content/browser/power_save_blocker_mac.cc

   1 // Copyright (c) 2012 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 "content/browser/power_save_blocker_impl.h"
   6
   7 #include <IOKit/pwr_mgt/IOPMLib.h>
   8
   9 #include "base/bind.h"
  10 #include "base/lazy_instance.h"
  11 #include "base/mac/scoped_cftyperef.h"
  12 #include "base/strings/sys_string_conversions.h"
  13 #include "base/threading/platform_thread.h"
  14 #include "base/threading/thread.h"
  15
  16 namespace content {
  17 namespace {
  18
  19 // Power management cannot be done on the UI thread. IOPMAssertionCreate does a
  20 // synchronous MIG call to configd, so if it is called on the main thread the UI
  21 // is at the mercy of another process. See http://crbug.com/79559 and
  22 // http://www.opensource.apple.com/source/IOKitUser/IOKitUser-514.16.31/pwr_mgt.subproj/IOPMLibPrivate.c .
  23 struct PowerSaveBlockerLazyInstanceTraits {
  24   static const bool kRegisterOnExit = false;
  25 #ifndef NDEBUG
  26   static const bool kAllowedToAccessOnNonjoinableThread = true;
  27 #endif
  28
  29   static base::Thread* New(void* instance) {
  30     base::Thread* thread = new (instance) base::Thread("PowerSaveBlocker");
  31     thread->Start();
  32     return thread;
  33   }
  34   static void Delete(base::Thread* instance) { }
  35 };
  36 base::LazyInstance<base::Thread, PowerSaveBlockerLazyInstanceTraits>
  37     g_power_thread = LAZY_INSTANCE_INITIALIZER;
  38
  39 }  // namespace
  40
  41 class PowerSaveBlockerImpl::Delegate
  42     : public base::RefCountedThreadSafe<PowerSaveBlockerImpl::Delegate> {
  43  public:
  44   Delegate(PowerSaveBlockerType type, const std::string& reason)
  45       : type_(type), reason_(reason), assertion_(kIOPMNullAssertionID) {}
  46
  47   // Does the actual work to apply or remove the desired power save block.
  48   void ApplyBlock();
  49   void RemoveBlock();
  50
  51  private:
  52   friend class base::RefCountedThreadSafe<Delegate>;
  53   ~Delegate() {}
  54   PowerSaveBlockerType type_;
  55   std::string reason_;
  56   IOPMAssertionID assertion_;
  57 };
  58
  59 void PowerSaveBlockerImpl::Delegate::ApplyBlock() {
  60   DCHECK_EQ(base::PlatformThread::CurrentId(),
  61             g_power_thread.Pointer()->thread_id());
  62
  63   CFStringRef level = NULL;
  64   // See QA1340 <http://developer.apple.com/library/mac/#qa/qa1340/> for more
  65   // details.
  66   switch (type_) {
  67     case PowerSaveBlocker::kPowerSaveBlockPreventAppSuspension:
  68       level = kIOPMAssertionTypeNoIdleSleep;
  69       break;
  70     case PowerSaveBlocker::kPowerSaveBlockPreventDisplaySleep:
  71       level = kIOPMAssertionTypeNoDisplaySleep;
  72       break;
  73     default:
  74       NOTREACHED();
  75       break;
  76   }
  77   if (level) {
  78     base::ScopedCFTypeRef<CFStringRef> cf_reason(
  79         base::SysUTF8ToCFStringRef(reason_));
  80     IOReturn result = IOPMAssertionCreateWithName(level,
  81                                                   kIOPMAssertionLevelOn,
  82                                                   cf_reason,
  83                                                   &assertion_);
  84     LOG_IF(ERROR, result != kIOReturnSuccess)
  85         << "IOPMAssertionCreate: " << result;
  86   }
  87 }
  88
  89 void PowerSaveBlockerImpl::Delegate::RemoveBlock() {
  90   DCHECK_EQ(base::PlatformThread::CurrentId(),
  91             g_power_thread.Pointer()->thread_id());
  92
  93   if (assertion_ != kIOPMNullAssertionID) {
  94     IOReturn result = IOPMAssertionRelease(assertion_);
  95     LOG_IF(ERROR, result != kIOReturnSuccess)
  96         << "IOPMAssertionRelease: " << result;
  97   }
  98 }
  99
 100 PowerSaveBlockerImpl::PowerSaveBlockerImpl(PowerSaveBlockerType type,
 101                                            const std::string& reason)
 102     : delegate_(new Delegate(type, reason)) {
 103   g_power_thread.Pointer()->message_loop()->PostTask(
 104       FROM_HERE,
 105       base::Bind(&Delegate::ApplyBlock, delegate_));
 106 }
 107
 108 PowerSaveBlockerImpl::~PowerSaveBlockerImpl() {
 109   g_power_thread.Pointer()->message_loop()->PostTask(
 110       FROM_HERE,
 111       base::Bind(&Delegate::RemoveBlock, delegate_));
 112 }
 113
 114 }  // namespace content