net/mail: move RFC 2047 code to internal/mime
The code concerning quoted-printable encoding (RFC 2045) and its
variant for MIME headers (RFC 2047) is currently spread in
mime/multipart and net/mail. It is also not exported.
This commit is the second step to fix that issue. It moves the
RFC 2047 encoding and decoding functions from net/mail to
internal/mime. The exported API is unchanged.
Updates #4943
Change-Id: I5f58aa58e74bbe4ec91b2e9b8c81921338053b00
Reviewed-on: https://go-review.googlesource.com/2101
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go
index 98201a5..d186a17 100644
--- a/src/go/build/deps_test.go
+++ b/src/go/build/deps_test.go
@@ -252,7 +252,7 @@
// Uses of networking.
"log/syslog": {"L4", "OS", "net"},
- "net/mail": {"L4", "NET", "OS"},
+ "net/mail": {"L4", "NET", "OS", "internal/mime"},
"net/textproto": {"L4", "OS", "net"},
// Core crypto.
diff --git a/src/internal/mime/header.go b/src/internal/mime/header.go
new file mode 100644
index 0000000..9bc3e5e
--- /dev/null
+++ b/src/internal/mime/header.go
@@ -0,0 +1,122 @@
+// Copyright 2015 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 mime
+
+import (
+ "bytes"
+ "encoding/base64"
+ "errors"
+ "fmt"
+ "io"
+ "io/ioutil"
+ "strconv"
+ "strings"
+ "unicode"
+)
+
+// EncodeWord encodes a string into an RFC 2047 encoded-word.
+func EncodeWord(s string) string {
+ // UTF-8 "Q" encoding
+ b := bytes.NewBufferString("=?utf-8?q?")
+ for i := 0; i < len(s); i++ {
+ switch c := s[i]; {
+ case c == ' ':
+ b.WriteByte('_')
+ case isVchar(c) && c != '=' && c != '?' && c != '_':
+ b.WriteByte(c)
+ default:
+ fmt.Fprintf(b, "=%02X", c)
+ }
+ }
+ b.WriteString("?=")
+ return b.String()
+}
+
+// DecodeWord decodes an RFC 2047 encoded-word.
+func DecodeWord(s string) (string, error) {
+ fields := strings.Split(s, "?")
+ if len(fields) != 5 || fields[0] != "=" || fields[4] != "=" {
+ return "", errors.New("address not RFC 2047 encoded")
+ }
+ charset, enc := strings.ToLower(fields[1]), strings.ToLower(fields[2])
+ if charset != "us-ascii" && charset != "iso-8859-1" && charset != "utf-8" {
+ return "", fmt.Errorf("charset not supported: %q", charset)
+ }
+
+ in := bytes.NewBufferString(fields[3])
+ var r io.Reader
+ switch enc {
+ case "b":
+ r = base64.NewDecoder(base64.StdEncoding, in)
+ case "q":
+ r = qDecoder{r: in}
+ default:
+ return "", fmt.Errorf("RFC 2047 encoding not supported: %q", enc)
+ }
+
+ dec, err := ioutil.ReadAll(r)
+ if err != nil {
+ return "", err
+ }
+
+ switch charset {
+ case "us-ascii":
+ b := new(bytes.Buffer)
+ for _, c := range dec {
+ if c >= 0x80 {
+ b.WriteRune(unicode.ReplacementChar)
+ } else {
+ b.WriteRune(rune(c))
+ }
+ }
+ return b.String(), nil
+ case "iso-8859-1":
+ b := new(bytes.Buffer)
+ for _, c := range dec {
+ b.WriteRune(rune(c))
+ }
+ return b.String(), nil
+ case "utf-8":
+ return string(dec), nil
+ }
+ panic("unreachable")
+}
+
+type qDecoder struct {
+ r io.Reader
+ scratch [2]byte
+}
+
+func (qd qDecoder) Read(p []byte) (n int, err error) {
+ // This method writes at most one byte into p.
+ if len(p) == 0 {
+ return 0, nil
+ }
+ if _, err := qd.r.Read(qd.scratch[:1]); err != nil {
+ return 0, err
+ }
+ switch c := qd.scratch[0]; {
+ case c == '=':
+ if _, err := io.ReadFull(qd.r, qd.scratch[:2]); err != nil {
+ return 0, err
+ }
+ x, err := strconv.ParseInt(string(qd.scratch[:2]), 16, 64)
+ if err != nil {
+ return 0, fmt.Errorf("mime: invalid RFC 2047 encoding: %q", qd.scratch[:2])
+ }
+ p[0] = byte(x)
+ case c == '_':
+ p[0] = ' '
+ default:
+ p[0] = c
+ }
+ return 1, nil
+}
+
+// isVchar returns true if c is an RFC 5322 VCHAR character.
+func isVchar(c byte) bool {
+ // Visible (printing) characters.
+ return '!' <= c && c <= '~'
+}
diff --git a/src/net/mail/message.go b/src/net/mail/message.go
index 19aa888..71fe74b 100644
--- a/src/net/mail/message.go
+++ b/src/net/mail/message.go
@@ -18,17 +18,14 @@
import (
"bufio"
"bytes"
- "encoding/base64"
"errors"
"fmt"
+ "internal/mime"
"io"
- "io/ioutil"
"log"
"net/textproto"
- "strconv"
"strings"
"time"
- "unicode"
)
var debug = debugT(false)
@@ -180,21 +177,7 @@
return b.String()
}
- // UTF-8 "Q" encoding
- b := bytes.NewBufferString("=?utf-8?q?")
- for i := 0; i < len(a.Name); i++ {
- switch c := a.Name[i]; {
- case c == ' ':
- b.WriteByte('_')
- case isVchar(c) && c != '=' && c != '?' && c != '_':
- b.WriteByte(c)
- default:
- fmt.Fprintf(b, "=%02X", c)
- }
- }
- b.WriteString("?= ")
- b.WriteString(s)
- return b.String()
+ return mime.EncodeWord(a.Name) + " " + s
}
type addrParser []byte
@@ -352,7 +335,7 @@
// RFC 2047 encoded-word starts with =?, ends with ?=, and has two other ?s.
if err == nil && strings.HasPrefix(word, "=?") && strings.HasSuffix(word, "?=") && strings.Count(word, "?") == 4 {
- word, err = decodeRFC2047Word(word)
+ word, err = mime.DecodeWord(word)
}
if err != nil {
@@ -440,86 +423,6 @@
return len(*p)
}
-func decodeRFC2047Word(s string) (string, error) {
- fields := strings.Split(s, "?")
- if len(fields) != 5 || fields[0] != "=" || fields[4] != "=" {
- return "", errors.New("address not RFC 2047 encoded")
- }
- charset, enc := strings.ToLower(fields[1]), strings.ToLower(fields[2])
- if charset != "us-ascii" && charset != "iso-8859-1" && charset != "utf-8" {
- return "", fmt.Errorf("charset not supported: %q", charset)
- }
-
- in := bytes.NewBufferString(fields[3])
- var r io.Reader
- switch enc {
- case "b":
- r = base64.NewDecoder(base64.StdEncoding, in)
- case "q":
- r = qDecoder{r: in}
- default:
- return "", fmt.Errorf("RFC 2047 encoding not supported: %q", enc)
- }
-
- dec, err := ioutil.ReadAll(r)
- if err != nil {
- return "", err
- }
-
- switch charset {
- case "us-ascii":
- b := new(bytes.Buffer)
- for _, c := range dec {
- if c >= 0x80 {
- b.WriteRune(unicode.ReplacementChar)
- } else {
- b.WriteRune(rune(c))
- }
- }
- return b.String(), nil
- case "iso-8859-1":
- b := new(bytes.Buffer)
- for _, c := range dec {
- b.WriteRune(rune(c))
- }
- return b.String(), nil
- case "utf-8":
- return string(dec), nil
- }
- panic("unreachable")
-}
-
-type qDecoder struct {
- r io.Reader
- scratch [2]byte
-}
-
-func (qd qDecoder) Read(p []byte) (n int, err error) {
- // This method writes at most one byte into p.
- if len(p) == 0 {
- return 0, nil
- }
- if _, err := qd.r.Read(qd.scratch[:1]); err != nil {
- return 0, err
- }
- switch c := qd.scratch[0]; {
- case c == '=':
- if _, err := io.ReadFull(qd.r, qd.scratch[:2]); err != nil {
- return 0, err
- }
- x, err := strconv.ParseInt(string(qd.scratch[:2]), 16, 64)
- if err != nil {
- return 0, fmt.Errorf("mail: invalid RFC 2047 encoding: %q", qd.scratch[:2])
- }
- p[0] = byte(x)
- case c == '_':
- p[0] = ' '
- default:
- p[0] = c
- }
- return 1, nil
-}
-
var atextChars = []byte("ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
"abcdefghijklmnopqrstuvwxyz" +
"0123456789" +
