1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // This file contains macros and macro-like constructs (e.g., templates) that 6 // are commonly used throughout Chromium source. (It may also contain things 7 // that are closely related to things that are commonly used that belong in this 8 // file.) 9 10 #ifndef BASE_MACROS_H_ 11 #define BASE_MACROS_H_ 12 13 #include <stddef.h> // For size_t. 14 15 #if defined(ANDROID) 16 // Prefer Android's libbase definitions to our own. 17 #include <android-base/macros.h> 18 #endif // defined(ANDROID) 19 20 // We define following macros conditionally as they may be defined by another libraries. 21 22 // Distinguish mips32. 23 #if defined(__mips__) && (_MIPS_SIM == _ABIO32) && !defined(__mips32__) 24 #define __mips32__ 25 #endif 26 27 // Distinguish mips64. 28 #if defined(__mips__) && (_MIPS_SIM == _ABI64) && !defined(__mips64__) 29 #define __mips64__ 30 #endif 31 32 // Put this in the declarations for a class to be uncopyable. 33 #if !defined(DISALLOW_COPY) 34 #define DISALLOW_COPY(TypeName) \ 35 TypeName(const TypeName&) = delete 36 #endif 37 38 // Put this in the declarations for a class to be unassignable. 39 #if !defined(DISALLOW_ASSIGN) 40 #define DISALLOW_ASSIGN(TypeName) TypeName& operator=(const TypeName&) = delete 41 #endif 42 43 // Put this in the declarations for a class to be uncopyable and unassignable. 44 #if !defined(DISALLOW_COPY_AND_ASSIGN) 45 #define DISALLOW_COPY_AND_ASSIGN(TypeName) \ 46 DISALLOW_COPY(TypeName); \ 47 DISALLOW_ASSIGN(TypeName) 48 #endif 49 50 // A macro to disallow all the implicit constructors, namely the 51 // default constructor, copy constructor and operator= functions. 52 // This is especially useful for classes containing only static methods. 53 #if !defined(DISALLOW_IMPLICIT_CONSTRUCTORS) 54 #define DISALLOW_IMPLICIT_CONSTRUCTORS(TypeName) \ 55 TypeName() = delete; \ 56 DISALLOW_COPY_AND_ASSIGN(TypeName) 57 #endif 58 59 // The arraysize(arr) macro returns the # of elements in an array arr. The 60 // expression is a compile-time constant, and therefore can be used in defining 61 // new arrays, for example. If you use arraysize on a pointer by mistake, you 62 // will get a compile-time error. For the technical details, refer to 63 // http://blogs.msdn.com/b/the1/archive/2004/05/07/128242.aspx. 64 65 // This template function declaration is used in defining arraysize. 66 // Note that the function doesn't need an implementation, as we only 67 // use its type. 68 // 69 // DEPRECATED, please use base::size(array) instead. 70 // TODO(https://crbug.com/837308): Replace existing arraysize usages. 71 #if !defined(arraysize) 72 template <typename T, size_t N> char (&ArraySizeHelper(T (&array)[N]))[N]; 73 #define arraysize(array) (sizeof(ArraySizeHelper(array))) 74 #endif 75 76 // Used to explicitly mark the return value of a function as unused. If you are 77 // really sure you don't want to do anything with the return value of a function 78 // that has been marked WARN_UNUSED_RESULT, wrap it with this. Example: 79 // 80 // std::unique_ptr<MyType> my_var = ...; 81 // if (TakeOwnership(my_var.get()) == SUCCESS) 82 // ignore_result(my_var.release()); 83 // 84 template<typename T> 85 inline void ignore_result(const T&) { 86 } 87 88 namespace base { 89 90 // Use these to declare and define a static local variable (static T;) so that 91 // it is leaked so that its destructors are not called at exit. This is 92 // thread-safe. 93 // 94 // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! DEPRECATED !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 95 // Please don't use this macro. Use a function-local static of type 96 // base::NoDestructor<T> instead: 97 // 98 // Factory& Factory::GetInstance() { 99 // static base::NoDestructor<Factory> instance; 100 // return *instance; 101 // } 102 // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 103 #if !defined(CR_DEFINE_STATIC_LOCAL) 104 #define CR_DEFINE_STATIC_LOCAL(type, name, arguments) \ 105 static type& name = *new type arguments 106 #endif 107 108 // Workaround for MSVC, which expands __VA_ARGS__ as one macro argument. To 109 // work around this bug, wrap the entire expression in this macro... 110 #define CR_EXPAND_ARG(arg) arg 111 112 } // base 113 114 #endif // BASE_MACROS_H_ 115
