Annotation of parser3/src/main/pa_db_manager.C, revision 1.6

1.1       parser      1: /** @file
                      2:        Parser: sql driver manager implementation.
                      3: 
                      4:        Copyright (c) 2001 ArtLebedev Group (http://www.artlebedev.com)
                      5:        Author: Alexander Petrosyan <paf@design.ru> (http://design.ru/paf)
                      6: 
1.6     ! paf         7:        $Id: pa_db_manager.C,v 1.5 2001/10/25 09:48:18 paf Exp $
1.1       parser      8: */
                      9: 
1.3       parser     10: #include "pa_config_includes.h"
                     11: #ifdef HAVE_LIBDB
                     12: 
1.1       parser     13: #include "pa_db_manager.h"
1.2       parser     14: #include "pa_db_connection.h"
1.1       parser     15: #include "pa_exception.h"
                     16: #include "pa_threads.h"
                     17: #include "pa_stack.h"
                     18: 
                     19: // globals
                     20: 
                     21: DB_Manager *DB_manager;
                     22: 
                     23: // consts
                     24: 
                     25: const int EXPIRE_UNUSED_CONNECTION_SECONDS=60;
                     26: const int CHECK_EXPIRED_CONNECTIONS_SECONDS=EXPIRE_UNUSED_CONNECTION_SECONDS*2;
                     27: 
1.4       parser     28: // callbacks
                     29: 
1.6     ! paf        30: static void expire_connection(Array::Item *value, void *info) {
        !            31:        DB_Connection& connection=*static_cast<DB_Connection *>(value);
        !            32:        time_t older_dies=reinterpret_cast<time_t>(info);
        !            33: 
        !            34:        if(connection.ping() && connection.expired(older_dies))
        !            35:                connection.disconnect();
1.4       parser     36: }
1.6     ! paf        37: static void expire_connections(const Hash::Key& key, Hash::Val *value, void *info) {
        !            38:        Stack& stack=*static_cast<Stack *>(value);
        !            39:        for(int i=0; i<=stack.top_index(); i++)
        !            40:                expire_connection(stack.get(i), info);
1.4       parser     41: }
1.1       parser     42: 
                     43: // DB_Manager
                     44: 
                     45: DB_Manager::DB_Manager(Pool& pool) : Pooled(pool),
                     46:        connection_cache(pool),
                     47:        prev_expiration_pass_time(0) {
                     48: 
                     49: }
                     50: 
                     51: DB_Manager::~DB_Manager() {
1.6     ! paf        52:        // close connections
        !            53:        connection_cache.for_each(expire_connections, 
        !            54:                reinterpret_cast<void *>(0/* =in the past = expire[close] all*/));
1.1       parser     55: }
                     56: 
                     57: 
1.6     ! paf        58: DB_Connection& DB_Manager::get_connection(const String& request_db_home,
        !            59:                                                                                                   const String& request_origin) {
        !            60:        if(request_db_home.size()==0)
        !            61:                throw Exception(0, 0,
        !            62:                        &request_origin,
        !            63:                        "empty DB_HOME specified");
1.1       parser     64: 
                     65:        Pool& pool=request_origin.pool(); // request pool                                                                                          
                     66: 
                     67:        // first trying to get cached connection
1.6     ! paf        68:        DB_Connection *result=get_connection_from_cache(request_db_home);
1.1       parser     69: 
1.6     ! paf        70:        char *request_db_home_cstr;
1.1       parser     71:        if(result)
1.6     ! paf        72:                request_db_home_cstr=0; // calm, compiler
1.1       parser     73:        else { // no cached connection
1.6     ! paf        74:                // make global_db_home C-string on global pool
        !            75:                request_db_home_cstr=request_db_home.cstr(String::UL_AS_IS);
        !            76:                char *global_db_home_cstr=(char *)malloc(strlen(request_db_home_cstr)+1);
        !            77:                strcpy(global_db_home_cstr, request_db_home_cstr);
        !            78:                // make global_db_home string on global pool
        !            79:                String& global_db_home=*new(this->pool()) String(this->pool(), global_db_home_cstr);
1.1       parser     80:                
                     81:                // allocate in global pool 
                     82:                // associate with services[request]
                     83:                // NOTE: never freed up!
1.6     ! paf        84:                result=new(this->pool()) DB_Connection(this->pool(), global_db_home);
1.1       parser     85:        }
                     86: 
                     87:        // associate with services[request]  (deassociates at close)
                     88:        result->set_services(&pool); 
                     89:        // if not connected yet, do that now, when result has services
                     90:        if(!result->connected())
                     91:                result->connect();
                     92:        // return it
                     93:        return *result;
1.2       parser     94: }
                     95: 
1.6     ! paf        96: void DB_Manager::close_connection(const String& db_home, 
1.1       parser     97:                                                                                  DB_Connection& connection) {
                     98:        // deassociate from services[request]
                     99:        connection.set_services(0);
1.6     ! paf       100:        put_connection_to_cache(db_home, connection);
1.1       parser    101: }
                    102: 
                    103: 
                    104: // connection cache
                    105: /// @todo get rid of memory spending Stack [zeros deep inside got accumulated]
1.6     ! paf       106: DB_Connection *DB_Manager::get_connection_from_cache(const String& db_home) { 
1.1       parser    107:        SYNCHRONIZED;
                    108: 
1.6     ! paf       109:        if(Stack *connections=static_cast<Stack *>(connection_cache.get(db_home)))
        !           110:                while(connections->top_index()>=0) { // there are cached connections to that 'db_home'
1.1       parser    111:                        DB_Connection *result=static_cast<DB_Connection *>(connections->pop());
                    112:                        if(result->connected()) // not expired?
                    113:                                return result;
                    114:                }
                    115: 
                    116:        return 0;
                    117: }
                    118: 
1.6     ! paf       119: void DB_Manager::put_connection_to_cache(const String& db_home, 
1.1       parser    120:                                                                                                 DB_Connection& connection) { 
                    121:        SYNCHRONIZED;
                    122: 
1.6     ! paf       123:        Stack *connections=static_cast<Stack *>(connection_cache.get(db_home));
        !           124:        if(!connections) { // there are no cached connections to that 'db_home' yet?
1.1       parser    125:                connections=NEW Stack(pool()); // NOTE: never freed up!
1.6     ! paf       126:                connection_cache.put(db_home, connections);
1.1       parser    127:        }       
                    128:        connections->push(&connection);
                    129: }
                    130: 
                    131: void DB_Manager::maybe_expire_connection_cache() {
                    132:        time_t now=time(0);
                    133: 
                    134:        if(prev_expiration_pass_time<now-CHECK_EXPIRED_CONNECTIONS_SECONDS) {
                    135:                connection_cache.for_each(expire_connections, 
                    136:                        reinterpret_cast<void *>(now-EXPIRE_UNUSED_CONNECTION_SECONDS));
                    137: 
                    138:                prev_expiration_pass_time=now;
                    139:        }
                    140: }
1.3       parser    141: 
                    142: #endif

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