зеркало из https://github.com/mozilla/gecko-dev.git
54 строки
1.6 KiB
C++
54 строки
1.6 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/. */
|
|
|
|
#ifndef dom_ipc_MemMapSnapshot_h
|
|
#define dom_ipc_MemMapSnapshot_h
|
|
|
|
#include "mozilla/Attributes.h"
|
|
#include "mozilla/Maybe.h"
|
|
#include "mozilla/RangedPtr.h"
|
|
#include "mozilla/Result.h"
|
|
#include "base/shared_memory.h"
|
|
|
|
namespace mozilla {
|
|
namespace loader {
|
|
class AutoMemMap;
|
|
}
|
|
|
|
namespace ipc {
|
|
|
|
/**
|
|
* A helper class for creating a read-only snapshot of memory-mapped data.
|
|
*
|
|
* The Init() method initializes a read-write memory mapped region of the given
|
|
* size, which can be initialized with arbitrary data. The Finalize() method
|
|
* remaps that region as read-only (and backs it with a read-only file
|
|
* descriptor), and initializes an AutoMemMap with the new contents.
|
|
*
|
|
* The file descriptor for the resulting AutoMemMap can be shared among
|
|
* processes, to safely access a shared, read-only copy of the data snapshot.
|
|
*/
|
|
class MOZ_RAII MemMapSnapshot {
|
|
public:
|
|
Result<Ok, nsresult> Init(size_t aSize);
|
|
Result<Ok, nsresult> Finalize(loader::AutoMemMap& aMap);
|
|
|
|
template <typename T>
|
|
RangedPtr<T> Get() {
|
|
MOZ_ASSERT(mInitialized);
|
|
return {static_cast<T*>(mMem.memory()), mMem.max_size() / sizeof(T)};
|
|
}
|
|
|
|
private:
|
|
base::SharedMemory mMem;
|
|
bool mInitialized = false;
|
|
};
|
|
|
|
} // namespace ipc
|
|
} // namespace mozilla
|
|
|
|
#endif // dom_ipc_MemMapSnapshot_h
|