src/YesNoNone.h

   1 #ifndef SQUID_YESNONONE_H_
   2 #define SQUID_YESNONONE_H_
   3 /*
   4  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   5  * ----------------------------------------------------------
   6  *
   7  *  Squid is the result of efforts by numerous individuals from
   8  *  the Internet community; see the CONTRIBUTORS file for full
   9  *  details.   Many organizations have provided support for Squid's
  10  *  development; see the SPONSORS file for full details.  Squid is
  11  *  Copyrighted (C) 2001 by the Regents of the University of
  12  *  California; see the COPYRIGHT file for full details.  Squid
  13  *  incorporates software developed and/or copyrighted by other
  14  *  sources; see the CREDITS file for full details.
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License as published by
  18  *  the Free Software Foundation; either version 2 of the License, or
  19  *  (at your option) any later version.
  20  *
  21  *  This program is distributed in the hope that it will be useful,
  22  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  *  GNU General Public License for more details.
  25  *
  26  *  You should have received a copy of the GNU General Public License
  27  *  along with this program; if not, write to the Free Software
  28  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  29  *
  30  */
  31
  32 /// Used for boolean enabled/disabled options with complex default logic.
  33 /// Allows Squid to compute the right default after configuration.
  34 /// Checks that not-yet-defined option values are not used.
  35 class YesNoNone
  36 {
  37 // TODO: generalize to non-boolean option types
  38 public:
  39     YesNoNone(): option(0) {}
  40
  41     /// returns true iff enabled; asserts if the option has not been configured
  42     operator void *() const; // TODO: use a fancy/safer version of the operator
  43
  44     /// enables or disables the option;
  45     void configure(bool beSet);
  46
  47     /// whether the option was enabled or disabled, by user or Squid
  48     bool configured() const { return option != 0; }
  49
  50 private:
  51     enum { optUnspecified = -1, optDisabled = 0, optEnabled = 1 };
  52     int option; ///< configured value or zero
  53 };
  54
  55 #endif /* SQUID_YESNONONE_H_ */