xref: /aosp_15_r20/external/skia/include/private/base/SkMacros.h (revision c8dee2aa9b3f27cf6c858bd81872bdeb2c07ed17)
1 /*
2  * Copyright 2018 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 #ifndef SkMacros_DEFINED
8 #define SkMacros_DEFINED
9 
10 #include "include/private/base/SkTo.h" // IWYU pragma: keep
11 
12 /*
13  *  Usage:  SK_MACRO_CONCAT(a, b)   to construct the symbol ab
14  *
15  *  SK_MACRO_CONCAT_IMPL_PRIV just exists to make this work. Do not use directly
16  *
17  */
18 #define SK_MACRO_CONCAT(X, Y)           SK_MACRO_CONCAT_IMPL_PRIV(X, Y)
19 #define SK_MACRO_CONCAT_IMPL_PRIV(X, Y)  X ## Y
20 
21 /*
22  *  Usage: SK_MACRO_APPEND_LINE(foo)    to make foo123, where 123 is the current
23  *                                      line number. Easy way to construct
24  *                                      unique names for local functions or
25  *                                      variables.
26  */
27 #define SK_MACRO_APPEND_LINE(name)  SK_MACRO_CONCAT(name, __LINE__)
28 
29 #define SK_MACRO_APPEND_COUNTER(name) SK_MACRO_CONCAT(name, __COUNTER__)
30 
31 ////////////////////////////////////////////////////////////////////////////////
32 
33 // Can be used to bracket data types that must be dense/packed, e.g. hash keys.
34 #if defined(__clang__)  // This should work on GCC too, but GCC diagnostic pop didn't seem to work!
35     #define SK_BEGIN_REQUIRE_DENSE _Pragma("GCC diagnostic push") \
36                                    _Pragma("GCC diagnostic error \"-Wpadded\"")
37     #define SK_END_REQUIRE_DENSE   _Pragma("GCC diagnostic pop")
38 #else
39     #define SK_BEGIN_REQUIRE_DENSE
40     #define SK_END_REQUIRE_DENSE
41 #endif
42 
43 #if defined(__clang__) && defined(__has_feature)
44     // Some compilers have a preprocessor that does not appear to do short-circuit
45     // evaluation as expected
46     #if __has_feature(leak_sanitizer) || __has_feature(address_sanitizer)
47         // Chrome had issues if we tried to include lsan_interface.h ourselves.
48         // https://github.com/llvm/llvm-project/blob/10a35632d55bb05004fe3d0c2d4432bb74897ee7/compiler-rt/include/sanitizer/lsan_interface.h#L26
49 extern "C" {
50         void __lsan_ignore_object(const void *p);
51 }
52         #define SK_INTENTIONALLY_LEAKED(X) __lsan_ignore_object(X)
53     #else
54         #define SK_INTENTIONALLY_LEAKED(X) ((void)0)
55     #endif
56 #else
57     #define SK_INTENTIONALLY_LEAKED(X) ((void)0)
58 #endif
59 
60 #define SK_INIT_TO_AVOID_WARNING    = 0
61 
62 ////////////////////////////////////////////////////////////////////////////////
63 
64 /**
65  * Defines overloaded bitwise operators to make it easier to use an enum as a
66  * bitfield.
67  */
68 #define SK_MAKE_BITFIELD_OPS(X) \
69     inline X operator ~(X a) { \
70         using U = std::underlying_type_t<X>; \
71         return (X) (~static_cast<U>(a)); \
72     } \
73     inline X operator |(X a, X b) { \
74         using U = std::underlying_type_t<X>; \
75         return (X) (static_cast<U>(a) | static_cast<U>(b)); \
76     } \
77     inline X& operator |=(X& a, X b) { \
78         return (a = a | b); \
79     } \
80     inline X operator &(X a, X b) { \
81         using U = std::underlying_type_t<X>; \
82         return (X) (static_cast<U>(a) & static_cast<U>(b)); \
83     } \
84     inline X& operator &=(X& a, X b) { \
85         return (a = a & b); \
86     }
87 
88 #define SK_DECL_BITFIELD_OPS_FRIENDS(X) \
89     friend X operator ~(X a); \
90     friend X operator |(X a, X b); \
91     friend X& operator |=(X& a, X b); \
92     \
93     friend X operator &(X a, X b); \
94     friend X& operator &=(X& a, X b);
95 
96 /**
97  * Wraps a C++11 enum that we use as a bitfield, and enables a limited amount of
98  * masking with type safety. Instantiated with the ~ operator.
99  */
100 template<typename TFlags> class SkTFlagsMask {
101 public:
SkTFlagsMask(TFlags value)102     constexpr explicit SkTFlagsMask(TFlags value) : SkTFlagsMask(static_cast<int>(value)) {}
SkTFlagsMask(int value)103     constexpr explicit SkTFlagsMask(int value) : fValue(value) {}
value()104     constexpr int value() const { return fValue; }
105 private:
106     const int fValue;
107 };
108 
109 /**
110  * Defines bitwise operators that make it possible to use an enum class as a
111  * basic bitfield.
112  */
113 #define SK_MAKE_BITFIELD_CLASS_OPS(X) \
114     [[maybe_unused]] constexpr SkTFlagsMask<X> operator~(X a) { \
115         return SkTFlagsMask<X>(~static_cast<int>(a)); \
116     } \
117     [[maybe_unused]] constexpr X operator|(X a, X b) { \
118         return static_cast<X>(static_cast<int>(a) | static_cast<int>(b)); \
119     } \
120     [[maybe_unused]] inline X& operator|=(X& a, X b) { \
121         return (a = a | b); \
122     } \
123     [[maybe_unused]] constexpr bool operator&(X a, X b) { \
124         return SkToBool(static_cast<int>(a) & static_cast<int>(b)); \
125     } \
126     [[maybe_unused]] constexpr SkTFlagsMask<X> operator|(SkTFlagsMask<X> a, SkTFlagsMask<X> b) { \
127         return SkTFlagsMask<X>(a.value() | b.value()); \
128     } \
129     [[maybe_unused]] constexpr SkTFlagsMask<X> operator|(SkTFlagsMask<X> a, X b) { \
130         return SkTFlagsMask<X>(a.value() | static_cast<int>(b)); \
131     } \
132     [[maybe_unused]] constexpr SkTFlagsMask<X> operator|(X a, SkTFlagsMask<X> b) { \
133         return SkTFlagsMask<X>(static_cast<int>(a) | b.value()); \
134     } \
135     [[maybe_unused]] constexpr X operator&(SkTFlagsMask<X> a, SkTFlagsMask<X> b) { \
136         return static_cast<X>(a.value() & b.value()); \
137     } \
138     [[maybe_unused]] constexpr X operator&(SkTFlagsMask<X> a, X b) { \
139         return static_cast<X>(a.value() & static_cast<int>(b)); \
140     } \
141     [[maybe_unused]] constexpr X operator&(X a, SkTFlagsMask<X> b) { \
142         return static_cast<X>(static_cast<int>(a) & b.value()); \
143     } \
144     [[maybe_unused]] inline X& operator&=(X& a, SkTFlagsMask<X> b) { \
145         return (a = a & b); \
146     } \
147 
148 #define SK_DECL_BITFIELD_CLASS_OPS_FRIENDS(X) \
149     friend constexpr SkTFlagsMask<X> operator ~(X); \
150     friend constexpr X operator |(X, X); \
151     friend X& operator |=(X&, X); \
152     friend constexpr bool operator &(X, X); \
153     friend constexpr SkTFlagsMask<X> operator|(SkTFlagsMask<X>, SkTFlagsMask<X>); \
154     friend constexpr SkTFlagsMask<X> operator|(SkTFlagsMask<X>, X); \
155     friend constexpr SkTFlagsMask<X> operator|(X, SkTFlagsMask<X>); \
156     friend constexpr X operator&(SkTFlagsMask<X>, SkTFlagsMask<X>); \
157     friend constexpr X operator&(SkTFlagsMask<X>, X); \
158     friend constexpr X operator&(X, SkTFlagsMask<X>); \
159     friend X& operator &=(X&, SkTFlagsMask<X>)
160 
161 #endif  // SkMacros_DEFINED
162