Move files in wtf/ to platform/wtf/ (Part 7).

third_party/WebKit/Source/wtf/Functional.h

-/*
- * Copyright (C) 2011 Apple Inc. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
- * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
- * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
- * THE POSSIBILITY OF SUCH DAMAGE.
- */
+// Copyright 2017 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 WTF_Functional_h
-#define WTF_Functional_h
+#include "platform/wtf/Functional.h"
 
-#include "base/bind.h"
-#include "base/threading/thread_checker.h"
-#include "wtf/Allocator.h"
-#include "wtf/Assertions.h"
-#include "wtf/PassRefPtr.h"
-#include "wtf/PtrUtil.h"
-#include "wtf/RefPtr.h"
-#include "wtf/ThreadSafeRefCounted.h"
-#include "wtf/TypeTraits.h"
-#include <utility>
-
-namespace blink {
-template <typename T>
-class Member;
-template <typename T>
-class WeakMember;
-}
-
-namespace WTF {
-
-// Functional.h provides a very simple way to bind a function pointer and
-// arguments together into a function object that can be stored, copied and
-// invoked, similar to boost::bind and std::bind in C++11.
-
-// Thread Safety:
-//
-// WTF::bind() and WTF::Closure should be used for same-thread closures
-// only, i.e. the closures must be created, executed and destructed on
-// the same thread.
-// Use crossThreadBind() and CrossThreadClosure if the function/task is called
-// or destructed on a (potentially) different thread from the current thread.
-
-// WTF::bind() and move semantics
-// ==============================
-//
-// For unbound parameters (arguments supplied later on the bound functor
-// directly), there are two ways to pass movable arguments:
-//
-//     1) Pass by rvalue reference.
-//
-//            void yourFunction(Argument&& argument) { ... }
-//            std::unique_ptr<Function<void(Argument&&)>> functor =
-//                bind<Argument&&>(yourFunction);
-//
-//     2) Pass by value.
-//
-//            void yourFunction(Argument argument) { ... }
-//            std::unique_ptr<Function<void(Argument)>> functor =
-//                bind<Argument>(yourFunction);
-//
-// Note that with the latter there will be *two* move constructions happening,
-// because there needs to be at least one intermediary function call taking an
-// argument of type "Argument" (i.e. passed by value). The former case does not
-// require any move constructions inbetween.
-//
-// For bound parameters (arguments supplied on the creation of a functor), you
-// can move your argument into the internal storage of the functor by supplying
-// an rvalue to that argument (this is done in wrap() of ParamStorageTraits).
-// However, to make the functor be able to get called multiple times, the
-// stored object does not get moved out automatically when the underlying
-// function is actually invoked. If you want to make an argument "auto-passed",
-// you can do so by wrapping your bound argument with WTF::passed() function, as
-// shown below:
-//
-//     void yourFunction(Argument argument)
-//     {
-//         // |argument| is passed from the internal storage of functor.
-//         ...
-//     }
-//
-//     ...
-//     std::unique_ptr<Function<void()>> functor = bind(yourFunction,
-//         WTF::passed(Argument()));
-//     ...
-//     (*functor)();
-//
-// The underlying function must receive the argument wrapped by WTF::passed() by
-// rvalue reference or by value.
-//
-// Obviously, if you create a functor this way, you shouldn't call the functor
-// twice or more; after the second call, the passed argument may be invalid.
-
-enum FunctionThreadAffinity { CrossThreadAffinity, SameThreadAffinity };
-
-template <typename T>
-class PassedWrapper final {
- public:
-  explicit PassedWrapper(T&& scoper) : m_scoper(std::move(scoper)) {}
-  PassedWrapper(PassedWrapper&& other) : m_scoper(std::move(other.m_scoper)) {}
-  T moveOut() const { return std::move(m_scoper); }
-
- private:
-  mutable T m_scoper;
-};
-
-template <typename T>
-PassedWrapper<T> passed(T&& value) {
-  static_assert(
-      !std::is_reference<T>::value,
-      "You must pass an rvalue to WTF::passed() so it can be moved. Add "
-      "std::move() if necessary.");
-  static_assert(!std::is_const<T>::value,
-                "|value| must not be const so it can be moved.");
-  return PassedWrapper<T>(std::move(value));
-}
-
-template <typename T, FunctionThreadAffinity threadAffinity>
-class UnretainedWrapper final {
- public:
-  explicit UnretainedWrapper(T* ptr) : m_ptr(ptr) {}
-  T* value() const { return m_ptr; }
-
- private:
-  T* m_ptr;
-};
-
-template <typename T>
-UnretainedWrapper<T, SameThreadAffinity> unretained(T* value) {
-  static_assert(!WTF::IsGarbageCollectedType<T>::value,
-                "WTF::unretained() + GCed type is forbidden");
-  return UnretainedWrapper<T, SameThreadAffinity>(value);
-}
-
-template <typename T>
-UnretainedWrapper<T, CrossThreadAffinity> crossThreadUnretained(T* value) {
-  static_assert(!WTF::IsGarbageCollectedType<T>::value,
-                "crossThreadUnretained() + GCed type is forbidden");
-  return UnretainedWrapper<T, CrossThreadAffinity>(value);
-}
-
-template <typename T>
-struct ParamStorageTraits {
-  typedef T StorageType;
-
-  static_assert(!std::is_pointer<T>::value,
-                "Raw pointers are not allowed to bind into WTF::Function. Wrap "
-                "it with either wrapPersistent, wrapWeakPersistent, "
-                "wrapCrossThreadPersistent, wrapCrossThreadWeakPersistent, "
-                "RefPtr or unretained.");
-  static_assert(!IsSubclassOfTemplate<T, blink::Member>::value &&
-                    !IsSubclassOfTemplate<T, blink::WeakMember>::value,
-                "Member and WeakMember are not allowed to bind into "
-                "WTF::Function. Wrap it with either wrapPersistent, "
-                "wrapWeakPersistent, wrapCrossThreadPersistent or "
-                "wrapCrossThreadWeakPersistent.");
-};
-
-template <typename T>
-struct ParamStorageTraits<PassRefPtr<T>> {
-  typedef RefPtr<T> StorageType;
-};
-
-template <typename T>
-struct ParamStorageTraits<RefPtr<T>> {
-  typedef RefPtr<T> StorageType;
-};
-
-template <typename>
-class RetainPtr;
-
-template <typename T>
-struct ParamStorageTraits<RetainPtr<T>> {
-  typedef RetainPtr<T> StorageType;
-};
-
-template <typename T>
-struct ParamStorageTraits<PassedWrapper<T>> {
-  typedef PassedWrapper<T> StorageType;
-};
-
-template <typename T, FunctionThreadAffinity threadAffinity>
-struct ParamStorageTraits<UnretainedWrapper<T, threadAffinity>> {
-  typedef UnretainedWrapper<T, threadAffinity> StorageType;
-};
-
-template <typename Signature,
-          FunctionThreadAffinity threadAffinity = SameThreadAffinity>
-class Function;
-
-template <typename R, typename... Args, FunctionThreadAffinity threadAffinity>
-class Function<R(Args...), threadAffinity> {
-  USING_FAST_MALLOC(Function);
-  WTF_MAKE_NONCOPYABLE(Function);
-
- public:
-  Function(base::Callback<R(Args...)> callback)
-      : m_callback(std::move(callback)) {}
-
-  ~Function() { DCHECK(m_threadChecker.CalledOnValidThread()); }
-
-  R operator()(Args... args) {
-    DCHECK(m_threadChecker.CalledOnValidThread());
-    return m_callback.Run(std::forward<Args>(args)...);
-  }
-
-  bool isCancelled() const { return m_callback.IsCancelled(); }
-
-  friend base::Callback<R(Args...)> convertToBaseCallback(
-      std::unique_ptr<Function> function) {
-    if (function)
-      return std::move(function->m_callback);
-    return base::Callback<R(Args...)>();
-  }
-
- private:
-  using MaybeThreadChecker =
-      typename std::conditional<threadAffinity == SameThreadAffinity,
-                                base::ThreadChecker,
-                                base::ThreadCheckerDoNothing>::type;
-  MaybeThreadChecker m_threadChecker;
-  base::Callback<R(Args...)> m_callback;
-};
-
-template <FunctionThreadAffinity threadAffinity,
-          typename FunctionType,
-          typename... BoundParameters>
-std::unique_ptr<
-    Function<base::MakeUnboundRunType<FunctionType, BoundParameters...>,
-             threadAffinity>>
-bindInternal(FunctionType function, BoundParameters&&... boundParameters) {
-  using UnboundRunType =
-      base::MakeUnboundRunType<FunctionType, BoundParameters...>;
-  return WTF::wrapUnique(new Function<UnboundRunType,
-                                      threadAffinity>(base::Bind(
-      function,
-      typename ParamStorageTraits<typename std::decay<BoundParameters>::type>::
-          StorageType(std::forward<BoundParameters>(boundParameters))...)));
-}
-
-template <typename FunctionType, typename... BoundParameters>
-std::unique_ptr<
-    Function<base::MakeUnboundRunType<FunctionType, BoundParameters...>,
-             SameThreadAffinity>>
-bind(FunctionType function, BoundParameters&&... boundParameters) {
-  return bindInternal<SameThreadAffinity>(
-      function, std::forward<BoundParameters>(boundParameters)...);
-}
-
-typedef Function<void(), SameThreadAffinity> Closure;
-typedef Function<void(), CrossThreadAffinity> CrossThreadClosure;
-
-}  // namespace WTF
-
-namespace base {
-
-template <typename T>
-struct BindUnwrapTraits<WTF::RefPtr<T>> {
-  static T* Unwrap(const WTF::RefPtr<T>& wrapped) { return wrapped.get(); }
-};
-
-template <typename T>
-struct BindUnwrapTraits<WTF::PassedWrapper<T>> {
-  static T Unwrap(const WTF::PassedWrapper<T>& wrapped) {
-    return wrapped.moveOut();
-  }
-};
-
-template <typename T, WTF::FunctionThreadAffinity threadAffinity>
-struct BindUnwrapTraits<WTF::UnretainedWrapper<T, threadAffinity>> {
-  static T* Unwrap(const WTF::UnretainedWrapper<T, threadAffinity>& wrapped) {
-    return wrapped.value();
-  }
-};
-
-}  // namespace base
-
-using WTF::crossThreadUnretained;
-
-using WTF::Function;
-using WTF::CrossThreadClosure;
-
-#endif  // WTF_Functional_h
+// The contents of this header was moved to platform/wtf as part of
+// WTF migration project. See the following post for details:
+// https://groups.google.com/a/chromium.org/d/msg/blink-dev/tLdAZCTlcAA/bYXVT8gYCAAJ