mirror of
https://github.com/rclone/rclone.git
synced 2024-11-26 02:09:55 +08:00
634 lines
16 KiB
Go
634 lines
16 KiB
Go
/*
|
||
Translate file names for usage on restrictive storage systems
|
||
|
||
The restricted set of characters are mapped to a unicode equivalent version
|
||
(most to their FULLWIDTH variant) to increase compatability with other
|
||
storage systems.
|
||
See: http://unicode-search.net/unicode-namesearch.pl?term=FULLWIDTH
|
||
|
||
Encoders will also quote reserved characters to differentiate between
|
||
the raw and encoded forms.
|
||
*/
|
||
|
||
package encoder
|
||
|
||
import (
|
||
"bytes"
|
||
"fmt"
|
||
"io"
|
||
"strconv"
|
||
"strings"
|
||
"unicode/utf8"
|
||
)
|
||
|
||
const (
|
||
// adding this to any printable ASCII character turns it into the
|
||
// FULLWIDTH variant
|
||
fullOffset = 0xFEE0
|
||
// the first rune of the SYMBOL FOR block for control characters
|
||
symbolOffset = '␀' // SYMBOL FOR NULL
|
||
// QuoteRune is the rune used for quoting reserved characters
|
||
QuoteRune = '‛' // SINGLE HIGH-REVERSED-9 QUOTATION MARK
|
||
// EncodeStandard contains the flags used for the Standard Encoder
|
||
EncodeStandard = EncodeZero | EncodeSlash | EncodeCtl | EncodeDel
|
||
// Standard defines the encoding that is used for paths in- and output by rclone.
|
||
//
|
||
// List of replaced characters:
|
||
// (0x00) -> '␀' // SYMBOL FOR NULL
|
||
// / (slash) -> '／' // FULLWIDTH SOLIDUS
|
||
Standard = MultiEncoder(EncodeStandard)
|
||
)
|
||
|
||
// Possible flags for the MultiEncoder
|
||
const (
|
||
EncodeZero uint = 0 // NUL(0x00)
|
||
EncodeSlash uint = 1 << iota // /
|
||
EncodeWin // :?"*<>|
|
||
EncodeBackSlash // \
|
||
EncodeHashPercent // #%
|
||
EncodeDel // DEL(0x7F)
|
||
EncodeCtl // CTRL(0x01-0x1F)
|
||
EncodeLeftSpace // Leading SPACE
|
||
EncodeLeftTilde // Leading ~
|
||
EncodeRightSpace // Trailing SPACE
|
||
EncodeRightPeriod // Trailing .
|
||
EncodeInvalidUtf8 // Invalid UTF-8 bytes
|
||
)
|
||
|
||
// Encoder can transform names to and from the original and translated version.
|
||
type Encoder interface {
|
||
// Encode takes a raw name and substitutes any reserved characters and
|
||
// patterns in it
|
||
Encode(string) string
|
||
// Decode takes a name and undoes any substitutions made by Encode
|
||
Decode(string) string
|
||
|
||
// FromStandardPath takes a / separated path in Standard encoding
|
||
// and converts it to a / separated path in this encoding.
|
||
FromStandardPath(string) string
|
||
// FromStandardName takes name in Standard encoding and converts
|
||
// it in this encoding.
|
||
FromStandardName(string) string
|
||
// ToStandardPath takes a / separated path in this encoding
|
||
// and converts it to a / separated path in Standard encoding.
|
||
ToStandardPath(string) string
|
||
// ToStandardName takes name in this encoding and converts
|
||
// it in Standard encoding.
|
||
ToStandardName(string) string
|
||
}
|
||
|
||
// MultiEncoder is a configurable Encoder. The Encode* constants in this
|
||
// package can be combined using bitwise or (|) to enable handling of multiple
|
||
// character classes
|
||
type MultiEncoder uint
|
||
|
||
// Encode takes a raw name and substitutes any reserved characters and
|
||
// patterns in it
|
||
func (mask MultiEncoder) Encode(in string) string {
|
||
var (
|
||
encodeWin = uint(mask)&EncodeWin != 0
|
||
encodeSlash = uint(mask)&EncodeSlash != 0
|
||
encodeBackSlash = uint(mask)&EncodeBackSlash != 0
|
||
encodeHashPercent = uint(mask)&EncodeHashPercent != 0
|
||
encodeDel = uint(mask)&EncodeDel != 0
|
||
encodeCtl = uint(mask)&EncodeCtl != 0
|
||
encodeLeftSpace = uint(mask)&EncodeLeftSpace != 0
|
||
encodeLeftTilde = uint(mask)&EncodeLeftTilde != 0
|
||
encodeRightSpace = uint(mask)&EncodeRightSpace != 0
|
||
encodeRightPeriod = uint(mask)&EncodeRightPeriod != 0
|
||
encodeInvalidUnicode = uint(mask)&EncodeInvalidUtf8 != 0
|
||
)
|
||
|
||
// handle prefix only replacements
|
||
prefix := ""
|
||
if encodeLeftSpace && len(in) > 0 { // Leading SPACE
|
||
if in[0] == ' ' {
|
||
prefix, in = "␠", in[1:] // SYMBOL FOR SPACE
|
||
} else if r, l := utf8.DecodeRuneInString(in); r == '␠' { // SYMBOL FOR SPACE
|
||
prefix, in = string(QuoteRune)+"␠", in[l:] // SYMBOL FOR SPACE
|
||
}
|
||
}
|
||
if encodeLeftTilde && len(in) > 0 { // Leading ~
|
||
if in[0] == '~' {
|
||
prefix, in = string('~'+fullOffset), in[1:] // FULLWIDTH TILDE
|
||
} else if r, l := utf8.DecodeRuneInString(in); r == '~'+fullOffset {
|
||
prefix, in = string(QuoteRune)+string('~'+fullOffset), in[l:] // FULLWIDTH TILDE
|
||
}
|
||
}
|
||
// handle suffix only replacements
|
||
suffix := ""
|
||
if encodeRightSpace && len(in) > 0 { // Trailing SPACE
|
||
if in[len(in)-1] == ' ' {
|
||
suffix, in = "␠", in[:len(in)-1] // SYMBOL FOR SPACE
|
||
} else if r, l := utf8.DecodeLastRuneInString(in); r == '␠' {
|
||
suffix, in = string(QuoteRune)+"␠", in[:len(in)-l] // SYMBOL FOR SPACE
|
||
}
|
||
}
|
||
if encodeRightPeriod && len(in) > 0 { // Trailing .
|
||
if in[len(in)-1] == '.' {
|
||
suffix, in = "．", in[:len(in)-1] // FULLWIDTH FULL STOP
|
||
} else if r, l := utf8.DecodeLastRuneInString(in); r == '．' {
|
||
suffix, in = string(QuoteRune)+"．", in[:len(in)-l] // FULLWIDTH FULL STOP
|
||
}
|
||
}
|
||
index := 0
|
||
if prefix == "" && suffix == "" {
|
||
// find the first rune which (most likely) needs to be replaced
|
||
index = strings.IndexFunc(in, func(r rune) bool {
|
||
switch r {
|
||
case 0, '␀', QuoteRune, utf8.RuneError:
|
||
return true
|
||
}
|
||
if encodeWin { // :?"*<>|
|
||
switch r {
|
||
case '*', '<', '>', '?', ':', '|', '"',
|
||
'＊', '＜', '＞', '？', '：', '｜', '＂':
|
||
return true
|
||
}
|
||
}
|
||
if encodeSlash { // /
|
||
switch r {
|
||
case '/',
|
||
'／':
|
||
return true
|
||
}
|
||
}
|
||
if encodeBackSlash { // \
|
||
switch r {
|
||
case '\\',
|
||
'＼':
|
||
return true
|
||
}
|
||
}
|
||
if encodeHashPercent { // #%
|
||
switch r {
|
||
case '#', '%',
|
||
'＃', '％':
|
||
return true
|
||
}
|
||
}
|
||
if encodeDel { // DEL(0x7F)
|
||
switch r {
|
||
case rune(0x7F), '␡':
|
||
return true
|
||
}
|
||
}
|
||
if encodeCtl { // CTRL(0x01-0x1F)
|
||
if r >= 1 && r <= 0x1F {
|
||
return true
|
||
} else if r > symbolOffset && r <= symbolOffset+0x1F {
|
||
return true
|
||
}
|
||
}
|
||
return false
|
||
})
|
||
}
|
||
// nothing to replace, return input
|
||
if index == -1 {
|
||
return in
|
||
}
|
||
|
||
var out bytes.Buffer
|
||
out.Grow(len(in) + len(prefix) + len(suffix))
|
||
out.WriteString(prefix)
|
||
// copy the clean part of the input and skip it
|
||
out.WriteString(in[:index])
|
||
in = in[index:]
|
||
|
||
for i, r := range in {
|
||
switch r {
|
||
case 0:
|
||
out.WriteRune(symbolOffset)
|
||
continue
|
||
case '␀', QuoteRune:
|
||
out.WriteRune(QuoteRune)
|
||
out.WriteRune(r)
|
||
continue
|
||
case utf8.RuneError:
|
||
if encodeInvalidUnicode {
|
||
// only encode invalid sequences and not utf8.RuneError
|
||
if i+3 > len(in) || in[i:i+3] != string(utf8.RuneError) {
|
||
_, l := utf8.DecodeRuneInString(in[i:])
|
||
appendQuotedBytes(&out, in[i:i+l])
|
||
continue
|
||
}
|
||
} else {
|
||
// append the real bytes instead of utf8.RuneError
|
||
_, l := utf8.DecodeRuneInString(in[i:])
|
||
out.WriteString(in[i : i+l])
|
||
continue
|
||
}
|
||
}
|
||
if encodeWin { // :?"*<>|
|
||
switch r {
|
||
case '*', '<', '>', '?', ':', '|', '"':
|
||
out.WriteRune(r + fullOffset)
|
||
continue
|
||
case '＊', '＜', '＞', '？', '：', '｜', '＂':
|
||
out.WriteRune(QuoteRune)
|
||
out.WriteRune(r)
|
||
continue
|
||
}
|
||
}
|
||
if encodeSlash { // /
|
||
switch r {
|
||
case '/':
|
||
out.WriteRune(r + fullOffset)
|
||
continue
|
||
case '／':
|
||
out.WriteRune(QuoteRune)
|
||
out.WriteRune(r)
|
||
continue
|
||
}
|
||
}
|
||
if encodeBackSlash { // \
|
||
switch r {
|
||
case '\\':
|
||
out.WriteRune(r + fullOffset)
|
||
continue
|
||
case '＼':
|
||
out.WriteRune(QuoteRune)
|
||
out.WriteRune(r)
|
||
continue
|
||
}
|
||
}
|
||
if encodeHashPercent { // #%
|
||
switch r {
|
||
case '#', '%':
|
||
out.WriteRune(r + fullOffset)
|
||
continue
|
||
case '＃', '％':
|
||
out.WriteRune(QuoteRune)
|
||
out.WriteRune(r)
|
||
continue
|
||
}
|
||
}
|
||
if encodeDel { // DEL(0x7F)
|
||
switch r {
|
||
case rune(0x7F):
|
||
out.WriteRune('␡') // SYMBOL FOR DELETE
|
||
continue
|
||
case '␡':
|
||
out.WriteRune(QuoteRune)
|
||
out.WriteRune(r)
|
||
continue
|
||
}
|
||
}
|
||
if encodeCtl { // CTRL(0x01-0x1F)
|
||
if r >= 1 && r <= 0x1F {
|
||
out.WriteRune('␀' + r) // SYMBOL FOR NULL
|
||
continue
|
||
} else if r > symbolOffset && r <= symbolOffset+0x1F {
|
||
out.WriteRune(QuoteRune)
|
||
out.WriteRune(r)
|
||
continue
|
||
}
|
||
}
|
||
out.WriteRune(r)
|
||
}
|
||
out.WriteString(suffix)
|
||
return out.String()
|
||
}
|
||
|
||
// Decode takes a name and undoes any substitutions made by Encode
|
||
func (mask MultiEncoder) Decode(in string) string {
|
||
var (
|
||
encodeWin = uint(mask)&EncodeWin != 0
|
||
encodeSlash = uint(mask)&EncodeSlash != 0
|
||
encodeBackSlash = uint(mask)&EncodeBackSlash != 0
|
||
encodeHashPercent = uint(mask)&EncodeHashPercent != 0
|
||
encodeDel = uint(mask)&EncodeDel != 0
|
||
encodeCtl = uint(mask)&EncodeCtl != 0
|
||
encodeLeftSpace = uint(mask)&EncodeLeftSpace != 0
|
||
encodeLeftTilde = uint(mask)&EncodeLeftTilde != 0
|
||
encodeRightSpace = uint(mask)&EncodeRightSpace != 0
|
||
encodeRightPeriod = uint(mask)&EncodeRightPeriod != 0
|
||
encodeInvalidUnicode = uint(mask)&EncodeInvalidUtf8 != 0
|
||
)
|
||
|
||
// handle prefix only replacements
|
||
prefix := ""
|
||
if r, l1 := utf8.DecodeRuneInString(in); encodeLeftSpace && r == '␠' { // SYMBOL FOR SPACE
|
||
prefix, in = " ", in[l1:]
|
||
} else if encodeLeftTilde && r == '～' { // FULLWIDTH TILDE
|
||
prefix, in = "~", in[l1:]
|
||
} else if r == QuoteRune {
|
||
if r, l2 := utf8.DecodeRuneInString(in[l1:]); encodeLeftSpace && r == '␠' { // SYMBOL FOR SPACE
|
||
prefix, in = "␠", in[l1+l2:]
|
||
} else if encodeLeftTilde && r == '～' { // FULLWIDTH TILDE
|
||
prefix, in = "～", in[l1+l2:]
|
||
}
|
||
}
|
||
|
||
// handle suffix only replacements
|
||
suffix := ""
|
||
if r, l := utf8.DecodeLastRuneInString(in); encodeRightSpace && r == '␠' { // SYMBOL FOR SPACE
|
||
in = in[:len(in)-l]
|
||
if r, l2 := utf8.DecodeLastRuneInString(in); r == QuoteRune {
|
||
suffix, in = "␠", in[:len(in)-l2]
|
||
} else {
|
||
suffix = " "
|
||
}
|
||
} else if encodeRightPeriod && r == '．' { // FULLWIDTH FULL STOP
|
||
in = in[:len(in)-l]
|
||
if r, l2 := utf8.DecodeLastRuneInString(in); r == QuoteRune {
|
||
suffix, in = "．", in[:len(in)-l2]
|
||
} else {
|
||
suffix = "."
|
||
}
|
||
}
|
||
index := 0
|
||
if prefix == "" && suffix == "" {
|
||
// find the first rune which (most likely) needs to be replaced
|
||
index = strings.IndexFunc(in, func(r rune) bool {
|
||
switch r {
|
||
case '␀', QuoteRune:
|
||
return true
|
||
}
|
||
if encodeWin { // :?"*<>|
|
||
switch r {
|
||
case '＊', '＜', '＞', '？', '：', '｜', '＂':
|
||
return true
|
||
}
|
||
}
|
||
if encodeSlash { // /
|
||
switch r {
|
||
case '／':
|
||
return true
|
||
}
|
||
}
|
||
if encodeBackSlash { // \
|
||
switch r {
|
||
case '＼':
|
||
return true
|
||
}
|
||
}
|
||
if encodeHashPercent { // #%
|
||
switch r {
|
||
case '＃', '％':
|
||
return true
|
||
}
|
||
}
|
||
if encodeDel { // DEL(0x7F)
|
||
switch r {
|
||
case '␡':
|
||
return true
|
||
}
|
||
}
|
||
if encodeCtl { // CTRL(0x01-0x1F)
|
||
if r > symbolOffset && r <= symbolOffset+0x1F {
|
||
return true
|
||
}
|
||
}
|
||
|
||
return false
|
||
})
|
||
}
|
||
// nothing to replace, return input
|
||
if index == -1 {
|
||
return in
|
||
}
|
||
|
||
var out bytes.Buffer
|
||
out.Grow(len(in))
|
||
out.WriteString(prefix)
|
||
// copy the clean part of the input and skip it
|
||
out.WriteString(in[:index])
|
||
in = in[index:]
|
||
var unquote, unquoteNext, skipNext bool
|
||
|
||
for i, r := range in {
|
||
if skipNext {
|
||
skipNext = false
|
||
continue
|
||
}
|
||
unquote, unquoteNext = unquoteNext, false
|
||
switch r {
|
||
case '␀': // SYMBOL FOR NULL
|
||
if unquote {
|
||
out.WriteRune(r)
|
||
} else {
|
||
out.WriteRune(0)
|
||
}
|
||
continue
|
||
case QuoteRune:
|
||
if unquote {
|
||
out.WriteRune(r)
|
||
} else {
|
||
unquoteNext = true
|
||
}
|
||
continue
|
||
}
|
||
if encodeWin { // :?"*<>|
|
||
switch r {
|
||
case '＊', '＜', '＞', '？', '：', '｜', '＂':
|
||
if unquote {
|
||
out.WriteRune(r)
|
||
} else {
|
||
out.WriteRune(r - fullOffset)
|
||
}
|
||
continue
|
||
}
|
||
}
|
||
if encodeSlash { // /
|
||
switch r {
|
||
case '／': // FULLWIDTH SOLIDUS
|
||
if unquote {
|
||
out.WriteRune(r)
|
||
} else {
|
||
out.WriteRune(r - fullOffset)
|
||
}
|
||
continue
|
||
}
|
||
}
|
||
if encodeBackSlash { // \
|
||
switch r {
|
||
case '＼': // FULLWIDTH REVERSE SOLIDUS
|
||
if unquote {
|
||
out.WriteRune(r)
|
||
} else {
|
||
out.WriteRune(r - fullOffset)
|
||
}
|
||
continue
|
||
}
|
||
}
|
||
if encodeHashPercent { // #%
|
||
switch r {
|
||
case '＃', '％':
|
||
if unquote {
|
||
out.WriteRune(r)
|
||
} else {
|
||
out.WriteRune(r - fullOffset)
|
||
}
|
||
continue
|
||
}
|
||
}
|
||
if encodeDel { // DEL(0x7F)
|
||
switch r {
|
||
case '␡': // SYMBOL FOR DELETE
|
||
if unquote {
|
||
out.WriteRune(r)
|
||
} else {
|
||
out.WriteRune(0x7F)
|
||
}
|
||
continue
|
||
}
|
||
}
|
||
if encodeCtl { // CTRL(0x01-0x1F)
|
||
if r > symbolOffset && r <= symbolOffset+0x1F {
|
||
if unquote {
|
||
out.WriteRune(r)
|
||
} else {
|
||
out.WriteRune(r - symbolOffset)
|
||
}
|
||
continue
|
||
}
|
||
}
|
||
if unquote {
|
||
if encodeInvalidUnicode {
|
||
skipNext = appendUnquotedByte(&out, in[i:])
|
||
if skipNext {
|
||
continue
|
||
}
|
||
}
|
||
out.WriteRune(QuoteRune)
|
||
}
|
||
switch r {
|
||
case utf8.RuneError:
|
||
// append the real bytes instead of utf8.RuneError
|
||
_, l := utf8.DecodeRuneInString(in[i:])
|
||
out.WriteString(in[i : i+l])
|
||
continue
|
||
}
|
||
|
||
out.WriteRune(r)
|
||
}
|
||
if unquoteNext {
|
||
out.WriteRune(QuoteRune)
|
||
}
|
||
out.WriteString(suffix)
|
||
return out.String()
|
||
}
|
||
|
||
// FromStandardPath takes a / separated path in Standard encoding
|
||
// and converts it to a / separated path in this encoding.
|
||
func (mask MultiEncoder) FromStandardPath(s string) string {
|
||
return FromStandardPath(mask, s)
|
||
}
|
||
|
||
// FromStandardName takes name in Standard encoding and converts
|
||
// it in this encoding.
|
||
func (mask MultiEncoder) FromStandardName(s string) string {
|
||
return FromStandardName(mask, s)
|
||
}
|
||
|
||
// ToStandardPath takes a / separated path in this encoding
|
||
// and converts it to a / separated path in Standard encoding.
|
||
func (mask MultiEncoder) ToStandardPath(s string) string {
|
||
return ToStandardPath(mask, s)
|
||
}
|
||
|
||
// ToStandardName takes name in this encoding and converts
|
||
// it in Standard encoding.
|
||
func (mask MultiEncoder) ToStandardName(s string) string {
|
||
return ToStandardName(mask, s)
|
||
}
|
||
|
||
func appendQuotedBytes(w io.Writer, s string) {
|
||
for _, b := range []byte(s) {
|
||
_, _ = fmt.Fprintf(w, string(QuoteRune)+"%02X", b)
|
||
}
|
||
}
|
||
func appendUnquotedByte(w io.Writer, s string) bool {
|
||
if len(s) < 2 {
|
||
return false
|
||
}
|
||
u, err := strconv.ParseUint(s[:2], 16, 8)
|
||
if err != nil {
|
||
return false
|
||
}
|
||
n, _ := w.Write([]byte{byte(u)})
|
||
return n == 1
|
||
}
|
||
|
||
type identity struct{}
|
||
|
||
func (identity) Encode(in string) string { return in }
|
||
func (identity) Decode(in string) string { return in }
|
||
|
||
func (i identity) FromStandardPath(s string) string {
|
||
return FromStandardPath(i, s)
|
||
}
|
||
func (i identity) FromStandardName(s string) string {
|
||
return FromStandardName(i, s)
|
||
}
|
||
func (i identity) ToStandardPath(s string) string {
|
||
return ToStandardPath(i, s)
|
||
}
|
||
func (i identity) ToStandardName(s string) string {
|
||
return ToStandardName(i, s)
|
||
}
|
||
|
||
// Identity returns a Encoder that always returns the input value
|
||
func Identity() Encoder {
|
||
return identity{}
|
||
}
|
||
|
||
// FromStandardPath takes a / separated path in Standard encoding
|
||
// and converts it to a / separated path in the given encoding.
|
||
func FromStandardPath(e Encoder, s string) string {
|
||
if e == Standard {
|
||
return s
|
||
}
|
||
parts := strings.Split(s, "/")
|
||
encoded := make([]string, len(parts))
|
||
changed := false
|
||
for i, p := range parts {
|
||
enc := FromStandardName(e, p)
|
||
changed = changed || enc != p
|
||
encoded[i] = enc
|
||
}
|
||
if !changed {
|
||
return s
|
||
}
|
||
return strings.Join(encoded, "/")
|
||
}
|
||
|
||
// FromStandardName takes name in Standard encoding and converts
|
||
// it in the given encoding.
|
||
func FromStandardName(e Encoder, s string) string {
|
||
if e == Standard {
|
||
return s
|
||
}
|
||
return e.Encode(Standard.Decode(s))
|
||
}
|
||
|
||
// ToStandardPath takes a / separated path in the given encoding
|
||
// and converts it to a / separated path in Standard encoding.
|
||
func ToStandardPath(e Encoder, s string) string {
|
||
if e == Standard {
|
||
return s
|
||
}
|
||
parts := strings.Split(s, "/")
|
||
encoded := make([]string, len(parts))
|
||
changed := false
|
||
for i, p := range parts {
|
||
dec := ToStandardName(e, p)
|
||
changed = changed || dec != p
|
||
encoded[i] = dec
|
||
}
|
||
if !changed {
|
||
return s
|
||
}
|
||
return strings.Join(encoded, "/")
|
||
}
|
||
|
||
// ToStandardName takes name in the given encoding and converts
|
||
// it in Standard encoding.
|
||
func ToStandardName(e Encoder, s string) string {
|
||
if e == Standard {
|
||
return s
|
||
}
|
||
return Standard.Encode(e.Decode(s))
|
||
}
|