gecko-dev/dom/media/FileMediaResource.h

142 строки
4.4 KiB
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/* 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/. */
#ifndef mozilla_dom_media_FileMediaResource_h
#define mozilla_dom_media_FileMediaResource_h
#include "BaseMediaResource.h"
#include "mozilla/Mutex.h"
namespace mozilla {
class FileMediaResource : public BaseMediaResource
{
public:
FileMediaResource(MediaResourceCallback* aCallback,
nsIChannel* aChannel,
nsIURI* aURI,
int64_t aSize = -1 /* unknown size */)
: BaseMediaResource(aCallback, aChannel, aURI)
, mSize(aSize)
, mLock("FileMediaResource.mLock")
, mSizeInitialized(aSize != -1)
{
}
~FileMediaResource()
{
}
// Main thread
nsresult Open(nsIStreamListener** aStreamListener) override;
nsresult Close() override;
void Suspend(bool aCloseImmediately) override {}
void Resume() override {}
already_AddRefed<nsIPrincipal> GetCurrentPrincipal() override;
nsresult ReadFromCache(char* aBuffer, int64_t aOffset, uint32_t aCount) override;
// These methods are called off the main thread.
// Other thread
void SetReadMode(MediaCacheStream::ReadMode aMode) override {}
void SetPlaybackRate(uint32_t aBytesPerSecond) override {}
nsresult ReadAt(int64_t aOffset, char* aBuffer,
uint32_t aCount, uint32_t* aBytes) override;
// (Probably) file-based, caching recommended.
bool ShouldCacheReads() override { return true; }
int64_t Tell() override;
// Any thread
void Pin() override {}
void Unpin() override {}
double GetDownloadRate(bool* aIsReliable) override
{
// The data's all already here
*aIsReliable = true;
return 100*1024*1024; // arbitray, use 100MB/s
}
int64_t GetLength() override
{
MutexAutoLock lock(mLock);
EnsureSizeInitialized();
return mSizeInitialized ? mSize : 0;
}
int64_t GetNextCachedData(int64_t aOffset) override
{
MutexAutoLock lock(mLock);
EnsureSizeInitialized();
return (aOffset < mSize) ? aOffset : -1;
}
int64_t GetCachedDataEnd(int64_t aOffset) override
{
MutexAutoLock lock(mLock);
EnsureSizeInitialized();
return std::max(aOffset, mSize);
}
bool IsDataCachedToEndOfResource(int64_t aOffset) override { return true; }
bool IsTransportSeekable() override { return true; }
nsresult GetCachedRanges(MediaByteRangeSet& aRanges) override;
size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override
{
// Might be useful to track in the future:
// - mInput
return BaseMediaResource::SizeOfExcludingThis(aMallocSizeOf);
}
size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override
{
return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
}
protected:
// These Unsafe variants of Read and Seek perform their operations
// without acquiring mLock. The caller must obtain the lock before
// calling. The implmentation of Read, Seek and ReadAt obtains the
// lock before calling these Unsafe variants to read or seek.
nsresult UnsafeRead(char* aBuffer, uint32_t aCount, uint32_t* aBytes);
nsresult UnsafeSeek(int32_t aWhence, int64_t aOffset);
private:
// Ensures mSize is initialized, if it can be.
// mLock must be held when this is called, and mInput must be non-null.
void EnsureSizeInitialized();
already_AddRefed<MediaByteBuffer> UnsafeMediaReadAt(
int64_t aOffset, uint32_t aCount);
// The file size, or -1 if not known. Immutable after Open().
// Can be used from any thread.
int64_t mSize;
// This lock handles synchronisation between calls to Close() and
// the Read, Seek, etc calls. Close must not be called while a
// Read or Seek is in progress since it resets various internal
// values to null.
// This lock protects mSeekable, mInput, mSize, and mSizeInitialized.
Mutex mLock;
// Seekable stream interface to file. This can be used from any
// thread.
nsCOMPtr<nsISeekableStream> mSeekable;
// Input stream for the media data. This can be used from any
// thread.
nsCOMPtr<nsIInputStream> mInput;
// Whether we've attempted to initialize mSize. Note that mSize can be -1
// when mSizeInitialized is true if we tried and failed to get the size
// of the file.
bool mSizeInitialized;
};
} // namespace mozilla
#endif // mozilla_dom_media_FileMediaResource_h