src/common/ResourceManager.h

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