base/memory/discardable_memory_shmem.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/memory/discardable_memory_shmem.h"
   6
   7 #include "base/lazy_instance.h"
   8 #include "base/memory/discardable_memory_shmem_allocator.h"
   9
  10 namespace base {
  11 namespace internal {
  12
  13 DiscardableMemoryShmem::DiscardableMemoryShmem(size_t bytes)
  14     : chunk_(DiscardableMemoryShmemAllocator::GetInstance()
  15                  ->AllocateLockedDiscardableMemory(bytes)),
  16       is_locked_(true) {
  17   DCHECK(chunk_);
  18 }
  19
  20 DiscardableMemoryShmem::~DiscardableMemoryShmem() {
  21   if (is_locked_)
  22     Unlock();
  23 }
  24
  25 bool DiscardableMemoryShmem::Lock() {
  26   DCHECK(!is_locked_);
  27   DCHECK(chunk_);
  28
  29   if (!chunk_->Lock()) {
  30     chunk_.reset();
  31     return false;
  32   }
  33
  34   is_locked_ = true;
  35   return true;
  36 }
  37
  38 void DiscardableMemoryShmem::Unlock() {
  39   DCHECK(is_locked_);
  40   chunk_->Unlock();
  41   is_locked_ = false;
  42 }
  43
  44 void* DiscardableMemoryShmem::Memory() const {
  45   DCHECK(is_locked_);
  46   return chunk_->Memory();
  47 }
  48
  49 }  // namespace internal
  50 }  // namespace base