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      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::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
    113