Initial commit

.gitignore

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+*.out
+*.[68]
+_obj
+_test
+_testmain.go

COPYING

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+Copyright (c) 2010, Simon Lipp
+
+Permission to use, copy, modify, and distribute this software for
+any purpose with or without fee is hereby granted, provided that
+the above copyright notice and this permission notice appear in all
+copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
+OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.

Makefile

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+include $(GOROOT)/src/Make.inc
+
+TARG=maildir
+GOFILES=\
+	maildir.go\
+
+include $(GOROOT)/src/Make.pkg

README.md

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+# PACKAGE
+
+package maildir
+
+This package is used for writing mails to a maildir, according to
+the specification located at http://www.courier-mta.org/maildir.html
+
+
+# TYPES
+
+	type Maildir struct {
+		// contains unexported fields
+	}
+Represent a folder in a maildir. The root folder is usually the Inbox.
+
+`func New(path string, create bool) (m *Maildir, err os.Error)`
+
+Open a maildir. If create is true and the maildir does not exist, create it.
+
+`func (m *Maildir) Child(name string, create bool) (*Maildir, os.Error)`
+
+Get a subfolder of the current folder. If create is true and the folder does not
+exist, create it.
+
+`func (m *Maildir) CreateMail(data io.Reader) (filename string, err os.Error)`
+Write a mail to the maildir folder. The data is not encoded or compressed in any way.

maildir.go

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+// Copyright 2010 Simon Lipp.
+// Distributed under a BSD-like license. See COPYING for more
+// details
+
+// This package is used for writing mails to a maildir, according to
+// the specification located at http://www.courier-mta.org/maildir.html
+package maildir
+
+import (
+	"encoding/base64"
+	"bytes"
+	"strings"
+	"sync"
+	"os"
+	"io"
+	"fmt"
+	"time"
+	"utf16"
+	paths "path"
+)
+
+var maildirBase64 = base64.NewEncoding("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,")
+var counter chan uint
+var counterInit sync.Once
+
+// Represent a folder in a maildir. The root folder is usually the Inbox.
+type Maildir struct {
+	// The root path ends with a /, others don't, so we can have 
+	// the child of a maildir just with path + "." + encodedChildName
+	path string
+}
+
+func newWithRawPath(path string, create bool) (m *Maildir, err os.Error) {
+	// start counter if needed, preventing race condition
+	counterInit.Do(func() {
+		counter = make(chan uint)
+		go (func() {
+			for i := uint(0); true; i++ {
+				counter <- i
+			}
+		})()
+	})
+
+	// Create if needed
+	_, err = os.Stat(path)
+	if err != nil {
+		if pe, ok := err.(*os.PathError); ok && pe.Error == os.ENOENT && create {
+			err = os.MkdirAll(path, 0775)
+			if err != nil {
+				return nil, err
+			}
+			for _, subdir := range []string{"tmp", "cur", "new"} {
+				err = os.Mkdir(paths.Join(path, subdir), 0775)
+				if err != nil {
+					return nil, err
+				}
+			}
+		} else {
+			return nil, err
+		}
+	}
+
+	return &Maildir{path}, nil
+}
+
+// Open a maildir. If create is true and the maildir does not exist, create it.
+func New(path string, create bool) (m *Maildir, err os.Error) {
+	// Ensure that path is not empty and ends with a /
+	if len(path) == 0 {
+		path = "." + string(paths.DirSeps[0])
+	} else if !strings.Contains(paths.DirSeps, string(path[len(path)-1])) {
+		path += string(paths.DirSeps[0])
+	}
+	return newWithRawPath(path, create)
+}
+
+// Get a subfolder of the current folder. If create is true and the folder does not
+// exist, create it.
+func (m *Maildir) Child(name string, create bool) (*Maildir, os.Error) {
+	var i int
+	encodedPath := bytes.NewBufferString(m.path + ".")
+	for i = nextInvalidChar(name); i < len(name); i = nextInvalidChar(name) {
+		encodedPath.WriteString(name[:i])
+		j := nextValidChar(name[i:])
+		encode(name[i:i+j], encodedPath)
+		if j < len(name[i:]) {
+			name = name[i+j:]
+		} else {
+			name = ""
+		}
+	}
+	encodedPath.WriteString(name)
+	return newWithRawPath(encodedPath.String(), create)
+}
+
+// Write a mail to the maildir folder. The data is not encoded or compressed in any way.
+func (m *Maildir) CreateMail(data io.Reader) (filename string, err os.Error) {
+	hostname, err := os.Hostname()
+	if err != nil {
+		return "", err
+	}
+
+	basename := fmt.Sprintf("%v.M%vP%v_%v.%v", time.Seconds(), time.Nanoseconds()/1000, os.Getpid(), <-counter, hostname)
+	tmpname := paths.Join(m.path, "tmp", basename)
+	file, err := os.Open(tmpname, os.O_WRONLY | os.O_CREAT, 0664)
+	if err != nil {
+		return "", err
+	}
+
+	size, err := io.Copy(file, data)
+	if err != nil {
+		os.Remove(tmpname)
+		return "", err
+	}
+
+	newname := paths.Join(m.path, "new", fmt.Sprintf("%v,S=%v", basename, size))
+	err = os.Rename(tmpname, newname)
+	if err != nil {
+		os.Remove(tmpname)
+		return "", err
+	}
+
+	return newname, nil
+}
+
+// Valid (valid = has not to be escaped) chars = 
+// ASCII 32-127 + "&" + "/" + "."
+// We disallow 32 (space) for obvious reasons (avoid to create folders with spaces into their names)
+// We disallow 127 because the spec is ambiguous here: it allows 127 but not control characters,
+// and 127 is a control character.
+func isValidChar(b byte) bool {
+	if b <= 0x20 || b >= 127 {
+		return false
+	}
+	if b == byte('.') || b == byte('/') || b == byte('&') {
+		return false
+	}
+	return true
+}
+
+func nextInvalidChar(s string) int {
+	for i := 0; i < len(s); i++ {
+		if !isValidChar(s[i]) {
+			return i
+		}
+	}
+	return len(s)
+}
+
+func nextValidChar(s string) int {
+	for i := 0; i < len(s); i++ {
+		if isValidChar(s[i]) {
+			return i
+		}
+	}
+	return len(s)
+}
+
+// s is a string of invalid chars, without any "&"
+// An encoded sequence is composed of (Python-like pseudo-code):
+// "&" + base64(rawSequence.encode('utf-16-be')).strip('=') + "-"
+func encodeSequence(s string, buf *bytes.Buffer) {
+	utf16data := utf16.Encode([]int(s))
+	utf16be := make([]byte, len(utf16data)*2)
+	for i := 0; i < len(utf16data); i++ {
+		utf16be[i*2] = byte(utf16data[i] >> 8)
+		utf16be[i*2+1] = byte(utf16data[i] & 0xff)
+	}
+	base64data := make([]byte, maildirBase64.EncodedLen(len(utf16be))+2)
+	maildirBase64.Encode(base64data[1:], utf16be)
+	endPos := bytes.IndexByte(base64data, byte('='))
+	if endPos == -1 {
+		endPos = len(base64data)
+	} else {
+		endPos++
+	}
+	base64data = base64data[:endPos]
+	base64data[0] = byte('&')
+	base64data[len(base64data)-1] = byte('-')
+	buf.Write(base64data)
+}
+
+// s in a string of invalid chars
+// "&" is not encoded in a sequence, and must be encoded as "&-",
+// so split s as sequences of [^&]* separated by "&" characters
+func encode(s string, buf *bytes.Buffer) {
+	if s[0] == byte('&') {
+		buf.WriteString("&-")
+		if len(s) > 1 {
+			encode(s[1:], buf)
+		}
+	} else {
+		i := strings.Index(s, "&")
+		if i != -1 {
+			encodeSequence(s[:i], buf)
+			encode(s[i:], buf)
+		} else {
+			encodeSequence(s, buf)
+		}
+	}
+}