chromium/third_party/blink/renderer/platform/wtf/std_lib_extras.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.
 */

#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_WTF_STD_LIB_EXTRAS_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_WTF_STD_LIB_EXTRAS_H_

#include <cstddef>
#include <cstdint>

#include "base/check.h"
#include "base/dcheck_is_on.h"
#include "build/build_config.h"
#include "third_party/blink/renderer/platform/wtf/leak_annotations.h"
#include "third_party/blink/renderer/platform/wtf/sanitizers.h"
#include "third_party/blink/renderer/platform/wtf/type_traits.h"

#if DCHECK_IS_ON()
#include "third_party/blink/renderer/platform/wtf/threading.h"
#endif

#define DEFINE_STATIC_LOCAL_IMPL(Type, Name, Arguments, allow_cross_thread) …

// 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.
//
// A |DEFINE_STATIC_LOCAL()| static should only be used on the thread it was
// created on.
//
#define DEFINE_STATIC_LOCAL(Type, Name, Arguments) …

// |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, Arguments) …

namespace WTF {

template <typename Type>
class StaticSingleton final { … };

}  // 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) …

/*
 * 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 defined(ARCH_CPU_ARMEL) && defined(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*) { … }
#define reinterpret_cast_ptr …
#endif

template <typename TypePtr>
NO_SANITIZE_UNRELATED_CAST
TypePtr unsafe_reinterpret_cast_ptr(void* ptr) { … }

template <typename TypePtr>
NO_SANITIZE_UNRELATED_CAST
TypePtr unsafe_reinterpret_cast_ptr(const void* ptr) { … }

namespace WTF {

// 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 …
#define STRICTLY_TYPED_ARG(argName) …
#define STRICT_ARG_TYPE(ExpectedArgType) …
#define ALLOW_NUMERIC_ARG_TYPES_PROMOTABLE_TO(ExpectedArgType) …

}  // namespace WTF

#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_WTF_STD_LIB_EXTRAS_H_