61 lines
1.9 KiB
C++
61 lines
1.9 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
// This defines helpful methods for dealing with Callbacks. Because Callbacks
|
|
// are implemented using templates, with a class per callback signature, adding
|
|
// methods to Callback<> itself is unattractive (lots of extra code gets
|
|
// generated). Instead, consider adding methods here.
|
|
//
|
|
// ResetAndReturn(&cb) is like cb.Reset() but allows executing a callback (via a
|
|
// copy) after the original callback is Reset(). This can be handy if Run()
|
|
// reads/writes the variable holding the Callback.
|
|
|
|
#ifndef BASE_CALLBACK_HELPERS_H_
|
|
#define BASE_CALLBACK_HELPERS_H_
|
|
|
|
#include "base/callback.h"
|
|
#include "base/compiler_specific.h"
|
|
#include "base/macros.h"
|
|
|
|
namespace base {
|
|
|
|
template <typename Sig>
|
|
base::Callback<Sig> ResetAndReturn(base::Callback<Sig>* cb) {
|
|
base::Callback<Sig> ret(*cb);
|
|
cb->Reset();
|
|
return ret;
|
|
}
|
|
|
|
// ScopedClosureRunner is akin to std::unique_ptr<> for Closures. It ensures
|
|
// that the Closure is executed no matter how the current scope exits.
|
|
class BASE_EXPORT ScopedClosureRunner {
|
|
public:
|
|
ScopedClosureRunner();
|
|
explicit ScopedClosureRunner(const Closure& closure);
|
|
~ScopedClosureRunner();
|
|
|
|
ScopedClosureRunner(ScopedClosureRunner&& other);
|
|
|
|
// Releases the current closure if it's set and replaces it with the closure
|
|
// from |other|.
|
|
ScopedClosureRunner& operator=(ScopedClosureRunner&& other);
|
|
|
|
// Calls the current closure and resets it, so it wont be called again.
|
|
void RunAndReset();
|
|
|
|
// Replaces closure with the new one releasing the old one without calling it.
|
|
void ReplaceClosure(const Closure& closure);
|
|
|
|
// Releases the Closure without calling.
|
|
Closure Release() WARN_UNUSED_RESULT;
|
|
|
|
private:
|
|
Closure closure_;
|
|
|
|
DISALLOW_COPY_AND_ASSIGN(ScopedClosureRunner);
|
|
};
|
|
|
|
} // namespace base
|
|
|
|
#endif // BASE_CALLBACK_HELPERS_H_
|