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source: code/branches/ggz2/src/libraries/util/Scope.h @ 8474

Last change on this file since 8474 was 5738, checked in by landauf, 15 years ago

merged libraries2 back to trunk

  • Property svn:eol-style set to native
File size: 4.8 KB
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1/*
2 *   ORXONOX - the hottest 3D action shooter ever to exist
3 *                    > www.orxonox.net <
4 *
5 *
6 *   License notice:
7 *
8 *   This program is free software; you can redistribute it and/or
9 *   modify it under the terms of the GNU General Public License
10 *   as published by the Free Software Foundation; either version 2
11 *   of the License, or (at your option) any later version.
12 *
13 *   This program is distributed in the hope that it will be useful,
14 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
15 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 *   GNU General Public License for more details.
17 *
18 *   You should have received a copy of the GNU General Public License
19 *   along with this program; if not, write to the Free Software
20 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
21 *
22 *   Author:
23 *      Fabian 'x3n' Landau
24 *   Co-authors:
25 *      ...
26 *
27 */
28
29#ifndef __Util_Scope_H__
30#define __Util_Scope_H__
31
32#include "UtilPrereqs.h"
33#include <cassert>
34#include <set>
35#include <map>
36#include "Debug.h"
37
38namespace orxonox
39{
40    namespace ScopeID
41    {
42        /**
43            @brief A list of available scopes for the Scope template.
44        */
45        enum Value
46        {
47            GSRoot,
48            GSGraphics,
49            GSLevel
50        };
51    }
52
53    class ScopeListener; // Forward declaration
54
55    /**
56        @brief The ScopeManager stores the variables of the scope templates in a statically linked context.
57    */
58    class _UtilExport ScopeManager
59    {
60        template <ScopeID::Value scope>
61        friend class Scope;
62        friend class ScopeListener;
63
64        private:
65            static std::map<ScopeID::Value, int> instanceCounts_s;                  //!< Counts the number of active instances (>0 means active) for a scope
66            static std::map<ScopeID::Value, std::set<ScopeListener*> > listeners_s; //!< Stores all listeners for a scope
67    };
68
69    /**
70        @brief ScopeListeners register themselves in the corresponding scope and wait for notifications.
71    */
72    class _UtilExport ScopeListener
73    {
74        template <ScopeID::Value scope>
75        friend class Scope;
76
77        protected:
78            //! Constructor: Registers the instance.
79            ScopeListener(ScopeID::Value scope) : scope_(scope)
80                { ScopeManager::listeners_s[this->scope_].insert(this); }
81            //! Destructor: Unregisters the instance.
82            virtual ~ScopeListener()
83                { ScopeManager::listeners_s[this->scope_].erase(this); }
84
85            //! Gets called if the scope is activated
86            virtual void activated() = 0;
87            //! Gets called if the scope is deactivated
88            virtual void deactivated() = 0;
89
90        private:
91            ScopeID::Value scope_; //!< Store the scope to unregister on destruction
92    };
93
94    /**
95        @brief A scope for a given template argument is either active or not.
96
97        Objects inheriting from a ScopeListener are registered in a list (different for each scope).
98        If the scope gets activated or deactivated, all objects in this list are notified.
99    */
100    template <ScopeID::Value scope>
101    class Scope
102    {
103        public:
104            //! Constructor: Increases the instance counter and activates the scope if the count went from 0 to 1. Counts >1 don't change anything.
105            Scope()
106            {
107                ScopeManager::instanceCounts_s[scope]++;
108                assert(ScopeManager::instanceCounts_s[scope] > 0);
109                if (ScopeManager::instanceCounts_s[scope] == 1)
110                {
111                    for (typename std::set<ScopeListener*>::iterator it = ScopeManager::listeners_s[scope].begin(); it != ScopeManager::listeners_s[scope].end(); )
112                        (*(it++))->activated();
113                }
114            }
115
116            //! Destructor: Decreases the instance counter and deactivates the scope if the count went from 1 to 0. Counts >0 don't change anything.
117            ~Scope()
118            {
119                ScopeManager::instanceCounts_s[scope]--;
120
121                // This shouldn't happen but just to be sure: check if the count is positive
122                assert(ScopeManager::instanceCounts_s[scope] >= 0);
123                if (ScopeManager::instanceCounts_s[scope] < 0)
124                    ScopeManager::instanceCounts_s[scope] = 0;
125
126                if (ScopeManager::instanceCounts_s[scope] == 0)
127                {
128                    for (typename std::set<ScopeListener*>::iterator it = ScopeManager::listeners_s[scope].begin(); it != ScopeManager::listeners_s[scope].end(); )
129                        (*(it++))->deactivated();
130                }
131            }
132
133            //! Returns true if the scope is active.
134            static bool isActive()
135            {
136                return (ScopeManager::instanceCounts_s[scope] > 0);
137            }
138    };
139}
140
141#endif /* __Util_Scope_H__ */
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