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 #ifndef BASE_CRITICAL_CLOSURE_H_ 6 #define BASE_CRITICAL_CLOSURE_H_ 7 8 #include <utility> 9 10 #include "base/callback.h" 11 #include "base/macros.h" 12 #include "build/build_config.h" 13 14 #if defined(OS_IOS) 15 #include "base/bind.h" 16 #include "base/ios/scoped_critical_action.h" 17 #endif 18 19 namespace base { 20 21 namespace internal { 22 23 #if defined(OS_IOS) 24 // Returns true if multi-tasking is supported on this iOS device. 25 bool IsMultiTaskingSupported(); 26 27 // This class wraps a closure so it can continue to run for a period of time 28 // when the application goes to the background by using 29 // |ios::ScopedCriticalAction|. 30 class CriticalClosure { 31 public: 32 explicit CriticalClosure(OnceClosure closure); 33 ~CriticalClosure(); 34 void Run(); 35 36 private: 37 ios::ScopedCriticalAction critical_action_; 38 OnceClosure closure_; 39 40 DISALLOW_COPY_AND_ASSIGN(CriticalClosure); 41 }; 42 #endif // defined(OS_IOS) 43 44 } // namespace internal 45 46 // Returns a closure that will continue to run for a period of time when the 47 // application goes to the background if possible on platforms where 48 // applications don't execute while backgrounded, otherwise the original task is 49 // returned. 50 // 51 // Example: 52 // file_task_runner_->PostTask( 53 // FROM_HERE, 54 // MakeCriticalClosure(base::Bind(&WriteToDiskTask, path_, data))); 55 // 56 // Note new closures might be posted in this closure. If the new closures need 57 // background running time, |MakeCriticalClosure| should be applied on them 58 // before posting. 59 #if defined(OS_IOS) MakeCriticalClosure(OnceClosure closure)60inline OnceClosure MakeCriticalClosure(OnceClosure closure) { 61 DCHECK(internal::IsMultiTaskingSupported()); 62 return base::BindOnce( 63 &internal::CriticalClosure::Run, 64 Owned(new internal::CriticalClosure(std::move(closure)))); 65 } 66 #else // defined(OS_IOS) MakeCriticalClosure(OnceClosure closure)67inline OnceClosure MakeCriticalClosure(OnceClosure closure) { 68 // No-op for platforms where the application does not need to acquire 69 // background time for closures to finish when it goes into the background. 70 return closure; 71 } 72 #endif // defined(OS_IOS) 73 74 } // namespace base 75 76 #endif // BASE_CRITICAL_CLOSURE_H_ 77