Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1 | // Copyright 2014 the V8 project 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 | #ifndef V8_BASE_FLAGS_H_ |
| 6 | #define V8_BASE_FLAGS_H_ |
| 7 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 8 | #include <cstddef> |
| 9 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 10 | #include "src/base/compiler-specific.h" |
| 11 | |
| 12 | namespace v8 { |
| 13 | namespace base { |
| 14 | |
| 15 | // The Flags class provides a type-safe way of storing OR-combinations of enum |
| 16 | // values. The Flags<T, S> class is a template class, where T is an enum type, |
| 17 | // and S is the underlying storage type (usually int). |
| 18 | // |
| 19 | // The traditional C++ approach for storing OR-combinations of enum values is to |
| 20 | // use an int or unsigned int variable. The inconvenience with this approach is |
| 21 | // that there's no type checking at all; any enum value can be OR'd with any |
| 22 | // other enum value and passed on to a function that takes an int or unsigned |
| 23 | // int. |
| 24 | template <typename T, typename S = int> |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 25 | class Flags final { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 26 | public: |
| 27 | typedef T flag_type; |
| 28 | typedef S mask_type; |
| 29 | |
| 30 | Flags() : mask_(0) {} |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 31 | Flags(flag_type flag) // NOLINT(runtime/explicit) |
| 32 | : mask_(static_cast<S>(flag)) {} |
| 33 | explicit Flags(mask_type mask) : mask_(static_cast<S>(mask)) {} |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 34 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 35 | bool operator==(flag_type flag) const { |
| 36 | return mask_ == static_cast<S>(flag); |
| 37 | } |
| 38 | bool operator!=(flag_type flag) const { |
| 39 | return mask_ != static_cast<S>(flag); |
| 40 | } |
| 41 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 42 | Flags& operator&=(const Flags& flags) { |
| 43 | mask_ &= flags.mask_; |
| 44 | return *this; |
| 45 | } |
| 46 | Flags& operator|=(const Flags& flags) { |
| 47 | mask_ |= flags.mask_; |
| 48 | return *this; |
| 49 | } |
| 50 | Flags& operator^=(const Flags& flags) { |
| 51 | mask_ ^= flags.mask_; |
| 52 | return *this; |
| 53 | } |
| 54 | |
| 55 | Flags operator&(const Flags& flags) const { return Flags(*this) &= flags; } |
| 56 | Flags operator|(const Flags& flags) const { return Flags(*this) |= flags; } |
| 57 | Flags operator^(const Flags& flags) const { return Flags(*this) ^= flags; } |
| 58 | |
| 59 | Flags& operator&=(flag_type flag) { return operator&=(Flags(flag)); } |
| 60 | Flags& operator|=(flag_type flag) { return operator|=(Flags(flag)); } |
| 61 | Flags& operator^=(flag_type flag) { return operator^=(Flags(flag)); } |
| 62 | |
| 63 | Flags operator&(flag_type flag) const { return operator&(Flags(flag)); } |
| 64 | Flags operator|(flag_type flag) const { return operator|(Flags(flag)); } |
| 65 | Flags operator^(flag_type flag) const { return operator^(Flags(flag)); } |
| 66 | |
| 67 | Flags operator~() const { return Flags(~mask_); } |
| 68 | |
| 69 | operator mask_type() const { return mask_; } |
| 70 | bool operator!() const { return !mask_; } |
| 71 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 72 | friend size_t hash_value(const Flags& flags) { return flags.mask_; } |
| 73 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 74 | private: |
| 75 | mask_type mask_; |
| 76 | }; |
| 77 | |
| 78 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 79 | #define DEFINE_OPERATORS_FOR_FLAGS(Type) \ |
| 80 | inline Type operator&( \ |
| 81 | Type::flag_type lhs, \ |
| 82 | Type::flag_type rhs)ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \ |
| 83 | inline Type operator&(Type::flag_type lhs, Type::flag_type rhs) { \ |
| 84 | return Type(lhs) & rhs; \ |
| 85 | } \ |
| 86 | inline Type operator&(Type::flag_type lhs, \ |
| 87 | const Type& rhs)ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \ |
| 88 | inline Type operator&(Type::flag_type lhs, const Type& rhs) { \ |
| 89 | return rhs & lhs; \ |
| 90 | } \ |
| 91 | inline void operator&(Type::flag_type lhs, \ |
| 92 | Type::mask_type rhs)ALLOW_UNUSED_TYPE; \ |
| 93 | inline void operator&(Type::flag_type lhs, Type::mask_type rhs) {} \ |
| 94 | inline Type operator|(Type::flag_type lhs, Type::flag_type rhs) \ |
| 95 | ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \ |
| 96 | inline Type operator|(Type::flag_type lhs, Type::flag_type rhs) { \ |
| 97 | return Type(lhs) | rhs; \ |
| 98 | } \ |
| 99 | inline Type operator|(Type::flag_type lhs, const Type& rhs) \ |
| 100 | ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \ |
| 101 | inline Type operator|(Type::flag_type lhs, const Type& rhs) { \ |
| 102 | return rhs | lhs; \ |
| 103 | } \ |
| 104 | inline void operator|(Type::flag_type lhs, Type::mask_type rhs) \ |
| 105 | ALLOW_UNUSED_TYPE; \ |
| 106 | inline void operator|(Type::flag_type lhs, Type::mask_type rhs) {} \ |
| 107 | inline Type operator^(Type::flag_type lhs, Type::flag_type rhs) \ |
| 108 | ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \ |
| 109 | inline Type operator^(Type::flag_type lhs, Type::flag_type rhs) { \ |
| 110 | return Type(lhs) ^ rhs; \ |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 111 | } inline Type \ |
| 112 | operator^(Type::flag_type lhs, const Type& rhs) \ |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 113 | ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \ |
| 114 | inline Type operator^(Type::flag_type lhs, const Type& rhs) { \ |
| 115 | return rhs ^ lhs; \ |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 116 | } inline void \ |
| 117 | operator^(Type::flag_type lhs, Type::mask_type rhs) ALLOW_UNUSED_TYPE; \ |
| 118 | inline void operator^(Type::flag_type lhs, Type::mask_type rhs) { \ |
| 119 | } inline Type \ |
| 120 | operator~(Type::flag_type val)ALLOW_UNUSED_TYPE; \ |
| 121 | inline Type operator~(Type::flag_type val) { return ~Type(val); } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 122 | |
| 123 | } // namespace base |
| 124 | } // namespace v8 |
| 125 | |
| 126 | #endif // V8_BASE_FLAGS_H_ |