Add a utils package for helpful things.

utils/utils.go

@@ -0,0 +1,63 @@
+// utils.go - A grab bag of useful utilitiy functions.
+//
+// To the extent possible under law, Yawning Angel waived all copyright
+// and related or neighboring rights to bulb, using the creative
+// commons "cc0" public domain dedication. See LICENSE or
+// <http://creativecommons.org/publicdomain/zero/1.0/> for full details.
+
+// Package utils implements useful utilities for dealing with Tor and it's
+// control port.
+package utils
+
+import (
+	"net"
+	"net/url"
+	"strconv"
+)
+
+// ParseControlPortString parses a string representation of a control port
+// address into a network/address string pair suitable for use with "dial".
+//
+// Valid string representations are:
+//  * tcp://address:port
+//  * unix://path
+//  * port (Translates to tcp://127.0.0.1:port)
+func ParseControlPortString(raw string) (network, addr string, err error) {
+	// Try parsing it as a naked port.
+	if _, err = strconv.ParseUint(raw, 10, 16); err == nil {
+		raw = "tcp://127.0.0.1:" + raw
+	}
+
+	// Ok, parse/validate the URI.
+	uri, err := url.Parse(raw)
+	if err != nil {
+		return "", "", err
+	}
+	if uri.Opaque != "" || uri.RawQuery != "" || uri.Fragment != "" {
+		return "", "", net.InvalidAddrError("uri has Opaque/Query/Fragment")
+	}
+	switch uri.Scheme {
+	case "tcp":
+		if uri.Path != "" {
+			return "", "", net.InvalidAddrError("tcp uri has a path")
+		}
+		tcpAddr, err := net.ResolveTCPAddr(uri.Scheme, uri.Host)
+		if err != nil {
+			return "", "", err
+		}
+		if tcpAddr.Port == 0 {
+			return "", "", net.InvalidAddrError("tcp uri is missing a port")
+		}
+		return uri.Scheme, uri.Host, nil
+	case "unix":
+		if uri.Host != "" {
+			return "", "", net.InvalidAddrError("unix uri has a host")
+		}
+		_, err := net.ResolveUnixAddr(uri.Scheme, uri.Path)
+		if err != nil {
+			return "", "", err
+		}
+		return uri.Scheme, uri.Path, nil
+	}
+	return "", "", net.InvalidAddrError("unknown scheme: " + uri.Scheme)
+}