gecko-dev/dom/file/MemoryStreams.cpp
2012-07-30 17:20:58 +03:00

91 lines
2.1 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=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 "MemoryStreams.h"
#include "nsStreamUtils.h"
USING_FILE_NAMESPACE
// static
already_AddRefed<MemoryOutputStream>
MemoryOutputStream::Create(PRUint64 aSize)
{
NS_ASSERTION(aSize, "Passed zero size!");
NS_ENSURE_TRUE(aSize <= PR_UINT32_MAX, nullptr);
nsRefPtr<MemoryOutputStream> stream = new MemoryOutputStream();
char* dummy;
PRUint32 length = stream->mData.GetMutableData(&dummy, aSize, fallible_t());
NS_ENSURE_TRUE(length == aSize, nullptr);
return stream.forget();
}
NS_IMPL_THREADSAFE_ISUPPORTS1(MemoryOutputStream, nsIOutputStream)
NS_IMETHODIMP
MemoryOutputStream::Close()
{
mData.Truncate(mOffset);
return NS_OK;
}
NS_IMETHODIMP
MemoryOutputStream::Write(const char* aBuf, PRUint32 aCount, PRUint32* _retval)
{
return WriteSegments(NS_CopySegmentToBuffer, (char*)aBuf, aCount, _retval);
}
NS_IMETHODIMP
MemoryOutputStream::Flush()
{
return NS_OK;
}
NS_IMETHODIMP
MemoryOutputStream::WriteFrom(nsIInputStream* aFromStream, PRUint32 aCount,
PRUint32* _retval)
{
return NS_ERROR_NOT_IMPLEMENTED;
}
NS_IMETHODIMP
MemoryOutputStream::WriteSegments(nsReadSegmentFun aReader, void* aClosure,
PRUint32 aCount, PRUint32* _retval)
{
NS_ASSERTION(mData.Length() >= mOffset, "Bad stream state!");
PRUint32 maxCount = mData.Length() - mOffset;
if (maxCount == 0) {
*_retval = 0;
return NS_OK;
}
if (aCount > maxCount) {
aCount = maxCount;
}
nsresult rv = aReader(this, aClosure, mData.BeginWriting() + mOffset, 0,
aCount, _retval);
if (NS_SUCCEEDED(rv)) {
NS_ASSERTION(*_retval <= aCount,
"Reader should not read more than we asked it to read!");
mOffset += *_retval;
}
return NS_OK;
}
NS_IMETHODIMP
MemoryOutputStream::IsNonBlocking(bool* _retval)
{
*_retval = false;
return NS_OK;
}