/* $Id: $ */
/** @file
 *
 * kLdr - The Dynamic Loader, Dyld module methods.
 *
 * Copyright (c) 2006 knut st. osmundsen <bird-kbuild-src@anduin.net>
 *
 *
 * This file is part of kLdr.
 *
 * kLdr 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.
 *
 * kLdr 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 kLdr; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */



/*******************************************************************************
*   Header Files                                                               *
*******************************************************************************/
#include <kLdr.h>
#include "kLdrInternal.h"
#include "kLdrHlp.h"


/*******************************************************************************
*   Defined Constants And Macros                                               *
*******************************************************************************/
/** @def KLDRDYLDMOD_ASSERT
 * Assert that an expression is true when KLDRDYLD_STRICT is defined.
 */
#ifdef KLDRDYLD_STRICT
# define KLDRDYLDMOD_ASSERT(expr)  kldrHlpAssert(expr)
#else
# define KLDRDYLDMOD_ASSERT(expr)  do {} while (0)
#endif




void kldrDyldModUnloadPrerequisites(PKLDRDYLDMOD pMod)
{

}


void kldrDyldModDeref(PKLDRDYLDMOD pMod)
{
    /* validate input */
    KLDRDYLDMOD_ASSERT(pMod->enmState > KLDRSTATE_INVALID && pMod->enmState < KLDRSTATE_END);
    KLDRDYLDMOD_ASSERT(pMod->cRefs > 0);
    KLDRDYLDMOD_ASSERT(pMod->cRefs >= pMod->cDepRefs + pMod->cDynRefs);

    /* decrement. */
    if (pMod->cRefs > 0)
        pMod->cRefs--;

    /*
     * Drop prerequisites for stats that implies that no recursion can have taken place yet.
     * This ASSUMES that we're only dereferencing modules when an operation completes.
     * (This is *required* for the reloaded state.)
     */
    switch (pMod->enmState)
    {
        case KLDRSTATE_MAPPED:
        case KLDRSTATE_LOADED_PREREQUISITES:
        case KLDRSTATE_FIXED_UP:
        case KLDRSTATE_RELOADED:
            kldrDyldModUnloadPrerequisites(pMod);
            pMod->enmState = KLDRSTATE_PENDING_GC;
            break;

        case KLDRSTATE_PENDING_INITIALIZATION:
        case KLDRSTATE_INITIALIZING:
        case KLDRSTATE_GOOD:
        case KLDRSTATE_PENDING_TERMINATION:
        case KLDRSTATE_TERMINATING:
        case KLDRSTATE_PENDING_GC:
        case KLDRSTATE_GC:
        case KLDRSTATE_PENDING_DESTROY:
            break;

        default:
            KLDRDYLDMOD_ASSERT(!"Invalid deref state");
            break;
    }

    /*
     * Also drop prerequisites if noone is referencing the module.
     */
    if (!pMod->cDepRefs && !pMod->cDynRefs)
    {
        switch (pMod->enmState)
        {
            case KLDRSTATE_MAPPED:
            case KLDRSTATE_LOADED_PREREQUISITES:
            case KLDRSTATE_FIXED_UP:
            case KLDRSTATE_RELOADED:
                /* already dropped. */
                break;

            case KLDRSTATE_PENDING_INITIALIZATION:
                kldrDyldModUnloadPrerequisites(pMod);
                pMod->enmState = KLDRSTATE_PENDING_GC;
                break;

            case KLDRSTATE_GOOD:
                pMod->enmState = KLDRSTATE_PENDING_TERMINATION;
            case KLDRSTATE_PENDING_TERMINATION:
            case KLDRSTATE_PENDING_GC:
                kldrDyldModUnloadPrerequisites(pMod);
                break;

            case KLDRSTATE_TERMINATING:
            case KLDRSTATE_GC:
            case KLDRSTATE_PENDING_DESTROY:
                break;

            default:
                KLDRDYLDMOD_ASSERT(!"Invalid deref state (b)");
                break;
        }
    }

    /*
     * If there are no references whatsoever now and the module
     * is pending destruction, destroy it.
     */
    if (    !pMod->cRefs
        &&  (   pMod->enmState == KLDRSTATE_PENDING_DESTROY
             || pMod->enmState == KLDRSTATE_GC))
        kldrDyldModDestroy(pMod);
}