATION_SIZE - 1, 1);
+    // Allocation should still be held.
+    assertAllocationCount(1);
+    sampleQueue.discardToRead();
     // The allocation should have been released.
     assertAllocationCount(0);
   }
@@ -168,6 +177,8 @@ public class SampleQueueTest extends TestCase {
         sampleQueue.getLargestQueuedTimestampUs());
     assertAllocationCount(10);
     assertReadTestData();
+    assertAllocationCount(10);
+    sampleQueue.discardToRead();
     assertAllocationCount(0);
   }
 
@@ -177,12 +188,42 @@ public class SampleQueueTest extends TestCase {
     assertAllocationCount(20);
     assertReadTestData(TEST_FORMAT_2);
     assertReadTestData(TEST_FORMAT_2);
+    assertAllocationCount(20);
+    sampleQueue.discardToRead();
+    assertAllocationCount(0);
+  }
+
+  public void testReadMultiWithRewind() {
+    writeTestData();
+    assertReadTestData();
+    assertEquals(8, sampleQueue.getReadIndex());
+    assertAllocationCount(10);
+    // Rewind.
+    sampleQueue.rewind();
+    assertAllocationCount(10);
+    // Read again.
+    assertEquals(0, sampleQueue.getReadIndex());
+    assertReadTestData();
+  }
+
+  public void testRewindAfterDiscard() {
+    writeTestData();
+    assertReadTestData();
+    sampleQueue.discardToRead();
+    assertAllocationCount(0);
+    // Rewind.
+    sampleQueue.rewind();
     assertAllocationCount(0);
+    // Can't read again.
+    assertEquals(8, sampleQueue.getReadIndex());
+    assertReadEndOfStream(false);
   }
 
   public void testSkipAll() {
     writeTestData();
-    sampleQueue.skipAll();
+    sampleQueue.skipAll2();
+    assertAllocationCount(10);
+    sampleQueue.discardToRead();
     assertAllocationCount(0);
     // Despite skipping all samples, we should still read the last format, since this is the
     // expected format for a subsequent sample.
@@ -194,7 +235,9 @@ public class SampleQueueTest extends TestCase {
   public void testSkipAllRetainsUnassignedData() {
     sampleQueue.format(TEST_FORMAT_1);
     sampleQueue.sampleData(new ParsableByteArray(TEST_DATA), ALLOCATION_SIZE);
-    sampleQueue.skipAll();
+    sampleQueue.skipAll2();
+    assertAllocationCount(1);
+    sampleQueue.discardToRead();
     // Skipping shouldn't discard data that may belong to a sample whose metadata has yet to be
     // written.
     assertAllocationCount(1);
@@ -207,12 +250,14 @@ public class SampleQueueTest extends TestCase {
     // Once the metadata has been written, check the sample can be read as expected.
     assertSampleRead(0, true, TEST_DATA, 0, ALLOCATION_SIZE);
     assertNoSamplesToRead(TEST_FORMAT_1);
+    assertAllocationCount(1);
+    sampleQueue.discardToRead();
     assertAllocationCount(0);
   }
 
   public void testSkipToKeyframeBeforeBuffer() {
     writeTestData();
-    boolean result = sampleQueue.skipToKeyframeBefore(TEST_SAMPLE_TIMESTAMPS[0] - 1, false);
+    boolean result = sampleQueue.skipToKeyframeBefore2(TEST_SAMPLE_TIMESTAMPS[0] - 1, false);
     // Should fail and have no effect.
     assertFalse(result);
     assertReadTestData();
@@ -221,7 +266,7 @@ public class SampleQueueTest extends TestCase {
 
   public void testSkipToKeyframeStartOfBuffer() {
     writeTestData();
-    boolean result = sampleQueue.skipToKeyframeBefore(TEST_SAMPLE_TIMESTAMPS[0], false);
+    boolean result = sampleQueue.skipToKeyframeBefore2(TEST_SAMPLE_TIMESTAMPS[0], false);
     // Should succeed but have no effect (we're already at the first frame).
     assertTrue(result);
     assertReadTestData();
@@ -230,7 +275,7 @@ public class SampleQueueTest extends TestCase {
 
   public void testSkipToKeyframeEndOfBuffer() {
     writeTestData();
-    boolean result = sampleQueue.skipToKeyframeBefore(
+    boolean result = sampleQueue.skipToKeyframeBefore2(
         TEST_SAMPLE_TIMESTAMPS[TEST_SAMPLE_TIMESTAMPS.length - 1], false);
     // Should succeed and skip to 2nd keyframe.
     assertTrue(result);
@@ -240,7 +285,7 @@ public class SampleQueueTest extends TestCase {
 
   public void testSkipToKeyframeAfterBuffer() {
     writeTestData();
-    boolean result = sampleQueue.skipToKeyframeBefore(
+    boolean result = sampleQueue.skipToKeyframeBefore2(
         TEST_SAMPLE_TIMESTAMPS[TEST_SAMPLE_TIMESTAMPS.length - 1] + 1, false);
     // Should fail and have no effect.
     assertFalse(result);
@@ -250,7 +295,7 @@ public class SampleQueueTest extends TestCase {
 
   public void testSkipToKeyframeAfterBufferAllowed() {
     writeTestData();
-    boolean result = sampleQueue.skipToKeyframeBefore(
+    boolean result = sampleQueue.skipToKeyframeBefore2(
         TEST_SAMPLE_TIMESTAMPS[TEST_SAMPLE_TIMESTAMPS.length - 1] + 1, true);
     // Should succeed and skip to 2nd keyframe.
     assertTrue(result);
@@ -305,6 +350,8 @@ public class SampleQueueTest extends TestCase {
     writeTestData();
     assertReadTestData(null, 0, 3);
     sampleQueue.discardUpstreamSamples(8);
+    assertAllocationCount(10);
+    sampleQueue.discardToRead();
     assertAllocationCount(7);
     sampleQueue.discardUpstreamSamples(7);
     assertAllocationCount(6);
@@ -359,6 +406,7 @@ public class SampleQueueTest extends TestCase {
    * Asserts correct reading of standard test data from {@code sampleQueue}.
    *
    * @param startFormat The format of the last sample previously read from {@code sampleQueue}.
+   * @param firstSampleIndex The index of the first sample that's expected to be read.
    */
   private void assertReadTestData(Format startFormat, int firstSampleIndex) {
     assertReadTestData(startFormat, firstSampleIndex,
@@ -428,7 +476,7 @@ public class SampleQueueTest extends TestCase {
    */
   private void assertReadNothing(boolean formatRequired) {
     clearFormatHolderAndInputBuffer();
-    int result = sampleQueue.readData(formatHolder, inputBuffer, formatRequired, false, 0);
+    int result = sampleQueue.readData2(formatHolder, inputBuffer, formatRequired, false, 0);
     assertEquals(C.RESULT_NOTHING_READ, result);
     // formatHolder should not be populated.
     assertNull(formatHolder.format);
@@ -445,7 +493,7 @@ public class SampleQueueTest extends TestCase {
    */
   private void assertReadEndOfStream(boolean formatRequired) {
     clearFormatHolderAndInputBuffer();
-    int result = sampleQueue.readData(formatHolder, inputBuffer, formatRequired, true, 0);
+    int result = sampleQueue.readData2(formatHolder, inputBuffer, formatRequired, true, 0);
     assertEquals(C.RESULT_BUFFER_READ, result);
     // formatHolder should not be populated.
     assertNull(formatHolder.format);
@@ -465,7 +513,7 @@ public class SampleQueueTest extends TestCase {
    */
   private void assertReadFormat(boolean formatRequired, Format format) {
     clearFormatHolderAndInputBuffer();
-    int result = sampleQueue.readData(formatHolder, inputBuffer, formatRequired, false, 0);
+    int result = sampleQueue.readData2(formatHolder, inputBuffer, formatRequired, false, 0);
     assertEquals(C.RESULT_FORMAT_READ, result);
     // formatHolder should be populated.
     assertEquals(format, formatHolder.format);
@@ -487,7 +535,7 @@ public class SampleQueueTest extends TestCase {
   private void assertSampleRead(long timeUs, boolean isKeyframe, byte[] sampleData, int offset,
       int length) {
     clearFormatHolderAndInputBuffer();
-    int result = sampleQueue.readData(formatHolder, inputBuffer, false, false, 0);
+    int result = sampleQueue.readData2(formatHolder, inputBuffer, false, false, 0);
     assertEquals(C.RESULT_BUFFER_READ, result);
     // formatHolder should not be populated.
     assertNull(formatHolder.format);

library/core/src/main/java/com/google/android/exoplayer2/source/SampleQueue.java

@@ -224,11 +224,17 @@ public final class SampleQueue implements TrackOutput {
   }
 
   /**
-   * Skips all samples currently in the buffer.
+   * Rewinds the read position to the first sample in the queue.
    */
-  public void skipAll() {
-    metadataQueue.skipAll();
-    // TODO - Remove the following block and expose explicit discard operations.
+  public void rewind() {
+    metadataQueue.rewind();
+    readAllocationNode = firstAllocationNode;
+  }
+
+  /**
+   * Discards samples up to the current read position.
+   */
+  public void discardToRead() {
     long nextOffset = metadataQueue.discardToRead();
     if (nextOffset != C.POSITION_UNSET) {
       dropDownstreamTo(nextOffset);
@@ -236,6 +242,33 @@ public final class SampleQueue implements TrackOutput {
   }
 
   /**
+   * @deprecated Use {@link #skipAll2()} followed by {@link #discardToRead()}.
+   */
+  @Deprecated
+  public void skipAll() {
+    skipAll2();
+    discardToRead();
+  }
+
+  /**
+   * Skips all samples currently in the buffer.
+   */
+  public void skipAll2() {
+    metadataQueue.skipAll();
+  }
+
+  /**
+   * @deprecated Use {@link #skipToKeyframeBefore2(long, boolean)} followed by
+   *     {@link #discardToRead()}.
+   */
+  @Deprecated
+  public boolean skipToKeyframeBefore(long timeUs, boolean allowTimeBeyondBuffer) {
+    boolean success = skipToKeyframeBefore2(timeUs, allowTimeBeyondBuffer);
+    discardToRead();
+    return success;
+  }
+
+  /**
    * Attempts to skip to the keyframe before or at the specified time. Succeeds only if the buffer
    * contains a keyframe with a timestamp of {@code timeUs} or earlier. If
    * {@code allowTimeBeyondBuffer} is {@code false} then it is also required that {@code timeUs}
@@ -246,18 +279,21 @@ public final class SampleQueue implements TrackOutput {
    *     of the buffer.
    * @return Whether the skip was successful.
    */
-  public boolean skipToKeyframeBefore(long timeUs, boolean allowTimeBeyondBuffer) {
-    boolean success = metadataQueue.skipToKeyframeBefore(timeUs, allowTimeBeyondBuffer);
-    if (success) {
-      // TODO - Remove the following block and expose explicit discard operations.
-      long nextOffset = metadataQueue.discardToRead();
-      if (nextOffset != C.POSITION_UNSET) {
-        dropDownstreamTo(nextOffset);
-      }
-      return true;
-    } else {
-      return false;
-    }
+  public boolean skipToKeyframeBefore2(long timeUs, boolean allowTimeBeyondBuffer) {
+    return metadataQueue.skipToKeyframeBefore(timeUs, allowTimeBeyondBuffer);
+  }
+
+  /**
+   * @deprecated Use {@link #readData2(FormatHolder, DecoderInputBuffer, boolean, boolean, long)}
+   *     followed by {@link #discardToRead()}.
+   */
+  @Deprecated
+  public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer, boolean formatRequired,
+      boolean loadingFinished, long decodeOnlyUntilUs) {
+    int result = readData2(formatHolder, buffer, formatRequired, loadingFinished,
+        decodeOnlyUntilUs);
+    discardToRead();
+    return result;
   }
 
   /**
@@ -276,7 +312,7 @@ public final class SampleQueue implements TrackOutput {
    * @return The result, which can be {@link C#RESULT_NOTHING_READ}, {@link C#RESULT_FORMAT_READ} or
    *     {@link C#RESULT_BUFFER_READ}.
    */
-  public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer, boolean formatRequired,
+  public int readData2(FormatHolder formatHolder, DecoderInputBuffer buffer, boolean formatRequired,
       boolean loadingFinished, long decodeOnlyUntilUs) {
     int result = metadataQueue.readData(formatHolder, buffer, formatRequired, loadingFinished,
         downstreamFormat, extrasHolder);
@@ -296,11 +332,6 @@ public final class SampleQueue implements TrackOutput {
           // Write the sample data into the holder.
           buffer.ensureSpaceForWrite(extrasHolder.size);
           readData(extrasHolder.offset, buffer.data, extrasHolder.size);
-          // TODO - Remove the following block and expose explicit discard operations.
-          long nextOffset = metadataQueue.discardToRead();
-          if (nextOffset != C.POSITION_UNSET) {
-            dropDownstreamTo(nextOffset);
-          }
         }
         return C.RESULT_BUFFER_READ;
       case C.RESULT_NOTHING_READ: