gecko-dev/content/media/BufferMediaResource.h

156 строки
4.6 KiB
C++

/* 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(BufferMediaResource_h_)
#define BufferMediaResource_h_
#include "MediaResource.h"
#include "nsISeekableStream.h"
#include "nsIPrincipal.h"
#include <algorithm>
namespace mozilla {
// A simple MediaResource based on an in memory buffer. This class accepts
// the address and the length of the buffer, and simulates a read/seek API
// on top of it. The Read implementation involves copying memory, which is
// unfortunate, but the MediaResource interface mandates that.
class BufferMediaResource : public MediaResource
{
public:
BufferMediaResource(const uint8_t* aBuffer,
uint32_t aLength,
nsIPrincipal* aPrincipal,
const nsACString& aContentType) :
mBuffer(aBuffer),
mLength(aLength),
mOffset(0),
mPrincipal(aPrincipal),
mContentType(aContentType)
{
MOZ_COUNT_CTOR(BufferMediaResource);
}
virtual ~BufferMediaResource()
{
MOZ_COUNT_DTOR(BufferMediaResource);
}
virtual nsresult Close() { return NS_OK; }
virtual void Suspend(bool aCloseImmediately) {}
virtual void Resume() {}
// Get the current principal for the channel
virtual already_AddRefed<nsIPrincipal> GetCurrentPrincipal()
{
nsCOMPtr<nsIPrincipal> principal = mPrincipal;
return principal.forget();
}
virtual bool CanClone() { return false; }
virtual already_AddRefed<MediaResource> CloneData(MediaDecoder* aDecoder)
{
return nullptr;
}
// These methods are called off the main thread.
// The mode is initially MODE_PLAYBACK.
virtual void SetReadMode(MediaCacheStream::ReadMode aMode) {}
virtual void SetPlaybackRate(uint32_t aBytesPerSecond) {}
virtual nsresult Read(char* aBuffer, uint32_t aCount, uint32_t* aBytes)
{
*aBytes = std::min(mLength - mOffset, aCount);
memcpy(aBuffer, mBuffer + mOffset, *aBytes);
mOffset += *aBytes;
MOZ_ASSERT(mOffset <= mLength);
return NS_OK;
}
virtual nsresult ReadAt(int64_t aOffset, char* aBuffer,
uint32_t aCount, uint32_t* aBytes)
{
nsresult rv = Seek(nsISeekableStream::NS_SEEK_SET, aOffset);
if (NS_FAILED(rv)) return rv;
return Read(aBuffer, aCount, aBytes);
}
virtual nsresult Seek(int32_t aWhence, int64_t aOffset)
{
MOZ_ASSERT(aOffset <= UINT32_MAX);
switch (aWhence) {
case nsISeekableStream::NS_SEEK_SET:
if (aOffset < 0 || aOffset > mLength) {
return NS_ERROR_FAILURE;
}
mOffset = static_cast<uint32_t> (aOffset);
break;
case nsISeekableStream::NS_SEEK_CUR:
if (aOffset >= mLength - mOffset) {
return NS_ERROR_FAILURE;
}
mOffset += static_cast<uint32_t> (aOffset);
break;
case nsISeekableStream::NS_SEEK_END:
if (aOffset < 0 || aOffset > mLength) {
return NS_ERROR_FAILURE;
}
mOffset = mLength - aOffset;
break;
}
return NS_OK;
}
virtual void StartSeekingForMetadata() {}
virtual void EndSeekingForMetadata() {}
virtual int64_t Tell() { return mOffset; }
virtual void Pin() {}
virtual void Unpin() {}
virtual double GetDownloadRate(bool* aIsReliable) { return 0.; }
virtual int64_t GetLength() { return mLength; }
virtual int64_t GetNextCachedData(int64_t aOffset) { return aOffset; }
virtual int64_t GetCachedDataEnd(int64_t aOffset) { return mLength; }
virtual bool IsDataCachedToEndOfResource(int64_t aOffset) { return true; }
virtual bool IsSuspendedByCache() { return false; }
virtual bool IsSuspended() { return false; }
virtual nsresult ReadFromCache(char* aBuffer,
int64_t aOffset,
uint32_t aCount)
{
if (aOffset < 0) {
return NS_ERROR_FAILURE;
}
uint32_t bytes = std::min(mLength - static_cast<uint32_t>(aOffset), aCount);
memcpy(aBuffer, mBuffer + aOffset, bytes);
return NS_OK;
}
virtual nsresult Open(nsIStreamListener** aStreamListener)
{
return NS_ERROR_FAILURE;
}
virtual nsresult GetCachedRanges(nsTArray<MediaByteRange>& aRanges)
{
aRanges.AppendElement(MediaByteRange(0, mLength));
return NS_OK;
}
bool IsTransportSeekable() MOZ_OVERRIDE { return true; }
virtual const nsCString& GetContentType() const MOZ_OVERRIDE
{
return mContentType;
}
private:
const uint8_t * mBuffer;
uint32_t mLength;
uint32_t mOffset;
nsCOMPtr<nsIPrincipal> mPrincipal;
const nsAutoCString mContentType;
};
}
#endif