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	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	schoenebeck	947	#include <vector>
30	schoenebeck	53
31	schoenebeck	947	#include "Exception.h"
32
33			namespace LinuxSampler {
34
35			/** @brief Interface class for Resource Consumers.
36			*
37	schoenebeck	53	* Interface class for consumer classes which use a resource managed
38	schoenebeck	947	* 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	schoenebeck	53	*/
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	schoenebeck	517
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	schoenebeck	53	};
84
85	schoenebeck	947	/** @brief Manager for sharing resources.
86			*
87	schoenebeck	53	* 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	schoenebeck	947	* gave back their pointer to the resource, the resource will (by default)
92			* be destroyed.
93			*
94	schoenebeck	53	* 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	schoenebeck	947	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	schoenebeck	53	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	schoenebeck	947	mode_t mode; ///< When should the resource be created? When should it be destroyed?
115	schoenebeck	53	ConsumerSet consumers; ///< list of all consumers who currently use the resource
116	schoenebeck	947	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	schoenebeck	53	};
119			typedef std::map<T_key, resource_entry_t> ResourceMap;
120			ResourceMap ResourceEntries;
121
122			public:
123			/**
124	schoenebeck	947	* 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	schoenebeck	53	* 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	schoenebeck	947	// search for an entry for this resource
149	schoenebeck	53	typename ResourceMap::iterator iterEntry = ResourceEntries.find(Key);
150	schoenebeck	947	if (iterEntry == ResourceEntries.end()) { // entry doesn't exist yet
151	schoenebeck	517	// already create an entry for the resource
152	schoenebeck	53	resource_entry_t entry;
153			entry.key = Key;
154	schoenebeck	517	entry.resource = NULL;
155	schoenebeck	947	entry.mode = ON_DEMAND; // default mode
156			entry.lifearg = NULL;
157			entry.entryarg = NULL;
158	schoenebeck	517	entry.consumers.insert(pConsumer);
159			ResourceEntries[Key] = entry;
160	schoenebeck	925	try {
161			// actually create the resource
162	schoenebeck	947	entry.resource = Create(Key, pConsumer, entry.lifearg);
163	schoenebeck	925	} catch (...) {
164			// creating the resource failed, so remove the entry
165			ResourceEntries.erase(Key);
166			// rethrow the same exception
167			throw;
168			}
169	schoenebeck	517	// now update the entry with the created resource
170			ResourceEntries[Key] = entry;
171	schoenebeck	947	OnBorrow(entry.resource, pConsumer, entry.lifearg);
172	schoenebeck	53	return entry.resource;
173	schoenebeck	947	} 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	schoenebeck	53	}
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	schoenebeck	947	* 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	schoenebeck	53	*
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	schoenebeck	947	// search for the entry associated with the given resource
202	schoenebeck	53	typename ResourceMap::iterator iter = ResourceEntries.begin();
203			typename ResourceMap::iterator end = ResourceEntries.end();
204			for (; iter != end; iter++) {
205	schoenebeck	947	if (iter->second.resource == pResource) { // found entry for resource
206	schoenebeck	53	resource_entry_t& entry = iter->second;
207			entry.consumers.erase(pConsumer);
208	schoenebeck	947	// remove entry if necessary
209			if (entry.mode == ON_DEMAND && !entry.entryarg && entry.consumers.empty()) {
210	persson	835	T_res* resource = entry.resource;
211	schoenebeck	947	void* arg = entry.lifearg;
212	schoenebeck	53	ResourceEntries.erase(iter);
213	schoenebeck	947	// destroy resource if necessary
214			if (resource) Destroy(resource, arg);
215	schoenebeck	53	}
216			return;
217			}
218			}
219			}
220
221			/**
222	schoenebeck	947	* 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	schoenebeck	53	*
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	schoenebeck	351	if (iter->second.resource == pResource) {
236	schoenebeck	53	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	schoenebeck	947	Destroy(entry.resource, entry.lifearg);
250			entry.resource = Create(entry.key, pConsumer, entry.lifearg);
251	schoenebeck	53	// 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	schoenebeck	947	/**
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	schoenebeck	53	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	schoenebeck	517
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	schoenebeck	53	};
446
447	schoenebeck	947	} // namespace LinuxSampler
448
449	schoenebeck	53	#endif // __RESOURCE_MANAGER__