The Tor Browser: content/media/ogg/OggReader.h@97036ab72558 (annotated)

content/media/ogg/OggReader.h@97036ab72558 (annotated)

content/media/ogg/OggReader.h

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim:set ts=2 sw=2 sts=2 et cindent: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #if !defined(OggReader_h_)
 #define OggReader_h_
 #include <ogg/ogg.h>
 #include <theora/theoradec.h>
 #ifdef MOZ_TREMOR
 #include <tremor/ivorbiscodec.h>
 #else
 #include <vorbis/codec.h>
 #endif
 #include "MediaDecoderReader.h"
 #include "OggCodecState.h"
 #include "VideoUtils.h"
 #include "mozilla/Monitor.h"
 namespace mozilla {
 namespace dom {
 class TimeRanges;
 }
 }
 namespace mozilla {
 // Thread safe container to store the codec information and the serial for each
 // streams.
 class OggCodecStore
 {
   public:
     OggCodecStore();
     void Add(uint32_t serial, OggCodecState* codecState);
     bool Contains(uint32_t serial);
     OggCodecState* Get(uint32_t serial);
     bool IsKnownStream(uint32_t aSerial);
   private:
     // Maps Ogg serialnos to OggStreams.
     nsClassHashtable<nsUint32HashKey, OggCodecState> mCodecStates;
     // Protects the |mCodecStates| and the |mKnownStreams| members.
     Monitor mMonitor;
 };
 class OggReader : public MediaDecoderReader
 {
 public:
   OggReader(AbstractMediaDecoder* aDecoder);
   ~OggReader();
   virtual nsresult Init(MediaDecoderReader* aCloneDonor);
   virtual nsresult ResetDecode();
   virtual bool DecodeAudioData();
   // If the Theora granulepos has not been captured, it may read several packets
   // until one with a granulepos has been captured, to ensure that all packets
   // read have valid time info.
   virtual bool DecodeVideoFrame(bool &aKeyframeSkip,
                                   int64_t aTimeThreshold);
   virtual bool HasAudio() {
     return (mVorbisState != 0 && mVorbisState->mActive)
 #ifdef MOZ_OPUS
       || (mOpusState != 0 && mOpusState->mActive)
 #endif /* MOZ_OPUS */
       ;
   }
   virtual bool HasVideo() {
     return mTheoraState != 0 && mTheoraState->mActive;
   }
   virtual nsresult ReadMetadata(MediaInfo* aInfo,
                                 MetadataTags** aTags);
   virtual nsresult Seek(int64_t aTime, int64_t aStartTime, int64_t aEndTime, int64_t aCurrentTime);
   virtual nsresult GetBuffered(dom::TimeRanges* aBuffered, int64_t aStartTime);
 private:
   // This monitor should be taken when reading or writing to mIsChained.
   ReentrantMonitor mMonitor;
   // Specialized Reset() method to signal if the seek is
   // to the start of the stream.
   nsresult ResetDecode(bool start);
   bool HasSkeleton() {
     return mSkeletonState != 0 && mSkeletonState->mActive;
   }
   // Seeks to the keyframe preceeding the target time using available
   // keyframe indexes.
   enum IndexedSeekResult {
     SEEK_OK,          // Success.
     SEEK_INDEX_FAIL,  // Failure due to no index, or invalid index.
     SEEK_FATAL_ERROR  // Error returned by a stream operation.
   };
   IndexedSeekResult SeekToKeyframeUsingIndex(int64_t aTarget);
   // Rolls back a seek-using-index attempt, returning a failure error code.
   IndexedSeekResult RollbackIndexedSeek(int64_t aOffset);
   // Represents a section of contiguous media, with a start and end offset,
   // and the timestamps of the start and end of that range, that is cached.
   // Used to denote the extremities of a range in which we can seek quickly
   // (because it's cached).
   class SeekRange {
   public:
     SeekRange()
       : mOffsetStart(0),
         mOffsetEnd(0),
         mTimeStart(0),
         mTimeEnd(0)
     {}
     SeekRange(int64_t aOffsetStart,
               int64_t aOffsetEnd,
               int64_t aTimeStart,
               int64_t aTimeEnd)
       : mOffsetStart(aOffsetStart),
         mOffsetEnd(aOffsetEnd),
         mTimeStart(aTimeStart),
         mTimeEnd(aTimeEnd)
     {}
     bool IsNull() const {
       return mOffsetStart == 0 &&
              mOffsetEnd == 0 &&
              mTimeStart == 0 &&
              mTimeEnd == 0;
     }
     int64_t mOffsetStart, mOffsetEnd; // in bytes.
     int64_t mTimeStart, mTimeEnd; // in usecs.
   };
   // Seeks to aTarget usecs in the buffered range aRange using bisection search,
   // or to the keyframe prior to aTarget if we have video. aAdjustedTarget is
   // an adjusted version of the target used to account for Opus pre-roll, if
   // necessary. aStartTime must be the presentation time at the start of media,
   // and aEndTime the time at end of media. aRanges must be the time/byte ranges
   // buffered in the media cache as per GetSeekRanges().
   nsresult SeekInBufferedRange(int64_t aTarget,
                                int64_t aAdjustedTarget,
                                int64_t aStartTime,
                                int64_t aEndTime,
                                const nsTArray<SeekRange>& aRanges,
                                const SeekRange& aRange);
   // Seeks to before aTarget usecs in media using bisection search. If the media
   // has video, this will seek to before the keyframe required to render the
   // media at aTarget. Will use aRanges in order to narrow the bisection
   // search space. aStartTime must be the presentation time at the start of
   // media, and aEndTime the time at end of media. aRanges must be the time/byte
   // ranges buffered in the media cache as per GetSeekRanges().
   nsresult SeekInUnbuffered(int64_t aTarget,
                             int64_t aStartTime,
                             int64_t aEndTime,
                             const nsTArray<SeekRange>& aRanges);
   // Get the end time of aEndOffset. This is the playback position we'd reach
   // after playback finished at aEndOffset.
   int64_t RangeEndTime(int64_t aEndOffset);
   // Get the end time of aEndOffset, without reading before aStartOffset.
   // This is the playback position we'd reach after playback finished at
   // aEndOffset. If bool aCachedDataOnly is true, then we'll only read
   // from data which is cached in the media cached, otherwise we'll do
   // regular blocking reads from the media stream. If bool aCachedDataOnly
   // is true, this can safely be called on the main thread, otherwise it
   // must be called on the state machine thread.
   int64_t RangeEndTime(int64_t aStartOffset,
                        int64_t aEndOffset,
                        bool aCachedDataOnly);
   // Get the start time of the range beginning at aOffset. This is the start
   // time of the first frame and or audio sample we'd be able to play if we
   // started playback at aOffset.
   int64_t RangeStartTime(int64_t aOffset);
   // Performs a seek bisection to move the media stream's read cursor to the
   // last ogg page boundary which has end time before aTarget usecs on both the
   // Theora and Vorbis bitstreams. Limits its search to data inside aRange;
   // i.e. it will only read inside of the aRange's start and end offsets.
   // aFuzz is the number of usecs of leniency we'll allow; we'll terminate the
   // seek when we land in the range (aTime - aFuzz, aTime) usecs.
   nsresult SeekBisection(int64_t aTarget,
                          const SeekRange& aRange,
                          uint32_t aFuzz);
   // Returns true if the serial number is for a stream we encountered
   // while reading metadata. Call on the main thread only.
   bool IsKnownStream(uint32_t aSerial);
   // Fills aRanges with SeekRanges denoting the sections of the media which
   // have been downloaded and are stored in the media cache. The reader
   // monitor must must be held with exactly one lock count. The MediaResource
   // must be pinned while calling this.
   nsresult GetSeekRanges(nsTArray<SeekRange>& aRanges);
   // Returns the range in which you should perform a seek bisection if
   // you wish to seek to aTarget usecs, given the known (buffered) byte ranges
   // in aRanges. If aExact is true, we only return an exact copy of a
   // range in which aTarget lies, or a null range if aTarget isn't contained
   // in any of the (buffered) ranges. Otherwise, when aExact is false,
   // we'll construct the smallest possible range we can, based on the times
   // and byte offsets known in aRanges. We can then use this to minimize our
   // bisection's search space when the target isn't in a known buffered range.
   SeekRange SelectSeekRange(const nsTArray<SeekRange>& aRanges,
                             int64_t aTarget,
                             int64_t aStartTime,
                             int64_t aEndTime,
                             bool aExact);
 private:
   // Decodes a packet of Vorbis data, and inserts its samples into the
   // audio queue.
   nsresult DecodeVorbis(ogg_packet* aPacket);
   // Decodes a packet of Opus data, and inserts its samples into the
   // audio queue.
   nsresult DecodeOpus(ogg_packet* aPacket);
   // Decodes a packet of Theora data, and inserts its frame into the
   // video queue. May return NS_ERROR_OUT_OF_MEMORY. Caller must have obtained
   // the reader's monitor. aTimeThreshold is the current playback position
   // in media time in microseconds. Frames with an end time before this will
   // not be enqueued.
   nsresult DecodeTheora(ogg_packet* aPacket, int64_t aTimeThreshold);
   // Read a page of data from the Ogg file. Returns true if a page has been
   // read, false if the page read failed or end of file reached.
   bool ReadOggPage(ogg_page* aPage);
   // Reads and decodes header packets for aState, until either header decode
   // fails, or is complete. Initializes the codec state before returning.
   // Returns true if reading headers and initializtion of the stream
   // succeeds.
   bool ReadHeaders(OggCodecState* aState);
   // Reads the next link in the chain.
   bool ReadOggChain();
   // Set this media as being a chain and notifies the state machine that the
   // media is no longer seekable.
   void SetChained(bool aIsChained);
   // Returns the next Ogg packet for an bitstream/codec state. Returns a
   // pointer to an ogg_packet on success, or nullptr if the read failed.
   // The caller is responsible for deleting the packet and its |packet| field.
   ogg_packet* NextOggPacket(OggCodecState* aCodecState);
   // Fills aTracks with the serial numbers of each active stream, for use by
   // various SkeletonState functions.
   void BuildSerialList(nsTArray<uint32_t>& aTracks);
   OggCodecStore mCodecStore;
   // Decode state of the Theora bitstream we're decoding, if we have video.
   TheoraState* mTheoraState;
   // Decode state of the Vorbis bitstream we're decoding, if we have audio.
   VorbisState* mVorbisState;
 #ifdef MOZ_OPUS
   // Decode state of the Opus bitstream we're decoding, if we have one.
   OpusState *mOpusState;
   // Represents the user pref media.opus.enabled at the time our
   // contructor was called. We can't check it dynamically because
   // we're not on the main thread;
   bool mOpusEnabled;
 #endif /* MOZ_OPUS */
   // Decode state of the Skeleton bitstream.
   SkeletonState* mSkeletonState;
   // Ogg decoding state.
   ogg_sync_state mOggState;
   // Vorbis/Opus/Theora data used to compute timestamps. This is written on the
   // decoder thread and read on the main thread. All reading on the main
   // thread must be done after metadataloaded. We can't use the existing
   // data in the codec states due to threading issues. You must check the
   // associated mTheoraState or mVorbisState pointer is non-null before
   // using this codec data.
   uint32_t mVorbisSerial;
   uint32_t mOpusSerial;
   uint32_t mTheoraSerial;
   vorbis_info mVorbisInfo;
   int mOpusPreSkip;
   th_info mTheoraInfo;
   // The picture region inside Theora frame to be displayed, if we have
   // a Theora video track.
   nsIntRect mPicture;
   // True if we are decoding a chained ogg. Reading or writing to this member
   // should be done with |mMonitor| acquired.
   bool mIsChained;
   // Number of audio frames decoded so far.
   int64_t mDecodedAudioFrames;
 };
 } // namespace mozilla
 #endif

The Tor Browser / annotate

content/media/ogg/OggReader.h@97036ab72558 (annotated)

content/media/ogg/OggReader.h