libcore/CharacterProxy.h

   1 // CharacterProxy.h - rebindable DisplayObject reference, for Gnash
   2 //
   3 //   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Free Software
   4 //   Foundation, Inc
   5 //
   6 // This program is free software; you can redistribute it and/or modify
   7 // it under the terms of the GNU General Public License as published by
   8 // the Free Software Foundation; either version 3 of the License, or
   9 // (at your option) any later version.
  10 //
  11 // This program is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15 //
  16 // You should have received a copy of the GNU General Public License
  17 // along with this program; if not, write to the Free Software
  18 // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19
  20 #ifndef GNASH_CHARACTER_PROXY_H
  21 #define GNASH_CHARACTER_PROXY_H
  22
  23 #include <string>
  24 #include <cassert>
  25 #include "dsodefs.h"
  26
  27 // Forward declarations
  28 namespace gnash {
  29         class DisplayObject;
  30     class movie_root;
  31 }
  32
  33 namespace gnash {
  34
  35 DisplayObject* findDisplayObjectByTarget(const std::string& target,
  36             movie_root& mr);
  37
  38 /// A proxy for DisplayObject pointers.
  39 //
  40 /// The proxy will store a pointer to a DisplayObject until the
  41 /// DisplayObject is destroyed, in which case it will only store the original
  42 /// target path of it and always use that for rebinding when needed.
  43 ///
  44 class CharacterProxy
  45 {
  46 public:
  47
  48         /// Construct a CharacterProxy pointing to the given sprite
  49         CharacterProxy(DisplayObject* sp, movie_root& mr)
  50                 :
  51                 _ptr(sp),
  52         _mr(&mr)
  53         {
  54                 checkDangling();
  55         }
  56
  57         /// Construct a copy of the given CharacterProxy
  58         //
  59         /// @param sp
  60         ///     The CharacterProxy to make a copy of.
  61         ///     NOTE: if the given proxy is dangling, this proxy
  62         ///           will also be dangling. If you want to
  63         ///           create a non-dangling proxy you can
  64         ///           use the constructor taking a DisplayObject
  65         ///           as in CharacterProxy newProxy(oldProxy.get())
  66         ///
  67         CharacterProxy(const CharacterProxy& sp)
  68         :
  69         _mr(sp._mr)
  70         {
  71                 sp.checkDangling();
  72                 _ptr = sp._ptr;
  73                 if (!_ptr) _tgt = sp._tgt;
  74         }
  75
  76         /// Make this proxy a copy of the given one
  77         //
  78         /// @param sp
  79         ///     The CharacterProxy to make a copy of.
  80         ///     NOTE: if the given proxy is dangling, this proxy
  81         ///           will also be dangling. If you want to
  82         ///           create a non-dangling proxy you can
  83         ///           use the constructor taking a DisplayObject
  84         ///           as in CharacterProxy newProxy(oldProxy.get())
  85         CharacterProxy& operator=(const CharacterProxy& sp)
  86         {
  87                 sp.checkDangling();
  88                 _ptr = sp._ptr;
  89                 if (!_ptr) _tgt = sp._tgt;
  90         _mr = sp._mr;
  91                 return *this;
  92         }
  93
  94         /// Get the pointed sprite, either original or rebound
  95         //
  96         /// @return the currently bound sprite, NULL if none
  97         ///
  98         DisplayObject* get(bool skipRebinding = false) const
  99         {
 100                 if (skipRebinding) return _ptr;
 101
 102         // set _ptr to NULL and _tgt to original target if destroyed
 103                 checkDangling();
 104                 if (_ptr) return _ptr;
 105                 return findDisplayObjectByTarget(_tgt, *_mr);
 106         }
 107
 108         /// Get the sprite target, either current (if not dangling) or
 109     /// bound one.
 110         std::string getTarget() const;
 111
 112         /// Return true if this sprite is dangling
 113         //
 114         /// Dangling means that it doesn't have a pointer to the original
 115         /// sprite anymore, not that it doesn't point to anything.
 116         /// To know if it points to something or not use get(), which will
 117         /// return NULL if it doesn't point to anyhing.
 118         ///
 119         bool isDangling() const
 120         {
 121                 checkDangling();
 122                 return !_ptr;
 123         }
 124
 125         /// \brief
 126         /// Two sprite_proxies are equal if they point to the
 127         /// same sprite
 128         ///
 129         bool operator==(const CharacterProxy& sp) const
 130         {
 131                 return get() == sp.get();
 132         }
 133
 134         /// Set the original sprite (if any) as reachable
 135         //
 136         /// NOTE: if this value is dangling, we won't keep anything
 137         ///       alive.
 138         ///
 139         void setReachable() const;
 140
 141 private:
 142
 143         /// If we still have a sprite pointer check if it was destroyed
 144         /// in which case we drop the pointer and only keep the target.
 145         DSOEXPORT void checkDangling() const;
 146
 147         mutable DisplayObject* _ptr;
 148
 149         mutable std::string _tgt;
 150
 151     movie_root* _mr;
 152
 153 };
 154
 155 } // end namespace gnash
 156
 157 #endif // GNASH_CHARACTER_PROXY_H
 158