/*  
 *  $Id$
 *
 *                              
 *                    L O S  A L A M O S
 *              Los Alamos National Laboratory
 *               Los Alamos, New Mexico 87545
 *                                  
 *  Copyright, 1986, The Regents of the University of California.
 *                                  
 *           
 *	Author Jeffrey O. Hill
 *	johill@lanl.gov
 *	505 665 1831
 */

#include <limits.h>

#include "epicsMutex.h"
#include "tsFreeList.h"

#include "cacIO.h"
#include "cadef.h" // this can be eliminated when the callbacks use the new interface
#include "db_access.h" // should be eliminated here in the future
#include "caerr.h" // should be eliminated here in the future
#include "epicsEvent.h"
#include "epicsThread.h"
#include "epicsSingleton.h"

#define epicsExportSharedSymbols
#include "db_access_routines.h"
#include "dbCAC.h"
#include "dbChannelIOIL.h"
#include "dbPutNotifyBlocker.h"

class dbServiceIOLoadTimeInit {
public:
    dbServiceIOLoadTimeInit ();
private:
    dbServiceIO dbio;
	dbServiceIOLoadTimeInit ( const dbServiceIOLoadTimeInit & );
	dbServiceIOLoadTimeInit & operator = ( const dbServiceIOLoadTimeInit & );
};

// The following is just to force lti to be constructed
extern "C" void dbServiceIOInit()
{
    static dbServiceIOLoadTimeInit lti;
}

dbBaseIO::dbBaseIO () {}

dbServiceIOLoadTimeInit::dbServiceIOLoadTimeInit ()
{
    pGlobalServiceListCAC->registerService ( this->dbio );
}

dbServiceIO::dbServiceIO () :
    ctx ( 0 ), stateNotifyCacheSize ( 0 ),
        pStateNotifyCache ( 0 )
{
}

dbServiceIO::~dbServiceIO ()
{
    delete [] this->pStateNotifyCache;
    if ( this->ctx ) {
        db_close_events ( this->ctx );
    }
}

cacChannel *dbServiceIO::createChannel ( // X aCC 361
            const char *pName, cacChannelNotify &notify, 
            cacChannel::priLev )
{
    struct dbAddr addr;

    int status = db_name_to_addr ( pName, &addr );
    if ( status ) {
        return 0;
    }
    else if ( ! ca_preemtive_callback_is_enabled () ) {
        errlogPrintf ( 
            "dbServiceIO: preemptive callback required for direct in\n"
            "memory interfacing of CA channels to the DB.\n" );
        return 0;
    }
    else {
        return new dbChannelIO ( notify, addr, *this ); 
    }
}

void dbServiceIO::callStateNotify ( struct dbAddr & addr, 
        unsigned type, unsigned long count, 
        const struct db_field_log * pfl, 
        cacStateNotify & notify )
{
    unsigned long size = dbr_size_n ( type, count );

    if ( type > INT_MAX ) {
        notify.exception ( ECA_BADTYPE, 
            "type code out of range (high side)", 
            type, count );
        return;
    }

    if ( count > INT_MAX ) {
        notify.exception ( ECA_BADCOUNT, 
            "element count out of range (high side)",
            type, count);
        return;
    }

    // no need to lock this because state notify is 
    // called from only one event queue consumer thread
    if ( this->stateNotifyCacheSize < size) {
        char * pTmp = new char [size];
        delete [] this->pStateNotifyCache;
        this->pStateNotifyCache = pTmp;
        this->stateNotifyCacheSize = size;
    }
    void *pvfl = (void *) pfl;
    int status = db_get_field ( &addr, static_cast <int> ( type ), 
                    this->pStateNotifyCache, static_cast <int> ( count ), pvfl );
    if ( status ) {
        notify.exception ( ECA_GETFAIL, 
            "db_get_field() completed unsuccessfuly", type, count );
    }
    else { 
        notify.current ( type, count, this->pStateNotifyCache );
    }
}

extern "C" void cacAttachClientCtx ( void * pPrivate )
{
    int status = ca_attach_context ( (ca_client_context *) pPrivate );
    assert ( status == ECA_NORMAL );
}

dbEventSubscription dbServiceIO::subscribe ( struct dbAddr & addr, dbChannelIO & chan,
             dbSubscriptionIO & subscr, unsigned mask )
{
    dbEventSubscription es;
    int status;

    {
        epicsGuard < epicsMutex > locker ( this->mutex );
        if ( ! this->ctx ) {
            this->ctx = db_init_events ();
            if ( ! this->ctx ) {
                return 0;
            }
   
            unsigned selfPriority = epicsThreadGetPrioritySelf ();
            unsigned above;
            epicsThreadBooleanStatus tbs = epicsThreadLowestPriorityLevelAbove (selfPriority, &above);
            if ( tbs != epicsThreadBooleanStatusSuccess ) {
                above = selfPriority;
            }
            status = db_start_events ( this->ctx, "CAC-event", 
                cacAttachClientCtx, ca_current_context (), above );
            if ( status ) {
                db_close_events ( this->ctx );
                this->ctx = 0;
                return 0;
            }
        }
        chan.dbServicePrivateListOfIO::eventq.add ( subscr );
        this->ioTable.add ( subscr );
    }

    es = db_add_event ( this->ctx, &addr,
        dbSubscriptionEventCallback, (void *) &subscr, mask );
    if ( ! es ) {
        epicsGuard < epicsMutex > locker ( this->mutex );
        chan.dbServicePrivateListOfIO::eventq.remove ( subscr );
        this->ioTable.remove ( subscr );
    }

    return es;
}

void dbServiceIO::initiatePutNotify ( 
    dbChannelIO & chan, struct dbAddr & addr, 
    unsigned type, unsigned long count, const void * pValue, 
    cacWriteNotify & notify, cacChannel::ioid * pId )
{
    epicsGuard < epicsMutex > locker ( this->mutex );
    if ( ! chan.dbServicePrivateListOfIO::pBlocker ) {
        chan.dbServicePrivateListOfIO::pBlocker = new dbPutNotifyBlocker ( chan );
        this->ioTable.add ( *chan.dbServicePrivateListOfIO::pBlocker );
    }
    chan.dbServicePrivateListOfIO::pBlocker->initiatePutNotify ( 
        locker, notify, addr, type, count, pValue );
    if ( pId ) {
        *pId = chan.dbServicePrivateListOfIO::pBlocker->getId ();
    }
}

void dbServiceIO::destroyAllIO ( dbChannelIO & chan )
{
    dbSubscriptionIO *pIO;
    tsDLList < dbSubscriptionIO > tmp;
    {
        epicsGuard < epicsMutex > locker ( this->mutex );
        while ( ( pIO = chan.dbServicePrivateListOfIO::eventq.get() ) ) {
            this->ioTable.remove ( *pIO );
            tmp.add ( *pIO );
        }
        if ( chan.dbServicePrivateListOfIO::pBlocker ) {
            this->ioTable.remove ( *chan.dbServicePrivateListOfIO::pBlocker );
        }
    }
    while ( ( pIO = tmp.get() ) ) {
        // This prevents a db event callback from coming 
        // through after the notify IO is deleted
        pIO->unsubscribe ();
        // If they call ioCancel() here it will be ignored
        // because the IO has been unregistered above.
        pIO->channelDeleteException ();
        pIO->destroy ();
    }
    if ( chan.dbServicePrivateListOfIO::pBlocker ) {
        chan.dbServicePrivateListOfIO::pBlocker->destroy ();
    }
}

void dbServiceIO::ioCancel ( dbChannelIO & chan, const cacChannel::ioid &id )
{
    epicsGuard < epicsMutex > locker ( this->mutex );
    dbBaseIO *pIO = this->ioTable.remove ( id );
    if ( pIO ) {
        dbSubscriptionIO *pSIO = pIO->isSubscription ();
        if ( pSIO ) {
            chan.dbServicePrivateListOfIO::eventq.remove ( *pSIO );
            pIO->destroy ();
        }
        else if ( pIO == chan.dbServicePrivateListOfIO::pBlocker ) {
            chan.dbServicePrivateListOfIO::pBlocker->cancel ();
        }
        else {
            errlogPrintf ( "dbServiceIO::ioCancel() unrecognized IO was probably leaked\n" );
        }
    }
}

void dbServiceIO::ioShow ( const cacChannel::ioid &id, unsigned level ) const
{
    epicsGuard < epicsMutex > locker ( this->mutex );
    const dbBaseIO *pIO = this->ioTable.lookup ( id );
    if ( pIO ) {
        pIO->show ( level );
    }
}

void dbServiceIO::showAllIO ( const dbChannelIO &chan, unsigned level ) const
{
    epicsGuard < epicsMutex > locker ( this->mutex );
    tsDLIterConstBD < dbSubscriptionIO > pItem = 
        chan.dbServicePrivateListOfIO::eventq.firstIter ();
    while ( pItem.valid () ) {
        pItem->show ( level );
        pItem++;
    }
    if ( chan.dbServicePrivateListOfIO::pBlocker ) {
        chan.dbServicePrivateListOfIO::pBlocker->show ( level );
    }
}

void dbServiceIO::show ( unsigned level ) const
{
    epicsGuard < epicsMutex > locker ( this->mutex );
    printf ( "dbServiceIO at %p\n", 
        static_cast <const void *> ( this ) );
    if ( level > 0u ) {
        printf ( "\tevent call back cache location %p, and its size %lu\n", 
            static_cast <void *> ( this->pStateNotifyCache ), this->stateNotifyCacheSize );
        this->readNotifyCache.show ( level - 1 );
    }
    if ( level > 1u ) {
        this->mutex.show ( level - 2u );
    }
}