82 lines
2.4 KiB
C++
82 lines
2.4 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_CRITICAL_CLOSURE_H_
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#define BASE_CRITICAL_CLOSURE_H_
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#include "base/callback.h"
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#include "base/macros.h"
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#include "build/build_config.h"
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#if defined(OS_IOS)
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#include "base/bind.h"
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#include "base/ios/scoped_critical_action.h"
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#endif
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namespace base {
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namespace internal {
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#if defined(OS_IOS)
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// Returns true if multi-tasking is supported on this iOS device.
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bool IsMultiTaskingSupported();
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// This class wraps a closure so it can continue to run for a period of time
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// when the application goes to the background by using
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// |ios::ScopedCriticalAction|.
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template <typename R>
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class CriticalClosure {
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public:
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explicit CriticalClosure(const Callback<R(void)>& closure)
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: closure_(closure) {}
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~CriticalClosure() {}
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R Run() {
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return closure_.Run();
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}
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private:
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ios::ScopedCriticalAction critical_action_;
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Callback<R(void)> closure_;
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DISALLOW_COPY_AND_ASSIGN(CriticalClosure);
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};
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#endif // defined(OS_IOS)
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} // namespace internal
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// Returns a closure (which may return a result, but must not require any extra
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// arguments) that will continue to run for a period of time when the
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// application goes to the background if possible on platforms where
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// applications don't execute while backgrounded, otherwise the original task is
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// returned.
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//
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// Example:
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// file_task_runner_->PostTask(
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// FROM_HERE,
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// MakeCriticalClosure(base::Bind(&WriteToDiskTask, path_, data)));
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//
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// Note new closures might be posted in this closure. If the new closures need
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// background running time, |MakeCriticalClosure| should be applied on them
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// before posting.
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#if defined(OS_IOS)
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template <typename R>
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Callback<R(void)> MakeCriticalClosure(const Callback<R(void)>& closure) {
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DCHECK(internal::IsMultiTaskingSupported());
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return base::Bind(&internal::CriticalClosure<R>::Run,
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Owned(new internal::CriticalClosure<R>(closure)));
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}
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#else // defined(OS_IOS)
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template <typename R>
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inline Callback<R(void)> MakeCriticalClosure(const Callback<R(void)>& closure) {
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// No-op for platforms where the application does not need to acquire
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// background time for closures to finish when it goes into the background.
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return closure;
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}
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#endif // defined(OS_IOS)
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} // namespace base
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#endif // BASE_CRITICAL_CLOSURE_H_
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