Remove CEA package from null-checking blacklist

PiperOrigin-RevId: 290610312

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;
-  private List<Cue> lastCues;
+  @Nullable private List<Cue> cues;
+  @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.

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;
-  private List<Cue> lastCues;
+  @Nullable private List<Cue> cues;
+  @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();
-    ccData.reset(inputBufferData, inputBuffer.data.limit());
+    byte[] inputBufferData = subtitleData.array();
+    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.

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++;
-      queuedInputBuffers.add(dequeuedInputBuffer);
+      ceaInputBuffer.queuedInputBufferCount = queuedInputBufferCount++;
+      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) {
-      CeaInputBuffer inputBuffer = queuedInputBuffers.poll();
+        && Util.castNonNull(queuedInputBuffers.peek()).timeUs <= playbackPositionUs) {
+      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);