OPeNDAP Hyrax Back End Server (BES)
Updated for version 3.8.3
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00001 // BESCache.h 00002 00003 // This file is part of bes, A C++ back-end server implementation framework 00004 // for the OPeNDAP Data Access Protocol. 00005 00006 // Copyright (c) 2004-2009 University Corporation for Atmospheric Research 00007 // Author: Patrick West <pwest@ucar.edu> and Jose Garcia <jgarcia@ucar.edu> 00008 // 00009 // This library is free software; you can redistribute it and/or 00010 // modify it under the terms of the GNU Lesser General Public 00011 // License as published by the Free Software Foundation; either 00012 // version 2.1 of the License, or (at your option) any later version. 00013 // 00014 // This library is distributed in the hope that it will be useful, 00015 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00016 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00017 // Lesser General Public License for more details. 00018 // 00019 // You should have received a copy of the GNU Lesser General Public 00020 // License along with this library; if not, write to the Free Software 00021 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 00022 // 00023 // You can contact University Corporation for Atmospheric Research at 00024 // 3080 Center Green Drive, Boulder, CO 80301 00025 00026 // (c) COPYRIGHT University Corporation for Atmospheric Research 2004-2005 00027 // Please read the full copyright statement in the file COPYRIGHT_UCAR. 00028 // 00029 // Authors: 00030 // pwest Patrick West <pwest@ucar.edu> 00031 // jgarcia Jose Garcia <jgarcia@ucar.edu> 00032 00033 #ifndef BESCache_h_ 00034 #define BESCache_h_ 1 00035 00036 #include <algorithm> 00037 #include <map> 00038 #include <string> 00039 #include <sstream> 00040 00041 #include "BESObj.h" 00042 00043 class BESKeys ; 00044 00045 static const unsigned int MAX_LOCK_RETRY_MS = 5000; // in microseconds 00046 static const unsigned int MAX_LOCK_TRIES = 16; 00047 00058 class BESCache : public BESObj 00059 { 00060 public: 00061 00063 struct cache_entry 00064 { 00065 string name ; 00066 unsigned long long size ; 00067 }; 00068 00071 typedef std::multimap<double, cache_entry, std::greater<double> > CacheFilesByAgeMap; 00072 00074 struct CacheDirInfo 00075 { 00076 CacheDirInfo() 00077 : _total_cache_files_size(0ULL) 00078 , _num_files_in_cache(0ULL) 00079 , _contents() 00080 {} 00081 00082 ~CacheDirInfo() 00083 { 00084 clear(); 00085 } 00086 00087 void clear() 00088 { 00089 _total_cache_files_size = 0ULL; 00090 _num_files_in_cache = 0ULL; 00091 _contents.clear(); 00092 } 00093 00094 unsigned long long get_avg_size() const 00095 { 00096 return ( (_num_files_in_cache > 0) ? 00097 ( _total_cache_files_size / _num_files_in_cache) : 00098 (0ULL) ); 00099 } 00100 00101 std::string toString() const 00102 { 00103 std::ostringstream oss; 00104 oss << "Numfiles: " << _num_files_in_cache << "" 00105 " Total size: " << _total_cache_files_size; 00106 return oss.str(); 00107 } 00108 00109 unsigned long long _total_cache_files_size; 00110 unsigned long long _num_files_in_cache; 00111 BESCache::CacheFilesByAgeMap _contents; 00112 }; // struct CacheDirInfo 00113 00114 00115 private: 00116 // slashes are replaced with this char to make cache file. 00117 static const char BES_CACHE_CHAR = '#'; 00118 00119 string _cache_dir ; 00120 string _prefix ; 00121 unsigned long long _cache_size_in_megs ; 00122 int _lock_fd ; 00123 00124 void check_ctor_params(); 00125 BESCache() {} 00126 public: 00127 BESCache( const string &cache_dir, 00128 const string &prefix, 00129 unsigned long long sizeInMegs ) ; 00130 BESCache( BESKeys &keys, 00131 const string &cache_dir_key, 00132 const string &prefix_key, 00133 const string &size_key ) ; 00134 virtual ~BESCache() {} 00135 00136 virtual bool lock( unsigned int retry_ms, 00137 unsigned int num_tries ) ; 00138 virtual bool unlock() ; 00139 00140 virtual bool is_cached( const string &src, string &target ) ; 00141 virtual void purge( ) ; 00142 00143 string cache_dir( ) const { return _cache_dir ; } 00144 string match_prefix() const { return _prefix + BES_CACHE_CHAR; }; 00145 string prefix( ) const { return _prefix ; } 00146 unsigned long long cache_size( ) const { return _cache_size_in_megs ; } 00147 00148 void collect_cache_dir_info( 00149 BESCache::CacheDirInfo& cd_info //output 00150 ) const; 00151 00152 virtual void dump( ostream &strm ) const ; 00153 }; 00154 00155 #endif // BESCache_h_ 00156