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   static const bool kAllowedToAccessOnNonjoinableThread = true;
  26
  27   static base::Thread* New(void* instance) {
  28     base::Thread* thread = new (instance) base::Thread("PowerSaveBlocker");
  29     thread->Start();
  30     return thread;
  31   }
  32   static void Delete(base::Thread* instance) { }
  33 };
  34 base::LazyInstance<base::Thread, PowerSaveBlockerLazyInstanceTraits>
  35     g_power_thread = LAZY_INSTANCE_INITIALIZER;
  36
  37 }  // namespace
  38
  39 class PowerSaveBlockerImpl::Delegate
  40     : public base::RefCountedThreadSafe<PowerSaveBlockerImpl::Delegate> {
  41  public:
  42   Delegate(PowerSaveBlockerType type, const std::string& reason)
  43       : type_(type), reason_(reason), assertion_(kIOPMNullAssertionID) {}
  44
  45   // Does the actual work to apply or remove the desired power save block.
  46   void ApplyBlock();
  47   void RemoveBlock();
  48
  49  private:
  50   friend class base::RefCountedThreadSafe<Delegate>;
  51   ~Delegate() {}
  52   PowerSaveBlockerType type_;
  53   std::string reason_;
  54   IOPMAssertionID assertion_;
  55 };
  56
  57 void PowerSaveBlockerImpl::Delegate::ApplyBlock() {
  58   DCHECK_EQ(base::PlatformThread::CurrentId(),
  59             g_power_thread.Pointer()->thread_id());
  60
  61   CFStringRef level = NULL;
  62   // See QA1340 <http://developer.apple.com/library/mac/#qa/qa1340/> for more
  63   // details.
  64   switch (type_) {
  65     case PowerSaveBlocker::kPowerSaveBlockPreventAppSuspension:
  66       level = kIOPMAssertionTypeNoIdleSleep;
  67       break;
  68     case PowerSaveBlocker::kPowerSaveBlockPreventDisplaySleep:
  69       level = kIOPMAssertionTypeNoDisplaySleep;
  70       break;
  71     default:
  72       NOTREACHED();
  73       break;
  74   }
  75   if (level) {
  76     base::mac::ScopedCFTypeRef<CFStringRef> cf_reason(
  77         base::SysUTF8ToCFStringRef(reason_));
  78     IOReturn result = IOPMAssertionCreateWithName(level,
  79                                                   kIOPMAssertionLevelOn,
  80                                                   cf_reason,
  81                                                   &assertion_);
  82     LOG_IF(ERROR, result != kIOReturnSuccess)
  83         << "IOPMAssertionCreate: " << result;
  84   }
  85 }
  86
  87 void PowerSaveBlockerImpl::Delegate::RemoveBlock() {
  88   DCHECK_EQ(base::PlatformThread::CurrentId(),
  89             g_power_thread.Pointer()->thread_id());
  90
  91   if (assertion_ != kIOPMNullAssertionID) {
  92     IOReturn result = IOPMAssertionRelease(assertion_);
  93     LOG_IF(ERROR, result != kIOReturnSuccess)
  94         << "IOPMAssertionRelease: " << result;
  95   }
  96 }
  97
  98 PowerSaveBlockerImpl::PowerSaveBlockerImpl(PowerSaveBlockerType type,
  99                                            const std::string& reason)
 100     : delegate_(new Delegate(type, reason)) {
 101   g_power_thread.Pointer()->message_loop()->PostTask(
 102       FROM_HERE,
 103       base::Bind(&Delegate::ApplyBlock, delegate_));
 104 }
 105
 106 PowerSaveBlockerImpl::~PowerSaveBlockerImpl() {
 107   g_power_thread.Pointer()->message_loop()->PostTask(
 108       FROM_HERE,
 109       base::Bind(&Delegate::RemoveBlock, delegate_));
 110 }
 111
 112 }  // namespace content