sbcachemanager.hpp

OSB-PIK-OpenVXI-3.0.0源代码 “中国XML论坛 - 专业的XML技术讨论区--XML在语音技术中的应用”

 /****************License************************************************
  *
  * Copyright 2000-2003.  ScanSoft, Inc.    
  *
  * Use of this software is subject to notices and obligations set forth 
  * in the SpeechWorks Public License - Software Version 1.2 which is 
  * included with this software. 
  *
  * ScanSoft is a registered trademark of ScanSoft, Inc., and OpenSpeech, 
  * SpeechWorks and the SpeechWorks logo are registered trademarks or 
  * trademarks of SpeechWorks International, Inc. in the United States 
  * and other countries.
  *
  ***********************************************************************/
 

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 #ifndef _SBCACHE_MANAGER_H__
 #define _SBCACHE_MANAGER_H__
 
 #include <time.h>             // For time_t
 #include <map>                // For STL map template class
 #include <list>
 
 #include "SBinetLogger.hpp"   // For SBinetLogger
 #include "SBcacheLog.h"       // For logging defines
 #include "SBcacheMisc.hpp"    // For SBcacheString, SBcacheKey, SBcachePath,
                               // SBcacheReaderWriterMutex
 #include "SBcacheCounter.hpp" // For SBcacheCounter, thread safe counters
 #include "SBcacheEntry.hpp"   // For SBcacheEntry, entry in the table
 
 class SBcacheManager : public SBinetLogger {
 public:
   // Constructor and destructor
   SBcacheManager(VXIlogInterface *log, VXIunsigned diagTagBase) : 
     SBinetLogger(MODULE_SBCACHE, log, diagTagBase), 
     _cacheDir(), _curSizeBytes(0), _maxSizeBytes(0), _entryMaxSizeBytes(0),
     _pathSeqNum(1), 
     _entryTableMutex(log, diagTagBase + SBCACHE_ET_MUTEX_TAGID), 
     _refCntMutexPool(), _entryTable() { }
   virtual ~SBcacheManager( );
   
   // Create the manager
   VXIcacheResult Create(const SBcacheNString &cacheDir,
 			VXIulong              cacheMaxSizeBytes,
 			VXIulong              entryMaxSizeBytes,
 			VXIulong              entryExpTimeSec,
 			VXIbool               unlockEntries,
                         VXIulong              cacheLowWaterBytes);
 
   // Open an entry
   VXIcacheResult Open(VXIlogInterface       *log,
 		      const SBcacheString   &moduleName,
 		      const SBcacheKey      &key,
 		      VXIcacheOpenMode       mode,
 		      VXIint32               flags,
 		      const VXIMap          *properties,
 		      VXIMap                *streamInfo,
 		      VXIcacheStream       **stream);
 
   // Notification of data writes
   VXIcacheResult WriteNotification (VXIlogInterface     *log,
 				    const SBcacheString &moduleName,
 				    VXIulong             nwritten,
                                     const SBcacheKey    &key);
 
   // Unlock an entry
   VXIcacheResult Unlock(VXIlogInterface       *log,
 			const SBcacheKey      &key);
 
   // Delete an entry
   VXIcacheResult Delete(VXIlogInterface       *log,
 			const SBcacheKey      &key,
 			bool                   haveEntryOpen = false);
 
   // Write out the index file, used to handle abnormal termination
   VXIcacheResult WriteIndex( );
 
   // Clear log resource to avoid crash during caught abnormal termination
   void ClearLogResource( ) { SetLog (NULL, GetDiagBase( )); }
 
 private:
   // Read the index file, used at startup
   VXIcacheResult ReadIndex(const SBcacheNString  &cacheDir);
 
   // Get a new path for an entry
   SBcachePath GetNewEntryPath(const SBcacheString &moduleName,
 			      const SBcacheKey    &key);
 
   // Clean up the cache to eliminate expired entries and if neccessary
   // delete other entries to remain within the allocated size
   VXIcacheResult Cleanup (bool forcedCleanup, const SBcacheKey& writingKey);
 
   // Disable the copy constructor and assignment operator
   SBcacheManager(const SBcacheManager &manager);
   const SBcacheManager &operator=(const SBcacheManager &manager);
 
   // Preallocation
   void ReserveEntries(int nentries);
   void EntryAdded();
   void EntryRemoved();
 
   // Synchronize LRU list and lookup map
   bool InsertEntry(SBcacheEntry& entry);
   void RemoveEntry(const SBcacheEntry& entry);
   void TouchEntry(const SBcacheEntry& entry);
 
 private:
   SBcacheNString           _cacheDir;
   SBcacheCounter           _curSizeBytes;
   VXIulong                 _maxSizeBytes;
   VXIulong                 _entryMaxSizeBytes;
   VXIulong                 _lowWaterBytes;
 
   SBcacheCounter           _pathSeqNum;
 
   SBcacheReaderWriterMutex _entryTableMutex;
   SBcacheMutexPool         _refCntMutexPool;
   typedef std::map<SBcacheKey, SBcacheEntry> SBcacheEntryTable;
   typedef std::list<SBcacheEntry> SBcacheEntryList;
   SBcacheEntryTable        _entryTable;
   SBcacheEntryList          _entryLRUList;
 
   // Reverse memory allocator, see note in .cpp file.
   struct SBcacheEntryEstimate { SBcacheEntryEstimate* next; char dummy[2048]; };
   SBcacheEntryEstimate* _entryReserve;
   int                      _entriesReserved;
   int                      _maxEntriesReserved;
 };
 
 #endif /* include guard */