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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 #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
    115