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>
#include <vector>

#include "Exception.h"

namespace LinuxSampler {

/** @brief Interface class for Resource Consumers.
 *
 * Interface class for consumer classes which use a resource managed
 * by the ResourceManager class. All classes which use the ResourceManager
 * to aquire resources have to derive from this interface class and
 * implement the abstract methods.
 */
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;
};

/** @brief Manager for sharing resources.
 *
 * 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 (by default)
 * 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 {
    public:
        /**
         * Defines life-time strategy for resources.
         */
        enum mode_t {
            ON_DEMAND      = 0, ///< Create resource when needed, free it once not needed anymore (default behavior).
            ON_DEMAND_HOLD = 1, ///< Create resource when needed and keep it even if not needed anymore.
            PERSISTENT     = 2  ///< Immediately create resource and keep it.
        };

    private:
        typedef std::set<ResourceConsumer<T_res>*> ConsumerSet;
        struct resource_entry_t {
            T_key       key;
            T_res*      resource;  ///< pointer to the resource
            mode_t      mode;      ///< When should the resource be created? When should it be destroyed?
            ConsumerSet consumers; ///< list of all consumers who currently use the resource
            void*       lifearg;   ///< optional pointer the descendant might use to store informations about a created resource
            void*       entryarg;  ///< optional pointer the descendant might use to store informations about an entry
        };
        typedef std::map<T_key, resource_entry_t> ResourceMap;
        ResourceMap ResourceEntries;

    public:
        /**
         * Returns (the keys of) all current entries of this
         * ResourceManager instance.
         */
        std::vector<T_key> Entries() {
            std::vector<T_key> result;
            for (typename ResourceMap::iterator iter = ResourceEntries.begin();
                 iter != ResourceEntries.end(); iter++)
            {
                result.push_back(iter->first);
            }
            return result;
        }

        /**
         * 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) {
            // search for an entry for this resource
            typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
            if (iterEntry == ResourceEntries.end()) { // entry doesn't exist yet
                // already create an entry for the resource
                resource_entry_t entry;
                entry.key      = Key;
                entry.resource = NULL;
                entry.mode     = ON_DEMAND; // default mode
                entry.lifearg  = NULL;
                entry.entryarg = NULL;
                entry.consumers.insert(pConsumer);
                ResourceEntries[Key] = entry;
                try {
                    // actually create the resource
                    entry.resource = Create(Key, pConsumer, entry.lifearg);
                } 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.lifearg);
                return entry.resource;
            } else { // entry already exists
                resource_entry_t& entry = iterEntry->second;
                if (!entry.resource) { // create resource if not created already
                    try {
                        entry.resource = Create(Key, pConsumer, entry.lifearg);
                    } catch (...) {
                        entry.resource = NULL;
                        throw; // rethrow the same exception
                    }
                }
                entry.consumers.insert(pConsumer);
                OnBorrow(entry.resource, pConsumer, entry.lifearg);
                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 and the
         * resource has a life-time strategy of ON_DEMAND (which is the
         * default setting) 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) {
            // search for the entry associated with the given resource
            typename ResourceMap::iterator iter = ResourceEntries.begin();
            typename ResourceMap::iterator end  = ResourceEntries.end();
            for (; iter != end; iter++) {
                if (iter->second.resource == pResource) { // found entry for resource
                    resource_entry_t& entry = iter->second;
                    entry.consumers.erase(pConsumer);
                    // remove entry if necessary
                    if (entry.mode == ON_DEMAND && !entry.entryarg && entry.consumers.empty()) {
                        T_res* resource = entry.resource;
                        void* arg       = entry.lifearg;
                        ResourceEntries.erase(iter);
                        // destroy resource if necessary
                        if (resource) Destroy(resource, arg);
                    }
                    return;
                }
            }
        }

        /**
         * Request update of a resource. All consumers will be informed
         * about the pending update of the resource so they can safely react
         * by stopping its usage first, then the resource will be recreated
         * and finally the consumers will be informed once the update was
         * completed, so they can continue to use the 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.lifearg);
                    entry.resource = Create(entry.key, pConsumer, entry.lifearg);
                    // 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;
                }
            }
        }

        /**
         * Returns the life-time strategy of the given resource.
         *
         * @param Key - ID of the resource
         */
        mode_t AvailabilityMode(T_key Key) {
            typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
            if (iterEntry == ResourceEntries.end())
                return ON_DEMAND; // resource entry doesn't exist, so we return the default mode
            resource_entry_t& entry = iterEntry->second;
            return entry.mode;
        }

        /**
         * Change life-time strategy of the given resource. If a life-time
         * strategy of PERSISTENT was given and the resource was not created
         * yet, it will immediately be created and this method will block
         * until the resource creation was completed.
         *
         * @param Key - ID of the resource
         * @param Mode - life-time strategy of resource to be set
         * @throws Exception in case an invalid Mode was given
         */
        void SetAvailabilityMode(T_key Key, mode_t Mode) throw (Exception) {
            if (Mode != ON_DEMAND && Mode != ON_DEMAND_HOLD && Mode != PERSISTENT)
                throw Exception("ResourceManager::SetAvailabilityMode(): invalid mode");

            // search for an entry for this resource
            typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
            resource_entry_t* pEntry = NULL;
            if (iterEntry == ResourceEntries.end()) { // resource entry doesn't exist
                if (Mode == ON_DEMAND) return; // we don't create an entry for the default value
                // create an entry for the resource
                pEntry = &ResourceEntries[Key];
                pEntry->key      = Key;
                pEntry->resource = NULL;
                pEntry->mode     = Mode;
                pEntry->lifearg  = NULL;
                pEntry->entryarg = NULL;
            } else { // resource entry exists
                pEntry = &iterEntry->second;
                // remove entry if necessary
                if (Mode == ON_DEMAND && !pEntry->entryarg && pEntry->consumers.empty()) {
                    T_res* resource = pEntry->resource;
                    void* arg       = pEntry->lifearg;
                    ResourceEntries.erase(iterEntry);
                    // destroy resource if necessary
                    if (resource) Destroy(resource, arg);
                    return; // done
                }
                pEntry->mode = Mode; // apply new mode
            }

            // already create the resource if necessary
            if (pEntry->mode == PERSISTENT && !pEntry->resource) {
                try {
                    // actually create the resource
                    pEntry->resource = Create(Key, NULL /*no consumer yet*/, pEntry->lifearg);
                } catch (...) {
                    // creating the resource failed, so skip it for now
                    pEntry->resource = NULL;
                    // rethrow the same exception
                    throw;
                }
            }
        }

        /**
         * Returns custom data sticked to the given resource previously by
         * a SetCustomData() call.
         *
         * @param Key - ID of resource
         */
        void* CustomData(T_key Key) {
            typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
            if (iterEntry == ResourceEntries.end()) return NULL; // resource entry doesn't exist, so we return the default mode
            resource_entry_t& entry = iterEntry->second;
            return entry.entryarg;
        }

        /**
         * This method can be used to stick custom data to an resource
         * entry. In case the custom data is not needed anymore, you should
         * call this method again and set \a pData to NULL, so the
         * ResourceManager might safe space by removing the respective
         * entry if not needed anymore.
         *
         * @param Key - ID of resource
         * @param pData - pointer to custom data, or NULL if not needed anymore
         */
        void SetCustomData(T_key Key, void* pData) {
            typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
            if (pData) {
                if (iterEntry == ResourceEntries.end()) { // entry doesnt exist, so create one
                    resource_entry_t* pEntry = &ResourceEntries[Key];
                    pEntry->key      = Key;
                    pEntry->resource = NULL;
                    pEntry->mode     = ON_DEMAND;
                    pEntry->lifearg  = NULL;
                    pEntry->entryarg = pData; // set custom data
                } else { // entry exists, so just update its custom data
                    iterEntry->second.entryarg = pData;
                }
            } else { // !pData
                if (iterEntry == ResourceEntries.end()) return; // entry doesnt exist, so nothing to do
                // entry exists, remove it if necessary
                resource_entry_t* pEntry = &iterEntry->second;
                if (pEntry->mode == ON_DEMAND && pEntry->consumers.empty()) {
                    ResourceEntries.erase(iterEntry);
                } else iterEntry->second.entryarg = NULL;
            }
        }

        virtual ~ResourceManager() {} // due to C++'s nature we cannot destroy created resources here

    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);
                }
            }
        }
};

} // namespace LinuxSampler

#endif // __RESOURCE_MANAGER__
1	/***************************************************************************
2	* *
3	* LinuxSampler - modular, streaming capable sampler *
4	* *
5	* Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck *
6	* Copyright (C) 2005, 2006 Christian Schoenebeck *
7	* *
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	#include <vector>
30
31	#include "Exception.h"
32
33	namespace LinuxSampler {
34
35	/** @brief Interface class for Resource Consumers.
36	*
37	* Interface class for consumer classes which use a resource managed
38	* by the ResourceManager class. All classes which use the ResourceManager
39	* to aquire resources have to derive from this interface class and
40	* implement the abstract methods.
41	*/
42	template<class T_res>
43	class ResourceConsumer {
44	public:
45	/**
46	* Will be called by the ResourceManager to inform the
47	* consumer that a resource currently used by him is going
48	* to be updated. The consumer can then react by stopping
49	* usage until resource is updated. The ResourceManager will
50	* not update the resource until this method returns. This
51	* method needs to be implemented by the consumer.
52	*
53	* @param pResource - resource going to be updated
54	* @param pUpdateArg - pointer the consumer might use to store
55	* informations he might need when update
56	* process was completed
57	*/
58	virtual void ResourceToBeUpdated(T_res* pResource, void*& pUpdateArg) = 0;
59
60	/**
61	* Will be called by the ResourceManager to inform the
62	* consumer that resource update was completed. This method
63	* needs to be implemented by the consumer.
64	*
65	* @param pOldResource - (now invalid) pointer to the old
66	* resource
67	* @param pNewResource - (valid) pointer to the updated
68	* resource
69	* @param pUpdateArg - pointer the consumer might have used when
70	* ResourceToBeUpdated() was called
71	*/
72	virtual void ResourceUpdated(T_res* pOldResource, T_res* pNewResource, void* pUpdateArg) = 0;
73
74	/**
75	* Might be called by the ResourceManager periodically during an
76	* update / creation of a resource to inform the consumer about the
77	* current progress of that process. This method needs to be
78	* implemented by the consumer.
79	*
80	* @param fProgress - current progress as value between 0.0 and 1.0
81	*/
82	virtual void OnResourceProgress(float fProgress) = 0;
83	};
84
85	/** @brief Manager for sharing resources.
86	*
87	* Abstract base class for sharing resources between multiple consumers.
88	* A consumer can borrow a resource from the ResourceManager, if the
89	* resource doesn't exist yet it will be created. Other consumers will
90	* just be given the same pointer to the resource then. When all consumers
91	* gave back their pointer to the resource, the resource will (by default)
92	* be destroyed.
93	*
94	* Descendants of this base class have to implement the (protected)
95	* Create() and Destroy() methods to create and destroy a resource.
96	*/
97	template<class T_key, class T_res>
98	class ResourceManager {
99	public:
100	/**
101	* Defines life-time strategy for resources.
102	*/
103	enum mode_t {
104	ON_DEMAND = 0, ///< Create resource when needed, free it once not needed anymore (default behavior).
105	ON_DEMAND_HOLD = 1, ///< Create resource when needed and keep it even if not needed anymore.
106	PERSISTENT = 2 ///< Immediately create resource and keep it.
107	};
108
109	private:
110	typedef std::set<ResourceConsumer<T_res>*> ConsumerSet;
111	struct resource_entry_t {
112	T_key key;
113	T_res* resource; ///< pointer to the resource
114	mode_t mode; ///< When should the resource be created? When should it be destroyed?
115	ConsumerSet consumers; ///< list of all consumers who currently use the resource
116	void* lifearg; ///< optional pointer the descendant might use to store informations about a created resource
117	void* entryarg; ///< optional pointer the descendant might use to store informations about an entry
118	};
119	typedef std::map<T_key, resource_entry_t> ResourceMap;
120	ResourceMap ResourceEntries;
121
122	public:
123	/**
124	* Returns (the keys of) all current entries of this
125	* ResourceManager instance.
126	*/
127	std::vector<T_key> Entries() {
128	std::vector<T_key> result;
129	for (typename ResourceMap::iterator iter = ResourceEntries.begin();
130	iter != ResourceEntries.end(); iter++)
131	{
132	result.push_back(iter->first);
133	}
134	return result;
135	}
136
137	/**
138	* Borrow a resource identified by \a Key. The ResourceManager will
139	* mark the resource as in usage by the consumer given with
140	* \a pConsumer. If the Resource doesn't exist yet it will be
141	* created.
142	*
143	* @param Key - resource identifier
144	* @param pConsumer - identifier of the consumer who borrows it
145	* @returns pointer to resource
146	*/
147	T_res* Borrow(T_key Key, ResourceConsumer<T_res>* pConsumer) {
148	// search for an entry for this resource
149	typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
150	if (iterEntry == ResourceEntries.end()) { // entry doesn't exist yet
151	// already create an entry for the resource
152	resource_entry_t entry;
153	entry.key = Key;
154	entry.resource = NULL;
155	entry.mode = ON_DEMAND; // default mode
156	entry.lifearg = NULL;
157	entry.entryarg = NULL;
158	entry.consumers.insert(pConsumer);
159	ResourceEntries[Key] = entry;
160	try {
161	// actually create the resource
162	entry.resource = Create(Key, pConsumer, entry.lifearg);
163	} catch (...) {
164	// creating the resource failed, so remove the entry
165	ResourceEntries.erase(Key);
166	// rethrow the same exception
167	throw;
168	}
169	// now update the entry with the created resource
170	ResourceEntries[Key] = entry;
171	OnBorrow(entry.resource, pConsumer, entry.lifearg);
172	return entry.resource;
173	} else { // entry already exists
174	resource_entry_t& entry = iterEntry->second;
175	if (!entry.resource) { // create resource if not created already
176	try {
177	entry.resource = Create(Key, pConsumer, entry.lifearg);
178	} catch (...) {
179	entry.resource = NULL;
180	throw; // rethrow the same exception
181	}
182	}
183	entry.consumers.insert(pConsumer);
184	OnBorrow(entry.resource, pConsumer, entry.lifearg);
185	return entry.resource;
186	}
187	}
188
189	/**
190	* Give back a resource. This tells the ResourceManager that the
191	* consumer given by \a pConsumer doesn't need the resource anymore.
192	* If the resource is not needed by any consumer anymore and the
193	* resource has a life-time strategy of ON_DEMAND (which is the
194	* default setting) then the resource will be destroyed.
195	*
196	* @param pResource - pointer to resource
197	* @param pConsumer - identifier of the consumer who borrowed the
198	* resource
199	*/
200	void HandBack(T_res* pResource, ResourceConsumer<T_res>* pConsumer) {
201	// search for the entry associated with the given resource
202	typename ResourceMap::iterator iter = ResourceEntries.begin();
203	typename ResourceMap::iterator end = ResourceEntries.end();
204	for (; iter != end; iter++) {
205	if (iter->second.resource == pResource) { // found entry for resource
206	resource_entry_t& entry = iter->second;
207	entry.consumers.erase(pConsumer);
208	// remove entry if necessary
209	if (entry.mode == ON_DEMAND && !entry.entryarg && entry.consumers.empty()) {
210	T_res* resource = entry.resource;
211	void* arg = entry.lifearg;
212	ResourceEntries.erase(iter);
213	// destroy resource if necessary
214	if (resource) Destroy(resource, arg);
215	}
216	return;
217	}
218	}
219	}
220
221	/**
222	* Request update of a resource. All consumers will be informed
223	* about the pending update of the resource so they can safely react
224	* by stopping its usage first, then the resource will be recreated
225	* and finally the consumers will be informed once the update was
226	* completed, so they can continue to use the resource.
227	*
228	* @param pResource - resource to be updated
229	* @param pConsumer - consumer who requested the update
230	*/
231	void Update(T_res* pResource, ResourceConsumer<T_res>* pConsumer) {
232	typename ResourceMap::iterator iter = ResourceEntries.begin();
233	typename ResourceMap::iterator end = ResourceEntries.end();
234	for (; iter != end; iter++) {
235	if (iter->second.resource == pResource) {
236	resource_entry_t& entry = iter->second;
237	// inform all consumers about pending update
238	std::map<ResourceConsumer<T_res>,void> updateargs;
239	typename ConsumerSet::iterator iterCons = entry.consumers.begin();
240	typename ConsumerSet::iterator endCons = entry.consumers.end();
241	for (; iterCons != endCons; iterCons++) {
242	if (*iterCons == pConsumer) continue;
243	void* updatearg = NULL;
244	(*iterCons)->ResourceToBeUpdated(entry.resource, updatearg);
245	if (updatearg) updateargs[*iterCons] = updatearg;
246	}
247	// update resource
248	T_res* pOldResource = entry.resource;
249	Destroy(entry.resource, entry.lifearg);
250	entry.resource = Create(entry.key, pConsumer, entry.lifearg);
251	// inform all consumers about update completed
252	iterCons = entry.consumers.begin();
253	endCons = entry.consumers.end();
254	for (; iterCons != endCons; iterCons++) {
255	if (*iterCons == pConsumer) continue;
256	typename std::map<ResourceConsumer<T_res>,void>::iterator iterArg = updateargs.find(*iterCons);
257	void* updatearg = (iterArg != updateargs.end()) ? iterArg->second : NULL;
258	(*iterCons)->ResourceUpdated(pOldResource, entry.resource, updatearg);
259	}
260	return;
261	}
262	}
263	}
264
265	/**
266	* Returns the life-time strategy of the given resource.
267	*
268	* @param Key - ID of the resource
269	*/
270	mode_t AvailabilityMode(T_key Key) {
271	typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
272	if (iterEntry == ResourceEntries.end())
273	return ON_DEMAND; // resource entry doesn't exist, so we return the default mode
274	resource_entry_t& entry = iterEntry->second;
275	return entry.mode;
276	}
277
278	/**
279	* Change life-time strategy of the given resource. If a life-time
280	* strategy of PERSISTENT was given and the resource was not created
281	* yet, it will immediately be created and this method will block
282	* until the resource creation was completed.
283	*
284	* @param Key - ID of the resource
285	* @param Mode - life-time strategy of resource to be set
286	* @throws Exception in case an invalid Mode was given
287	*/
288	void SetAvailabilityMode(T_key Key, mode_t Mode) throw (Exception) {
289	if (Mode != ON_DEMAND && Mode != ON_DEMAND_HOLD && Mode != PERSISTENT)
290	throw Exception("ResourceManager::SetAvailabilityMode(): invalid mode");
291
292	// search for an entry for this resource
293	typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
294	resource_entry_t* pEntry = NULL;
295	if (iterEntry == ResourceEntries.end()) { // resource entry doesn't exist
296	if (Mode == ON_DEMAND) return; // we don't create an entry for the default value
297	// create an entry for the resource
298	pEntry = &ResourceEntries[Key];
299	pEntry->key = Key;
300	pEntry->resource = NULL;
301	pEntry->mode = Mode;
302	pEntry->lifearg = NULL;
303	pEntry->entryarg = NULL;
304	} else { // resource entry exists
305	pEntry = &iterEntry->second;
306	// remove entry if necessary
307	if (Mode == ON_DEMAND && !pEntry->entryarg && pEntry->consumers.empty()) {
308	T_res* resource = pEntry->resource;
309	void* arg = pEntry->lifearg;
310	ResourceEntries.erase(iterEntry);
311	// destroy resource if necessary
312	if (resource) Destroy(resource, arg);
313	return; // done
314	}
315	pEntry->mode = Mode; // apply new mode
316	}
317
318	// already create the resource if necessary
319	if (pEntry->mode == PERSISTENT && !pEntry->resource) {
320	try {
321	// actually create the resource
322	pEntry->resource = Create(Key, NULL /no consumer yet/, pEntry->lifearg);
323	} catch (...) {
324	// creating the resource failed, so skip it for now
325	pEntry->resource = NULL;
326	// rethrow the same exception
327	throw;
328	}
329	}
330	}
331
332	/**
333	* Returns custom data sticked to the given resource previously by
334	* a SetCustomData() call.
335	*
336	* @param Key - ID of resource
337	*/
338	void* CustomData(T_key Key) {
339	typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
340	if (iterEntry == ResourceEntries.end()) return NULL; // resource entry doesn't exist, so we return the default mode
341	resource_entry_t& entry = iterEntry->second;
342	return entry.entryarg;
343	}
344
345	/**
346	* This method can be used to stick custom data to an resource
347	* entry. In case the custom data is not needed anymore, you should
348	* call this method again and set \a pData to NULL, so the
349	* ResourceManager might safe space by removing the respective
350	* entry if not needed anymore.
351	*
352	* @param Key - ID of resource
353	* @param pData - pointer to custom data, or NULL if not needed anymore
354	*/
355	void SetCustomData(T_key Key, void* pData) {
356	typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
357	if (pData) {
358	if (iterEntry == ResourceEntries.end()) { // entry doesnt exist, so create one
359	resource_entry_t* pEntry = &ResourceEntries[Key];
360	pEntry->key = Key;
361	pEntry->resource = NULL;
362	pEntry->mode = ON_DEMAND;
363	pEntry->lifearg = NULL;
364	pEntry->entryarg = pData; // set custom data
365	} else { // entry exists, so just update its custom data
366	iterEntry->second.entryarg = pData;
367	}
368	} else { // !pData
369	if (iterEntry == ResourceEntries.end()) return; // entry doesnt exist, so nothing to do
370	// entry exists, remove it if necessary
371	resource_entry_t* pEntry = &iterEntry->second;
372	if (pEntry->mode == ON_DEMAND && pEntry->consumers.empty()) {
373	ResourceEntries.erase(iterEntry);
374	} else iterEntry->second.entryarg = NULL;
375	}
376	}
377
378	virtual ~ResourceManager() {} // due to C++'s nature we cannot destroy created resources here
379
380	protected:
381	/**
382	* Has to be implemented by the descendant to create (allocate) a
383	* resource identified by \a Key.
384	*
385	* @param Key - identifier of the resource
386	* @param pConsumer - identifier of the consumer who borrows the
387	* resource
388	* @param pArg - pointer the descendant can use to store
389	* informations he might need for destruction of
390	* the resource
391	* @returns pointer to new resource
392	*/
393	virtual T_res* Create(T_key Key, ResourceConsumer<T_res>* pConsumer, void*& pArg) = 0;
394
395	/**
396	* Has to be implemented by the descendant to destroy (free) a
397	* resource pointed by \a pResource.
398	*
399	* @param pResource - pointer to the resource
400	* @param pArg - pointer the descendant might have used when
401	* Create() was called to store informations
402	* about the resource
403	*/
404	virtual void Destroy(T_res* pResource, void* pArg) = 0;
405
406	/**
407	* Has to be implemented by the descendant to react when a consumer
408	* borrows a resource (no matter if freshly created or an already
409	* created one). Of course reacting is optional, but the descendant
410	* at least has to provide a method with empty body.
411	*
412	* @param pResource - pointer to the resource
413	* @param pConsumer - identifier of the consumer who borrows the
414	* resource
415	* @param pArg - pointer the descendant might have used when
416	* Create() was called to store informations
417	* about the resource, this information can be
418	* updated by the descendant here
419	*/
420	virtual void OnBorrow(T_res* pResource, ResourceConsumer<T_res>* pConsumer, void*& pArg) = 0;
421
422	/**
423	* Dispatcher method which should be periodically called by the
424	* descendant during update or creation of the resource associated
425	* with \a Key. This method will inform all associated consumers
426	* of the given resource about the current progress.
427	*
428	* @param Key - unique identifier of the resource which is
429	* currently creating or updating
430	* @param fProgress - current progress of that creation / update
431	* process as value between 0.0 and 1.0
432	*/
433	void DispatchResourceProgressEvent(T_key Key, float fProgress) {
434	typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
435	if (iterEntry != ResourceEntries.end()) {
436	resource_entry_t& entry = iterEntry->second;
437	// inform all consumers of that resource about current progress
438	typename ConsumerSet::iterator iterCons = entry.consumers.begin();
439	typename ConsumerSet::iterator endCons = entry.consumers.end();
440	for (; iterCons != endCons; iterCons++) {
441	(*iterCons)->OnResourceProgress(fProgress);
442	}
443	}
444	}
445	};
446
447	} // namespace LinuxSampler
448
449	#endif // __RESOURCE_MANAGER__