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/* -*- Mode: C++; tab-width: 4; 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 "RawShmem.h"
#include "mozilla/ipc/ProtocolUtils.h"
namespace mozilla::ipc {
UnsafeSharedMemoryHandle::UnsafeSharedMemoryHandle()
: mHandle(ipc::SharedMemoryBasic::NULLHandle()), mSize(0) {}
UnsafeSharedMemoryHandle::UnsafeSharedMemoryHandle(
UnsafeSharedMemoryHandle&& aOther) noexcept
: mHandle(std::move(aOther.mHandle)), mSize(aOther.mSize) {
aOther.mHandle = ipc::SharedMemoryBasic::NULLHandle();
aOther.mSize = 0;
}
UnsafeSharedMemoryHandle& UnsafeSharedMemoryHandle::operator=(
UnsafeSharedMemoryHandle&& aOther) noexcept {
if (this == &aOther) {
return *this;
}
mHandle = std::move(aOther.mHandle);
mSize = aOther.mSize;
aOther.mHandle = ipc::SharedMemoryBasic::NULLHandle();
aOther.mSize = 0;
return *this;
}
Maybe<std::pair<UnsafeSharedMemoryHandle, WritableSharedMemoryMapping>>
UnsafeSharedMemoryHandle::CreateAndMap(size_t aSize) {
if (aSize == 0) {
return Some(std::make_pair(UnsafeSharedMemoryHandle(),
WritableSharedMemoryMapping()));
}
RefPtr<ipc::SharedMemoryBasic> shm = MakeAndAddRef<ipc::SharedMemoryBasic>();
if (NS_WARN_IF(!shm->Create(aSize)) || NS_WARN_IF(!shm->Map(aSize))) {
return Nothing();
}
// TODO(bug 1797039): At the moment the handle/mapping distinction is
// implemented on top of a single class SharedMemoryBasic. It leads to a few
// awkward or sub-optimal things such as how the following few lines clone
// then close the handle. It would be better to separate the underlying
// implementation or steal the handle to avoid cloning it.
auto handle = shm->CloneHandle();
shm->CloseHandle();
auto size = shm->Size();
return Some(std::make_pair(UnsafeSharedMemoryHandle(std::move(handle), size),
WritableSharedMemoryMapping(std::move(shm))));
}
WritableSharedMemoryMapping::WritableSharedMemoryMapping(
RefPtr<ipc::SharedMemoryBasic>&& aRef)
: mRef(aRef) {}
Maybe<WritableSharedMemoryMapping> WritableSharedMemoryMapping::Open(
UnsafeSharedMemoryHandle aHandle) {
if (aHandle.mSize == 0) {
return Some(WritableSharedMemoryMapping(nullptr));
}
RefPtr<ipc::SharedMemoryBasic> shm = MakeAndAddRef<ipc::SharedMemoryBasic>();
if (NS_WARN_IF(!shm->SetHandle(std::move(aHandle.mHandle),
ipc::SharedMemory::RightsReadWrite)) ||
NS_WARN_IF(!shm->Map(aHandle.mSize))) {
return Nothing();
}
shm->CloseHandle();
return Some(WritableSharedMemoryMapping(std::move(shm)));
}
size_t WritableSharedMemoryMapping::Size() const {
if (!mRef) {
return 0;
}
return mRef->Size();
}
Span<uint8_t> WritableSharedMemoryMapping::Bytes() {
if (!mRef) {
return Span<uint8_t>();
}
uint8_t* mem = static_cast<uint8_t*>(mRef->memory());
return Span(mem, mRef->Size());
}
} // namespace mozilla::ipc
namespace IPC {
auto ParamTraits<mozilla::ipc::UnsafeSharedMemoryHandle>::Write(
IPC::MessageWriter* aWriter, paramType&& aVar) -> void {
IPC::WriteParam(aWriter, std::move(aVar.mHandle));
IPC::WriteParam(aWriter, aVar.mSize);
}
auto ParamTraits<mozilla::ipc::UnsafeSharedMemoryHandle>::Read(
IPC::MessageReader* aReader, paramType* aVar) -> bool {
return IPC::ReadParam(aReader, &aVar->mHandle) &&
IPC::ReadParam(aReader, &aVar->mSize);
}
} // namespace IPC
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