BufferMediaResource.h (2499B)
1 /* vim:set ts=2 sw=2 sts=2 et cindent: */ 2 /* This Source Code Form is subject to the terms of the Mozilla Public 3 * License, v. 2.0. If a copy of the MPL was not distributed with this 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 5 6 #if !defined(BufferMediaResource_h_) 7 # define BufferMediaResource_h_ 8 9 # include <algorithm> 10 11 # include "MediaResource.h" 12 # include "nsISeekableStream.h" 13 14 namespace mozilla { 15 16 DDLoggedTypeDeclNameAndBase(BufferMediaResource, MediaResource); 17 18 // A simple MediaResource based on an in memory buffer. This class accepts 19 // the address and the length of the buffer, and simulates a read/seek API 20 // on top of it. The Read implementation involves copying memory, which is 21 // unfortunate, but the MediaResource interface mandates that. 22 class BufferMediaResource 23 : public MediaResource, 24 public DecoderDoctorLifeLogger<BufferMediaResource> { 25 public: 26 BufferMediaResource(const uint8_t* aBuffer, uint32_t aLength) 27 : mBuffer(aBuffer), mLength(aLength) {} 28 29 protected: 30 virtual ~BufferMediaResource() = default; 31 32 private: 33 // These methods are called off the main thread. 34 nsresult ReadAt(int64_t aOffset, char* aBuffer, uint32_t aCount, 35 uint32_t* aBytes) override { 36 if (aOffset < 0 || aOffset > mLength) { 37 return NS_ERROR_FAILURE; 38 } 39 *aBytes = std::min(mLength - static_cast<uint32_t>(aOffset), aCount); 40 memcpy(aBuffer, mBuffer + aOffset, *aBytes); 41 return NS_OK; 42 } 43 // Memory-based and no locks, caching discouraged. 44 bool ShouldCacheReads() override { return false; } 45 46 void Pin() override {} 47 void Unpin() override {} 48 int64_t GetLength() override { return mLength; } 49 int64_t GetNextCachedData(int64_t aOffset) override { return aOffset; } 50 int64_t GetCachedDataEnd(int64_t aOffset) override { 51 return std::max(aOffset, int64_t(mLength)); 52 } 53 bool IsDataCachedToEndOfResource(int64_t aOffset) override { return true; } 54 nsresult ReadFromCache(char* aBuffer, int64_t aOffset, 55 uint32_t aCount) override { 56 if (aOffset < 0) { 57 return NS_ERROR_FAILURE; 58 } 59 60 uint32_t bytes = std::min(mLength - static_cast<uint32_t>(aOffset), aCount); 61 memcpy(aBuffer, mBuffer + aOffset, bytes); 62 return NS_OK; 63 } 64 65 nsresult GetCachedRanges(MediaByteRangeSet& aRanges) override { 66 aRanges += MediaByteRange(0, int64_t(mLength)); 67 return NS_OK; 68 } 69 70 private: 71 const uint8_t* mBuffer; 72 uint32_t mLength; 73 }; 74 75 } // namespace mozilla 76 77 #endif