go*: one go module for the repo, no more nested

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

vendor/github.com/luksen/maildir/LICENSE.txt

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Lukas Senger
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/github.com/luksen/maildir/README.mkdn

@@ -0,0 +1,9 @@
+The maildir package provides an interface to mailboxes in the Maildir format.
+
+Documentation can be found online here:
+https://pkg.go.dev/github.com/luksen/maildir
+
+This is what I used as a reference:
+- https://en.wikipedia.org/wiki/Maildir
+- http://www.qmail.org/qmail-manual-html/man5/maildir.html
+- http://cr.yp.to/proto/maildir.html

vendor/github.com/luksen/maildir/go.mod

@@ -0,0 +1,3 @@
+module github.com/luksen/maildir
+
+go 1.15

vendor/github.com/luksen/maildir/maildir.go

@@ -0,0 +1,520 @@
+// The maildir package provides an interface to mailboxes in the Maildir format.
+package maildir
+
+import (
+	"bufio"
+	"bytes"
+	"crypto/rand"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"net/mail"
+	"net/textproto"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"sync/atomic"
+	"time"
+)
+
+// The Separator separates a messages unique key from its flags in the filename.
+// This should only be changed on operating systems where the colon isn't
+// allowed in filenames.
+var Separator rune = ':'
+
+var id int64 = 10000
+
+// CreateMode holds the permissions used when creating a directory.
+const CreateMode = 0700
+
+// A KeyError occurs when a key matches more or less than one message.
+type KeyError struct {
+	Key string // the (invalid) key
+	N   int    // number of matches (!= 1)
+}
+
+func (e *KeyError) Error() string {
+	return "maildir: key " + e.Key + " matches " + strconv.Itoa(e.N) + " files."
+}
+
+// A FlagError occurs when a non-standard info section is encountered.
+type FlagError struct {
+	Info         string // the encountered info section
+	Experimental bool   // info section starts with 1
+}
+
+func (e *FlagError) Error() string {
+	if e.Experimental {
+		return "maildir: experimental info section encountered: " + e.Info[2:]
+	}
+	return "maildir: bad info section encountered: " + e.Info
+}
+
+// A Dir represents a single directory in a Maildir mailbox.
+type Dir string
+
+// Unseen moves messages from new to cur and returns their keys.
+// This means the messages are now known to the application. To find out whether
+// a user has seen a message, use Flags().
+func (d Dir) Unseen() ([]string, error) {
+	f, err := os.Open(filepath.Join(string(d), "new"))
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	names, err := f.Readdirnames(0)
+	if err != nil {
+		return nil, err
+	}
+	var keys []string
+	for _, n := range names {
+		if n[0] != '.' {
+			split := strings.FieldsFunc(n, func(r rune) bool {
+				return r == Separator
+			})
+			key := split[0]
+			info := "2,"
+			// Messages in new shouldn't have an info section but
+			// we act as if, in case some other program didn't
+			// follow the spec.
+			if len(split) > 1 {
+				info = split[1]
+			}
+			keys = append(keys, key)
+			err = os.Rename(filepath.Join(string(d), "new", n),
+				filepath.Join(string(d), "cur", key+string(Separator)+info))
+		}
+	}
+	return keys, err
+}
+
+// UnseenCount returns the number of messages in new without looking at them.
+func (d Dir) UnseenCount() (int, error) {
+	f, err := os.Open(filepath.Join(string(d), "new"))
+	if err != nil {
+		return 0, err
+	}
+	defer f.Close()
+	names, err := f.Readdirnames(0)
+	if err != nil {
+		return 0, err
+	}
+	c := 0
+	for _, n := range names {
+		if n[0] != '.' {
+			c += 1
+		}
+	}
+	return c, nil
+}
+
+// Keys returns a slice of valid keys to access messages by. This only returns
+// keys for messages in cur. Use Unseen to access messages in new. All keys,
+// whether returned here or by Unseen, point to messages in cur.
+func (d Dir) Keys() ([]string, error) {
+	f, err := os.Open(filepath.Join(string(d), "cur"))
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	names, err := f.Readdirnames(0)
+	if err != nil {
+		return nil, err
+	}
+	var keys []string
+	for _, n := range names {
+		if n[0] != '.' {
+			split := strings.FieldsFunc(n, func(r rune) bool {
+				return r == Separator
+			})
+			keys = append(keys, split[0])
+		}
+	}
+	return keys, nil
+}
+
+func fileExists(filename string) bool {
+	finfo, err := os.Stat(filename)
+	return err == nil && finfo.Mode().IsRegular()
+}
+
+var suffices []string = []string{
+	"",
+	"S",
+	"D",
+	"F",
+	"P",
+	"R",
+	"T",
+	"DF",
+	"DP",
+	"DR",
+	"DS",
+	"DT",
+	"FP",
+	"FR",
+	"FS",
+	"FT",
+	"PR",
+	"PS",
+	"PT",
+	"RS",
+	"RT",
+	"ST",
+	"DFP",
+	"DFR",
+	"DFS",
+	"DFT",
+	"DPR",
+	"DPS",
+	"DPT",
+	"DRS",
+	"DRT",
+	"DST",
+	"FPR",
+	"FPS",
+	"FPT",
+	"FRS",
+	"FRT",
+	"FST",
+	"PRS",
+	"PRT",
+	"PST",
+	"RST",
+	"DFPR",
+	"DFPS",
+	"DFPT",
+	"DFRS",
+	"DFRT",
+	"DFST",
+	"DPRS",
+	"DPRT",
+	"DPST",
+	"DRST",
+	"FPRS",
+	"FPRT",
+	"FPST",
+	"FRST",
+	"PRST",
+	"DFPRS",
+	"DFPRT",
+	"DFPST",
+	"DFRST",
+	"DPRST",
+	"FPRST",
+	"DFPRST"}
+
+// quick check for existance of legal (per DJB) file names for a key
+func (d Dir) quickFilename(key string) string {
+	// "cur" files must have :info suffix
+	filePrefix := filepath.Join(string(d), "cur", key+string(Separator)+"2,")
+	for _, suffix := range suffices {
+		if filename := filePrefix + suffix; fileExists(filename) {
+			return filename
+		}
+	}
+	return ""
+}
+
+// Filename returns the path to the file corresponding to the key.
+func (d Dir) Filename(key string) (string, error) {
+	if matchedFile := d.quickFilename(key); matchedFile != "" {
+		return matchedFile, nil
+	}
+	dirPath := filepath.Join(string(d), "cur")
+	f, err := os.Open(dirPath)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+	names, err := f.Readdirnames(-1)
+	if err != nil {
+		return "", err
+	}
+	for _, name := range names {
+		if strings.HasPrefix(name, key) {
+			return filepath.Join(dirPath, name), nil
+		}
+	}
+	return "", &KeyError{key, 0}
+}
+
+// Header returns the corresponding mail header to a key.
+func (d Dir) Header(key string) (header mail.Header, err error) {
+	filename, err := d.Filename(key)
+	if err != nil {
+		return
+	}
+	file, err := os.Open(filename)
+	if err != nil {
+		return
+	}
+	defer file.Close()
+	tp := textproto.NewReader(bufio.NewReader(file))
+	hdr, err := tp.ReadMIMEHeader()
+	if err != nil {
+		return
+	}
+	header = mail.Header(hdr)
+	return
+}
+
+// Message returns a Message by key.
+func (d Dir) Message(key string) (*mail.Message, error) {
+	filename, err := d.Filename(key)
+	if err != nil {
+		return &mail.Message{}, err
+	}
+	r, err := os.Open(filename)
+	if err != nil {
+		return &mail.Message{}, err
+	}
+	defer r.Close()
+	buf := new(bytes.Buffer)
+	_, err = io.Copy(buf, r)
+	if err != nil {
+		return &mail.Message{}, err
+	}
+	msg, err := mail.ReadMessage(buf)
+	if err != nil {
+		return msg, err
+	}
+	return msg, nil
+}
+
+type runeSlice []rune
+
+func (s runeSlice) Len() int           { return len(s) }
+func (s runeSlice) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s runeSlice) Less(i, j int) bool { return s[i] < s[j] }
+
+// Flags returns the flags for a message sorted in ascending order.
+// See the documentation of SetFlags for details.
+func (d Dir) Flags(key string) (string, error) {
+	filename, err := d.Filename(key)
+	if err != nil {
+		return "", err
+	}
+	split := strings.FieldsFunc(filename, func(r rune) bool {
+		return r == Separator
+	})
+	switch {
+	case len(split[1]) < 2,
+		split[1][1] != ',':
+		return "", &FlagError{split[1], false}
+	case split[1][0] == '1':
+		return "", &FlagError{split[1], true}
+	case split[1][0] != '2':
+		return "", &FlagError{split[1], false}
+	}
+	rs := runeSlice(split[1][2:])
+	sort.Sort(rs)
+	return string(rs), nil
+}
+
+// SetFlags appends an info section to the filename according to the given flags.
+// This function removes duplicates and sorts the flags, but doesn't check
+// whether they conform with the Maildir specification.
+//
+// The following flags are listed in the specification
+// (http://cr.yp.to/proto/maildir.html):
+//
+//	Flag "P" (passed): the user has resent/forwarded/bounced this message to someone else.
+//	Flag "R" (replied): the user has replied to this message.
+//	Flag "S" (seen): the user has viewed this message, though perhaps he didn't read all the way through it.
+//	Flag "T" (trashed): the user has moved this message to the trash; the trash will be emptied by a later user action.
+//	Flag "D" (draft): the user considers this message a draft; toggled at user discretion.
+//	Flag "F" (flagged): user-defined flag; toggled at user discretion.
+//
+// Using only these standard flags will improve message retrieval speed.
+func (d Dir) SetFlags(key string, flags string) error {
+	info := "2,"
+	rs := runeSlice(flags)
+	sort.Sort(rs)
+	for _, r := range rs {
+		if []rune(info)[len(info)-1] != r {
+			info += string(r)
+		}
+	}
+	return d.SetInfo(key, info)
+}
+
+// Set the info part of the filename.
+// Only use this if you plan on using a non-standard info part.
+func (d Dir) SetInfo(key, info string) error {
+	filename, err := d.Filename(key)
+	if err != nil {
+		return err
+	}
+	err = os.Rename(filename, filepath.Join(string(d), "cur", key+
+		string(Separator)+info))
+	return err
+}
+
+// Key exposes the internal unique key generation. This function is deprecated.
+func Key() (string, error) {
+	fmt.Println("maildir: Key() is deprecated without replacement. See https://github.com/luksen/maildir/issues/5 for details.")
+	return generateKey()
+}
+
+// generateKey generates a new unique key as described in the Maildir
+// specification.  For the third part of the key (delivery identifier) it uses
+// an internal counter, the process id and a cryptographical random number to
+// ensure uniqueness among messages delivered in the same second.
+func generateKey() (string, error) {
+	var key string
+	key += strconv.FormatInt(time.Now().Unix(), 10)
+	key += "."
+	host, err := os.Hostname()
+	if err != err {
+		return "", err
+	}
+	host = strings.Replace(host, "/", "\057", -1)
+	host = strings.Replace(host, string(Separator), "\072", -1)
+	key += host
+	key += "."
+	key += strconv.FormatInt(int64(os.Getpid()), 10)
+	key += strconv.FormatInt(id, 10)
+	atomic.AddInt64(&id, 1)
+	bs := make([]byte, 10)
+	_, err = io.ReadFull(rand.Reader, bs)
+	if err != nil {
+		return "", err
+	}
+	key += hex.EncodeToString(bs)
+	return key, nil
+}
+
+// Create creates the directory structure for a Maildir.
+// If the main directory already exists, it tries to create the subdirectories
+// in there. If an error occurs while creating one of the subdirectories, this
+// function may leave a partially created directory structure.
+func (d Dir) Create() error {
+	err := os.Mkdir(string(d), os.ModeDir|CreateMode)
+	if err != nil && !os.IsExist(err) {
+		return err
+	}
+	err = os.Mkdir(filepath.Join(string(d), "tmp"), os.ModeDir|CreateMode)
+	if err != nil && !os.IsExist(err) {
+		return err
+	}
+	err = os.Mkdir(filepath.Join(string(d), "new"), os.ModeDir|CreateMode)
+	if err != nil && !os.IsExist(err) {
+		return err
+	}
+	err = os.Mkdir(filepath.Join(string(d), "cur"), os.ModeDir|CreateMode)
+	if err != nil && !os.IsExist(err) {
+		return err
+	}
+	return nil
+}
+
+// Delivery represents an ongoing message delivery to the mailbox.
+// It implements the WriteCloser interface. On closing the underlying file is
+// moved/relinked to new.
+type Delivery struct {
+	file *os.File
+	d    Dir
+	key  string
+}
+
+// NewDelivery creates a new Delivery.
+func (d Dir) NewDelivery() (*Delivery, error) {
+	key, err := generateKey()
+	if err != nil {
+		return nil, err
+	}
+	del := &Delivery{}
+	time.AfterFunc(24*time.Hour, func() { del.Abort() })
+	file, err := os.Create(filepath.Join(string(d), "tmp", key))
+	if err != nil {
+		return nil, err
+	}
+	del.file = file
+	del.d = d
+	del.key = key
+	return del, nil
+}
+
+func (d *Delivery) Write(p []byte) (int, error) {
+	return d.file.Write(p)
+}
+
+// Close closes the underlying file and moves it to new.
+func (d *Delivery) Close() error {
+	err := d.file.Close()
+	if err != nil {
+		return err
+	}
+	err = os.Link(filepath.Join(string(d.d), "tmp", d.key),
+		filepath.Join(string(d.d), "new", d.key))
+	if err != nil {
+		return err
+	}
+	err = os.Remove(filepath.Join(string(d.d), "tmp", d.key))
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// Abort closes the underlying file and removes it completely.
+func (d *Delivery) Abort() error {
+	err := d.file.Close()
+	if err != nil {
+		return err
+	}
+	err = os.Remove(filepath.Join(string(d.d), "tmp", d.key))
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// Move moves a message from this Maildir to another.
+func (d Dir) Move(target Dir, key string) error {
+	path, err := d.Filename(key)
+	if err != nil {
+		return err
+	}
+	return os.Rename(path, filepath.Join(string(target), "cur", filepath.Base(path)))
+}
+
+// Purge removes the actual file behind this message.
+func (d Dir) Purge(key string) error {
+	f, err := d.Filename(key)
+	if err != nil {
+		return err
+	}
+	return os.Remove(f)
+}
+
+// Clean removes old files from tmp and should be run periodically.
+// This does not use access time but modification time for portability reasons.
+func (d Dir) Clean() error {
+	f, err := os.Open(filepath.Join(string(d), "tmp"))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	names, err := f.Readdirnames(0)
+	if err != nil {
+		return err
+	}
+	now := time.Now()
+	for _, n := range names {
+		fi, err := os.Stat(filepath.Join(string(d), "tmp", n))
+		if err != nil {
+			continue
+		}
+		if now.Sub(fi.ModTime()).Hours() > 36 {
+			err = os.Remove(filepath.Join(string(d), "tmp", n))
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}