dom/ipc/MemMapSnapshot.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "MemMapSnapshot.h"
   8
   9 #include "mozilla/AutoMemMap.h"
  10 #include "mozilla/ResultExtensions.h"
  11 #include "mozilla/Try.h"
  12 #include "mozilla/ipc/FileDescriptor.h"
  13
  14 namespace mozilla::ipc {
  15
  16 Result<Ok, nsresult> MemMapSnapshot::Init(size_t aSize) {
  17   MOZ_ASSERT(!mInitialized);
  18
  19   if (NS_WARN_IF(!mMem.CreateFreezeable(aSize))) {
  20     return Err(NS_ERROR_FAILURE);
  21   }
  22   if (NS_WARN_IF(!mMem.Map(aSize))) {
  23     return Err(NS_ERROR_FAILURE);
  24   }
  25
  26   mInitialized = true;
  27   return Ok();
  28 }
  29
  30 Result<Ok, nsresult> MemMapSnapshot::Finalize(loader::AutoMemMap& aMem) {
  31   MOZ_ASSERT(mInitialized);
  32
  33   if (NS_WARN_IF(!mMem.Freeze())) {
  34     return Err(NS_ERROR_FAILURE);
  35   }
  36   // TakeHandle resets mMem, so call max_size first.
  37   size_t size = mMem.max_size();
  38   FileDescriptor memHandle(mMem.TakeHandle());
  39   MOZ_TRY(aMem.initWithHandle(memHandle, size));
  40
  41   mInitialized = false;
  42   return Ok();
  43 }
  44
  45 }  // namespace mozilla::ipc