Developer CD Series 1996 June: Reference Library/Dev.CD Jun 96 RL/Dev.CD Jun 96 RL.toast/Technical Documentation/develop/develop Issue 26/develop Issue 26 code/Truffles - Display Mgr./Sprocket/ExperimentalStuff/UAppleObject.cp

Text File | 1995-12-10 | 13.2 KB | 594 lines | [TEXT/MMCC]

// UAppleObject.cp
// by Eric Berdahl
// AppleLink: BERDAHL
// Interget: [e-mail]
// May XX, 1992
//
// Copyright © 1992 Eric M. Berdahl
// All rights reserved.
//
// LICENSE
//
// UAppleObject is provided under the ego-ware™ system.  If you send me a note
// telling me how cool you think it UAppleObject is, you may incorporate it into
// any product you like (six-packs of good beer are also acceptable, no C.O.D.
// shipments, please).  Also, you must keep all copyright and other notices in
// the source code, especially MY NAME (The system is called ego-ware™.  Get it?).


#ifndef __AEOBJECTS__
#include <AEObjects.h>
#endif

#ifndef    __EXCEPTIONS__
#include "Exceptions.h"
#endif

#ifndef __RESOURCES__
#include <Resources.h>
#endif

#ifndef _UAPPLEOBJECT_
#include "UAppleObject.h"
#endif


// This unit requires a definition for DEBUG (indicating whether or not you
// want debugging code compiled in).  If you don’t set the flag, I’ll just
// assume you don’t want any.
#ifndef DEBUG
#define    DEBUG 0
#endif

//--------------------------------------------------------------------------------
// TAppleObjectDispatcher
//--------------------------------------------------------------------------------

TAppleObjectDispatcher* TAppleObjectDispatcher::fgDispatcher = nil;
Boolean TAppleObjectDispatcher::fgInited = false;


TAppleObjectDispatcher::TAppleObjectDispatcher()
{
    fDisposalList = nil;
    fDisposalListSize = 0;
    fApplication = nil;
}


TAppleObjectDispatcher::~TAppleObjectDispatcher()
{
    if (fDisposalList != nil)
        DisposeHandle((Handle) fDisposalList);
}

struct MAEventTableRec
{
    OSType theClass;
    OSType theID;
    long theValue;
};
typedef MAEventTableRec* MAEventTablePointer;

void TAppleObjectDispatcher::Install()
{
    if (fgDispatcher != nil)
        FailOSErr(errAppleObjectDispatcherAlreadyInstalled);

    Try
    {
        if (!fgInited)
        {
            AEObjectInit();
            fgInited = true;
        }

        fgDispatcher = this;

        // Install AppleEvent handlers from all aedt resources
        // Look for all AppleEvent dispatch tables…
        short numberOfTables = Count1Resources('aedt');
        FailResError();

        for (short tableIndex = 1; tableIndex <= numberOfTables; ++tableIndex)
        {
            Handle tableHandle = Get1IndResource('aedt', tableIndex);

            Try
            {
                FailResError();

                SignedByte savedState = HGetState(tableHandle);
                HLockHi(tableHandle);

                long tableSize = GetHandleSize(tableHandle);
                FailMemError();

                short tableElements = (short)(tableSize / sizeof(MAEventTableRec));

                MAEventTablePointer tablePtr = (MAEventTablePointer) *tableHandle;

                // Install a single event handler for all events
                for (short eventIndex = 1; eventIndex <= tableElements; ++eventIndex, ++tablePtr)
                    this->InstallAppleEventHandler(tablePtr->theClass, tablePtr->theID, tablePtr->theValue);

                HSetState(tableHandle, savedState);
            }
            Catch(err)
            {
                if (tableHandle)
                    ReleaseResource(tableHandle);
                Throw(err);
            }

            ReleaseResource(tableHandle);
        }




            // Install a universal object accessor
        FailOSErr(AEInstallObjectAccessor(typeWildCard, typeWildCard,
                                   NewOSLAccessorProc(TAppleObjectDispatcher::OSLObjectAccessorHandler),
                                   0, false));

            // Set up the object support library callbacks
        FailOSErr(AESetObjectCallbacks(
                            NewOSLCompareProc(TAppleObjectDispatcher::OSLCompareObjectsHandler),
                            NewOSLCountProc(TAppleObjectDispatcher::OSLCountObjectsHandler),
                            NewOSLDisposeTokenProc(TAppleObjectDispatcher::OSLDisposeTokenHandler),
                            nil, nil, nil, nil));
    }
    Catch(err)
    {
        fgDispatcher = nil;
        Throw(err);
    }
}


MAppleObject* TAppleObjectDispatcher::ExtractObject(const AEDesc& descriptor)
{
    MAppleObject* result;

    if (descriptor.descriptorType == typeNull)
        result = MAppleObject::GetDefaultAppleObject();
    else
        result = (MAppleObject*)descriptor.dataHandle;

#if DEBUG
        if (descriptor.descriptorType != result->GetAppleClass())
            DebugStr((ConstStr255Param) "Protocol error: object isn’t what it says it is");
#endif

    return result;
}


MAppleObject* TAppleObjectDispatcher::GetTarget(const AppleEvent& message)
{
    // The target defaults to the application
    MAppleObject* result = MAppleObject::GetDefaultAppleObject();

    Try
    {
        AEDesc    theDirectParameter;
        FailOSErr(AEGetParamDesc(&message, keyDirectObject, typeWildCard, &theDirectParameter));
        Try
        {
            // If the direct object is an object specifier, resolve it into
            // an application domain object.
            if (theDirectParameter.descriptorType == typeObjectSpecifier)
                result = this->ResolveSpecifier(theDirectParameter);
        }
        Catch(err)
        {
            OSErr ignoreErr = AEDisposeDesc(&theDirectParameter);
            Throw(err);
        }
    }
    Catch(err)
    {
        // It’s all right for there to be no direct object.  In that
        // case, we stick with the default.
        if (err != errAEDescNotFound)
            Throw(err);
    }

NoDescriptor:
    FailNIL(result);

    return result;
}


void TAppleObjectDispatcher::StuffDescriptor(AEDesc& descriptor,
                                             MAppleObject* object)
{
    descriptor.descriptorType = object->GetAppleClass();
    descriptor.dataHandle = (Handle) object;
}


void TAppleObjectDispatcher::HandleAppleEvent(const AppleEvent& message,
                                  AppleEvent& reply,
                                  long refCon)
{
    MAppleObject* theTarget = this->GetTarget(message);
    theTarget->DoAppleEvent(message, reply, refCon);

    // Dispose of the token object
    AEDesc    fakeToken;
    this->StuffDescriptor(fakeToken, theTarget);
    FailOSErr(AEDisposeToken(&fakeToken));
}


void TAppleObjectDispatcher::AccessContainedObjects(DescType desiredClass,
                                        const AEDesc& container,
                                        DescType containerClass,
                                        DescType form,
                                        const AEDesc& selectionData,
                                        AEDesc& value,
                                        long /* refCon */)
{
    MAppleObject* containerObject = this->ExtractObject(container);

#if DEBUG
        if (containerObject->GetAppleClass() != containerClass)
            DebugStr((ConstStr255Param) "Protocol error: object isn’t what the AE Manager thinks it is");
#endif

    Boolean    needsDisposal;
    MAppleObject* resultObject = containerObject->GetContainedObject(desiredClass,
                                                        form, selectionData,
                                                        needsDisposal);
    if (resultObject == nil)
        FailOSErr(errAENoSuchObject);

    this->StuffDescriptor(value, resultObject);

    if (needsDisposal)
        this->SetTokenObjectDisposal(resultObject, true);
}


long TAppleObjectDispatcher::CountObjects(const AEDesc& containerToken,
                              DescType countObjectsOfType)
{
    MAppleObject* containerObject = this->ExtractObject(containerToken);
    return containerObject->CountContainedObjects(countObjectsOfType);
}

Boolean TAppleObjectDispatcher::CompareObjects(DescType operation,
                                               const AEDesc& obj1,
                                               const AEDesc& obj2)
{
    MAppleObject*    mObj1 = this->ExtractObject(obj1);
    MAppleObject*    mObj2 = this->ExtractObject(obj2);

    return mObj1->CompareAppleObjects(operation, *mObj2);
}

void TAppleObjectDispatcher::DisposeToken(AEDesc& unneededToken)
{
    MAppleObject*    theObject = this->ExtractObject(unneededToken);
    if (this->GetTokenObjectDisposal(theObject))
        delete theObject;
}


Boolean TAppleObjectDispatcher::GetTokenObjectDisposal(const MAppleObject* theObject)
{
    Boolean    result = false;

    // Search the list of objects to be disposed.  Return true if the object is
    // in the list.
    MAppleObject** curObj = *fDisposalList;
    for (long i = 0; i < fDisposalListSize; i++, curObj++)
    {
        if (theObject == *curObj)
        {
            result = true;
            break;
        }
    }

    return result;
}


void TAppleObjectDispatcher::SetTokenObjectDisposal(MAppleObject* theObject,
                                               Boolean needsDisposal)
{
    // Search the list of objects to be disposed to see if it currently exists.
    Boolean nilFound = false;
    Boolean    found = false;
    MAppleObject** curObj = *fDisposalList;
    for (long i = 0; i < fDisposalListSize; i++, curObj++)
    {
        if (theObject == *curObj)
        {
            found = true;

            if (!needsDisposal)
                // remove it from the disposal list
                *curObj = nil;

            break;
        }
        else if (*curObj == nil)
            nilFound = true;
    }

    if (!found  &&  needsDisposal)
    {
        // it needs to be added to the list

        if (nilFound)
        {
            // we can sneak into a nil spot
            curObj = *fDisposalList;
            for (long i = 0; i < fDisposalListSize; i++, curObj++)
            {
                if (*curObj == nil)
                {
                    *curObj = theObject;
                    break;
                }
            }
        }
        else
        {
            // If the list hasn’t been created yet, create a zero-sized list
            if (fDisposalList == nil)
            {
                fDisposalList = (MAppleObject***) NewHandle(0);
                FailNIL(fDisposalList);
            }

            Try
            {
                fDisposalListSize++;
                SetHandleSize((Handle) fDisposalList, fDisposalListSize*sizeof(MAppleObject*));
                FailMemError();
                curObj = *fDisposalList;
                curObj += fDisposalListSize - 1;
                *curObj = theObject;
            }
            Catch(err)
            {
                fDisposalListSize--;
                Throw(err);
            }
        }
    }
}


MAppleObject* TAppleObjectDispatcher::ResolveSpecifier(AEDesc& objectSpecifier)
{
    AEDesc    tokenDesc;
    FailOSErr(AEResolve(&objectSpecifier, kAEIDoMinimum, &tokenDesc));
    MAppleObject* result = this->ExtractObject(tokenDesc);
    return result;
}


pascal OSErr TAppleObjectDispatcher::AppleEventHandler(const AppleEvent* message,
                                          AppleEvent* reply,
                                          long refCon)
{
    OSErr    result = noErr;

    Try
    {
        GetDispatcher()->HandleAppleEvent(*message, *reply, refCon);
    }
    Catch(err)
    {
        result = err;
    }

    return result;
}

pascal OSErr TAppleObjectDispatcher::OSLObjectAccessorHandler(DescType desiredClass,
                                         const AEDesc* container,
                                         DescType containerClass,
                                         DescType form,
                                         const AEDesc* selectionData,
                                         AEDesc* value,
                                         long refCon)
{
    OSErr    result = noErr;

    Try
    {
        GetDispatcher()->AccessContainedObjects(desiredClass, *container,
                                                containerClass, form,
                                                *selectionData,
                                                *value, refCon);
    }
    Catch(err)
    {
        result = err;
    }

    return result;
}

pascal OSErr TAppleObjectDispatcher::OSLCountObjectsHandler(DescType countObjectsOfType,
                                            DescType /* containerClass */,
                                            const AEDesc* containerToken,
                                            long* result)
{
    OSErr    theErr = noErr;

    Try
    {
        *result = GetDispatcher()->CountObjects(*containerToken, countObjectsOfType);
    }
    Catch(err)
    {
        theErr = err;
    }

    return theErr;
}


pascal OSErr TAppleObjectDispatcher::OSLCompareObjectsHandler(DescType operation,
                                         const AEDesc *obj1,
                                         const AEDesc *obj2,
                                         Boolean *answer)
{
    OSErr    result = noErr;

    Try
    {
        *answer = GetDispatcher()->CompareObjects(operation, *obj1, *obj2);
    }
    Catch(err)
    {
        result = err;
    }

    return result;
}


pascal OSErr TAppleObjectDispatcher::OSLDisposeTokenHandler(AEDesc* unneededToken)
{
    OSErr    result = noErr;

    Try
    {
        GetDispatcher()->DisposeToken(*unneededToken);
    }
    Catch(err)
    {
        result = err;
    }

    return result;
}


void TAppleObjectDispatcher::InstallAppleEventHandler(AEEventClass theClass,
                                                     AEEventID theID,
                                                     long refCon)
{
    FailOSErr(AEInstallEventHandler(theClass, theID,
                                    NewAEEventHandlerProc(TAppleObjectDispatcher::AppleEventHandler),
                                    refCon, false));
}


//--------------------------------------------------------------------------------
// MAppleObject
//--------------------------------------------------------------------------------

Boolean MAppleObject::fgInited = false;
MAppleObject* MAppleObject::fgDefaultAppleObject = nil;


MAppleObject::MAppleObject()
{
}


MAppleObject::MAppleObject(const MAppleObject& /* copy */)
{
}


MAppleObject::~MAppleObject()
{
    if (MAppleObject::GetDefaultAppleObject() == this)
        MAppleObject::SetDefaultAppleObject(nil);

    TAppleObjectDispatcher::GetDispatcher()->SetTokenObjectDisposal(this, false);
}


MAppleObject& MAppleObject::operator=(const MAppleObject& /* assignTo */)
{
    return *this;
}


void MAppleObject::InitAppleObject(TAppleObjectDispatcher* dispatcher)
{
    // create a dispatcher if one wasn't passed in
    if (dispatcher == nil)
    {
        dispatcher = new TAppleObjectDispatcher();
        FailNIL(dispatcher);
    }

    // Install the dispatcher
    dispatcher->Install();

    fgInited = true;
}


long MAppleObject::CountContainedObjects(DescType /* ofType */)
{
    return 0;
}


Boolean MAppleObject::CompareAppleObjects(DescType /* operation */,
                                          const MAppleObject& /* toWhat */)
{
    return false;
}


void MAppleObject::DoAppleEvent(const AppleEvent& /* message */,
                                AppleEvent& /* reply */, long /* refCon */)
{
    FailOSErr(errAEEventNotHandled);
}


MAppleObject* MAppleObject::GetContainedObject(DescType /* desiredType */,
                                               DescType /* keyForm */,
                                               const AEDesc& /* keyData */,
                                               Boolean& /* needDisposal */)
{
    return nil;
}


void MAppleObject::GotRequiredParameters(const AppleEvent& theAppleEvent)
{
    // look for the keyMissedKeywordAttr, just to see if it's there
    DescType    returnedType;
    Size        actualSize;
    OSErr theErr = AEGetAttributePtr(&theAppleEvent, keyMissedKeywordAttr,
                                     typeWildCard, &returnedType, nil, 0,
                                     &actualSize);

    if (theErr == noErr)
    {
        // Since the attribute exists, we missed a parameter somewhere.
        FailOSErr(errAEParamMissed);
    }
    else if (theErr != errAEDescNotFound)
    {
        // The only error that is OK is to say that the descriptor was not
        // found (indicating that we got all the parameters).  If any other
        // error occurred, throw it.
        FailOSErr(theErr);
    }
}


void MAppleObject::SetDefaultAppleObject(MAppleObject* defaultObject)
{
    fgDefaultAppleObject = defaultObject;
}