MySQL 8.4.3
Source Code Documentation
scope_guard.h
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23
24#ifndef SCOPE_GUARD_H
25#define SCOPE_GUARD_H
26
27/**
28 @brief A Lambda to be called at scope exit.
29
30 Used as std::scope_exit of sorts.
31 Useful if you can't use unique_ptr to install a
32 specific deleter but still want to do automatic
33 cleanup at scope exit.
34
35 @note Always use @ref create_scope_guard() instead of this template directly!
36
37 Typical use is:
38 @code
39 ...
40 foo_init();
41 auto cleanup_foo = create_scope_guard([&] {
42 foo_deinit();
43 }
44 ...
45 if (some_error)
46 return; // cleanup_foo calls foo_deinit()
47 ...
48 // foo_deinit is not going to be called past this point
49 cleanup_foo.release();
50 return; // return with foo initialized.
51 ...
52 @endcode
53*/
54template <typename TLambda>
56 public:
57 Scope_guard(const TLambda &cleanup_lambda)
58 : m_is_released(false), m_cleanup_lambda(cleanup_lambda) {}
63 /* Set moved guard to "invalid" state, the one in which the cleanup lambda
64 will not be executed. */
65 moved.m_is_released = true;
66 }
68 if (!m_is_released) {
70 }
71 }
72
73 /**
74 @brief Releases the scope guard
75
76 Makes sure that when scope guard goes out of scope the
77 cleanup lambda is not going to be called.
78 */
79 inline void release() { m_is_released = true; }
80
81 /**
82 @brief Calls the cleanup lambda and releases the scope guard
83
84 Useful if you want to explicitly provoke the cleanup earlier
85 than when going out of scope.
86 */
87 inline void reset() {
88 if (!m_is_released) {
90 m_is_released = true;
91 }
92 }
93
94 private:
95 /** If true the cleanup is not going to be called */
97 /** The cleanup to be called */
98 const TLambda m_cleanup_lambda;
99};
100
101/**
102 @brief Create a scope guard object
103
104 Always use this instead of the @ref Scope_guard template itself!
105 @sa @ref Scope_guard
106
107 @tparam TLambda The type of the lambda. Inferred, never specify it.
108 @param rollback_lambda The lambda to execute.
109 @return Scope_guard<TLambda> An specialization of the @ref Scope_guard
110 template.
111*/
112template <typename TLambda>
113Scope_guard<TLambda> create_scope_guard(const TLambda rollback_lambda) {
114 return Scope_guard<TLambda>(rollback_lambda);
115}
116
117/**
118 Template class to scope guard variables.
119*/
120template <typename T>
122 public:
125
128
131
133
134 private:
137};
138#endif /* SCOPE_GUARD_H */
A Lambda to be called at scope exit.
Definition: scope_guard.h:55
bool m_is_released
If true the cleanup is not going to be called.
Definition: scope_guard.h:96
Scope_guard(Scope_guard< TLambda > &&moved)
Definition: scope_guard.h:60
Scope_guard(const Scope_guard< TLambda > &)=delete
void release()
Releases the scope guard.
Definition: scope_guard.h:79
void reset()
Calls the cleanup lambda and releases the scope guard.
Definition: scope_guard.h:87
Scope_guard(const TLambda &cleanup_lambda)
Definition: scope_guard.h:57
~Scope_guard()
Definition: scope_guard.h:67
const TLambda m_cleanup_lambda
The cleanup to be called.
Definition: scope_guard.h:98
Template class to scope guard variables.
Definition: scope_guard.h:121
T & m_var_ref
Definition: scope_guard.h:135
Variable_scope_guard(Variable_scope_guard &&)=delete
Variable_scope_guard & operator=(const Variable_scope_guard &)=delete
Variable_scope_guard & operator=(Variable_scope_guard &&)=delete
T m_var_val
Definition: scope_guard.h:136
Variable_scope_guard(const Variable_scope_guard &)=delete
Variable_scope_guard(T &var)
Definition: scope_guard.h:124
Variable_scope_guard()=delete
~Variable_scope_guard()
Definition: scope_guard.h:132
Scope_guard< TLambda > create_scope_guard(const TLambda rollback_lambda)
Create a scope guard object.
Definition: scope_guard.h:113