gecko-dev/dom/media/mediasource/SourceBufferResource.cpp

214 строки
6.0 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */
#include "SourceBufferResource.h"
#include <algorithm>
#include "nsISeekableStream.h"
#include "nsISupports.h"
#include "mozilla/Logging.h"
#include "MediaData.h"
mozilla::LogModule* GetSourceBufferResourceLog()
{
static mozilla::LazyLogModule sLogModule("SourceBufferResource");
return sLogModule;
}
#define SBR_DEBUG(arg, ...) MOZ_LOG(GetSourceBufferResourceLog(), mozilla::LogLevel::Debug, ("SourceBufferResource(%p:%s)::%s: " arg, this, mType.get(), __func__, ##__VA_ARGS__))
#define SBR_DEBUGV(arg, ...) MOZ_LOG(GetSourceBufferResourceLog(), mozilla::LogLevel::Verbose, ("SourceBufferResource(%p:%s)::%s: " arg, this, mType.get(), __func__, ##__VA_ARGS__))
namespace mozilla {
nsresult
SourceBufferResource::Close()
{
ReentrantMonitorAutoEnter mon(mMonitor);
SBR_DEBUG("Close");
//MOZ_ASSERT(!mClosed);
mClosed = true;
mon.NotifyAll();
return NS_OK;
}
nsresult
SourceBufferResource::ReadInternal(char* aBuffer, uint32_t aCount, uint32_t* aBytes, bool aMayBlock)
{
mMonitor.AssertCurrentThreadIn();
MOZ_ASSERT_IF(!aMayBlock, aBytes);
// Cache the offset for the read in case mOffset changes while waiting on the
// monitor below. It's basically impossible to implement these API semantics
// sanely. :-(
uint64_t readOffset = mOffset;
while (aMayBlock &&
!mEnded &&
readOffset + aCount > static_cast<uint64_t>(GetLength())) {
SBR_DEBUGV("waiting for data");
mMonitor.Wait();
// The callers of this function should have checked this, but it's
// possible that we had an eviction while waiting on the monitor.
if (readOffset < mInputBuffer.GetOffset()) {
return NS_ERROR_FAILURE;
}
}
uint32_t available = GetLength() - readOffset;
uint32_t count = std::min(aCount, available);
SBR_DEBUGV("readOffset=%llu GetLength()=%u available=%u count=%u mEnded=%d",
readOffset, GetLength(), available, count, mEnded);
if (available == 0) {
SBR_DEBUGV("reached EOF");
*aBytes = 0;
return NS_OK;
}
mInputBuffer.CopyData(readOffset, count, aBuffer);
*aBytes = count;
// From IRC:
// <@cpearce>bholley: *this* is why there should only every be a ReadAt() and
// no Read() on a Stream abstraction! there's no good answer, they all suck.
mOffset = readOffset + count;
return NS_OK;
}
nsresult
SourceBufferResource::ReadAt(int64_t aOffset, char* aBuffer, uint32_t aCount, uint32_t* aBytes)
{
SBR_DEBUG("ReadAt(aOffset=%lld, aBuffer=%p, aCount=%u, aBytes=%p)",
aOffset, aBytes, aCount, aBytes);
ReentrantMonitorAutoEnter mon(mMonitor);
return ReadAtInternal(aOffset, aBuffer, aCount, aBytes, /* aMayBlock = */ true);
}
nsresult
SourceBufferResource::ReadAtInternal(int64_t aOffset, char* aBuffer, uint32_t aCount, uint32_t* aBytes,
bool aMayBlock)
{
mMonitor.AssertCurrentThreadIn();
nsresult rv = SeekInternal(aOffset);
if (NS_FAILED(rv)) {
return rv;
}
return ReadInternal(aBuffer, aCount, aBytes, aMayBlock);
}
nsresult
SourceBufferResource::SeekInternal(int64_t aOffset)
{
mMonitor.AssertCurrentThreadIn();
if (mClosed ||
aOffset < 0 ||
uint64_t(aOffset) < mInputBuffer.GetOffset() ||
aOffset > GetLength()) {
return NS_ERROR_FAILURE;
}
mOffset = aOffset;
return NS_OK;
}
nsresult
SourceBufferResource::ReadFromCache(char* aBuffer, int64_t aOffset, uint32_t aCount)
{
SBR_DEBUG("ReadFromCache(aBuffer=%p, aOffset=%lld, aCount=%u)",
aBuffer, aOffset, aCount);
ReentrantMonitorAutoEnter mon(mMonitor);
uint32_t bytesRead;
int64_t oldOffset = mOffset;
nsresult rv = ReadAtInternal(aOffset, aBuffer, aCount, &bytesRead, /* aMayBlock = */ false);
mOffset = oldOffset; // ReadFromCache isn't supposed to affect the seek position.
NS_ENSURE_SUCCESS(rv, rv);
// ReadFromCache return failure if not all the data is cached.
return bytesRead == aCount ? NS_OK : NS_ERROR_FAILURE;
}
uint32_t
SourceBufferResource::EvictData(uint64_t aPlaybackOffset, uint32_t aThreshold,
ErrorResult& aRv)
{
SBR_DEBUG("EvictData(aPlaybackOffset=%llu,"
"aThreshold=%u)", aPlaybackOffset, aThreshold);
ReentrantMonitorAutoEnter mon(mMonitor);
uint32_t result = mInputBuffer.Evict(aPlaybackOffset, aThreshold, aRv);
if (result > 0) {
// Wake up any waiting threads in case a ReadInternal call
// is now invalid.
mon.NotifyAll();
}
return result;
}
void
SourceBufferResource::EvictBefore(uint64_t aOffset, ErrorResult& aRv)
{
SBR_DEBUG("EvictBefore(aOffset=%llu)", aOffset);
ReentrantMonitorAutoEnter mon(mMonitor);
// If aOffset is past the current playback offset we don't evict.
if (aOffset < mOffset) {
mInputBuffer.EvictBefore(aOffset, aRv);
}
// Wake up any waiting threads in case a ReadInternal call
// is now invalid.
mon.NotifyAll();
}
uint32_t
SourceBufferResource::EvictAll()
{
SBR_DEBUG("EvictAll()");
ReentrantMonitorAutoEnter mon(mMonitor);
return mInputBuffer.EvictAll();
}
void
SourceBufferResource::AppendData(MediaByteBuffer* aData)
{
SBR_DEBUG("AppendData(aData=%p, aLength=%u)",
aData->Elements(), aData->Length());
ReentrantMonitorAutoEnter mon(mMonitor);
mInputBuffer.AppendItem(aData);
mEnded = false;
mon.NotifyAll();
}
void
SourceBufferResource::Ended()
{
SBR_DEBUG("");
ReentrantMonitorAutoEnter mon(mMonitor);
mEnded = true;
mon.NotifyAll();
}
SourceBufferResource::~SourceBufferResource()
{
SBR_DEBUG("");
MOZ_COUNT_DTOR(SourceBufferResource);
}
SourceBufferResource::SourceBufferResource(const nsACString& aType)
: mType(aType)
, mMonitor("mozilla::SourceBufferResource::mMonitor")
, mOffset(0)
, mClosed(false)
, mEnded(false)
{
SBR_DEBUG("");
MOZ_COUNT_CTOR(SourceBufferResource);
}
#undef SBR_DEBUG
#undef SBR_DEBUGV
} // namespace mozilla