gecko-dev/devtools/shared/heapsnapshot/ZeroCopyNSIOutputStream.cpp

80 строки
2.2 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2; -*- */
/* 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 "mozilla/devtools/ZeroCopyNSIOutputStream.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/Unused.h"
namespace mozilla {
namespace devtools {
ZeroCopyNSIOutputStream::ZeroCopyNSIOutputStream(nsCOMPtr<nsIOutputStream>& out)
: out(out), result_(NS_OK), amountUsed(0), writtenCount(0) {
DebugOnly<bool> nonBlocking = false;
MOZ_ASSERT(out->IsNonBlocking(&nonBlocking) == NS_OK);
MOZ_ASSERT(!nonBlocking);
}
ZeroCopyNSIOutputStream::~ZeroCopyNSIOutputStream() {
if (!failed()) Unused << NS_WARN_IF(NS_FAILED(writeBuffer()));
}
nsresult ZeroCopyNSIOutputStream::writeBuffer() {
if (failed()) return result_;
if (amountUsed == 0) return NS_OK;
int32_t amountWritten = 0;
while (amountWritten < amountUsed) {
uint32_t justWritten = 0;
result_ = out->Write(buffer + amountWritten, amountUsed - amountWritten,
&justWritten);
if (NS_WARN_IF(NS_FAILED(result_))) return result_;
amountWritten += justWritten;
}
writtenCount += amountUsed;
amountUsed = 0;
return NS_OK;
}
// ZeroCopyOutputStream Interface
bool ZeroCopyNSIOutputStream::Next(void** data, int* size) {
MOZ_ASSERT(data != nullptr);
MOZ_ASSERT(size != nullptr);
if (failed()) return false;
if (amountUsed == BUFFER_SIZE) {
if (NS_FAILED(writeBuffer())) return false;
}
*data = buffer + amountUsed;
*size = BUFFER_SIZE - amountUsed;
amountUsed = BUFFER_SIZE;
return true;
}
void ZeroCopyNSIOutputStream::BackUp(int count) {
MOZ_ASSERT(count >= 0, "Cannot back up a negative amount of bytes.");
MOZ_ASSERT(amountUsed == BUFFER_SIZE,
"Can only call BackUp directly after calling Next.");
MOZ_ASSERT(count <= amountUsed,
"Can't back up further than we've given out.");
amountUsed -= count;
}
::google::protobuf::int64 ZeroCopyNSIOutputStream::ByteCount() const {
return writtenCount + amountUsed;
}
} // namespace devtools
} // namespace mozilla