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

third_party/WebKit/Source/wtf/StdLibExtras.h

-/*
- * Copyright (C) 2008 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. ``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
- * 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_StdLibExtras_h
-#define WTF_StdLibExtras_h
+#include "platform/wtf/StdLibExtras.h"
 
-#include <cstddef>
-#include "base/numerics/safe_conversions.h"
-#include "wtf/Assertions.h"
-#include "wtf/CPU.h"
-#include "wtf/LeakAnnotations.h"
-#include "wtf/Noncopyable.h"
-#include "wtf/TypeTraits.h"
-
-#if DCHECK_IS_ON()
-#include "wtf/Threading.h"
-#endif
-
-// Use |DEFINE_STATIC_LOCAL()| to declare and define a static local variable
-// (|static T;|) so that it is leaked and its destructors are not called at
-// exit. T may also be a Blink garbage collected object, in which case it is
-// wrapped up by an off-heap |Persistent<T>| reference to the object, keeping
-// it alive across GCs.
-//
-// A |DEFINE_STATIC_LOCAL()| static should only be used on the thread it was
-// created on.
-//
-#define DEFINE_STATIC_LOCAL(Type, Name, Arguments)            \
-  static WTF::StaticSingleton<Type> s_##Name(                 \
-      new WTF::StaticSingleton<Type>::WrapperType Arguments); \
-  Type& Name = s_##Name.get(false)
-
-// |DEFINE_THREAD_SAFE_STATIC_LOCAL()| is the cross-thread accessible variant
-// of |DEFINE_STATIC_LOCAL()|; use it if the singleton can be accessed by
-// multiple threads.
-//
-// TODO: rename as DEFINE_CROSS_THREAD_STATIC_LOCAL() ?
-#define DEFINE_THREAD_SAFE_STATIC_LOCAL(Type, Name, Initializer) \
-  static WTF::StaticSingleton<Type> s_##Name(Initializer);       \
-  Type& Name = s_##Name.get(true)
-
-namespace blink {
-template <typename T>
-class Persistent;
-
-}  // namespace blink
-
-namespace WTF {
-
-template <typename Type>
-class StaticSingleton final {
-  WTF_MAKE_NONCOPYABLE(StaticSingleton);
-
- public:
-  template <typename T,
-            bool = WTF::IsGarbageCollectedType<T>::value &&
-                   !WTF::IsPersistentReferenceType<T>::value>
-  struct Wrapper {
-    using type = T;
-
-    static T& unwrap(T* singleton) { return *singleton; }
-  };
-
-  template <typename T>
-  struct Wrapper<T, true> {
-    using type = blink::Persistent<T>;
-
-    static T& unwrap(blink::Persistent<T>* singleton) {
-      DCHECK(singleton);
-      // If this assert triggers, you're supplying an empty ("()") 'Arguments'
-      // argument to DEFINE_STATIC_LOCAL() - it must be the heap object you wish
-      // to create as a static singleton and wrapped up with a Persistent
-      // reference.
-      DCHECK(*singleton);
-      return **singleton;
-    }
-  };
-
-  using WrapperType = typename Wrapper<Type>::type;
-
-  // To cooperate with leak detection(LSan) for Blink garbage collected objects,
-  // the objects owned by persistent local statics will in some cases have to be
-  // finalized prior to leak checking. This only applies to static references to
-  // Blink heap objects and what they transitively hold on to. Hence the
-  // LEAK_SANITIZER_REGISTER_STATIC_LOCAL() use, it taking care of the grungy
-  // details.
-
-  explicit StaticSingleton(WrapperType* instance)
-      : m_instance(LEAK_SANITIZER_REGISTER_STATIC_LOCAL(WrapperType, instance))
-#if DCHECK_IS_ON()
-        ,
-        m_safelyInitialized(WTF::isBeforeThreadCreated()),
-        m_thread(WTF::internal::currentThreadSyscall())
-#endif
-  {
-  }
-
-  Type& get(bool allowCrossThreadUse) const {
-#if DCHECK_IS_ON()
-    DCHECK(isNotRacy(allowCrossThreadUse));
-#endif
-    ALLOW_UNUSED_LOCAL(allowCrossThreadUse);
-    return Wrapper<Type>::unwrap(m_instance);
-  }
-
-  operator Type&() { return get(); }
-
- private:
-#if DCHECK_IS_ON()
-
-  bool isNotRacy(bool allowCrossThreadUse) const {
-    // Make sure that singleton is safely initialized, or
-    // keeps being called on the same thread if cross-thread
-    // use is not permitted.
-    return allowCrossThreadUse || m_safelyInitialized ||
-           m_thread == WTF::internal::currentThreadSyscall();
-  }
-#endif
-
-  WrapperType* m_instance;
-#if DCHECK_IS_ON()
-  bool m_safelyInitialized;
-  ThreadIdentifier m_thread;
-#endif
-};
-
-}  // namespace WTF
-
-// Use this to declare and define a static local pointer to a ref-counted object
-// so that it is leaked so that the object's destructors are not called at
-// exit.  This macro should be used with ref-counted objects rather than
-// DEFINE_STATIC_LOCAL macro, as this macro does not lead to an extra memory
-// allocation.
-#define DEFINE_STATIC_REF(type, name, arguments) \
-  static type* name = PassRefPtr<type>(arguments).leakRef();
-
-/*
- * The reinterpret_cast<Type1*>([pointer to Type2]) expressions - where
- * sizeof(Type1) > sizeof(Type2) - cause the following warning on ARM with GCC:
- * increases required alignment of target type.
- *
- * An implicit or an extra static_cast<void*> bypasses the warning.
- * For more info see the following bugzilla entries:
- * - https://bugs.webkit.org/show_bug.cgi?id=38045
- * - http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43976
- */
-#if CPU(ARM) && COMPILER(GCC)
-template <typename Type>
-bool isPointerTypeAlignmentOkay(Type* ptr) {
-  return !(reinterpret_cast<intptr_t>(ptr) % __alignof__(Type));
-}
-
-template <typename TypePtr>
-TypePtr reinterpret_cast_ptr(void* ptr) {
-  DCHECK(isPointerTypeAlignmentOkay(reinterpret_cast<TypePtr>(ptr)));
-  return reinterpret_cast<TypePtr>(ptr);
-}
-
-template <typename TypePtr>
-TypePtr reinterpret_cast_ptr(const void* ptr) {
-  DCHECK(isPointerTypeAlignmentOkay(reinterpret_cast<TypePtr>(ptr)));
-  return reinterpret_cast<TypePtr>(ptr);
-}
-#else
-template <typename Type>
-bool isPointerTypeAlignmentOkay(Type*) {
-  return true;
-}
-#define reinterpret_cast_ptr reinterpret_cast
-#endif
-
-namespace WTF {
-
-/*
- * C++'s idea of a reinterpret_cast lacks sufficient cojones.
- */
-template <typename TO, typename FROM>
-inline TO bitwiseCast(FROM from) {
-  static_assert(sizeof(TO) == sizeof(FROM),
-                "WTF::bitwiseCast sizeof casted types should be equal");
-  union {
-    FROM from;
-    TO to;
-  } u;
-  u.from = from;
-  return u.to;
-}
-
-template <typename To, typename From>
-inline To safeCast(From value) {
-  return base::checked_cast<To>(value);
-}
-
-// Use the following macros to prevent errors caused by accidental
-// implicit casting of function arguments.  For example, this can
-// be used to prevent overflows from non-promoting conversions.
-//
-// Example:
-//
-// HAS_STRICTLY_TYPED_ARG
-// void sendData(void* data, STRICTLY_TYPED_ARG(size))
-// {
-//    ALLOW_NUMERIC_ARG_TYPES_PROMOTABLE_TO(size_t);
-//    ...
-// }
-//
-// The previous example will prevent callers from passing, for example, an
-// 'int'. On a 32-bit build, it will prevent use of an 'unsigned long long'.
-#define HAS_STRICTLY_TYPED_ARG template <typename ActualArgType>
-#define STRICTLY_TYPED_ARG(argName) ActualArgType argName
-#define STRICT_ARG_TYPE(ExpectedArgType)                                     \
-  static_assert(std::is_same<ActualArgType, ExpectedArgType>::value,         \
-                "Strictly typed argument must be of type '" #ExpectedArgType \
-                "'.")
-#define ALLOW_NUMERIC_ARG_TYPES_PROMOTABLE_TO(ExpectedArgType)              \
-  static_assert(                                                            \
-      std::numeric_limits<ExpectedArgType>::is_integer ==                   \
-          std::numeric_limits<ActualArgType>::is_integer,                   \
-      "Conversion between integer and non-integer types not allowed.");     \
-  static_assert(sizeof(ExpectedArgType) >= sizeof(ActualArgType),           \
-                "Truncating conversions not allowed.");                     \
-  static_assert(!std::numeric_limits<ActualArgType>::is_signed ||           \
-                    std::numeric_limits<ExpectedArgType>::is_signed,        \
-                "Signed to unsigned conversion not allowed.");              \
-  static_assert((sizeof(ExpectedArgType) != sizeof(ActualArgType)) ||       \
-                    (std::numeric_limits<ActualArgType>::is_signed ==       \
-                     std::numeric_limits<ExpectedArgType>::is_signed),      \
-                "Unsigned to signed conversion not allowed for types with " \
-                "identical size (could overflow).");
-
-// Macro that returns a compile time constant with the length of an array, but
-// gives an error if passed a non-array.
-template <typename T, size_t Size>
-char (&ArrayLengthHelperFunction(T (&)[Size]))[Size];
-// GCC needs some help to deduce a 0 length array.
-#if COMPILER(GCC)
-template <typename T>
-char (&ArrayLengthHelperFunction(T (&)[0]))[0];
-#endif
-#define WTF_ARRAY_LENGTH(array) sizeof(::WTF::ArrayLengthHelperFunction(array))
-
-}  // namespace WTF
-
-using WTF::bitwiseCast;
-using WTF::safeCast;
-
-#endif  // WTF_StdLibExtras_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