MacWorld 1998 September/Macworld (1998-09).dmg/Shareware World/Info/For Developers/MacZoop 1.8.3/More Classes/Plug-In Classes/ZPlugInHandler.cpp

C/C++ Source or Header | 1997-12-18 | 5.4 KB | 218 lines | [TEXT/CWIE]

/*************************************************************************************************
*
*
*            MacZoop - "the framework for the rest of us"
*
*
*
*            ZPlugInHandler.cp    -- an object for managing plug-ins
*
*
*
*
*
*            © 1997, Graham Cox
*
*
*
*
*************************************************************************************************/


#include    "ZPlugInHandler.h"
#include    "ZProgress.h"
#include    "ZObjectArray.cpp"
#include    "MacZoop.h"

/*------------------------------***  CONSTRUCTOR  ***-----------------------------------*/

ZPlugInHandler::ZPlugInHandler( const FSSpec& rootFolder )
    : ZFolderScanner( rootFolder )
{
    FailNIL( itsPlugIns = new ZPlugInList());
}


/*-------------------------------***  DESTRUCTOR  ***-----------------------------------*/

ZPlugInHandler::~ZPlugInHandler()
{
    if ( itsPlugIns )
    {
        // close them all, then dispose of them

        ZPlugIn*    zp;
        short        i;

        for( i = 1; i<= itsPlugIns->CountItems(); i++ )
        {
            zp = itsPlugIns->GetObject( i );

            if ( zp )
                zp->ClosePlugIn();
        }

        itsPlugIns->DisposeAll();
        ForgetObject( itsPlugIns );
    }
}


/*------------------------------***  INITPLUGINS  ***-----------------------------------*/
/*
called after making the object to actually load and initialise the plug-ins. The standard
behaviour is to scan the nominated folder and pass each file to Process1File. For each file
the relevant ZPlugIn derived object is made and added to the plug-in list.
----------------------------------------------------------------------------------------*/

void        ZPlugInHandler::InitPlugIns()
{
    ScanFolder();

    // after scanning, we have a list of raw unopened plug-ins. Now we need to
    // initialise them and open them.

    ZPlugIn*    zp;
    short        i;

    for( i = 1; i<= itsPlugIns->CountItems(); i++ )
    {
        zp = itsPlugIns->GetObject( i );

        if ( zp )
            zp->InitPlugIn();
    }

    // and open them all:

    for( i = 1; i<= itsPlugIns->CountItems(); i++ )
    {
        zp = itsPlugIns->GetObject( i );

        if ( zp )
            zp->OpenPlugIn();
    }
}


/*--------------------------***  SENDMESSAGETOPLUGIN  ***-------------------------------*/
/*
passes the message and data to the plug-in with id passed. Plug-in IDs range from 1 and
are generally in alphabetical order.
----------------------------------------------------------------------------------------*/

void        ZPlugInHandler::SendMessageToPlugIn( const short plugID, const long message, void* msgData )
{
    ZPlugIn*    zp;

    zp = itsPlugIns->GetObject( plugID );

    if ( zp )
        zp->CallPlugIn( message, msgData );
}


/*----------------------------***  SENDMESSAGETOALL  ***--------------------------------*/
/*
sends the same message and data to all of the plug-ins.
----------------------------------------------------------------------------------------*/

void        ZPlugInHandler::SendMessageToAll( const long message, void* msgData )
{
    short    i;

    for( i = 1; i <= itsPlugIns->CountItems(); i++ )
        SendMessageToPlugIn( i, message, msgData );
}


/*--------------------------***  BUILDMENUOFPLUGINS  ***--------------------------------*/
/*
builds a menu of the names of the plug-ins. This is one (crude) way of making a user-
interface to call the plug-ins from an application, though this is not recommended for
sophisticated applications.
----------------------------------------------------------------------------------------*/

void        ZPlugInHandler::BuildMenuOfPlugIns( MenuHandle aMenu )
{
    FailNILParam( aMenu );

    if ( itsPlugIns->CountItems() > 0 )
    {
        ZPlugIn*    zp;
        Str255        plName;
        short        i, n = CountMenuItems( aMenu );

        while( n )
            DeleteMenuItem( aMenu, n-- );

        for ( i = 1; i <= itsPlugIns->CountItems(); i++ )
        {
            zp = itsPlugIns->GetObject( i );

            if ( zp )
            {
                zp->GetName( plName );

                AppendMenu( aMenu, "\px" );
                SetMenuItemText( aMenu, i, plName );
            }
        }
    }
}


/*------------------------------***  PROCESS1FILE  ***----------------------------------*/
/*
for each plug-in file, make a plug-in object and append to our list.
----------------------------------------------------------------------------------------*/

void        ZPlugInHandler::Process1File( const FSSpec& aSpec, const OSType fType )
{
    // if using progress, set title to something suitable

    Str255    phTitle;

    if ( useProgressDialog )
    {
        GetIndString( phTitle, 202, 20 );

        itsPD->SetTitle( phTitle );
    }

    // make a plug-in object and add it to the list

    ZPlugIn*    zp = MakePlugIn( aSpec, fType );

    if ( zp )
    {
        itsPlugIns->AppendItem( zp );

        // inherit progress bar behaviour

        ZFolderScanner::Process1File( aSpec, fType );
    }
}


/*-------------------------------***  MAKEPLUGIN  ***-----------------------------------*/
/*
Make the plug-in object associated with the passed file. You need to override this method
to make useful plug-in objects that implement your desired protocol and plug-in file
format.
----------------------------------------------------------------------------------------*/

ZPlugIn*    ZPlugInHandler::MakePlugIn( const FSSpec& aSpec, const OSType fType )
{
    ZPlugIn*    zp = NULL;

    // make the plug-in object. You need to override this to make objects of your desired
    // kind. This makes generic ZPlugIns but they do nothing. Normally you'll check fType
    // at least to see if the filetype is what you wanted. It is advisable to make other
    // sanity checks on the file format as part of your plug-in protocol.

    FailNIL( zp = new ZPlugIn( aSpec ));

    return zp;
}