Getting inode number from URL

Code Block  
/// Adapts `getattrlistbulk` to use Swift-style errors.
func getattrlistbulk2(_ dirFD: CInt, _ attrListPtr: UnsafeMutablePointer<attrlist>, _ attrBuf: UnsafeMutableRawBufferPointer, _ options: UInt64) throws -> Int {
		while true {
				let result = getattrlistbulk(dirFD, attrListPtr, attrBuf.baseAddress!, attrBuf.count, 0)
				if result >= 0 {
						return Int(result)
				}
				let err = errno
				if err != EINTR {
						throw NSError(domain: NSPOSIXErrorDomain, code: Int(errno), userInfo: nil)
				}
				// continue on `EINTR`
		}
}
/// A copy of `vtype`.
///
/// This system enum is not available to Swift. In a real project you’d access it via a
/// bridging header.
enum vtype: fsobj_type_t {
		/* 0 */
		case VNON
		/* 1 - 5 */
		case VREG; case VDIR; case VBLK; case VCHR; case VLNK
		/* 6 - 10 */
		case VSOCK; case VFIFO; case VBAD; case VSTR; case VCPLX
};
/// Prints the attributes in the supplied buffer.
func printAttrs(_ itemCount: Int, _ attrBuf: UnsafeMutableRawBufferPointer) {
		var entryStart = attrBuf.baseAddress!
		for _ in 0..<itemCount {
				var field = entryStart
				let length = Int(field.load(as: UInt32.self))
				field += MemoryLayout<UInt32>.size
				entryStart += length
				let returned = field.load(as: attribute_set_t.self)
				field += MemoryLayout<attribute_set_t>.size
		
				var error: UInt32 = 0
				if (returned.commonattr & attrgroup_t(bitPattern: ATTR_CMN_ERROR)) != 0 {
						error = field.load(as: UInt32.self)
						field += MemoryLayout<UInt32>.size
				}
				var name: String = ""
				if (returned.commonattr & attrgroup_t(bitPattern: ATTR_CMN_NAME)) != 0 {
						let base = field
						let nameInfo = field.load(as: attrreference_t.self)
						field += MemoryLayout<attrreference_t>.size
				
						name = String(cString: (base + Int(nameInfo.attr_dataoffset)).assumingMemoryBound(to: CChar.self))
				}
		
				if error != 0 {
						print("Error in reading attributes for directory entry \(error)");
						continue
				}
				var objectType: fsobj_type_t = vtype.VNON.rawValue
				if (returned.commonattr & attrgroup_t(bitPattern: ATTR_CMN_OBJTYPE)) != 0 {
						objectType = field.load(as: fsobj_type_t.self)
						field += MemoryLayout<fsobj_type_t>.size
				
						switch objectType {
						case vtype.VREG.rawValue:
								print("file \(name)")
						case vtype.VDIR.rawValue:
								print(" dir \(name)")
						default:
								print(" *** \(name)")
						}
				}
		}
}
func demo(_ dirPath: String) throws {
		let dirFD = open(dirPath, O_RDONLY)
		guard dirFD >= 0 else {
				throw NSError(domain: NSPOSIXErrorDomain, code: Int(errno), userInfo: nil)
		}
		defer {
				let junk = close(dirFD)
				assert(junk == 0)
		}
		var attrList = attrlist()
		attrList.bitmapcount = u_short( ATTR_BIT_MAP_COUNT )
		attrList.commonattr =
				attrgroup_t(ATTR_CMN_RETURNED_ATTRS) |
				attrgroup_t(bitPattern: ATTR_CMN_NAME) |
				attrgroup_t(bitPattern: ATTR_CMN_ERROR) |
				attrgroup_t(bitPattern: ATTR_CMN_OBJTYPE)
		let attrBuf = UnsafeMutableRawBufferPointer.allocate(byteCount: 256, alignment: 16)
		defer {
				attrBuf.deallocate()
		}
		while true {
				let itemCount = try getattrlistbulk2(dirFD, &attrList, attrBuf, 0)
				guard itemCount > 0 else {
						return
				}
				printAttrs(itemCount, attrBuf)
		}
}