| // Copyright 2015 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. |
| |
| #ifndef CrossThreadFunctional_h |
| #define CrossThreadFunctional_h |
| |
| #include <type_traits> |
| #include "base/bind.h" |
| #include "platform/CrossThreadCopier.h" |
| #include "platform/wtf/Functional.h" |
| |
| namespace blink { |
| |
| // CrossThreadBind() is Bind() for cross-thread task posting. |
| // CrossThreadBind() applies CrossThreadCopier to the arguments. |
| // |
| // Example: |
| // void Func1(int, const String&); |
| // f = CrossThreadBind(&Func1, 42, str); |
| // Func1(42, str2) will be called when |f()| is executed, |
| // where |str2| is a deep copy of |str| (created by str.IsolatedCopy()). |
| // |
| // CrossThreadBind(str) is similar to Bind(str.IsolatedCopy()), but the latter |
| // is NOT thread-safe due to temporary objects (https://crbug.com/390851). |
| // |
| // Don't (if you pass the task across threads): |
| // Bind(&Func1, 42, str); |
| // Bind(&Func1, 42, str.IsolatedCopy()); |
| |
| template <typename FunctionType, typename... Ps> |
| Function<base::MakeUnboundRunType<FunctionType, Ps...>, |
| WTF::kCrossThreadAffinity> |
| CrossThreadBind(FunctionType function, Ps&&... parameters) { |
| static_assert( |
| WTF::internal::CheckGCedTypeRestrictions<std::index_sequence_for<Ps...>, |
| std::decay_t<Ps>...>::ok, |
| "A bound argument uses a bad pattern."); |
| using UnboundRunType = base::MakeUnboundRunType<FunctionType, Ps...>; |
| return WTF::Function<UnboundRunType, WTF::kCrossThreadAffinity>( |
| base::Bind(function, CrossThreadCopier<std::decay_t<Ps>>::Copy( |
| std::forward<Ps>(parameters))...)); |
| } |
| |
| } // namespace blink |
| |
| #endif // CrossThreadFunctional_h |
