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51415ba462
A lot of the overhead in MoofParser::RebuildFragmentedIndex(BoxContext&) is copying data into the BoxReader's storage. In the MSE case the underlying data being read is actually buffered in memory, so we may be able to just read the in-memory data directly, avoiding the copy. Note that the data may not be stored in a single contiguous ResourceItem in the SourceBufferResource's ResourQueue. If so, it's not as straightforward to hand out a uint8_t* to the underlying data. So we just copy it in that case for simplicity. In most cases, the data in a single MP4 box would be appended in a single append, and so is likely to be in a single ResourceItem. Differential Revision: https://phabricator.services.mozilla.com/D33877 --HG-- extra : moz-landing-system : lando
100 lines
2.9 KiB
C++
100 lines
2.9 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim:set ts=2 sw=2 sts=2 et cindent: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef BOX_H_
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#define BOX_H_
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#include <stdint.h>
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#include "nsTArray.h"
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#include "MediaResource.h"
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#include "mozilla/EndianUtils.h"
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#include "AtomType.h"
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#include "BufferReader.h"
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namespace mozilla {
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class ByteStream;
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class BumpAllocator {
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public:
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uint8_t* Allocate(size_t aNumBytes);
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private:
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nsTArray<nsTArray<uint8_t>> mBuffers;
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};
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class BoxContext {
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public:
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BoxContext(ByteStream* aSource, const MediaByteRangeSet& aByteRanges)
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: mSource(aSource), mByteRanges(aByteRanges) {}
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RefPtr<ByteStream> mSource;
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const MediaByteRangeSet& mByteRanges;
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BumpAllocator mAllocator;
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};
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struct ByteSlice {
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const uint8_t* mBytes;
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size_t mSize;
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};
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class Box {
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public:
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Box(BoxContext* aContext, uint64_t aOffset, const Box* aParent = nullptr);
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Box();
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bool IsAvailable() const { return !mRange.IsEmpty(); }
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uint64_t Offset() const { return mRange.mStart; }
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uint64_t Length() const { return mRange.mEnd - mRange.mStart; }
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uint64_t NextOffset() const { return mRange.mEnd; }
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const MediaByteRange& Range() const { return mRange; }
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const Box* Parent() const { return mParent; }
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bool IsType(const char* aType) const { return mType == AtomType(aType); }
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Box Next() const;
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Box FirstChild() const;
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// Reads the box contents, excluding the header.
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nsTArray<uint8_t> Read() const;
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// Reads the complete box; its header and body.
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nsTArray<uint8_t> ReadCompleteBox() const;
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// Reads from the content of the box, excluding header.
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bool Read(nsTArray<uint8_t>* aDest, const MediaByteRange& aRange) const;
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static const uint64_t kMAX_BOX_READ;
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// Returns a slice, pointing to the data of this box. The lifetime of
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// the memory this slice points to matches the box's context's lifetime.
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ByteSlice ReadAsSlice();
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private:
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bool Contains(MediaByteRange aRange) const;
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BoxContext* mContext;
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mozilla::MediaByteRange mRange;
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uint64_t mBodyOffset;
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uint64_t mChildOffset;
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AtomType mType;
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const Box* mParent;
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};
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// BoxReader serves box data through an AutoByteReader. The box data is
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// stored either in the box's context's bump allocator, or in the ByteStream
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// itself if the ByteStream implements the Access() method.
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// NOTE: The data the BoxReader reads may be stored in the Box's BoxContext.
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// Ensure that the BoxReader doesn't outlive the BoxContext!
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class MOZ_RAII BoxReader {
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public:
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explicit BoxReader(Box& aBox)
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: mData(aBox.ReadAsSlice()), mReader(mData.mBytes, mData.mSize) {}
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BufferReader* operator->() { return &mReader; }
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private:
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ByteSlice mData;
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BufferReader mReader;
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};
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} // namespace mozilla
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#endif
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