messageviewer/autoqpointer.h

   1 /*
   2  *  autoqpointer.h  -  QPointer which on destruction deletes object
   3  *  This is a (mostly) verbatim, private copy of kdepim/kalarm/lib/autoqpointer.h
   4  *
   5  *  Copyright © 2009 by David Jarvie <djarvie@kde.org>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License along
  18  *  with this program; if not, write to the Free Software Foundation, Inc.,
  19  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  */
  21
  22 #ifndef MESSAGEVIEWER_AUTOQPOINTER_H
  23 #define MESSAGEVIEWER_AUTOQPOINTER_H
  24
  25 #include <QPointer>
  26 #include <QObject>
  27
  28 #include <kdemacros.h>
  29
  30 namespace MessageViewer {
  31
  32 /**
  33  *  A QPointer which when destructed, deletes the object it points to.
  34  *
  35  *  @author David Jarvie <djarvie@kde.org>, Marc Mutz <mutz@kde.org>
  36  */
  37 template <class T>
  38 class AutoQPointer
  39 {
  40   Q_DISABLE_COPY( AutoQPointer )
  41   struct SafeBool { void func() {} };
  42   typedef void (SafeBool::*save_bool)();
  43   QPointer<QObject> o;
  44 public:
  45     AutoQPointer() : o() {}
  46     explicit AutoQPointer( T * p ) : o(p) {}
  47     ~AutoQPointer()  { delete o; }
  48     T * data() const { return static_cast<T*>(o.data()); }
  49     T * get()  const { return data(); }
  50     bool isNull() const { return o.isNull(); }
  51     T * operator->() const { return data(); }
  52     T & operator*() const { return *data(); }
  53 #if 0 // enable when all users of operator T*() have been converted to use .get()
  54     operator save_bool() const { return isNull() ? 0 : &SafeBool::func ; }
  55 #else
  56     // unsafe - use explicit .get()
  57     KDE_DEPRECATED operator T*() const { return get(); }
  58     // unsafe - only provided to prevent the above warning in bool contexts
  59     operator bool() const { return get(); }
  60 #endif
  61
  62 };
  63
  64 }
  65
  66 #endif // MESSAGEVIEWER_AUTOQPOINTER_H