gecko-dev/dom/quota/MemoryOutputStream.cpp
Nika Layzell de1e97c891 Bug 1754040 - Clean up common shared WriteSegments helper functions, r=necko-reviewers,xpcom-reviewers,mccr8
These helper methods are similar to the related ones for
nsIInputStream::ReadSegments, and can be used to implement
nsIOutputStream::Write and nsIOutputStream::WriteFrom in terms of
WriteSegments.

There were various places which used manual copies of these methods, which are
being unified.

Differential Revision: https://phabricator.services.mozilla.com/D138334
2022-02-14 23:59:35 +00:00

97 lines
2.4 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 "MemoryOutputStream.h"
#include "ErrorList.h"
#include "mozilla/Assertions.h"
#include "mozilla/MacroForEach.h"
#include "mozilla/RefPtr.h"
#include "mozilla/fallible.h"
#include "nsDebug.h"
#include "nsError.h"
#include "nsStreamUtils.h"
#include "nscore.h"
class nsIInputStream;
namespace mozilla::dom::quota {
// static
already_AddRefed<MemoryOutputStream> MemoryOutputStream::Create(
uint64_t aSize) {
MOZ_ASSERT(aSize, "Passed zero size!");
if (NS_WARN_IF(aSize > UINT32_MAX)) {
return nullptr;
}
RefPtr<MemoryOutputStream> stream = new MemoryOutputStream();
if (NS_WARN_IF(!stream->mData.SetLength(aSize, fallible))) {
return nullptr;
}
return stream.forget();
}
NS_IMPL_ISUPPORTS(MemoryOutputStream, nsIOutputStream)
NS_IMETHODIMP
MemoryOutputStream::Close() {
mData.Truncate(mOffset);
return NS_OK;
}
NS_IMETHODIMP
MemoryOutputStream::Write(const char* aBuf, uint32_t aCount,
uint32_t* _retval) {
return WriteSegments(NS_CopyBufferToSegment, (char*)aBuf, aCount, _retval);
}
NS_IMETHODIMP
MemoryOutputStream::Flush() { return NS_OK; }
NS_IMETHODIMP
MemoryOutputStream::WriteFrom(nsIInputStream* aFromStream, uint32_t aCount,
uint32_t* _retval) {
return NS_ERROR_NOT_IMPLEMENTED;
}
NS_IMETHODIMP
MemoryOutputStream::WriteSegments(nsReadSegmentFun aReader, void* aClosure,
uint32_t aCount, uint32_t* _retval) {
MOZ_ASSERT(mData.Length() >= mOffset, "Bad stream state!");
uint32_t 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)) {
MOZ_ASSERT(*_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;
}
} // namespace mozilla::dom::quota