src/common/ResourceManager.h

/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *   Copyright (C) 2005, 2006 Christian Schoenebeck                        *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the Free Software           *
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#ifndef __RESOURCE_MANAGER__
#define __RESOURCE_MANAGER__

#include <set>
#include <map>

/**
 * Interface class for consumer classes which use a resource managed
 * by the ResourceManager class.
 */
template<class T_res>
class ResourceConsumer {
    public:
        /**
         * Will be called by the ResourceManager to inform the
         * consumer that a resource currently used by him is going
         * to be updated. The consumer can then react by stopping
         * usage until resource is updated. The ResourceManager will
         * not update the resource until this method returns. This
         * method needs to be implemented by the consumer.
         *
         * @param pResource  - resource going to be updated
         * @param pUpdateArg - pointer the consumer might use to store
         *                     informations he might need when update
         *                     process was completed
         */
        virtual void ResourceToBeUpdated(T_res* pResource, void*& pUpdateArg) = 0;

        /**
         * Will be called by the ResourceManager to inform the
         * consumer that resource update was completed. This method
         * needs to be implemented by the consumer.
         *
         * @param pOldResource - (now invalid) pointer to the old
         *                       resource
         * @param pNewResource - (valid) pointer to the updated
         *                       resource
         * @param pUpdateArg   - pointer the consumer might have used when
         *                       ResourceToBeUpdated() was called
         */
        virtual void ResourceUpdated(T_res* pOldResource, T_res* pNewResource, void* pUpdateArg) = 0;

        /**
         * Might be called by the ResourceManager periodically during an
         * update / creation of a resource to inform the consumer about the
         * current progress of that process. This method needs to be
         * implemented by the consumer.
         *
         * @param fProgress - current progress as value between 0.0 and 1.0
         */
        virtual void OnResourceProgress(float fProgress) = 0;
};

/**
 * Abstract base class for sharing resources between multiple consumers.
 * A consumer can borrow a resource from the ResourceManager, if the
 * resource doesn't exist yet it will be created. Other consumers will
 * just be given the same pointer to the resource then. When all consumers
 * gave back their pointer to the resource, the resource will be destroyed.
 * Descendants of this base class have to implement the (protected)
 * Create() and Destroy() methods to create and destroy a resource.
 */
template<class T_key, class T_res>
class ResourceManager {
    private:
        typedef std::set<ResourceConsumer<T_res>*> ConsumerSet;
        struct resource_entry_t {
            T_key       key;
            T_res*      resource;  ///< pointer to the resource
            ConsumerSet consumers; ///< list of all consumers who currently use the resource
            void*       arg;       ///< optional pointer the descendant might use to store informations about the resource
        };
        typedef std::map<T_key, resource_entry_t> ResourceMap;
        ResourceMap ResourceEntries;

    public:
                virtual ~ResourceManager() {}
        /**
         * Borrow a resource identified by \a Key. The ResourceManager will
         * mark the resource as in usage by the consumer given with
         * \a pConsumer. If the Resource doesn't exist yet it will be
         * created.
         *
         * @param Key       - resource identifier
         * @param pConsumer - identifier of the consumer who borrows it
         * @returns  pointer to resource
         */
        T_res* Borrow(T_key Key, ResourceConsumer<T_res>* pConsumer) {
            typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
            if (iterEntry == ResourceEntries.end()) {
                // already create an entry for the resource
                resource_entry_t entry;
                entry.key      = Key;
                entry.resource = NULL;
                entry.consumers.insert(pConsumer);
                ResourceEntries[Key] = entry;
                try {
                    // actually create the resource
                    entry.resource = Create(Key, pConsumer, entry.arg);
                } catch (...) {
                    // creating the resource failed, so remove the entry
                    ResourceEntries.erase(Key);
                    // rethrow the same exception
                    throw;
                }
                // now update the entry with the created resource
                ResourceEntries[Key] = entry;
                OnBorrow(entry.resource, pConsumer, entry.arg);
                return entry.resource;
            }
            resource_entry_t& entry = iterEntry->second;
            entry.consumers.insert(pConsumer);
            OnBorrow(entry.resource, pConsumer, entry.arg);
            return entry.resource;
        }

        /**
         * Give back a resource. This tells the ResourceManager that the
         * consumer given by \a pConsumer doesn't need the resource anymore.
         * If the resource is not needed by any consumer anymore then the
         * resource will be destroyed.
         *
         * @param pResource - pointer to resource
         * @param pConsumer - identifier of the consumer who borrowed the
         *                    resource
         */
        void HandBack(T_res* pResource, ResourceConsumer<T_res>* pConsumer) {
            typename ResourceMap::iterator iter = ResourceEntries.begin();
            typename ResourceMap::iterator end  = ResourceEntries.end();
            for (; iter != end; iter++) {
                if (iter->second.resource == pResource) {
                    resource_entry_t& entry = iter->second;
                    entry.consumers.erase(pConsumer);
                    if (entry.consumers.empty()) {
                        T_res* resource = entry.resource;
                        void* arg = entry.arg;
                        ResourceEntries.erase(iter);
                        Destroy(resource, arg);
                    }
                    return;
                }
            }
        }

        /**
         * Request update of a resource.
         *
         * @param pResource - resource to be updated
         * @param pConsumer - consumer who requested the update
         */
        void Update(T_res* pResource, ResourceConsumer<T_res>* pConsumer) {
            typename ResourceMap::iterator iter = ResourceEntries.begin();
            typename ResourceMap::iterator end  = ResourceEntries.end();
            for (; iter != end; iter++) {
                if (iter->second.resource == pResource) {
                    resource_entry_t& entry = iter->second;
                    // inform all consumers about pending update
                    std::map<ResourceConsumer<T_res>*,void*> updateargs;
                    typename ConsumerSet::iterator iterCons = entry.consumers.begin();
                    typename ConsumerSet::iterator endCons  = entry.consumers.end();
                    for (; iterCons != endCons; iterCons++) {
                        if (*iterCons == pConsumer) continue;
                        void* updatearg = NULL;
                        (*iterCons)->ResourceToBeUpdated(entry.resource, updatearg);
                        if (updatearg) updateargs[*iterCons] = updatearg;
                    }
                    // update resource
                    T_res* pOldResource = entry.resource;
                    Destroy(entry.resource, entry.arg);
                    entry.resource = Create(entry.key, pConsumer, entry.arg);
                    // inform all consumers about update completed
                    iterCons = entry.consumers.begin();
                    endCons  = entry.consumers.end();
                    for (; iterCons != endCons; iterCons++) {
                        if (*iterCons == pConsumer) continue;
                        typename std::map<ResourceConsumer<T_res>*,void*>::iterator iterArg = updateargs.find(*iterCons);
                        void* updatearg = (iterArg != updateargs.end()) ? iterArg->second : NULL;
                        (*iterCons)->ResourceUpdated(pOldResource, entry.resource, updatearg);
                    }
                    return;
                }
            }
        }

    protected:
        /**
         * Has to be implemented by the descendant to create (allocate) a
         * resource identified by \a Key.
         *
         * @param Key       - identifier of the resource
         * @param pConsumer - identifier of the consumer who borrows the
         *                    resource
         * @param pArg      - pointer the descendant can use to store
         *                    informations he might need for destruction of
         *                    the resource
         * @returns  pointer to new resource
         */
        virtual T_res* Create(T_key Key, ResourceConsumer<T_res>* pConsumer, void*& pArg) = 0;

        /**
         * Has to be implemented by the descendant to destroy (free) a
         * resource pointed by \a pResource.
         *
         * @param pResource - pointer to the resource
         * @param pArg      - pointer the descendant might have used when
         *                    Create() was called to store informations
         *                    about the resource
         */
        virtual void Destroy(T_res* pResource, void* pArg) = 0;

        /**
         * Has to be implemented by the descendant to react when a consumer
         * borrows a resource (no matter if freshly created or an already
         * created one). Of course reacting is optional, but the descendant
         * at least has to provide a method with empty body.
         *
         * @param pResource - pointer to the resource
         * @param pConsumer - identifier of the consumer who borrows the
         *                    resource
         * @param pArg      - pointer the descendant might have used when
         *                    Create() was called to store informations
         *                    about the resource, this information can be
         *                    updated by the descendant here
         */
        virtual void OnBorrow(T_res* pResource, ResourceConsumer<T_res>* pConsumer, void*& pArg) = 0;

        /**
         * Dispatcher method which should be periodically called by the
         * descendant during update or creation of the resource associated
         * with \a Key. This method will inform all associated consumers
         * of the given resource about the current progress.
         *
         * @param Key       - unique identifier of the resource which is
         *                    currently creating or updating
         * @param fProgress - current progress of that creation / update
         *                    process as value between 0.0 and 1.0
         */
        void DispatchResourceProgressEvent(T_key Key, float fProgress) {
            typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
            if (iterEntry != ResourceEntries.end()) {
                resource_entry_t& entry = iterEntry->second;
                // inform all consumers of that resource about current progress
                typename ConsumerSet::iterator iterCons = entry.consumers.begin();
                typename ConsumerSet::iterator endCons  = entry.consumers.end();
                for (; iterCons != endCons; iterCons++) {
                    (*iterCons)->OnResourceProgress(fProgress);
                }
            }
        }
};

#endif // __RESOURCE_MANAGER__
1	schoenebeck	53	/***************************************************************************
2			* *
3			* LinuxSampler - modular, streaming capable sampler *
4			* *
5	schoenebeck	56	* Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck *
6	schoenebeck	925	* Copyright (C) 2005, 2006 Christian Schoenebeck *
7	schoenebeck	53	* *
8			* This program is free software; you can redistribute it and/or modify *
9			* it under the terms of the GNU General Public License as published by *
10			* the Free Software Foundation; either version 2 of the License, or *
11			* (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., 59 Temple Place, Suite 330, Boston, *
21			* MA 02111-1307 USA *
22			***************************************************************************/
23
24			#ifndef __RESOURCE_MANAGER__
25			#define __RESOURCE_MANAGER__
26
27			#include <set>
28			#include <map>
29
30			/**
31			* Interface class for consumer classes which use a resource managed
32			* by the ResourceManager class.
33			*/
34			template<class T_res>
35			class ResourceConsumer {
36			public:
37			/**
38			* Will be called by the ResourceManager to inform the
39			* consumer that a resource currently used by him is going
40			* to be updated. The consumer can then react by stopping
41			* usage until resource is updated. The ResourceManager will
42			* not update the resource until this method returns. This
43			* method needs to be implemented by the consumer.
44			*
45			* @param pResource - resource going to be updated
46			* @param pUpdateArg - pointer the consumer might use to store
47			* informations he might need when update
48			* process was completed
49			*/
50			virtual void ResourceToBeUpdated(T_res* pResource, void*& pUpdateArg) = 0;
51
52			/**
53			* Will be called by the ResourceManager to inform the
54			* consumer that resource update was completed. This method
55			* needs to be implemented by the consumer.
56			*
57			* @param pOldResource - (now invalid) pointer to the old
58			* resource
59			* @param pNewResource - (valid) pointer to the updated
60			* resource
61			* @param pUpdateArg - pointer the consumer might have used when
62			* ResourceToBeUpdated() was called
63			*/
64			virtual void ResourceUpdated(T_res* pOldResource, T_res* pNewResource, void* pUpdateArg) = 0;
65	schoenebeck	517
66			/**
67			* Might be called by the ResourceManager periodically during an
68			* update / creation of a resource to inform the consumer about the
69			* current progress of that process. This method needs to be
70			* implemented by the consumer.
71			*
72			* @param fProgress - current progress as value between 0.0 and 1.0
73			*/
74			virtual void OnResourceProgress(float fProgress) = 0;
75	schoenebeck	53	};
76
77			/**
78			* Abstract base class for sharing resources between multiple consumers.
79			* A consumer can borrow a resource from the ResourceManager, if the
80			* resource doesn't exist yet it will be created. Other consumers will
81			* just be given the same pointer to the resource then. When all consumers
82			* gave back their pointer to the resource, the resource will be destroyed.
83			* Descendants of this base class have to implement the (protected)
84			* Create() and Destroy() methods to create and destroy a resource.
85			*/
86			template<class T_key, class T_res>
87			class ResourceManager {
88			private:
89			typedef std::set<ResourceConsumer<T_res>*> ConsumerSet;
90			struct resource_entry_t {
91			T_key key;
92			T_res* resource; ///< pointer to the resource
93			ConsumerSet consumers; ///< list of all consumers who currently use the resource
94			void* arg; ///< optional pointer the descendant might use to store informations about the resource
95			};
96			typedef std::map<T_key, resource_entry_t> ResourceMap;
97			ResourceMap ResourceEntries;
98
99			public:
100	letz	386	virtual ~ResourceManager() {}
101	schoenebeck	53	/**
102			* Borrow a resource identified by \a Key. The ResourceManager will
103			* mark the resource as in usage by the consumer given with
104			* \a pConsumer. If the Resource doesn't exist yet it will be
105			* created.
106			*
107			* @param Key - resource identifier
108			* @param pConsumer - identifier of the consumer who borrows it
109			* @returns pointer to resource
110			*/
111			T_res* Borrow(T_key Key, ResourceConsumer<T_res>* pConsumer) {
112			typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
113			if (iterEntry == ResourceEntries.end()) {
114	schoenebeck	517	// already create an entry for the resource
115	schoenebeck	53	resource_entry_t entry;
116			entry.key = Key;
117	schoenebeck	517	entry.resource = NULL;
118			entry.consumers.insert(pConsumer);
119			ResourceEntries[Key] = entry;
120	schoenebeck	925	try {
121			// actually create the resource
122			entry.resource = Create(Key, pConsumer, entry.arg);
123			} catch (...) {
124			// creating the resource failed, so remove the entry
125			ResourceEntries.erase(Key);
126			// rethrow the same exception
127			throw;
128			}
129	schoenebeck	517	// now update the entry with the created resource
130			ResourceEntries[Key] = entry;
131	schoenebeck	53	OnBorrow(entry.resource, pConsumer, entry.arg);
132			return entry.resource;
133			}
134			resource_entry_t& entry = iterEntry->second;
135			entry.consumers.insert(pConsumer);
136			OnBorrow(entry.resource, pConsumer, entry.arg);
137			return entry.resource;
138			}
139
140			/**
141			* Give back a resource. This tells the ResourceManager that the
142			* consumer given by \a pConsumer doesn't need the resource anymore.
143			* If the resource is not needed by any consumer anymore then the
144			* resource will be destroyed.
145			*
146			* @param pResource - pointer to resource
147			* @param pConsumer - identifier of the consumer who borrowed the
148			* resource
149			*/
150			void HandBack(T_res* pResource, ResourceConsumer<T_res>* pConsumer) {
151			typename ResourceMap::iterator iter = ResourceEntries.begin();
152			typename ResourceMap::iterator end = ResourceEntries.end();
153			for (; iter != end; iter++) {
154	schoenebeck	351	if (iter->second.resource == pResource) {
155	schoenebeck	53	resource_entry_t& entry = iter->second;
156			entry.consumers.erase(pConsumer);
157			if (entry.consumers.empty()) {
158	persson	835	T_res* resource = entry.resource;
159			void* arg = entry.arg;
160	schoenebeck	53	ResourceEntries.erase(iter);
161	persson	835	Destroy(resource, arg);
162	schoenebeck	53	}
163			return;
164			}
165			}
166			}
167
168			/**
169			* Request update of a resource.
170			*
171			* @param pResource - resource to be updated
172			* @param pConsumer - consumer who requested the update
173			*/
174			void Update(T_res* pResource, ResourceConsumer<T_res>* pConsumer) {
175			typename ResourceMap::iterator iter = ResourceEntries.begin();
176			typename ResourceMap::iterator end = ResourceEntries.end();
177			for (; iter != end; iter++) {
178	schoenebeck	351	if (iter->second.resource == pResource) {
179	schoenebeck	53	resource_entry_t& entry = iter->second;
180			// inform all consumers about pending update
181			std::map<ResourceConsumer<T_res>,void> updateargs;
182			typename ConsumerSet::iterator iterCons = entry.consumers.begin();
183			typename ConsumerSet::iterator endCons = entry.consumers.end();
184			for (; iterCons != endCons; iterCons++) {
185			if (*iterCons == pConsumer) continue;
186			void* updatearg = NULL;
187			(*iterCons)->ResourceToBeUpdated(entry.resource, updatearg);
188			if (updatearg) updateargs[*iterCons] = updatearg;
189			}
190			// update resource
191			T_res* pOldResource = entry.resource;
192			Destroy(entry.resource, entry.arg);
193			entry.resource = Create(entry.key, pConsumer, entry.arg);
194			// inform all consumers about update completed
195			iterCons = entry.consumers.begin();
196			endCons = entry.consumers.end();
197			for (; iterCons != endCons; iterCons++) {
198			if (*iterCons == pConsumer) continue;
199			typename std::map<ResourceConsumer<T_res>,void>::iterator iterArg = updateargs.find(*iterCons);
200			void* updatearg = (iterArg != updateargs.end()) ? iterArg->second : NULL;
201			(*iterCons)->ResourceUpdated(pOldResource, entry.resource, updatearg);
202			}
203			return;
204			}
205			}
206			}
207
208			protected:
209			/**
210			* Has to be implemented by the descendant to create (allocate) a
211			* resource identified by \a Key.
212			*
213			* @param Key - identifier of the resource
214			* @param pConsumer - identifier of the consumer who borrows the
215			* resource
216			* @param pArg - pointer the descendant can use to store
217			* informations he might need for destruction of
218			* the resource
219			* @returns pointer to new resource
220			*/
221			virtual T_res* Create(T_key Key, ResourceConsumer<T_res>* pConsumer, void*& pArg) = 0;
222
223			/**
224			* Has to be implemented by the descendant to destroy (free) a
225			* resource pointed by \a pResource.
226			*
227			* @param pResource - pointer to the resource
228			* @param pArg - pointer the descendant might have used when
229			* Create() was called to store informations
230			* about the resource
231			*/
232			virtual void Destroy(T_res* pResource, void* pArg) = 0;
233
234			/**
235			* Has to be implemented by the descendant to react when a consumer
236			* borrows a resource (no matter if freshly created or an already
237			* created one). Of course reacting is optional, but the descendant
238			* at least has to provide a method with empty body.
239			*
240			* @param pResource - pointer to the resource
241			* @param pConsumer - identifier of the consumer who borrows the
242			* resource
243			* @param pArg - pointer the descendant might have used when
244			* Create() was called to store informations
245			* about the resource, this information can be
246			* updated by the descendant here
247			*/
248			virtual void OnBorrow(T_res* pResource, ResourceConsumer<T_res>* pConsumer, void*& pArg) = 0;
249	schoenebeck	517
250			/**
251			* Dispatcher method which should be periodically called by the
252			* descendant during update or creation of the resource associated
253			* with \a Key. This method will inform all associated consumers
254			* of the given resource about the current progress.
255			*
256			* @param Key - unique identifier of the resource which is
257			* currently creating or updating
258			* @param fProgress - current progress of that creation / update
259			* process as value between 0.0 and 1.0
260			*/
261			void DispatchResourceProgressEvent(T_key Key, float fProgress) {
262			typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
263			if (iterEntry != ResourceEntries.end()) {
264			resource_entry_t& entry = iterEntry->second;
265			// inform all consumers of that resource about current progress
266			typename ConsumerSet::iterator iterCons = entry.consumers.begin();
267			typename ConsumerSet::iterator endCons = entry.consumers.end();
268			for (; iterCons != endCons; iterCons++) {
269			(*iterCons)->OnResourceProgress(fProgress);
270			}
271			}
272			}
273	schoenebeck	53	};
274
275			#endif // __RESOURCE_MANAGER__