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// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_TEST_RECTIFY_CALLBACK_H_
#define BASE_TEST_RECTIFY_CALLBACK_H_
#include <utility>
#include "base/test/rectify_callback_internal.h"
namespace base {
// RectifyCallback:
//
// CallbackType<DesiredSignature> RectifyCallback<DesiredSignature>(
// CallbackType<ActualSignature> callback)
//
// DesiredCallbackType RectifyCallback<DesiredCallbackType>(
// ActualCallbackType callback)
//
// Rectifies the signature of `callback` with `DesiredSignature` or
// `DesiredCallbackType` by ignoring the first N arguments of the desired
// callback type. Useful when binding callbacks with lots of arguments you don't
// actually care about.
//
// For now, `ActualSignature` and `DesiredSignature` must have the same return
// type, and the common arguments between the two must match.
//
// Example:
//
// using CbType = OnceCallback<bool(A, B, C)>;
// void Fn(CbType);
//
// // These all ignore arguments when passing the callback:
// Fn(RectifyCallback<CbType>(BindOnce([]{ return true; })));
// Fn(RectifyCallback<CbType>(BindOnce([](C c){ return true; })));
// Fn(RectifyCallback<CbType>(BindOnce([](B c, C c){ return true; })));
//
// // This also works, though it makes no change to the input callback:
// Fn(RectifyCallback<CbType>(
// BindOnce([](A a, B c, C c){ return true; })));
//
// You can also make RectifyCallback implicit by embedding it in a template
// version of your function.
//
// template <typename T>
// void Fn(T&& t) { FnImpl(RectifyCallback<CbType>(std::forward<T>(t))); }
//
template <typename Desired, typename Actual>
auto RectifyCallback(Actual&& callback) {
using Impl = internal::RectifyCallbackImpl<Desired, std::decay_t<Actual>>;
return Impl::Rectify(std::move(callback));
}
} // namespace base
#endif // BASE_TEST_RECTIFY_CALLBACK_H_
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