Commit 58382a8c authored by Alastor Wu's avatar Alastor Wu
Browse files

Bug 1362440 - part1 : add timecode checking for parser r=kinetik 

The spec [1] defines that
"Timecode (e7) MUST appear before Block (a1) or SimpleBlock (a3)".

[1] https://www.matroska.org/technical/specs/index.html

MozReview-Commit-ID: 7g8lgckuNif

--HG--
extra : rebase_source : 4945dc4b0ab4b7480bf9c6416f9776fd6313c1e1
parent bd50b903

dom/media/webm/WebMBufferedParser.cpp

+9 −0
Original line number Diff line number Diff line
@@ -113,6 +113,7 @@ bool WebMBufferedParser::Append(const unsigned char* aBuffer, uint32_t aLength, 
        } else {

          mClusterEndOffset = -1;

        }

        mGotClusterTimecode = false;

        mState = READ_ELEMENT_ID;

        break;

      case BLOCKGROUP_ID:
@@ -121,6 +122,11 @@ bool WebMBufferedParser::Append(const unsigned char* aBuffer, uint32_t aLength, 
      case SIMPLEBLOCK_ID:

        /* FALLTHROUGH */

      case BLOCK_ID:

        if (!mGotClusterTimecode) {

          WEBM_DEBUG("The Timecode element must appear before any Block or "

                     "SimpleBlock elements in a Cluster");

          return false;

        }

        mBlockSize = mElement.mSize.mValue;

        mBlockTimecode = 0;

        mBlockTimecodeLength = BLOCK_TIMECODE_LENGTH;
@@ -164,6 +170,7 @@ bool WebMBufferedParser::Append(const unsigned char* aBuffer, uint32_t aLength, 
      break;

    case READ_TIMECODESCALE:

      if (!mGotTimecodeScale) {

        WEBM_DEBUG("Should get the SegmentInfo first");

        return false;

      }

      mTimecodeScale = mVInt.mValue;
@@ -171,6 +178,7 @@ bool WebMBufferedParser::Append(const unsigned char* aBuffer, uint32_t aLength, 
      break;

    case READ_CLUSTER_TIMECODE:

      mClusterTimecode = mVInt.mValue;

      mGotClusterTimecode = true;

      mState = READ_ELEMENT_ID;

      break;

    case READ_BLOCK_TIMECODE:
@@ -190,6 +198,7 @@ bool WebMBufferedParser::Append(const unsigned char* aBuffer, uint32_t aLength, 
            // Don't insert invalid negative timecodes.

            if (mBlockTimecode >= 0 || mClusterTimecode >= uint16_t(abs(mBlockTimecode))) {

              if (!mGotTimecodeScale) {

                WEBM_DEBUG("Should get the TimecodeScale first");

                return false;

              }

              uint64_t absTimecode = mClusterTimecode + mBlockTimecode;

dom/media/webm/WebMBufferedParser.h

+4 −0
Original line number Diff line number Diff line
@@ -75,6 +75,7 @@ struct WebMBufferedParser 
    , mSkipBytes(0)

    , mTimecodeScale(1000000)

    , mGotTimecodeScale(false)

    , mGotClusterTimecode(false)

  {

    if (mStartOffset != 0) {

      mState = FIND_CLUSTER_SYNC;
@@ -260,6 +261,9 @@ private: 
  // True if we read the timecode scale from the segment info or have

  // confirmed that the default value is to be used.

  bool mGotTimecodeScale;



  // True if we've read the cluster time code.

  bool mGotClusterTimecode;

};



class WebMBufferedState final