src/base/memory/discardable_memory_ashmem.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_ashmem.h"
   6
   7 #include "base/memory/discardable_memory_ashmem_allocator.h"
   8
   9 namespace base {
  10 namespace internal {
  11
  12 DiscardableMemoryAshmem::DiscardableMemoryAshmem(
  13     size_t bytes,
  14     DiscardableMemoryAshmemAllocator* allocator,
  15     DiscardableMemoryManager* manager)
  16     : bytes_(bytes),
  17       allocator_(allocator),
  18       manager_(manager),
  19       is_locked_(false) {
  20   manager_->Register(this, bytes_);
  21 }
  22
  23 DiscardableMemoryAshmem::~DiscardableMemoryAshmem() {
  24   if (is_locked_)
  25     manager_->ReleaseLock(this);
  26
  27   manager_->Unregister(this);
  28 }
  29
  30 bool DiscardableMemoryAshmem::Initialize() {
  31   return Lock() == DISCARDABLE_MEMORY_LOCK_STATUS_PURGED;
  32 }
  33
  34 DiscardableMemoryLockStatus DiscardableMemoryAshmem::Lock() {
  35   bool purged = false;
  36   if (!manager_->AcquireLock(this, &purged))
  37     return DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
  38
  39   return purged ? DISCARDABLE_MEMORY_LOCK_STATUS_PURGED
  40                 : DISCARDABLE_MEMORY_LOCK_STATUS_SUCCESS;
  41 }
  42
  43 void DiscardableMemoryAshmem::Unlock() {
  44   manager_->ReleaseLock(this);
  45 }
  46
  47 void* DiscardableMemoryAshmem::Memory() const {
  48   DCHECK(ashmem_chunk_);
  49   return ashmem_chunk_->Memory();
  50 }
  51
  52 bool DiscardableMemoryAshmem::AllocateAndAcquireLock() {
  53   DCHECK(!is_locked_);
  54   is_locked_ = true;
  55
  56   if (ashmem_chunk_)
  57     return ashmem_chunk_->Lock();
  58
  59   ashmem_chunk_ = allocator_->Allocate(bytes_);
  60   return false;
  61 }
  62
  63 void DiscardableMemoryAshmem::ReleaseLock() {
  64   DCHECK(is_locked_);
  65   ashmem_chunk_->Unlock();
  66   is_locked_ = false;
  67 }
  68
  69 void DiscardableMemoryAshmem::Purge() {
  70   DCHECK(!is_locked_);
  71   ashmem_chunk_.reset();
  72 }
  73
  74 }  // namespace internal
  75 }  // namespace base