Beesnest/DcEnginesBank.cpp

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/*
Copyright 2007 Erez Bibi (erezbibi@users.sourceforge.net)
This file is part of Beesnest.

Beesnest is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

Beesnest is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Beesnest; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

/**
 * DcEnginesBank.cpp: implementation of the CdcEnginesBank class.
 * for documentation see the header file.
 */

#include "DcEnginesBank.h"

#define FUNC_NAME       "GetEngine"
#define INIT_FUNC_NAME  "Init"
#define TERM_FUNC_NAME  "Term"

/* The GetEngine LIB proto function */
typedef bool (__stdcall *cfunc)(IdcEngine** pp_engine,
                                const char* name,
                                bool (*pGetParam)(const char*, char*, int));
/* The Init/Term function proto */
typedef void (__stdcall *cfunc_void)();

CdcEnginesBank::t_engines_lib_map CdcEnginesBank::mLibs;
CdcMutex CdcEnginesBank::oMutex;
CdcString CdcEnginesBank::sDefaultEngine;

CdcEnginesBank::CdcEnginesBank (IdcRequest* preq, IdcResponse* pres,
    CdcUserStatus* pstatus)
: pRequest (preq), pResponse (pres), pAdaptersSet (NULL), pEnginesSet (NULL)
{
    if (pstatus)
    {
        pAdaptersSet = pstatus->GetAdaptersSet ();
        pEnginesSet = pstatus->GetEnginesSet ();
    }
}

CdcEnginesBank::~CdcEnginesBank ()
{   /* Either store each engines in the Engines Set, or delete it. */
    for (CdcEnginesBank::t_engines_map::iterator pos = mEngines.begin ();
        pos != mEngines.end (); ++pos)
        if (pos->second)
        {
            if (pEnginesSet && pos->second->IsStorable () &&
                CdcParameters::GetParam ("Engines->" + pos->first + "->Storable")
                == "yes")
            {   /* Need to store the engine in the user EnginesSet. */
                if (pEnginesSet->PutEngine (pos->first, pos->second) == false)
                    delete pos->second;     /* Engine didn't get stored. */
            }
            else    /* Need to delete this engine. */
                delete pos->second;
        }
}


/* Note: I insert engine/lib to map also if I cannot load the library, so I
    won't need to try to load them again. */
IdcEngine* CdcEnginesBank::GetEngine (const CdcString& name)
{
    CdcString eng_name = name;
    if (eng_name.IsEmpty () == true)
        eng_name = sDefaultEngine;
    if (eng_name.IsEmpty () == true)
        return NULL;
    /* Try to find the engine in the map (if processing scripts on the same page). */
    CdcEnginesBank::t_engines_map::iterator itr;
    itr = mEngines.find (eng_name);
    if (itr != mEngines.end () && itr->second)
        return itr->second;
    /* Try to find the engine in the users Engine Set - user is logged in .*/
    IdcEngine* peng = NULL;
    if (pEnginesSet)
    {
        peng = pEnginesSet->GetEngine (eng_name);
        if (peng)
        {
            mEngines [eng_name] = peng;
            peng->Prepare (pRequest, pResponse, pAdaptersSet);
            return peng;
        }
    }
    /* Need to load the engine from a dynamic library. */
    CdcDynamicLibrary* plib = NULL;
    CdcString lib_name = CdcParameters::GetParam ("Engines->" + eng_name +
        "->File-Name");
    if (lib_name.IsEmpty () == false)
    {   /* Found library. */
        CdcEnginesBank::t_engines_lib_map::iterator ditr = mLibs.find (lib_name);
        if (ditr != mLibs.end ())
            plib = ditr->second;        /* Found Lib in the libs map. */
        else
            plib = LoadLib (lib_name);  /* Load Lib for the first time. */
    }
    if (plib != NULL)
        peng = LoadEngine (*plib, eng_name);    /* plib may point to an un-opend library! */
    mEngines [eng_name] = peng;
    return peng;                        /* peng may be NULL! */
}

void CdcEnginesBank::DeleteEngine (const CdcString& name)
{
    CdcString eng_name = name;
    if (eng_name.IsEmpty () == true)
        eng_name = sDefaultEngine;
    if (eng_name.IsEmpty () == true)
        return;

    CdcEnginesBank::t_engines_map::iterator itr;
    itr = mEngines.find (eng_name);
    if (itr != mEngines.end () && itr->second)
    {
        delete (itr->second);
        mEngines.erase (itr);
    }
}

IdcEngine* CdcEnginesBank::LoadEngine (CdcDynamicLibrary& lib,
                                        const CdcString& name)
{
    /* Get the LIB "GetEngine" function. */
    cfunc libGetEngine = (cfunc)lib.GetFunctionByName (FUNC_NAME);
    if (libGetEngine == NULL)
    {
        PrintString (lib.GetLastError (), PS_GEN);
        return NULL;
    }
    /* Get the engine (just here I send 'name' to the lib). */
    IdcEngine* pengine = NULL;
    libGetEngine (&pengine, name.GetBuffer (), &ExtGetParam);
    if (pengine == NULL)
    {
        PrintString ("Unable to get the engine - " + name, PS_GEN);
        return NULL;
    }
    /* Init the engine */
    pengine->Prepare (pRequest, pResponse, pAdaptersSet);
    return pengine;
}

CdcDynamicLibrary* CdcEnginesBank::LoadLib (const CdcString& name)
{
    oMutex.Lock ();
        CdcDynamicLibrary* plib = NULL;
        /* just check again to be sure. */
        CdcEnginesBank::t_engines_lib_map::iterator itr;
        itr = mLibs.find (name);
        if (itr == mLibs.end ())
        {
            plib = new CdcDynamicLibrary (name);
            if (plib != NULL)
            {
                CdcEnginesBank::ExecInit (*plib);
                mLibs [name] = plib;
            }
        }
        else
            plib = itr->second;
    oMutex.Unlock ();
    return plib;
}

void CdcEnginesBank::Init ()
{
    sDefaultEngine = CdcParameters::GetParam ("Server->Default-Engine");
}

void CdcEnginesBank::Term ()
{
    /* Release all Libs. */
    oMutex.Lock ();
    for (CdcEnginesBank::t_engines_lib_map::iterator pos = mLibs.begin ();
        pos != mLibs.end (); ++pos)
        if (pos->second)
        {
            CdcEnginesBank::ExecTerm (*(pos->second));
            delete pos->second;     /* Here the dynamic library get freed. */
        }
    oMutex.Unlock ();
}

void CdcEnginesBank::ExecInit (CdcDynamicLibrary& lib)
{
    /* Get the library "Init" function. */
    cfunc_void libInit = (cfunc_void)lib.GetFunctionByName (INIT_FUNC_NAME);
    if (libInit != NULL)
        libInit ();
}

void CdcEnginesBank::ExecTerm (CdcDynamicLibrary& lib)
{
    /* Get the LIB "Term" function. */
    cfunc_void libTerm = NULL;
    libTerm = (cfunc_void)lib.GetFunctionByName (TERM_FUNC_NAME);
    if (libTerm != NULL)
        libTerm ();
}