src/YesNoNone.h

   1 /*
   2  * Copyright (C) 1996-2015 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID_YESNONONE_H_
  10 #define SQUID_YESNONONE_H_
  11
  12 /// Used for boolean enabled/disabled options with complex default logic.
  13 /// Allows Squid to compute the right default after configuration.
  14 /// Checks that not-yet-defined option values are not used.
  15 class YesNoNone
  16 {
  17 // TODO: generalize to non-boolean option types
  18 public:
  19     YesNoNone(): option(0) {}
  20
  21     /// returns true iff enabled; asserts if the option has not been configured
  22     operator void *() const; // TODO: use a fancy/safer version of the operator
  23
  24     /// enables or disables the option;
  25     void configure(bool beSet);
  26
  27     /// whether the option was enabled or disabled, by user or Squid
  28     bool configured() const { return option != 0; }
  29
  30 private:
  31     enum { optUnspecified = -1, optDisabled = 0, optEnabled = 1 };
  32     int option; ///< configured value or zero
  33 };
  34
  35 #endif /* SQUID_YESNONONE_H_ */
  36