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Annotation of parser3/src/include/pa_db_connection.h, revision 1.13

1.1       parser      1: /** @file
1.9       paf         2:        Parser: sql driver connection decl.
                      3:        global sql driver connection, must be thread-safe
1.1       parser      4: 
                      5:        Copyright (c) 2001 ArtLebedev Group (http://www.artlebedev.com)
                      6:        Author: Alexander Petrosyan <paf@design.ru> (http://design.ru/paf)
                      7: 
1.13    ! paf         8:        $Id: pa_db_connection.h,v 1.12 2001/10/27 10:14:45 paf Exp $
1.1       parser      9: */
                     10: 
                     11: #ifndef PA_DB_CONNECTION_H
                     12: #define PA_DB_CONNECTION_H
                     13: 
                     14: #include "pa_config_includes.h"
                     15: #include "pa_pool.h"
1.9       paf        16: #include "pa_hash.h"
1.10      paf        17: #include "pa_db_table.h"
1.1       parser     18: 
1.13    ! paf        19: #ifdef DB2
1.1       parser     20: #      include <db.h>
                     21: #endif
                     22: 
                     23: // defines
                     24: 
1.2       parser     25: // forwards
                     26: 
1.9       paf        27: class DB_Table;
1.10      paf        28: class DB_Connection_ptr;
1.1       parser     29: 
1.9       paf        30: /// sql driver connection
1.1       parser     31: class DB_Connection : public Pooled {
1.9       paf        32:        friend DB_Table;
1.10      paf        33:        friend DB_Connection_ptr;
1.1       parser     34: public:
                     35: 
1.10      paf        36:        DB_Connection(Pool& apool, const String& db_home);
                     37:        ~DB_Connection();
1.1       parser     38: 
                     39:        bool expired(time_t older_dies) {
1.10      paf        40:                return !used && time_used<older_dies;
1.1       parser     41:        }
                     42: 
1.9       paf        43:        /**
                     44:                connect to specified file_name, 
                     45:                using driver dynamic library found in table, if not loaded yet
                     46:                checks driver version
                     47:        */
1.11      paf        48:        DB_Table_ptr get_table_ptr(const String& file_name, const String *source);
1.9       paf        49: 
1.10      paf        50: private: // connection usage methods
                     51: 
                     52:        void use() {
                     53:                time_used=time(0); // they started to use at this time
                     54:                used++;
                     55:        }
                     56:        void unuse() {
                     57:                used--;
                     58:        }
                     59: 
                     60: private: // connection usage data
                     61: 
                     62:        int used;
                     63: 
1.9       paf        64: private: // table cache
                     65: 
                     66:        DB_Table *get_table_from_cache(const String& file_name);
                     67:        void put_table_to_cache(const String& file_name, DB_Table& table);
                     68:        void maybe_expire_table_cache();
1.1       parser     69: private:
1.9       paf        70:        time_t prev_expiration_pass_time;
1.1       parser     71: 
1.9       paf        72: private: // for DB_Table
1.1       parser     73: 
1.9       paf        74:        /// caches table
                     75:        void close_table(const String& file_name, DB_Table& table);
1.2       parser     76: 
1.9       paf        77: private:
1.2       parser     78: 
1.9       paf        79:        time_t time_used;
1.2       parser     80: 
1.9       paf        81:        const String& fdb_home;
                     82:        DB_ENV dbenv;
                     83:        Hash table_cache;
1.2       parser     84: 
1.1       parser     85: private:
                     86: 
                     87:        void check(const char *operation, const String *source, int error);
1.10      paf        88: };
                     89: 
                     90: /// Auto-object used to track DB_Connection usage
                     91: class DB_Connection_ptr {
                     92:        DB_Connection *fconnection;
                     93: public:
                     94:        DB_Connection_ptr(DB_Connection *aconnection) : fconnection(aconnection) {
                     95:                fconnection->use();
                     96:        }
                     97:        ~DB_Connection_ptr() {
                     98:                fconnection->unuse();
                     99:        }
                    100:        DB_Connection* operator->() {
                    101:                return fconnection;
                    102:        }
                    103: 
                    104:        // copying
                    105:        DB_Connection_ptr(const DB_Connection_ptr& src) : fconnection(src.fconnection) {
                    106:                fconnection->use();
                    107:        }
                    108:        DB_Connection_ptr& operator =(const DB_Connection_ptr& src) {
                    109:                // may do without this=src check
                    110:                fconnection->unuse();
                    111:                fconnection=src.fconnection;
                    112:                fconnection->use();
                    113: 
                    114:                return *this;
                    115:        }
1.1       parser    116: };
                    117: 
                    118: #endif