Remove CEA package from null-checking blacklist

PiperOrigin-RevId: 290610312

Remove CEA package from null-checking blacklist
PiperOrigin-RevId: 290610312
f7470c51 · ibaker · Ian Baker · de3f04b7 · f7470c51 · f7470c51
Commit f7470c51 authored Jan 20, 2020 by ibaker Committed by Ian Baker Jan 24, 2020
Showing with 49 additions and 29 deletions
library/core/src/main/java/com/google/android/exoplayer2/text/cea/Cea608Decoder.java
library/core/src/main/java/com/google/android/exoplayer2/text/cea/Cea708Decoder.java
library/core/src/main/java/com/google/android/exoplayer2/text/cea/CeaDecoder.java
--- a/library/core/src/main/java/com/google/android/exoplayer2/text/cea/Cea608Decoder.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/text/cea/Cea608Decoder.java
@@ -24,17 +24,21 @@ import android.text.Spanned;
 import android.text.style.ForegroundColorSpan;
 import android.text.style.StyleSpan;
 import android.text.style.UnderlineSpan;
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.text.Cue;
 import com.google.android.exoplayer2.text.Subtitle;
 import com.google.android.exoplayer2.text.SubtitleDecoder;
 import com.google.android.exoplayer2.text.SubtitleInputBuffer;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Log;
 import com.google.android.exoplayer2.util.MimeTypes;
 import com.google.android.exoplayer2.util.ParsableByteArray;
+import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import org.checkerframework.checker.nullness.compatqual.NullableType;
 /**
 * A {@link SubtitleDecoder} for CEA-608 (also known as "line 21 captions" and "EIA-608").
@@ -236,8 +240,8 @@ public final class Cea608Decoder extends CeaDecoder {
  private final ArrayList<CueBuilder> cueBuilders;
  private CueBuilder currentCueBuilder;
-  private List<Cue> cues;
+  @Nullable private List<Cue> cues;
-  private List<Cue> lastCues;
+  @Nullable private List<Cue> lastCues;
  private int captionMode;
  private int captionRowCount;
@@ -321,13 +325,14 @@ public final class Cea608Decoder extends CeaDecoder {
  @Override
  protected Subtitle createSubtitle() {
    lastCues = cues;
-    return new CeaSubtitle(cues);
+    return new CeaSubtitle(Assertions.checkNotNull(cues));
  }
  @SuppressWarnings("ByteBufferBackingArray")
  @Override
  protected void decode(SubtitleInputBuffer inputBuffer) {
-    ccData.reset(inputBuffer.data.array(), inputBuffer.data.limit());
+    ByteBuffer subtitleData = Assertions.checkNotNull(inputBuffer.data);
+    ccData.reset(subtitleData.array(), subtitleData.limit());
    boolean captionDataProcessed = false;
    while (ccData.bytesLeft() >= packetLength) {
      byte ccHeader = packetLength == 2 ? CC_IMPLICIT_DATA_HEADER
@@ -572,9 +577,9 @@ public final class Cea608Decoder extends CeaDecoder {
    // preference, then middle alignment, then end alignment.
    @Cue.AnchorType int positionAnchor = Cue.ANCHOR_TYPE_END;
    int cueBuilderCount = cueBuilders.size();
-    List<Cue> cueBuilderCues = new ArrayList<>(cueBuilderCount);
+    List<@NullableType Cue> cueBuilderCues = new ArrayList<>(cueBuilderCount);
    for (int i = 0; i < cueBuilderCount; i++) {
-      Cue cue = cueBuilders.get(i).build(/* forcedPositionAnchor= */ Cue.TYPE_UNSET);
+      @Nullable Cue cue = cueBuilders.get(i).build(/* forcedPositionAnchor= */ Cue.TYPE_UNSET);
      cueBuilderCues.add(cue);
      if (cue != null) {
        positionAnchor = Math.min(positionAnchor, cue.positionAnchor);
@@ -584,10 +589,11 @@ public final class Cea608Decoder extends CeaDecoder {
    // Skip null cues and rebuild any that don't have the preferred alignment.
    List<Cue> displayCues = new ArrayList<>(cueBuilderCount);
    for (int i = 0; i < cueBuilderCount; i++) {
-      Cue cue = cueBuilderCues.get(i);
+      @Nullable Cue cue = cueBuilderCues.get(i);
      if (cue != null) {
        if (cue.positionAnchor != positionAnchor) {
-          cue = cueBuilders.get(i).build(positionAnchor);
+          // The last time we built this cue it was non-null, it will be non-null this time too.
+          cue = Assertions.checkNotNull(cueBuilders.get(i).build(positionAnchor));
        }
        displayCues.add(cue);
      }
@@ -745,7 +751,7 @@ public final class Cea608Decoder extends CeaDecoder {
    return (cc1 & 0xF7) == 0x14;
  }
-  private static class CueBuilder {
+  private static final class CueBuilder {
    // 608 captions define a 15 row by 32 column screen grid. These constants convert from 608
    // positions to normalized screen position.
@@ -767,7 +773,7 @@ public final class Cea608Decoder extends CeaDecoder {
      rolledUpCaptions = new ArrayList<>();
      captionStringBuilder = new StringBuilder();
      reset(captionMode);
-      setCaptionRowCount(captionRowCount);
+      this.captionRowCount = captionRowCount;
    }
    public void reset(int captionMode) {
@@ -829,6 +835,7 @@ public final class Cea608Decoder extends CeaDecoder {
      }
    }
+    @Nullable
    public Cue build(@Cue.AnchorType int forcedPositionAnchor) {
      SpannableStringBuilder cueString = new SpannableStringBuilder();
      // Add any rolled up captions, separated by new lines.

--- a/library/core/src/main/java/com/google/android/exoplayer2/text/cea/Cea708Decoder.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/text/cea/Cea708Decoder.java
@@ -37,9 +37,11 @@ import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Log;
 import com.google.android.exoplayer2.util.ParsableBitArray;
 import com.google.android.exoplayer2.util.ParsableByteArray;
+import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 /**
 * A {@link SubtitleDecoder} for CEA-708 (also known as "EIA-708").
@@ -147,10 +149,10 @@ public final class Cea708Decoder extends CeaDecoder {
  private final CueInfoBuilder[] cueInfoBuilders;
  private CueInfoBuilder currentCueInfoBuilder;
-  private List<Cue> cues;
+  @Nullable private List<Cue> cues;
-  private List<Cue> lastCues;
+  @Nullable private List<Cue> lastCues;
-  private DtvCcPacket currentDtvCcPacket;
+  @Nullable private DtvCcPacket currentDtvCcPacket;
  private int currentWindow;
  // TODO: Retrieve isWideAspectRatio from initializationData and use it.
@@ -165,7 +167,6 @@ public final class Cea708Decoder extends CeaDecoder {
    }
    currentCueInfoBuilder = cueInfoBuilders[0];
-    resetCueBuilders();
  }
  @Override
@@ -192,15 +193,16 @@ public final class Cea708Decoder extends CeaDecoder {
  @Override
  protected Subtitle createSubtitle() {
    lastCues = cues;
-    return new CeaSubtitle(cues);
+    return new CeaSubtitle(Assertions.checkNotNull(cues));
  }
  @Override
  protected void decode(SubtitleInputBuffer inputBuffer) {
    // Subtitle input buffers are non-direct and the position is zero, so calling array() is safe.
+    ByteBuffer subtitleData = Assertions.checkNotNull(inputBuffer.data);
    @SuppressWarnings("ByteBufferBackingArray")
-    byte[] inputBufferData = inputBuffer.data.array();
+    byte[] inputBufferData = subtitleData.array();
-    ccData.reset(inputBufferData, inputBuffer.data.limit());
+    ccData.reset(inputBufferData, subtitleData.limit());
    while (ccData.bytesLeft() >= 3) {
      int ccTypeAndValid = (ccData.readUnsignedByte() & 0x07);
@@ -259,6 +261,7 @@ public final class Cea708Decoder extends CeaDecoder {
    currentDtvCcPacket = null;
  }
+  @RequiresNonNull("currentDtvCcPacket")
  private void processCurrentPacket() {
    if (currentDtvCcPacket.currentIndex != (currentDtvCcPacket.packetSize * 2 - 1)) {
      Log.w(TAG, "DtvCcPacket ended prematurely; size is " + (currentDtvCcPacket.packetSize * 2 - 1)
@@ -761,7 +764,10 @@ public final class Cea708Decoder extends CeaDecoder {
    List<Cea708CueInfo> displayCueInfos = new ArrayList<>();
    for (int i = 0; i < NUM_WINDOWS; i++) {
      if (!cueInfoBuilders[i].isEmpty() && cueInfoBuilders[i].isVisible()) {
-        displayCueInfos.add(cueInfoBuilders[i].build());
+        @Nullable Cea708CueInfo cueInfo = cueInfoBuilders[i].build();
+        if (cueInfo != null) {
+          displayCueInfos.add(cueInfo);
+        }
      }
    }
    Collections.sort(
@@ -1157,6 +1163,7 @@ public final class Cea708Decoder extends CeaDecoder {
      return new SpannableString(spannableStringBuilder);
    }
+    @Nullable
    public Cea708CueInfo build() {
      if (isEmpty()) {
        // The cue is empty.

--- a/library/core/src/main/java/com/google/android/exoplayer2/text/cea/CeaDecoder.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/text/cea/CeaDecoder.java
@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.text.cea;
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.text.Subtitle;
@@ -24,6 +25,7 @@ import com.google.android.exoplayer2.text.SubtitleDecoderException;
 import com.google.android.exoplayer2.text.SubtitleInputBuffer;
 import com.google.android.exoplayer2.text.SubtitleOutputBuffer;
 import com.google.android.exoplayer2.util.Assertions;
+import com.google.android.exoplayer2.util.Util;
 import java.util.ArrayDeque;
 import java.util.PriorityQueue;
@@ -39,7 +41,7 @@ import java.util.PriorityQueue;
  private final ArrayDeque<SubtitleOutputBuffer> availableOutputBuffers;
  private final PriorityQueue<CeaInputBuffer> queuedInputBuffers;
-  private CeaInputBuffer dequeuedInputBuffer;
+  @Nullable private CeaInputBuffer dequeuedInputBuffer;
  private long playbackPositionUs;
  private long queuedInputBufferCount;
@@ -64,6 +66,7 @@ import java.util.PriorityQueue;
  }
  @Override
+  @Nullable
  public SubtitleInputBuffer dequeueInputBuffer() throws SubtitleDecoderException {
    Assertions.checkState(dequeuedInputBuffer == null);
    if (availableInputBuffers.isEmpty()) {
@@ -76,18 +79,20 @@ import java.util.PriorityQueue;
  @Override
  public void queueInputBuffer(SubtitleInputBuffer inputBuffer) throws SubtitleDecoderException {
    Assertions.checkArgument(inputBuffer == dequeuedInputBuffer);
-    if (inputBuffer.isDecodeOnly()) {
+    CeaInputBuffer ceaInputBuffer = (CeaInputBuffer) inputBuffer;
+    if (ceaInputBuffer.isDecodeOnly()) {
      // We can drop this buffer early (i.e. before it would be decoded) as the CEA formats allow
      // for decoding to begin mid-stream.
-      releaseInputBuffer(dequeuedInputBuffer);
+      releaseInputBuffer(ceaInputBuffer);
    } else {
-      dequeuedInputBuffer.queuedInputBufferCount = queuedInputBufferCount++;
+      ceaInputBuffer.queuedInputBufferCount = queuedInputBufferCount++;
-      queuedInputBuffers.add(dequeuedInputBuffer);
+      queuedInputBuffers.add(ceaInputBuffer);
    }
    dequeuedInputBuffer = null;
  }
  @Override
+  @Nullable
  public SubtitleOutputBuffer dequeueOutputBuffer() throws SubtitleDecoderException {
    if (availableOutputBuffers.isEmpty()) {
      return null;
@@ -96,13 +101,14 @@ import java.util.PriorityQueue;
    // to the current playback position; processing input buffers for future content should
    // be deferred until they would be applicable
    while (!queuedInputBuffers.isEmpty()
-        && queuedInputBuffers.peek().timeUs <= playbackPositionUs) {
+        && Util.castNonNull(queuedInputBuffers.peek()).timeUs <= playbackPositionUs) {
-      CeaInputBuffer inputBuffer = queuedInputBuffers.poll();
+      CeaInputBuffer inputBuffer = Util.castNonNull(queuedInputBuffers.poll());
      // If the input buffer indicates we've reached the end of the stream, we can
      // return immediately with an output buffer propagating that
      if (inputBuffer.isEndOfStream()) {
-        SubtitleOutputBuffer outputBuffer = availableOutputBuffers.pollFirst();
+        // availableOutputBuffers.isEmpty() is checked at the top of the method, so this is safe.
+        SubtitleOutputBuffer outputBuffer = Util.castNonNull(availableOutputBuffers.pollFirst());
        outputBuffer.addFlag(C.BUFFER_FLAG_END_OF_STREAM);
        releaseInputBuffer(inputBuffer);
        return outputBuffer;
@@ -116,7 +122,8 @@ import java.util.PriorityQueue;
        // isn't accidentally prepended to the next subtitle
        Subtitle subtitle = createSubtitle();
        if (!inputBuffer.isDecodeOnly()) {
-          SubtitleOutputBuffer outputBuffer = availableOutputBuffers.pollFirst();
+          // availableOutputBuffers.isEmpty() is checked at the top of the method, so this is safe.
+          SubtitleOutputBuffer outputBuffer = Util.castNonNull(availableOutputBuffers.pollFirst());
          outputBuffer.setContent(inputBuffer.timeUs, subtitle, Format.OFFSET_SAMPLE_RELATIVE);
          releaseInputBuffer(inputBuffer);
          return outputBuffer;
@@ -125,7 +132,6 @@ import java.util.PriorityQueue;
      releaseInputBuffer(inputBuffer);
    }
    return null;
  }
@@ -144,7 +150,7 @@ import java.util.PriorityQueue;
    queuedInputBufferCount = 0;
    playbackPositionUs = 0;
    while (!queuedInputBuffers.isEmpty()) {
-      releaseInputBuffer(queuedInputBuffers.poll());
+      releaseInputBuffer(Util.castNonNull(queuedInputBuffers.poll()));
    }
    if (dequeuedInputBuffer != null) {
      releaseInputBuffer(dequeuedInputBuffer);