// Copyright 2014 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.

// This file contains macros and macro-like constructs (e.g., templates) that

// are commonly used throughout Chromium source. (It may also contain things

// that are closely related to things that are commonly used that belong in this

// file.)

#ifndef BASE_MACROS_H_

#define BASE_MACROS_H_

#include <stddef.h>  // For size_t.

// Put this in the declarations for a class to be uncopyable.

#define DISALLOW_COPY(TypeName) \

  TypeName(const TypeName&) = delete

// Put this in the declarations for a class to be unassignable.

#define DISALLOW_ASSIGN(TypeName) TypeName& operator=(const TypeName&) = delete

// Put this in the declarations for a class to be uncopyable and unassignable.

#define DISALLOW_COPY_AND_ASSIGN(TypeName) \

  DISALLOW_COPY(TypeName);                 \

  DISALLOW_ASSIGN(TypeName)

// A macro to disallow all the implicit constructors, namely the

// default constructor, copy constructor and operator= functions.

// This is especially useful for classes containing only static methods.

#define DISALLOW_IMPLICIT_CONSTRUCTORS(TypeName) \

  TypeName() = delete;                           \

  DISALLOW_COPY_AND_ASSIGN(TypeName)

// The arraysize(arr) macro returns the # of elements in an array arr.  The

// expression is a compile-time constant, and therefore can be used in defining

// new arrays, for example.  If you use arraysize on a pointer by mistake, you

// will get a compile-time error.  For the technical details, refer to

// http://blogs.msdn.com/b/the1/archive/2004/05/07/128242.aspx.

// This template function declaration is used in defining arraysize.

// Note that the function doesn't need an implementation, as we only

// use its type.

template <typename T, size_t N> char (&ArraySizeHelper(T (&array)[N]))[N];

#define arraysize(array) (sizeof(ArraySizeHelper(array)))

// Used to explicitly mark the return value of a function as unused. If you are

// really sure you don't want to do anything with the return value of a function

// that has been marked WARN_UNUSED_RESULT, wrap it with this. Example:

//

//   std::unique_ptr<MyType> my_var = ...;

//   if (TakeOwnership(my_var.get()) == SUCCESS)

//     ignore_result(my_var.release());

//

template<typename T>

inline void ignore_result(const T&) {

}

Unexecuted instantiation: platform_thread_posix.cc:void ignore_result<base::(anonymous namespace)::ThreadParams*>(base::(anonymous namespace)::ThreadParams* const&)

Unexecuted instantiation: void ignore_result<long>(long const&)

// The following enum should be used only as a constructor argument to indicate

// that the variable has static storage class, and that the constructor should

// do nothing to its state.  It indicates to the reader that it is legal to

// declare a static instance of the class, provided the constructor is given

// the base::LINKER_INITIALIZED argument.  Normally, it is unsafe to declare a

// static variable that has a constructor or a destructor because invocation

// order is undefined.  However, IF the type can be initialized by filling with

// zeroes (which the loader does for static variables), AND the destructor also

// does nothing to the storage, AND there are no virtual methods, then a

// constructor declared as

//       explicit MyClass(base::LinkerInitialized x) {}

// and invoked as

//       static MyClass my_variable_name(base::LINKER_INITIALIZED);

namespace base {

enum LinkerInitialized { LINKER_INITIALIZED };

// Use these to declare and define a static local variable (static T;) so that

// it is leaked so that its destructors are not called at exit. If you need

// thread-safe initialization, use base/lazy_instance.h instead.

#define CR_DEFINE_STATIC_LOCAL(type, name, arguments) \

  static type& name = *new type arguments

}  // base

#endif  // BASE_MACROS_H_