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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
#include "MP4Stream.h"
#include "MediaResource.h"
namespace mozilla {
MP4Stream::MP4Stream(MediaResource* aResource)
: mResource(aResource)
, mPinCount(0)
{
MOZ_COUNT_CTOR(MP4Stream);
MOZ_ASSERT(aResource);
}
MP4Stream::~MP4Stream()
{
MOZ_COUNT_DTOR(MP4Stream);
MOZ_ASSERT(mPinCount == 0);
}
bool
MP4Stream::BlockingReadIntoCache(int64_t aOffset, size_t aCount, Monitor* aToUnlock)
{
MOZ_ASSERT(mPinCount > 0);
CacheBlock block(aOffset, aCount);
if (!block.Init()) {
return false;
}
uint32_t bytesRead = 0;
{
MonitorAutoUnlock unlock(*aToUnlock);
nsresult rv = mResource.ReadAt(aOffset, block.Buffer(), aCount, &bytesRead);
if (NS_FAILED(rv)) {
return false;
}
}
MOZ_ASSERT(block.mCount >= bytesRead);
block.mCount = bytesRead;
mCache.AppendElement(Move(block));
return true;
}
// We surreptitiously reimplement the supposedly-blocking ReadAt as a non-
// blocking CachedReadAt, and record when it fails. This allows MP4Reader
// to retry the read as an actual blocking read without holding the lock.
bool
MP4Stream::ReadAt(int64_t aOffset, void* aBuffer, size_t aCount,
size_t* aBytesRead)
{
if (mFailedRead.isSome()) {
mFailedRead.reset();
}
if (!CachedReadAt(aOffset, aBuffer, aCount, aBytesRead)) {
mFailedRead.emplace(aOffset, aCount);
return false;
}
return true;
}
bool
MP4Stream::CachedReadAt(int64_t aOffset, void* aBuffer, size_t aCount,
size_t* aBytesRead)
{
// First, check our local cache.
for (size_t i = 0; i < mCache.Length(); ++i) {
if (mCache[i].mOffset == aOffset && mCache[i].mCount >= aCount) {
memcpy(aBuffer, mCache[i].Buffer(), aCount);
*aBytesRead = aCount;
return true;
}
}
nsresult rv =
mResource.GetResource()->ReadFromCache(reinterpret_cast<char*>(aBuffer),
aOffset, aCount);
if (NS_FAILED(rv)) {
*aBytesRead = 0;
return false;
}
*aBytesRead = aCount;
return true;
}
bool
MP4Stream::Length(int64_t* aSize)
{
if (mResource.GetLength() < 0)
return false;
*aSize = mResource.GetLength();
return true;
}
} // namespace mozilla
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