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/* -*- 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 AutoObjectMapper_h
#define AutoObjectMapper_h
#include <string>
#include "mozilla/Attributes.h"
#include "PlatformMacros.h"
// A (nearly-) RAII class that maps an object in and then unmaps it on
// destruction. This base class version uses the "normal" POSIX
// functions: open, fstat, close, mmap, munmap.
class MOZ_STACK_CLASS AutoObjectMapperPOSIX {
public:
// The constructor does not attempt to map the file, because that
// might fail. Instead, once the object has been constructed,
// call Map() to attempt the mapping. There is no corresponding
// Unmap() since the unmapping is done in the destructor. Failure
// messages are sent to |aLog|.
explicit AutoObjectMapperPOSIX(void (*aLog)(const char*));
// Unmap the file on destruction of this object.
~AutoObjectMapperPOSIX();
// Map |fileName| into the address space and return the mapping
// extents. If the file is zero sized this will fail. The file is
// mapped read-only and private. Returns true iff the mapping
// succeeded, in which case *start and *length hold its extent.
// Once a call to Map succeeds, all subsequent calls to it will
// fail.
bool Map(/*OUT*/ void** start, /*OUT*/ size_t* length, std::string fileName);
protected:
// If we are currently holding a mapped object, these record the
// mapped address range.
void* mImage;
size_t mSize;
// A logging sink, for complaining about mapping failures.
void (*mLog)(const char*);
private:
// Are we currently holding a mapped object? This is private to
// the base class. Derived classes need to have their own way to
// track whether they are holding a mapped object.
bool mIsMapped;
// Disable copying and assignment.
AutoObjectMapperPOSIX(const AutoObjectMapperPOSIX&);
AutoObjectMapperPOSIX& operator=(const AutoObjectMapperPOSIX&);
// Disable heap allocation of this class.
void* operator new(size_t);
void* operator new[](size_t);
void operator delete(void*);
void operator delete[](void*);
};
#endif // AutoObjectMapper_h
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