Add HlsCheckedSampleQueue to check timstamp range

Add a SampleQueue subclass that checks the timestamp range of media samples queued to it and reports an exception on load if the timestamp is outside of spec bounds.
(Smashed to a single commit prior to rebase)

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

@@ -488,7 +488,7 @@ public class SampleQueue implements TrackOutput {
   }
 
   @Override
-  public final void sampleMetadata(
+  public void sampleMetadata(
       long timeUs,
       @C.BufferFlags int flags,
       int size,

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

@@ -0,0 +1,26 @@
+package com.google.android.exoplayer2.source;
+
+import android.net.Uri;
+import com.google.android.exoplayer2.C;
+
+/**
+ * Thrown from the loader thread when an attempt is made to commit a sample that is far
+ * deviant from the expected sequence of timestamps in the SampleStream.   This is likely
+ * caused by a discontinuity in a segment that was not split and reported by metadata in
+ * an HLS (EXT-X-DISCONTINUITY) or DASH stream.
+ */
+public class UnreportedDiscontinuityException extends RuntimeException {
+
+  public final long timesUs;
+
+  /**
+   * Consturct the exception
+   *
+   * @param timesUs last timestamp before attempted commit of the deviant sample
+   * @param uri uri of the segment with the unreported discontinuity
+   */
+  public UnreportedDiscontinuityException(long timesUs, Uri uri) {
+    super("Unreported discontinuity timeMs: " + C.usToMs(timesUs) + " in URI: " + uri);
+    this.timesUs = timesUs;
+  }
+}

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsCheckedSampleQueue.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2020 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.source.hls;
+
+import androidx.annotation.Nullable;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.drm.DrmSessionManager;
+import com.google.android.exoplayer2.source.SampleQueue;
+import com.google.android.exoplayer2.source.UnreportedDiscontinuityException;
+import com.google.android.exoplayer2.upstream.Allocator;
+import com.google.android.exoplayer2.util.Log;
+
+public class HlsCheckedSampleQueue extends SampleQueue {
+  private static final String TAG = "HlsCheckedSampleQueue";
+
+  private long lowestTimeUs = C.TIME_UNSET;
+  private long highestTimeUs = C.TIME_UNSET;
+
+  private HlsMediaChunk chunk;
+  private boolean loggedFirst = false;
+
+  HlsCheckedSampleQueue(Allocator allocator, DrmSessionManager drmSessionManager) {
+    super(allocator, drmSessionManager);
+  }
+
+  void setCurrentLoadingChunk(HlsMediaChunk chunk) {
+    double tolerance = (chunk.endTimeUs - chunk.startTimeUs) * 0.1;
+    this.lowestTimeUs = chunk.startTimeUs;
+    this.highestTimeUs = (long) (chunk.endTimeUs + tolerance);
+    this.chunk = chunk;
+    loggedFirst = false;
+  }
+
+
+  @Override
+  public void sampleMetadata(long timeUs, int flags, int size, int offset,  @Nullable CryptoData cryptoData) {
+    if (lowestTimeUs != C.TIME_UNSET && timeUs < lowestTimeUs && ! loggedFirst) {
+      Log.d(TAG, "sampleMetadata() - committed timeUs: " + timeUs + " is " + C.usToMs(lowestTimeUs - timeUs) + "ms less then segment start time.  chunk: " + chunk.dataSpec.uri);
+      loggedFirst = true;
+    }
+    if (lowestTimeUs != C.TIME_UNSET && timeUs < (lowestTimeUs - C.msToUs(50_000))) {
+      Log.d(TAG, "sampleMetadata() - committed timeUs: " + timeUs + " is " + C.usToMs(lowestTimeUs - timeUs) + "ms less (MUCH!) then segment start time.  chunk: " + chunk.dataSpec.uri);
+      throw new UnreportedDiscontinuityException(timeUs, chunk.dataSpec.uri);
+    }
+    if (highestTimeUs != C.TIME_UNSET && timeUs > highestTimeUs) {
+      Log.d(TAG, "sampleMetadata() - committed timeUs: " + timeUs + " is " + C.usToMs(lowestTimeUs - timeUs) + "ms greater then segment end time.  chunk: " + chunk.dataSpec.uri);
+      throw new UnreportedDiscontinuityException(timeUs, chunk.dataSpec.uri);
+    }
+    super.sampleMetadata(timeUs, flags, size, offset, cryptoData);
+  }
+
+}

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaChunk.java

@@ -27,11 +27,13 @@ import com.google.android.exoplayer2.extractor.PositionHolder;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.id3.Id3Decoder;
 import com.google.android.exoplayer2.metadata.id3.PrivFrame;
+import com.google.android.exoplayer2.source.UnreportedDiscontinuityException;
 import com.google.android.exoplayer2.source.chunk.MediaChunk;
 import com.google.android.exoplayer2.source.hls.playlist.HlsMediaPlaylist;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.util.Assertions;
+import com.google.android.exoplayer2.util.Log;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.TimestampAdjuster;
 import com.google.android.exoplayer2.util.UriUtil;
@@ -50,6 +52,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
  * An HLS {@link MediaChunk}.
  */
 /* package */ final class HlsMediaChunk extends MediaChunk {
+  private static final String TAG = "HlsMediaChunk";
 
   /**
    * Creates a new instance.
@@ -282,7 +285,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
    */
   public void init(HlsSampleStreamWrapper output) {
     this.output = output;
-    output.init(uid, shouldSpliceIn);
+    output.init(uid, this, shouldSpliceIn);
   }
 
   @Override
@@ -376,6 +379,10 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
         while (result == Extractor.RESULT_CONTINUE && !loadCanceled) {
           result = extractor.read(input, DUMMY_POSITION_HOLDER);
         }
+      } catch (UnreportedDiscontinuityException e) {
+        Log.d(TAG, "Unreported discontinuity at timeUs: "+ e.timesUs + " uri: " + dataSpec.uri);
+        throw new IOException("Timestamp error", e);
+        
       } finally {
         nextLoadPosition = (int) (input.getPosition() - dataSpec.position);
       }

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsSampleStreamWrapper.java

@@ -820,15 +820,16 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
   /**
    * Initializes the wrapper for loading a chunk.
-   *
    * @param chunkUid The chunk's uid.
+   * @param loadingChunk the Chunk that is about to start loading.
    * @param shouldSpliceIn Whether the samples parsed from the chunk should be spliced into any
    *     samples already queued to the wrapper.
    */
-  public void init(int chunkUid, boolean shouldSpliceIn) {
+  public void init(int chunkUid, HlsMediaChunk loadingChunk, boolean shouldSpliceIn) {
     this.chunkUid = chunkUid;
-    for (SampleQueue sampleQueue : sampleQueues) {
+    for (HlsCheckedSampleQueue sampleQueue : sampleQueues) {
       sampleQueue.sourceId(chunkUid);
+      sampleQueue.setCurrentLoadingChunk(loadingChunk);
     }
     if (shouldSpliceIn) {
       for (SampleQueue sampleQueue : sampleQueues) {
@@ -1342,7 +1343,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
     return new DummyTrackOutput();
   }
 
-  private static final class FormatAdjustingSampleQueue extends SampleQueue {
+  private static final class FormatAdjustingSampleQueue extends HlsCheckedSampleQueue {
 
     private final Map<String, DrmInitData> overridingDrmInitData;
     @Nullable private DrmInitData drmInitData;