Loading and Using a Plug-in

Boolean foundInterface = false;

// Create a URL that points to the plug-in using a CFString path 'aPath'.

CFURLRef url =

    CFURLCreateWithFileSystemPath(NULL, aPath, kCFURLPOSIXPathStyle, TRUE);

// Create a CFPlugin using the URL.

// This causes the plug-in's types and factories to be registered with the system.

// The plug-in's code is not loaded unless it is using dynamic registration.

CFPlugInRef plugin = CFPlugInCreate(NULL, url);

if (!plugin)

{

    printf("Could not create CFPluginRef.\n");

}

else

{

    // Test whether this plug-in implements the Test type.

    CFArrayRef factories = CFPlugInFindFactoriesForPlugInType(kTestTypeID);

    // If there are factories for the requested type, attempt to

    // get the IUnknown interface.

    if (factories != NULL)

    {

        CFIndex factoryCount = CFArrayGetCount(factories);

        if (factoryCount <= 0)

        {

            printf("Could not find any factories.\n");

        }

        else

        {

            CFIndex index;

            for (index = 0;

                (index < factoryCount) && (!foundInterface);

                index++)

            {

                // Get the factory ID at the current index.

                CFUUIDRef factoryID =

                            CFArrayGetValueAtIndex(factories, index);

                // Use the factory ID to get an IUnknown interface.

                // The code for the PlugIn is loaded here.

                IUnknownVTbl **iunknown =

                    CFPlugInInstanceCreate(NULL, factoryID, kTestTypeID);

                // If this is an IUnknown interface,

                // query for the Test interface.

                if (iunknown)

                {

                    TestInterfaceStruct **interface = NULL;

                    (*iunknown)->QueryInterface(iunknown,

                                CFUUIDGetUUIDBytes(kTestInterfaceID),

                                (LPVOID *)(&interface));

                    // Finished with IUnknown.

                    (*iunknown)->Release(iunknown);

                    // If this is a Test interface, try to call its function.

                    if (interface)

                    {

                        (*interface)->fooMe(interface, TRUE);

                        (*interface)->fooMe(interface, FALSE);

                        // Finished with test interface.

                        // This causes the plug-in's code to be unloaded.

                        (*interface)->Release(interface);

                        foundInterface = true;

                    }

                }

                // end of iunknown

            }

            // end of index loop

        }

        // factoryCount > 0

        // Release the factories array.

        CFRelease(factories);

    }

    if (!foundInterface)

    {

        printf("Failed to get interface.\n");

    }

    // Release the CFPlugin -- memory for the plug-in is deallocated here.

    CFRelease(plugin);

}