exp/cookiejar: implement IDNA/Punycode's toASCII.

R=dr.volker.dobler
CC=golang-dev
https://golang.org/cl/7398049

src/pkg/exp/cookiejar/jar.go

@@ -301,18 +301,11 @@ func canonicalHost(host string) (string, error) {
 			return "", err
 		}
 	}
-
 	if strings.HasSuffix(host, ".") {
 		// Strip trailing dot from fully qualified domain names.
 		host = host[:len(host)-1]
 	}
-
-	// TODO: the "canonicalized host name" of RFC 6265 requires the idna ToASCII
-	// transformation. Possible solutions:
-	//  - promote package idna from go.net to go and import "net/idna"
-	//  - document behavior as a BUG
-
-	return host, nil
+	return toASCII(host)
 }
 
 // hasPort returns whether host contains a port number. host may be a host

src/pkg/exp/cookiejar/jar_test.go

@@ -49,8 +49,8 @@ var canonicalHostTests = map[string]string{
 	"192.168.0.5:8080":        "192.168.0.5",
 	"2001:4860:0:2001::68":    "2001:4860:0:2001::68",
 	"[2001:4860:0:::68]:8080": "2001:4860:0:::68",
-	// "www.bücher.de":        "www.xn--bcher-kva.de",  // TODO de-comment once proper idna is available
-	"www.example.com.": "www.example.com",
+	"www.bücher.de":           "www.xn--bcher-kva.de",
+	"www.example.com.":        "www.example.com",
 }
 
 func TestCanonicalHost(t *testing.T) {

src/pkg/exp/cookiejar/punycode.go

+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cookiejar
+
+// This file implements the Punycode algorithm from RFC 3492.
+
+import (
+	"fmt"
+	"strings"
+	"unicode/utf8"
+)
+
+// These parameter values are specified in section 5.
+//
+// All computation is done with int32s, so that overflow behavior is identical
+// regardless of whether int is 32-bit or 64-bit.
+const (
+	base        int32 = 36
+	damp        int32 = 700
+	initialBias int32 = 72
+	initialN    int32 = 128
+	skew        int32 = 38
+	tmax        int32 = 26
+	tmin        int32 = 1
+)
+
+// encode encodes a string as specified in section 6.3 and prepends prefix to
+// the result.
+//
+// The "while h < length(input)" line in the specification becomes "for
+// remaining != 0" in the Go code, because len(s) in Go is in bytes, not runes.
+func encode(prefix, s string) (string, error) {
+	output := make([]byte, len(prefix), len(prefix)+1+2*len(s))
+	copy(output, prefix)
+	delta, n, bias := int32(0), initialN, initialBias
+	b, remaining := int32(0), int32(0)
+	for _, r := range s {
+		if r < 0x80 {
+			b++
+			output = append(output, byte(r))
+		} else {
+			remaining++
+		}
+	}
+	h := b
+	if b > 0 {
+		output = append(output, '-')
+	}
+	for remaining != 0 {
+		m := int32(0x7fffffff)
+		for _, r := range s {
+			if m > r && r >= n {
+				m = r
+			}
+		}
+		delta += (m - n) * (h + 1)
+		if delta < 0 {
+			return "", fmt.Errorf("cookiejar: invalid label %q", s)
+		}
+		n = m
+		for _, r := range s {
+			if r < n {
+				delta++
+				if delta < 0 {
+					return "", fmt.Errorf("cookiejar: invalid label %q", s)
+				}
+				continue
+			}
+			if r > n {
+				continue
+			}
+			q := delta
+			for k := base; ; k += base {
+				t := k - bias
+				if t < tmin {
+					t = tmin
+				} else if t > tmax {
+					t = tmax
+				}
+				if q < t {
+					break
+				}
+				output = append(output, encodeDigit(t+(q-t)%(base-t)))
+				q = (q - t) / (base - t)
+			}
+			output = append(output, encodeDigit(q))
+			bias = adapt(delta, h+1, h == b)
+			delta = 0
+			h++
+			remaining--
+		}
+		delta++
+		n++
+	}
+	return string(output), nil
+}
+
+func encodeDigit(digit int32) byte {
+	switch {
+	case 0 <= digit && digit < 26:
+		return byte(digit + 'a')
+	case 26 <= digit && digit < 36:
+		return byte(digit + ('0' - 26))
+	}
+	panic("cookiejar: internal error in punycode encoding")
+}
+
+// adapt is the bias adaptation function specified in section 6.1.
+func adapt(delta, numPoints int32, firstTime bool) int32 {
+	if firstTime {
+		delta /= damp
+	} else {
+		delta /= 2
+	}
+	delta += delta / numPoints
+	k := int32(0)
+	for delta > ((base-tmin)*tmax)/2 {
+		delta /= base - tmin
+		k += base
+	}
+	return k + (base-tmin+1)*delta/(delta+skew)
+}
+
+// Strictly speaking, the remaining code below deals with IDNA (RFC 5890 and
+// friends) and not Punycode (RFC 3492) per se.
+
+// acePrefix is the ASCII Compatible Encoding prefix.
+const acePrefix = "xn--"
+
+// toASCII converts a domain or domain label to its ASCII form. For example,
+// toASCII("bücher.example.com") is "xn--bcher-kva.example.com", and
+// toASCII("golang") is "golang".
+func toASCII(s string) (string, error) {
+	if ascii(s) {
+		return s, nil
+	}
+	labels := strings.Split(s, ".")
+	for i, label := range labels {
+		if !ascii(label) {
+			a, err := encode(acePrefix, label)
+			if err != nil {
+				return "", err
+			}
+			labels[i] = a
+		}
+	}
+	return strings.Join(labels, "."), nil
+}
+
+func ascii(s string) bool {
+	for i := 0; i < len(s); i++ {
+		if s[i] >= utf8.RuneSelf {
+			return false
+		}
+	}
+	return true
+}

src/pkg/exp/cookiejar/punycode_test.go

+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cookiejar
+
+import (
+	"testing"
+)
+
+var punycodeTestCases = [...]struct {
+	s, encoded string
+}{
+	{"", ""},
+	{"-", "--"},
+	{"-a", "-a-"},
+	{"-a-", "-a--"},
+	{"a", "a-"},
+	{"a-", "a--"},
+	{"a-b", "a-b-"},
+	{"books", "books-"},
+	{"bücher", "bcher-kva"},
+	{"Hello世界", "Hello-ck1hg65u"},
+	{"ü", "tda"},
+	{"üý", "tdac"},
+
+	// The test cases below come from RFC 3492 section 7.1 with Errata 3026.
+	{
+		// (A) Arabic (Egyptian).
+		"\u0644\u064A\u0647\u0645\u0627\u0628\u062A\u0643\u0644" +
+			"\u0645\u0648\u0634\u0639\u0631\u0628\u064A\u061F",
+		"egbpdaj6bu4bxfgehfvwxn",
+	},
+	{
+		// (B) Chinese (simplified).
+		"\u4ED6\u4EEC\u4E3A\u4EC0\u4E48\u4E0D\u8BF4\u4E2D\u6587",
+		"ihqwcrb4cv8a8dqg056pqjye",
+	},
+	{
+		// (C) Chinese (traditional).
+		"\u4ED6\u5011\u7232\u4EC0\u9EBD\u4E0D\u8AAA\u4E2D\u6587",
+		"ihqwctvzc91f659drss3x8bo0yb",
+	},
+	{
+		// (D) Czech.
+		"\u0050\u0072\u006F\u010D\u0070\u0072\u006F\u0073\u0074" +
+			"\u011B\u006E\u0065\u006D\u006C\u0075\u0076\u00ED\u010D" +
+			"\u0065\u0073\u006B\u0079",
+		"Proprostnemluvesky-uyb24dma41a",
+	},
+	{
+		// (E) Hebrew.
+		"\u05DC\u05DE\u05D4\u05D4\u05DD\u05E4\u05E9\u05D5\u05D8" +
+			"\u05DC\u05D0\u05DE\u05D3\u05D1\u05E8\u05D9\u05DD\u05E2" +
+			"\u05D1\u05E8\u05D9\u05EA",
+		"4dbcagdahymbxekheh6e0a7fei0b",
+	},
+	{
+		// (F) Hindi (Devanagari).
+		"\u092F\u0939\u0932\u094B\u0917\u0939\u093F\u0928\u094D" +
+			"\u0926\u0940\u0915\u094D\u092F\u094B\u0902\u0928\u0939" +
+			"\u0940\u0902\u092C\u094B\u0932\u0938\u0915\u0924\u0947" +
+			"\u0939\u0948\u0902",
+		"i1baa7eci9glrd9b2ae1bj0hfcgg6iyaf8o0a1dig0cd",
+	},
+	{
+		// (G) Japanese (kanji and hiragana).
+		"\u306A\u305C\u307F\u3093\u306A\u65E5\u672C\u8A9E\u3092" +
+			"\u8A71\u3057\u3066\u304F\u308C\u306A\u3044\u306E\u304B",
+		"n8jok5ay5dzabd5bym9f0cm5685rrjetr6pdxa",
+	},
+	{
+		// (H) Korean (Hangul syllables).
+		"\uC138\uACC4\uC758\uBAA8\uB4E0\uC0AC\uB78C\uB4E4\uC774" +
+			"\uD55C\uAD6D\uC5B4\uB97C\uC774\uD574\uD55C\uB2E4\uBA74" +
+			"\uC5BC\uB9C8\uB098\uC88B\uC744\uAE4C",
+		"989aomsvi5e83db1d2a355cv1e0vak1dwrv93d5xbh15a0dt30a5j" +
+			"psd879ccm6fea98c",
+	},
+	{
+		// (I) Russian (Cyrillic).
+		"\u043F\u043E\u0447\u0435\u043C\u0443\u0436\u0435\u043E" +
+			"\u043D\u0438\u043D\u0435\u0433\u043E\u0432\u043E\u0440" +
+			"\u044F\u0442\u043F\u043E\u0440\u0443\u0441\u0441\u043A" +
+			"\u0438",
+		"b1abfaaepdrnnbgefbadotcwatmq2g4l",
+	},
+	{
+		// (J) Spanish.
+		"\u0050\u006F\u0072\u0071\u0075\u00E9\u006E\u006F\u0070" +
+			"\u0075\u0065\u0064\u0065\u006E\u0073\u0069\u006D\u0070" +
+			"\u006C\u0065\u006D\u0065\u006E\u0074\u0065\u0068\u0061" +
+			"\u0062\u006C\u0061\u0072\u0065\u006E\u0045\u0073\u0070" +
+			"\u0061\u00F1\u006F\u006C",
+		"PorqunopuedensimplementehablarenEspaol-fmd56a",
+	},
+	{
+		// (K) Vietnamese.
+		"\u0054\u1EA1\u0069\u0073\u0061\u006F\u0068\u1ECD\u006B" +
+			"\u0068\u00F4\u006E\u0067\u0074\u0068\u1EC3\u0063\u0068" +
+			"\u1EC9\u006E\u00F3\u0069\u0074\u0069\u1EBF\u006E\u0067" +
+			"\u0056\u0069\u1EC7\u0074",
+		"TisaohkhngthchnitingVit-kjcr8268qyxafd2f1b9g",
+	},
+	{
+		// (L) 3<nen>B<gumi><kinpachi><sensei>.
+		"\u0033\u5E74\u0042\u7D44\u91D1\u516B\u5148\u751F",
+		"3B-ww4c5e180e575a65lsy2b",
+	},
+	{
+		// (M) <amuro><namie>-with-SUPER-MONKEYS.
+		"\u5B89\u5BA4\u5948\u7F8E\u6075\u002D\u0077\u0069\u0074" +
+			"\u0068\u002D\u0053\u0055\u0050\u0045\u0052\u002D\u004D" +
+			"\u004F\u004E\u004B\u0045\u0059\u0053",
+		"-with-SUPER-MONKEYS-pc58ag80a8qai00g7n9n",
+	},
+	{
+		// (N) Hello-Another-Way-<sorezore><no><basho>.
+		"\u0048\u0065\u006C\u006C\u006F\u002D\u0041\u006E\u006F" +
+			"\u0074\u0068\u0065\u0072\u002D\u0057\u0061\u0079\u002D" +
+			"\u305D\u308C\u305E\u308C\u306E\u5834\u6240",
+		"Hello-Another-Way--fc4qua05auwb3674vfr0b",
+	},
+	{
+		// (O) <hitotsu><yane><no><shita>2.
+		"\u3072\u3068\u3064\u5C4B\u6839\u306E\u4E0B\u0032",
+		"2-u9tlzr9756bt3uc0v",
+	},
+	{
+		// (P) Maji<de>Koi<suru>5<byou><mae>
+		"\u004D\u0061\u006A\u0069\u3067\u004B\u006F\u0069\u3059" +
+			"\u308B\u0035\u79D2\u524D",
+		"MajiKoi5-783gue6qz075azm5e",
+	},
+	{
+		// (Q) <pafii>de<runba>
+		"\u30D1\u30D5\u30A3\u30FC\u0064\u0065\u30EB\u30F3\u30D0",
+		"de-jg4avhby1noc0d",
+	},
+	{
+		// (R) <sono><supiido><de>
+		"\u305D\u306E\u30B9\u30D4\u30FC\u30C9\u3067",
+		"d9juau41awczczp",
+	},
+	{
+		// (S) -> $1.00 <-
+		"\u002D\u003E\u0020\u0024\u0031\u002E\u0030\u0030\u0020" +
+			"\u003C\u002D",
+		"-> $1.00 <--",
+	},
+}
+
+func TestPunycode(t *testing.T) {
+	for _, tc := range punycodeTestCases {
+		if got, err := encode("", tc.s); err != nil {
+			t.Errorf(`encode("", %q): %v`, tc.s, err)
+		} else if got != tc.encoded {
+			t.Errorf(`encode("", %q): got %q, want %q`, tc.s, got, tc.encoded)
+		}
+	}
+}