| // Copyright 2014 the V8 project 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 V8_BASE_FLAGS_H_ |
| #define V8_BASE_FLAGS_H_ |
| |
| #include "src/base/compiler-specific.h" |
| |
| namespace v8 { |
| namespace base { |
| |
| // The Flags class provides a type-safe way of storing OR-combinations of enum |
| // values. The Flags<T, S> class is a template class, where T is an enum type, |
| // and S is the underlying storage type (usually int). |
| // |
| // The traditional C++ approach for storing OR-combinations of enum values is to |
| // use an int or unsigned int variable. The inconvenience with this approach is |
| // that there's no type checking at all; any enum value can be OR'd with any |
| // other enum value and passed on to a function that takes an int or unsigned |
| // int. |
| template <typename T, typename S = int> |
| class Flags FINAL { |
| public: |
| typedef T flag_type; |
| typedef S mask_type; |
| |
| Flags() : mask_(0) {} |
| Flags(flag_type flag) // NOLINT(runtime/explicit) |
| : mask_(static_cast<S>(flag)) {} |
| explicit Flags(mask_type mask) : mask_(static_cast<S>(mask)) {} |
| |
| Flags& operator&=(const Flags& flags) { |
| mask_ &= flags.mask_; |
| return *this; |
| } |
| Flags& operator|=(const Flags& flags) { |
| mask_ |= flags.mask_; |
| return *this; |
| } |
| Flags& operator^=(const Flags& flags) { |
| mask_ ^= flags.mask_; |
| return *this; |
| } |
| |
| Flags operator&(const Flags& flags) const { return Flags(*this) &= flags; } |
| Flags operator|(const Flags& flags) const { return Flags(*this) |= flags; } |
| Flags operator^(const Flags& flags) const { return Flags(*this) ^= flags; } |
| |
| Flags& operator&=(flag_type flag) { return operator&=(Flags(flag)); } |
| Flags& operator|=(flag_type flag) { return operator|=(Flags(flag)); } |
| Flags& operator^=(flag_type flag) { return operator^=(Flags(flag)); } |
| |
| Flags operator&(flag_type flag) const { return operator&(Flags(flag)); } |
| Flags operator|(flag_type flag) const { return operator|(Flags(flag)); } |
| Flags operator^(flag_type flag) const { return operator^(Flags(flag)); } |
| |
| Flags operator~() const { return Flags(~mask_); } |
| |
| operator mask_type() const { return mask_; } |
| bool operator!() const { return !mask_; } |
| |
| private: |
| mask_type mask_; |
| }; |
| |
| |
| #define DEFINE_OPERATORS_FOR_FLAGS(Type) \ |
| inline Type operator&( \ |
| Type::flag_type lhs, \ |
| Type::flag_type rhs)ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \ |
| inline Type operator&(Type::flag_type lhs, Type::flag_type rhs) { \ |
| return Type(lhs) & rhs; \ |
| } \ |
| inline Type operator&(Type::flag_type lhs, \ |
| const Type& rhs)ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \ |
| inline Type operator&(Type::flag_type lhs, const Type& rhs) { \ |
| return rhs & lhs; \ |
| } \ |
| inline void operator&(Type::flag_type lhs, \ |
| Type::mask_type rhs)ALLOW_UNUSED_TYPE; \ |
| inline void operator&(Type::flag_type lhs, Type::mask_type rhs) {} \ |
| inline Type operator|(Type::flag_type lhs, Type::flag_type rhs) \ |
| ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \ |
| inline Type operator|(Type::flag_type lhs, Type::flag_type rhs) { \ |
| return Type(lhs) | rhs; \ |
| } \ |
| inline Type operator|(Type::flag_type lhs, const Type& rhs) \ |
| ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \ |
| inline Type operator|(Type::flag_type lhs, const Type& rhs) { \ |
| return rhs | lhs; \ |
| } \ |
| inline void operator|(Type::flag_type lhs, Type::mask_type rhs) \ |
| ALLOW_UNUSED_TYPE; \ |
| inline void operator|(Type::flag_type lhs, Type::mask_type rhs) {} \ |
| inline Type operator^(Type::flag_type lhs, Type::flag_type rhs) \ |
| ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \ |
| inline Type operator^(Type::flag_type lhs, Type::flag_type rhs) { \ |
| return Type(lhs) ^ rhs; \ |
| } inline Type operator^(Type::flag_type lhs, const Type& rhs) \ |
| ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \ |
| inline Type operator^(Type::flag_type lhs, const Type& rhs) { \ |
| return rhs ^ lhs; \ |
| } inline void operator^(Type::flag_type lhs, Type::mask_type rhs) \ |
| ALLOW_UNUSED_TYPE; \ |
| inline void operator^(Type::flag_type lhs, Type::mask_type rhs) {} |
| |
| } // namespace base |
| } // namespace v8 |
| |
| #endif // V8_BASE_FLAGS_H_ |