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/* -*- Mode: C++; tab-width: 8; 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/. */
#ifndef mozilla_devtools_AutoMemMap_h
#define mozilla_devtools_AutoMemMap_h
#include <prio.h>
#include "mozilla/GuardObjects.h"
namespace mozilla {
namespace devtools {
// # AutoMemMap
//
// AutoMemMap is an RAII class to manage mapping a file to memory. It is a
// wrapper aorund managing opening and closing a file and calling PR_MemMap and
// PR_MemUnmap.
//
// Example usage:
//
// {
// AutoMemMap mm;
// if (NS_FAILED(mm.init("/path/to/desired/file"))) {
// // Handle the error however you see fit.
// return false;
// }
//
// doStuffWithMappedMemory(mm.address());
// }
// // The memory is automatically unmapped when the AutoMemMap leaves scope.
class MOZ_RAII AutoMemMap
{
MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER;
PRFileInfo64 fileInfo;
PRFileDesc* fd;
PRFileMap* fileMap;
void* addr;
AutoMemMap(const AutoMemMap& aOther) = delete;
void operator=(const AutoMemMap& aOther) = delete;
public:
explicit AutoMemMap(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM)
: fd(nullptr)
, fileMap(nullptr)
, addr(nullptr)
{
MOZ_GUARD_OBJECT_NOTIFIER_INIT;
};
~AutoMemMap();
// Initialize this AutoMemMap.
nsresult init(const char* filePath, int flags = PR_RDONLY, int mode = 0,
PRFileMapProtect prot = PR_PROT_READONLY);
// Get the size of the memory mapped file.
uint32_t size() const {
MOZ_ASSERT(fileInfo.size <= UINT32_MAX,
"Should only call size() if init() succeeded.");
return uint32_t(fileInfo.size);
}
// Get the mapped memory.
void* address() { MOZ_ASSERT(addr); return addr; }
const void* address() const { MOZ_ASSERT(addr); return addr; }
};
} // namespace devtools
} // namespace mozilla
#endif // mozilla_devtools_AutoMemMap_h
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