gecko-dev/memory/mozalloc/winheap.cpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: sw=4 ts=4 et :
 */
/* 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/Types.h"
#include <windows.h>

#if defined(MOZ_MEMORY)
// mozalloc.cpp is part of the same library as mozmemory, thus MOZ_MEMORY_IMPL
// is needed.
#define MOZ_MEMORY_IMPL
#include "mozmemory_wrap.h"

// See mozmemory_wrap.h for more details. This file is part of libmozglue, so
// it needs to use _impl suffixes. However, with libmozglue growing, this is
// becoming cumbersome, so we will likely use a malloc.h wrapper of some sort
// and allow the use of the functions without a _impl suffix.
#define MALLOC_DECL(name, return_type, ...) \
  MOZ_MEMORY_API return_type name ## _impl(__VA_ARGS__);
#define MALLOC_FUNCS MALLOC_FUNCS_MALLOC
#include "malloc_decls.h"
#else

#include <malloc.h>
#define malloc_impl malloc
#define calloc_impl calloc
#define realloc_impl realloc
#define free_impl free

#endif

// Warning: C4273: 'HeapAlloc': inconsistent dll linkage
// The Windows headers define HeapAlloc as dllimport, but we define it as
// dllexport, which is a voluntary inconsistency.
#pragma warning(disable: 4273)

MFBT_API
LPVOID WINAPI HeapAlloc(_In_ HANDLE hHeap, _In_ DWORD dwFlags,
                        _In_ SIZE_T dwBytes)
{
    if (dwFlags & HEAP_ZERO_MEMORY) {
        return calloc_impl(1, dwBytes);
    }
    return malloc_impl(dwBytes);
}

MFBT_API
LPVOID WINAPI HeapReAlloc(_In_ HANDLE hHeap, _In_ DWORD dwFlags,
                          _In_ LPVOID lpMem, _In_ SIZE_T dwBytes)
{
    // The HeapReAlloc contract is that failures preserve the existing
    // allocation. We can't try to realloc in-place without possibly
    // freeing the original allocation, breaking the contract.
    // We also can't guarantee we zero all the memory from the end of
    // the original allocation to the end of the new one because of the
    // difference between the originally requested size and what
    // malloc_usable_size would return us.
    // So for both cases, just tell the caller we can't do what they
    // requested.
    if (dwFlags & (HEAP_REALLOC_IN_PLACE_ONLY | HEAP_ZERO_MEMORY)) {
        return NULL;
    }
    return realloc_impl(lpMem, dwBytes);
}

MFBT_API
BOOL WINAPI HeapFree(_In_ HANDLE hHeap, _In_ DWORD dwFlags,
                     _In_ LPVOID lpMem)
{
    free_impl(lpMem);
    return true;
}