LibreOffice Module comphelper (master)  1
flagguard.hxx
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19 
20 #ifndef INCLUDED_COMPHELPER_FLAGGUARD_HXX
21 #define INCLUDED_COMPHELPER_FLAGGUARD_HXX
22 
24 #include <utility>
25 
26 namespace comphelper
27 {
28 
29  //= ValueRestorationGuard
30 
31  // note: can't store the originalValue in a ValueRestorationGuard member,
32  // because it will be used from base class dtor
33  template <typename T> struct ValueRestorationGuard_Impl
34  {
35  T& rVal;
36  T const originalValue;
38  : rVal(i_valRef), originalValue(i_valRef) {}
39  void operator()()
40  {
41  rVal = originalValue;
42  }
43  };
44 
45  template <typename T>
46  class ValueRestorationGuard : public ScopeGuard<ValueRestorationGuard_Impl<T>>
47  {
48  public:
49  template <typename T1>
50  ValueRestorationGuard(T& i_valRef, T1&& i_temporaryValue)
52  {
53  i_valRef = std::forward<T1>(i_temporaryValue);
54  }
55  };
56 
58 
59  //= FlagGuard
60 
61  // Guarantees that the flag is true within the scope of the guard, and is set to false after
62  // its destruction, regardless of initial flag value
63  class FlagGuard : public FlagRestorationGuard
64  {
65  public:
66  // Set flag to false before passing its reference to base class ctor, so that it would be
67  // reset back to false in base class dtor
68  explicit FlagGuard(bool& i_flagRef)
69  : FlagRestorationGuard((i_flagRef = false), true)
70  {
71  }
72  };
73 
74 
75 } // namespace comphelper
76 
77 
78 #endif // INCLUDED_COMPHELPER_FLAGGUARD_HXX
79 
80 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
ScopeGuard to ease writing exception-safe code.
Definition: scopeguard.hxx:52
ValueRestorationGuard< bool > FlagRestorationGuard
Definition: flagguard.hxx:57
FlagGuard(bool &i_flagRef)
Definition: flagguard.hxx:68
ValueRestorationGuard(T &i_valRef, T1 &&i_temporaryValue)
Definition: flagguard.hxx:50