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- package fs
- import (
- "crypto/md5"
- "errors"
- "fmt"
- "os"
- "path"
- "sort"
- "strconv"
- "strings"
- "time"
- )
- var ErrPathIsNotDirectory = errors.New("the path is not a directory")
- var ErrMalformedName = errors.New("file name is not recognised")
- var ErrUnknownFlag = errors.New("flag not known")
- type Flag string
- func cat(f []Flag) string {
- sort.Slice(f, func(i, j int) bool { return f[i] < f[j] })
- var list []string
- for _, el := range f {
- list = append(list, string(el))
- }
- return strings.Join(list, "")
- }
- const (
- FlagSeen Flag = "S"
- FlagAnswered = "R"
- FlagFlagged = "F"
- FlagDeleted = "T"
- FlagDraft = "D"
- FlagUnknown = ""
- )
- func flagFromChar(char rune) (Flag, error) {
- switch string(char) {
- case "S":
- return FlagSeen, nil
- case "R":
- return FlagAnswered, nil
- case "F":
- return FlagFlagged, nil
- case "T":
- return FlagDeleted, nil
- case "D":
- return FlagDraft, nil
- default:
- return FlagUnknown, ErrUnknownFlag
- }
- }
- func flagsFromString(flags string) ([]Flag, error) {
- result := []Flag{}
- knownFlags := map[Flag]bool{
- FlagSeen: true,
- FlagAnswered: true,
- FlagFlagged: true,
- FlagDeleted: true,
- FlagDraft: true,
- }
- if flags == "" {
- return result, nil
- }
- for _, f := range flags {
- if flag, err := flagFromChar(f); err != nil {
- return []Flag{}, err
- } else {
- if knownFlags[flag] {
- result = append(result, flag)
- knownFlags[flag] = false
- } else {
- return []Flag{}, ErrMalformedName
- }
- }
- }
- sort.Slice(result, func(i, j int) bool { return result[i] < result[j] })
- return result, nil
- }
- // MailFile holds the information needed to format the name of the file
- // containing a single email. The format is:
- // `<%d_%d.%d.%s>,U=<%d>,FMD5=<%s>:2,<FLAGS>`
- // (logical groups being enclosed by angle brackets) where:
- // - `<%d_%d.%d.%s>` is the concatenation of:
- // * system unix timestamp of arrival time of the message
- // * a progressive number to distinguish messages arrived at once
- // * pid of the current process
- // * hostname of the local machine
- // - `,U=<%d>` holds the UID of the message as decided by the server
- // - `,FMD5=<%s>:2` holds the md5sum of the name of the current mailbox
- // - `,<FLAGS>` carries the flags active on the message
- type MailFile struct {
- timestamp time.Time
- progressive int
- pid int
- hostname string
- uid int
- md5 string
- flags []Flag
- }
- func (m *MailFile) SetUid(uid int) {
- m.uid = uid
- }
- func (m *MailFile) SetMd5(md5sum string) {
- m.md5 = md5sum
- }
- func (m *MailFile) SetMd5FromName(name string) {
- md5sum := md5.Sum([]byte(name))
- m.SetMd5(fmt.Sprintf("%x", md5sum))
- }
- func (m *MailFile) SetFlags(flags []Flag) {
- sort.Slice(flags, func(i, j int) bool { return flags[i] < flags[j] })
- m.flags = flags
- }
- func (m *MailFile) String() string {
- return fmt.Sprintf(
- "%d_%d.%d.%s,U=%d,FMD5=%s:2,%s",
- m.timestamp.Unix(),
- m.progressive,
- m.pid,
- m.hostname,
- m.uid,
- m.md5,
- cat(m.flags),
- )
- }
- func NewMailFile(name string) (*MailFile, error) {
- mailFile := &MailFile{}
- parts := strings.Split(name, ",")
- if len(parts) != 4 {
- return mailFile, ErrMalformedName
- }
- sub1 := strings.Split(parts[0], ".")
- if len(sub1) != 3 {
- return mailFile, ErrMalformedName
- }
- sub2 := strings.Split(sub1[0], "_")
- if len(sub2) != 2 {
- return mailFile, ErrMalformedName
- }
- unix, err := strconv.ParseInt(sub2[0], 10, 64)
- if err != nil {
- return mailFile, err
- }
- mailFile.timestamp = time.Unix(unix, 0)
- progressive, err := strconv.ParseInt(sub2[1], 10, 32)
- if err != nil {
- return mailFile, err
- }
- mailFile.progressive = int(progressive)
- pid, err := strconv.ParseInt(sub1[1], 10, 32)
- if err != nil {
- return mailFile, err
- }
- mailFile.pid = int(pid)
- mailFile.hostname = sub1[2]
- sub3 := strings.Split(parts[1], "=")
- if len(sub3) != 2 || sub3[0] != "U" {
- return mailFile, ErrMalformedName
- }
- uid, err := strconv.ParseInt(sub3[1], 10, 32)
- if err != nil {
- return mailFile, err
- }
- mailFile.uid = int(uid)
- sub4 := strings.Split(parts[2], "=")
- if len(sub4) != 2 || sub4[0] != "FMD5" {
- return mailFile, ErrMalformedName
- }
- sub5 := strings.Split(sub4[1], ":")
- if len(sub5) != 2 || sub5[1] != "2" {
- return mailFile, ErrMalformedName
- }
- mailFile.md5 = sub5[0]
- flags, err := flagsFromString(parts[3])
- if err != nil {
- return mailFile, err
- }
- mailFile.flags = flags
- return mailFile, nil
- }
- type MailDir struct {
- basePath string
- name string
- MailFiles []MailFile
- }
- func NewMailDir(name, basePath string) (*MailDir, error) {
- mailDirPath := path.Join(basePath, name)
- mailDir := &MailDir{basePath: basePath, name: name, MailFiles: []MailFile{}}
- info, err := os.Stat(mailDirPath)
- if err != nil {
- if err == os.ErrNotExist {
- err = os.Mkdir(mailDirPath, 0750)
- }
- }
- if !info.IsDir() {
- return mailDir, ErrPathIsNotDirectory
- }
- return mailDir, err
- }
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