driver_mgr.cpp

ncbi源码

/*
 * ===========================================================================
 * PRODUCTION $Log: driver_mgr.cpp,v $
 * PRODUCTION Revision 1000.3  2004/06/01 19:18:33  gouriano
 * PRODUCTION PRODUCTION: UPGRADED [GCC34_MSVC7] Dev-tree R1.13
 * PRODUCTION
 * ===========================================================================
 */

/* $Id: driver_mgr.cpp,v 1000.3 2004/06/01 19:18:33 gouriano Exp $
* ===========================================================================
*
*                            PUBLIC DOMAIN NOTICE                          
*               National Center for Biotechnology Information
*                                                                          
*  This software/database is a "United States Government Work" under the   
*  terms of the United States Copyright Act.  It was written as part of    
*  the author's official duties as a United States Government employee and 
*  thus cannot be copyrighted.  This software/database is freely available 
*  to the public for use. The National Library of Medicine and the U.S.    
*  Government have not placed any restriction on its use or reproduction.  
*                                                                          
*  Although all reasonable efforts have been taken to ensure the accuracy  
*  and reliability of the software and data, the NLM and the U.S.          
*  Government do not and cannot warrant the performance or results that    
*  may be obtained by using this software or data. The NLM and the U.S.    
*  Government disclaim all warranties, express or implied, including       
*  warranties of performance, merchantability or fitness for any particular
*  purpose.                                                                
*                                                                          
*  Please cite the author in any work or product based on this material.   
*
* ===========================================================================
*
* File Name:  $Id: driver_mgr.cpp,v 1000.3 2004/06/01 19:18:33 gouriano Exp $
*
* Author:  Michael Kholodov, Denis Vakatov
*   
* File Description:  Driver Manager implementation
*
*
* $Log: driver_mgr.cpp,v $
* Revision 1000.3  2004/06/01 19:18:33  gouriano
* PRODUCTION: UPGRADED [GCC34_MSVC7] Dev-tree R1.13
*
* Revision 1.13  2004/05/17 21:10:28  gorelenk
* Added include of PCH ncbi_pch.hpp
*
* Revision 1.12  2004/04/22 11:29:53  ivanov
* Use pointer to driver manager instance instead auto_ptr
*
* Revision 1.11  2003/12/17 14:56:33  ivanov
* Changed type of the Driver Manager instance to auto_ptr.
* Added RemoveInstance() method.
*
* Revision 1.10  2003/02/10 17:30:05  kholodov
* Fixed: forgot to add actual deletion code to DestroyDs()
*
* Revision 1.9  2003/02/10 17:19:27  kholodov
* Added: DestroyDs() method
*
* Revision 1.8  2002/09/23 18:35:24  kholodov
* Added: GetErrorInfo() and GetErrorAsEx() methods.
*
* Revision 1.7  2002/09/04 22:18:57  vakatov
* CDriverManager::CreateDs() -- Get rid of comp.warning, improve diagnostics
*
* Revision 1.6  2002/07/09 17:12:29  kholodov
* Fixed duplicate context creation
*
* Revision 1.5  2002/07/03 15:03:05  kholodov
* Added: throw exception when driver cannot be loaded
*
* Revision 1.4  2002/04/29 19:13:13  kholodov
* Modified: using C_DriverMgr as parent class of CDriverManager
*
* Revision 1.3  2002/04/02 18:16:03  ucko
* More fixes to CDriverManager::LoadDriverDll.
*
* Revision 1.2  2002/04/01 22:31:40  kholodov
* Fixed DLL entry point names
*
* Revision 1.1  2002/01/30 14:51:21  kholodov
* User DBAPI implementation, first commit
*
*
*
*
*/

#include <ncbi_pch.hpp>
#include <dbapi/driver_mgr.hpp>
#include "ds_impl.hpp"

#include <corelib/ncbistr.hpp>


BEGIN_NCBI_SCOPE


CDriverManager* CDriverManager::sm_Instance = 0;


DEFINE_CLASS_STATIC_MUTEX(CDriverManager::sm_Mutex);


CDriverManager& CDriverManager::GetInstance()
{
    if ( !sm_Instance ) {
        CMutexGuard GUARD(sm_Mutex);
        // Check again with the lock to avoid races
        if ( !sm_Instance ) {
            sm_Instance = new CDriverManager;
        }
    }
    return *sm_Instance;
}


void CDriverManager::RemoveInstance()
{
    CMutexGuard GUARD(sm_Mutex);
    delete sm_Instance;
    sm_Instance = 0;
}


CDriverManager::CDriverManager()
{
}


CDriverManager::~CDriverManager()
{
    map<string, IDataSource*>::iterator i_ds_list = m_ds_list.begin();

    for( ; i_ds_list != m_ds_list.end(); ++i_ds_list ) {
        delete (*i_ds_list).second;
    }
    m_ds_list.clear();
}


IDataSource* CDriverManager::CreateDs(const string&        driver_name,
                                      map<string, string>* attr)
{
    map<string, IDataSource*>::iterator i_ds = m_ds_list.find(driver_name);
    if (i_ds != m_ds_list.end()) {
        return (*i_ds).second;
    }

    string err;
    FDBAPI_CreateContext ctx_func = GetDriver(driver_name, &err);
    if ( !ctx_func ) {
        throw CDbapiException(err);
    }

    I_DriverContext* ctx = ctx_func(attr);
    if ( !ctx ) {
        throw CDbapiException
            ("CDriverManager::CreateDs() -- Failed to get context for driver: "
             + driver_name);
    }

    return RegisterDs(driver_name, ctx);
}


IDataSource* CDriverManager::CreateDsFrom(const string& drivers,
                                          CNcbiRegistry* reg)
{
    list<string> names;
    NStr::Split(drivers, ":", names);

    list<string>::iterator i_name = names.begin();
    for( ; i_name != names.end(); ++i_name ) {
        FDBAPI_CreateContext ctx_func = GetDriver(*i_name);
        if( ctx_func != 0 ) {
            I_DriverContext *ctx = 0;
            if( reg != 0 ) {
                // Get parameters from registry, if any
                map<string, string> attr;
                list<string> entries;
                reg->EnumerateEntries(*i_name, &entries);
                list<string>::iterator i_param = entries.begin();
                for( ; i_param != entries.end(); ++i_param ) {
                    attr[*i_param] = reg->Get(*i_name, *i_param);
                }
                ctx = ctx_func(&attr);
            }
            else {
                ctx = ctx_func(0);
            }

            if( ctx != 0 ) { 
                return RegisterDs(*i_name, ctx);
            }
        }
    }
    return 0;
}

IDataSource* CDriverManager::RegisterDs(const string& driver_name,
                                        I_DriverContext* ctx)
{
    IDataSource *ds = new CDataSource(ctx);
    m_ds_list[driver_name] = ds;
    return ds;
}

void CDriverManager::DestroyDs(const string& driver_name)
{
    map<string, IDataSource*>::iterator i_ds = m_ds_list.find(driver_name);
    if (i_ds != m_ds_list.end()) {
        delete (*i_ds).second;
        m_ds_list.erase(i_ds);
    }
}


END_NCBI_SCOPE