How to badge file and folder using Cocoa

I want to badge a file and folder with some color (image). How can this be achieved?

I tried with icon service, and it works for files, but it is not working with folders.

I saw this beh开发者_如何学Goavior working Dropbox (10.4, 10.5 and 10.6)- how can this be done?

The blog post Cocoa Tutorial: Custom Folder Icons was very close one for me, but it was not working as expected.

Is there another solution other than icon service?

The following function is the solution I found for the problem

BOOL AddBadgeToItem(NSString* path,NSData* tag)

{   
    FSCatalogInfo info;
    FSRef par;
    FSRef ref;
    Boolean dir = false;

    if (tag&&(FSPathMakeRef([path fileSystemRepresentation],&par,&dir)==noErr)) 
    {
        HFSUniStr255 fork = {0,{0}};
        sint16 refnum = kResFileNotOpened;
        FSGetResourceForkName(&fork);

        if (dir) 
        {

            NSString *name = @"Icon\r";
            memset(&info,0,sizeof(info));
            ((FileInfo*)(&info.finderInfo))->finderFlags = kIsInvisible;

            OSErr error = FSCreateResourceFile(&par,[name lengthOfBytesUsingEncoding:NSUTF16LittleEndianStringEncoding],(UniChar*)[name cStringUsingEncoding:NSUTF16LittleEndianStringEncoding],kFSCatInfoFinderXInfo,&info,fork.length, fork.unicode,&ref,NULL);

            if( error == dupFNErr )
            {
                // file already exists; prepare to try to open it
                const char *iconFileSystemPath = [[path stringByAppendingPathComponent:@"\000I\000c\000o\000n\000\r"] fileSystemRepresentation];

                OSStatus status = FSPathMakeRef((const UInt8 *)iconFileSystemPath, &ref, NULL);
                if (status != noErr)
                {
                    fprintf(stderr, "error: FSPathMakeRef() returned %d for file \"%s\"\n", (int)status, iconFileSystemPath);

                }
            }else if ( error != noErr)
            {
                return NO;
            }

        } 
        else 
        {
            BlockMoveData(&par,&ref,sizeof(FSRef));
            if (FSCreateResourceFork(&ref,fork.length,fork.unicode,0)!=noErr) 
            {
                //test

                if (FSOpenResourceFile(&ref,fork.length,fork.unicode,fsRdWrPerm,&refnum)!=noErr) {
                    return NO;
                }
                if (refnum!=kResFileNotOpened) {

                    UpdateResFile(refnum);
                    CloseResFile(refnum);

                    if (FSGetCatalogInfo(&par,kFSCatInfoFinderXInfo,&info,NULL,NULL,NULL)==noErr) {
                        ((ExtendedFileInfo*)(&info.extFinderInfo))->extendedFinderFlags = kExtendedFlagsAreInvalid;
                        FSSetCatalogInfo(&par,kFSCatInfoFinderXInfo,&info);
                    }
                }

                //Test end
                return NO;
            }
        }
        OSErr errorr = FSOpenResourceFile(&ref,fork.length,fork.unicode,fsRdWrPerm,&refnum);
        if (errorr!=noErr) {
            return NO;
        }
        if (refnum!=kResFileNotOpened) {
            CustomBadgeResource* cbr;

            int len = [tag length]; 
            Handle h = NewHandle(len);
            if (h) {
                BlockMoveData([tag bytes],*h,len);
                AddResource(h,kIconFamilyType,128,"\p");
                WriteResource(h);
                ReleaseResource(h);
            }

            h = NewHandle(sizeof(CustomBadgeResource)); 
            if (h) {
                cbr = (CustomBadgeResource*)*h;
                memset(cbr,0,sizeof(CustomBadgeResource));
                cbr->version = kCustomBadgeResourceVersion;
                cbr->customBadgeResourceID = 128;
                AddResource(h,kCustomBadgeResourceType,kCustomBadgeResourceID,"\p");
                WriteResource(h);
                ReleaseResource(h);
            }

            UpdateResFile(refnum);
            CloseResFile(refnum);

            if (FSGetCatalogInfo(&par,kFSCatInfoFinderXInfo,&info,NULL,NULL,NULL)==noErr) {
                ((ExtendedFileInfo*)(&info.extFinderInfo))->extendedFinderFlags = kExtendedFlagHasCustomBadge;
                FSSetCatalogInfo(&par,kFSCatInfoFinderXInfo,&info);
            }
        }
    }
    return NO;
}

You can do this using the -setIcon:forFile:options: method on NSWorkspace, which lets you just specify an NSImage to apply to the file/folder at the path you give it.

The intended approach is to create a Finder Sync app extension.