Check for existence of a custom icon

gistfile1.m

- (BOOL)fileHasCustomIcon:(NSString *)path {
    struct FinderInfoAttrBuf {
        u_int32_t length;
        FileInfo fileInfo;
        ExtendedFileInfo extendedFileInfo;
    } __attribute__((aligned(4), packed));

    struct attrlist attrList = {};
    struct FinderInfoAttrBuf attrBuf = {};
    attrList.bitmapcount = ATTR_BIT_MAP_COUNT;
    attrList.commonattr  = ATTR_CMN_FNDRINFO;

    if (getattrlist([path fileSystemRepresentation], &attrList, &attrBuf, sizeof(attrBuf), 0) != 0)
        return NO;

    return !!(OSSwapBigToHostInt16(attrBuf.fileInfo.finderFlags) & kHasCustomIcon);
}