Fix resetting TimestampAdjuster with DO_NOT_OFFSET

Prior to this change, an initalized TimestampAdjuster that's then
reset with DO_NOT_OFFSET would incorrectly continue to apply the
offset.

Also add a test case for this issue, and for some other simple use
cases.

#minor-release

PiperOrigin-RevId: 388182645

library/common/src/main/java/com/google/android/exoplayer2/util/TimestampAdjuster.java

@@ -53,8 +53,7 @@ public final class TimestampAdjuster {
    *     microseconds, or {@link #DO_NOT_OFFSET} if timestamps should not be offset.
    *     microseconds, or {@link #DO_NOT_OFFSET} if timestamps should not be offset.
    */
    */
   public TimestampAdjuster(long firstSampleTimestampUs) {
   public TimestampAdjuster(long firstSampleTimestampUs) {
-    this.firstSampleTimestampUs = firstSampleTimestampUs;
-    lastSampleTimestampUs = C.TIME_UNSET;
+    reset(firstSampleTimestampUs);
   }
   }
 
 
   /**
   /**
@@ -80,18 +79,18 @@ public final class TimestampAdjuster {
    * </ul>
    * </ul>
    *
    *
    * @param canInitialize Whether the caller is able to initialize the adjuster, if needed.
    * @param canInitialize Whether the caller is able to initialize the adjuster, if needed.
-   * @param startTimeUs The desired first sample timestamp of the caller, in microseconds. Only used
-   *     if {@code canInitialize} is {@code true}.
+   * @param firstSampleTimestampUs The desired value of the first adjusted sample timestamp in
+   *     microseconds. Only used if {@code canInitialize} is {@code true}.
    * @throws InterruptedException If the thread is interrupted whilst blocked waiting for
    * @throws InterruptedException If the thread is interrupted whilst blocked waiting for
    *     initialization to complete.
    *     initialization to complete.
    */
    */
-  public synchronized void sharedInitializeOrWait(boolean canInitialize, long startTimeUs)
-      throws InterruptedException {
+  public synchronized void sharedInitializeOrWait(
+      boolean canInitialize, long firstSampleTimestampUs) throws InterruptedException {
     if (canInitialize && !sharedInitializationStarted) {
     if (canInitialize && !sharedInitializationStarted) {
-      firstSampleTimestampUs = startTimeUs;
+      reset(firstSampleTimestampUs);
       sharedInitializationStarted = true;
       sharedInitializationStarted = true;
     }
     }
-    if (!canInitialize || startTimeUs != firstSampleTimestampUs) {
+    if (!canInitialize || this.firstSampleTimestampUs != firstSampleTimestampUs) {
       while (lastSampleTimestampUs == C.TIME_UNSET) {
       while (lastSampleTimestampUs == C.TIME_UNSET) {
         wait();
         wait();
       }
       }
@@ -134,7 +133,7 @@ public final class TimestampAdjuster {
   }
   }
 
 
   /**
   /**
-   * Resets the instance to its initial state.
+   * Resets the instance.
    *
    *
    * @param firstSampleTimestampUs The desired value of the first adjusted sample timestamp after
    * @param firstSampleTimestampUs The desired value of the first adjusted sample timestamp after
    *     this reset, in microseconds, or {@link #DO_NOT_OFFSET} if timestamps should not be offset.
    *     this reset, in microseconds, or {@link #DO_NOT_OFFSET} if timestamps should not be offset.
@@ -142,6 +141,7 @@ public final class TimestampAdjuster {
   public synchronized void reset(long firstSampleTimestampUs) {
   public synchronized void reset(long firstSampleTimestampUs) {
     this.firstSampleTimestampUs = firstSampleTimestampUs;
     this.firstSampleTimestampUs = firstSampleTimestampUs;
     lastSampleTimestampUs = C.TIME_UNSET;
     lastSampleTimestampUs = C.TIME_UNSET;
+    timestampOffsetUs = 0;
     sharedInitializationStarted = false;
     sharedInitializationStarted = false;
   }
   }
 
 

library/common/src/test/java/com/google/android/exoplayer2/util/TimestampAdjusterTest.java

+/*
+ * Copyright (C) 2021 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 com.google.android.exoplayer2.util;
+
+import static com.google.android.exoplayer2.util.TimestampAdjuster.DO_NOT_OFFSET;
+import static com.google.common.truth.Truth.assertThat;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/** Tests for {@link TimestampAdjuster}. */
+@RunWith(AndroidJUnit4.class)
+public class TimestampAdjusterTest {
+
+  @Test
+  public void adjustSampleTimestamp_fromZero() {
+    TimestampAdjuster adjuster = new TimestampAdjuster(/* firstSampleTimestampUs= */ 0);
+    long firstAdjustedTimestampUs = adjuster.adjustSampleTimestamp(/* timeUs= */ 2000);
+    long secondAdjustedTimestampUs = adjuster.adjustSampleTimestamp(/* timeUs= */ 6000);
+
+    assertThat(firstAdjustedTimestampUs).isEqualTo(0);
+    assertThat(secondAdjustedTimestampUs).isEqualTo(4000);
+  }
+
+  @Test
+  public void adjustSampleTimestamp_fromNonZero() {
+    TimestampAdjuster adjuster = new TimestampAdjuster(/* firstSampleTimestampUs= */ 1000);
+    long firstAdjustedTimestampUs = adjuster.adjustSampleTimestamp(/* timeUs= */ 2000);
+    long secondAdjustedTimestampUs = adjuster.adjustSampleTimestamp(/* timeUs= */ 6000);
+
+    assertThat(firstAdjustedTimestampUs).isEqualTo(1000);
+    assertThat(secondAdjustedTimestampUs).isEqualTo(5000);
+  }
+
+  @Test
+  public void adjustSampleTimestamp_doNotOffset() {
+    TimestampAdjuster adjuster = new TimestampAdjuster(/* firstSampleTimestampUs= */ DO_NOT_OFFSET);
+    long firstAdjustedTimestampUs = adjuster.adjustSampleTimestamp(/* timeUs= */ 2000);
+    long secondAdjustedTimestampUs = adjuster.adjustSampleTimestamp(/* timeUs= */ 6000);
+
+    assertThat(firstAdjustedTimestampUs).isEqualTo(2000);
+    assertThat(secondAdjustedTimestampUs).isEqualTo(6000);
+  }
+
+  @Test
+  public void adjustSampleTimestamp_afterResetToNotOffset() {
+    TimestampAdjuster adjuster = new TimestampAdjuster(/* firstSampleTimestampUs= */ 0);
+    // Let the adjuster establish an offset, to make sure that reset really clears it.
+    adjuster.adjustSampleTimestamp(/* timeUs= */ 1000);
+    adjuster.reset(/* firstSampleTimestampUs= */ DO_NOT_OFFSET);
+    long firstAdjustedTimestampUs = adjuster.adjustSampleTimestamp(/* timeUs= */ 2000);
+    long secondAdjustedTimestampUs = adjuster.adjustSampleTimestamp(/* timeUs= */ 6000);
+
+    assertThat(firstAdjustedTimestampUs).isEqualTo(2000);
+    assertThat(secondAdjustedTimestampUs).isEqualTo(6000);
+  }
+
+  @Test
+  public void adjustSampleTimestamp_afterResetToDifferentStartTime() {
+    TimestampAdjuster adjuster = new TimestampAdjuster(/* firstSampleTimestampUs= */ 0);
+    // Let the adjuster establish an offset, to make sure that reset really clears it.
+    adjuster.adjustSampleTimestamp(/* timeUs= */ 1000);
+    adjuster.reset(/* firstSampleTimestampUs= */ 5000);
+    long firstAdjustedTimestampUs = adjuster.adjustSampleTimestamp(/* timeUs= */ 2000);
+    long secondAdjustedTimestampUs = adjuster.adjustSampleTimestamp(/* timeUs= */ 6000);
+
+    assertThat(firstAdjustedTimestampUs).isEqualTo(5000);
+    assertThat(secondAdjustedTimestampUs).isEqualTo(9000);
+  }
+}