memory/mozalloc/winheap.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: sw=2 ts=4 et :
   3  */
   4 /* This Source Code Form is subject to the terms of the Mozilla Public
   5  * License, v. 2.0. If a copy of the MPL was not distributed with this
   6  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   7
   8 #include "mozilla/mozalloc.h"
   9 #include <windows.h>
  10
  11 #if !defined(MOZ_MEMORY)
  12 #  include <malloc.h>
  13 #  define malloc_impl malloc
  14 #  define calloc_impl calloc
  15 #  define realloc_impl realloc
  16 #  define free_impl free
  17 #endif
  18
  19 // Warning: C4273: 'HeapAlloc': inconsistent dll linkage
  20 // The Windows headers define HeapAlloc as dllimport, but we define it as
  21 // dllexport, which is a voluntary inconsistency.
  22 #pragma warning(disable : 4273)
  23
  24 MFBT_API
  25 LPVOID WINAPI HeapAlloc(_In_ HANDLE hHeap, _In_ DWORD dwFlags,
  26                         _In_ SIZE_T dwBytes) {
  27   if (dwFlags & HEAP_ZERO_MEMORY) {
  28     return calloc_impl(1, dwBytes);
  29   }
  30   return malloc_impl(dwBytes);
  31 }
  32
  33 MFBT_API
  34 LPVOID WINAPI HeapReAlloc(_In_ HANDLE hHeap, _In_ DWORD dwFlags,
  35                           _In_ LPVOID lpMem, _In_ SIZE_T dwBytes) {
  36   // The HeapReAlloc contract is that failures preserve the existing
  37   // allocation. We can't try to realloc in-place without possibly
  38   // freeing the original allocation, breaking the contract.
  39   // We also can't guarantee we zero all the memory from the end of
  40   // the original allocation to the end of the new one because of the
  41   // difference between the originally requested size and what
  42   // malloc_usable_size would return us.
  43   // So for both cases, just tell the caller we can't do what they
  44   // requested.
  45   if (dwFlags & (HEAP_REALLOC_IN_PLACE_ONLY | HEAP_ZERO_MEMORY)) {
  46     return NULL;
  47   }
  48   return realloc_impl(lpMem, dwBytes);
  49 }
  50
  51 MFBT_API
  52 BOOL WINAPI HeapFree(_In_ HANDLE hHeap, _In_ DWORD dwFlags, _In_ LPVOID lpMem) {
  53   free_impl(lpMem);
  54   return true;
  55 }