// MSAEObjectsExist.c

//

// Original version by Jon Lansdell and Nigel Humphreys.

// 4.0 and 3.1 updates by Greg Sutton.

// ©Apple Computer Inc 1996, all rights reserved.

/*  

    Changes for 4.0

    27-Feb-96 : GS : Added call to HandleGetData() to see if properties etc. exist

*/

#include "MSAEObjectsExist.h"

#include "MSAEUtils.h"

#include "MSAEGetData.h"

#pragma segment AppleEvent

// -----------------------------------------------------------------------

//  Name:       DoObjectsExist

//  Purpose:    Handles the kAEDoObjectsExist AppleEvent. Basically just

//              tries to resolve the object to see if it exists.

// -----------------------------------------------------------------------

pascal OSErr DoObjectsExist(const AppleEvent    *theAppleEvent,

                                    AppleEvent  *reply, 

                                    long        handlerRefCon)

{

#ifdef __MWERKS__

    #pragma unused (handlerRefCon)

#endif

    AEDesc          directObject = {typeNull, NULL},

                    directDesc = {typeNull, NULL},

                    replyDesc = {typeNull, NULL},

                    aDesc = {typeNull, NULL};

    long            itemCount;

    Boolean         exists;

    OSErr           existsErr,

                    err;

    err = AEGetParamDesc(theAppleEvent, keyDirectObject, typeWildCard, &directObject);

    err = GotRequiredParams(theAppleEvent);

    if (noErr != err) goto done;

    if (typeNull == directObject.descriptorType)

        exists = true;      // Yes, our application does exist?????

    else

    {

        existsErr = AEResolve(&directObject, kAEIDoMinimum, &directDesc);

        if (noErr == existsErr)

        {

            switch ( directDesc.descriptorType )

            {

                case typeAEList:

                case typeAERecord:

                    err = AECountItems( &directDesc, &itemCount );  // If not empty then

                    if (noErr != err) goto done;                    //  it exists

                    exists = ( itemCount > 0 );

                    break;

                default:

                    err = HandleGetData( &directDesc, typeWildCard, &aDesc );

                    exists = ( noErr == err );

            }

        }                                       

        else

            exists = false;

    }

    err = AECreateDesc(typeBoolean, (Ptr)&exists, sizeof(exists), &replyDesc);

    if (noErr != err) goto done;

    err = AddResultToReply(&replyDesc, reply, err);

done:

    (void)AEDisposeDesc( &directObject );

    (void)AEDisposeDesc( &directDesc );

    (void)AEDisposeDesc( &replyDesc );

    (void)AEDisposeDesc( &aDesc );

    return err;

} // DoObjectsExist