Ydb stable 22-4-4322.4.43

x-stable-origin-commit: 8d49d46cc834835bf3e50870516acd7376a63bcf

10 files changed, 2295 insertions, 0 deletions

diff --git a/contrib/go/_std_1.18/src/mime/encodedword.go b/contrib/go/_std_1.18/src/mime/encodedword.go
new file mode 100644
index 0000000000..e6b470b1fb
--- /dev/null
+++ b/contrib/go/_std_1.18/src/mime/encodedword.go
@@ -0,0 +1,414 @@
+// 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"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+// A WordEncoder is an RFC 2047 encoded-word encoder.
+type WordEncoder byte
+
+const (
+	// BEncoding represents Base64 encoding scheme as defined by RFC 2045.
+	BEncoding = WordEncoder('b')
+	// QEncoding represents the Q-encoding scheme as defined by RFC 2047.
+	QEncoding = WordEncoder('q')
+)
+
+var (
+	errInvalidWord = errors.New("mime: invalid RFC 2047 encoded-word")
+)
+
+// Encode returns the encoded-word form of s. If s is ASCII without special
+// characters, it is returned unchanged. The provided charset is the IANA
+// charset name of s. It is case insensitive.
+func (e WordEncoder) Encode(charset, s string) string {
+	if !needsEncoding(s) {
+		return s
+	}
+	return e.encodeWord(charset, s)
+}
+
+func needsEncoding(s string) bool {
+	for _, b := range s {
+		if (b < ' ' || b > '~') && b != '\t' {
+			return true
+		}
+	}
+	return false
+}
+
+// encodeWord encodes a string into an encoded-word.
+func (e WordEncoder) encodeWord(charset, s string) string {
+	var buf strings.Builder
+	// Could use a hint like len(s)*3, but that's not enough for cases
+	// with word splits and too much for simpler inputs.
+	// 48 is close to maxEncodedWordLen/2, but adjusted to allocator size class.
+	buf.Grow(48)
+
+	e.openWord(&buf, charset)
+	if e == BEncoding {
+		e.bEncode(&buf, charset, s)
+	} else {
+		e.qEncode(&buf, charset, s)
+	}
+	closeWord(&buf)
+
+	return buf.String()
+}
+
+const (
+	// The maximum length of an encoded-word is 75 characters.
+	// See RFC 2047, section 2.
+	maxEncodedWordLen = 75
+	// maxContentLen is how much content can be encoded, ignoring the header and
+	// 2-byte footer.
+	maxContentLen = maxEncodedWordLen - len("=?UTF-8?q?") - len("?=")
+)
+
+var maxBase64Len = base64.StdEncoding.DecodedLen(maxContentLen)
+
+// bEncode encodes s using base64 encoding and writes it to buf.
+func (e WordEncoder) bEncode(buf *strings.Builder, charset, s string) {
+	w := base64.NewEncoder(base64.StdEncoding, buf)
+	// If the charset is not UTF-8 or if the content is short, do not bother
+	// splitting the encoded-word.
+	if !isUTF8(charset) || base64.StdEncoding.EncodedLen(len(s)) <= maxContentLen {
+		io.WriteString(w, s)
+		w.Close()
+		return
+	}
+
+	var currentLen, last, runeLen int
+	for i := 0; i < len(s); i += runeLen {
+		// Multi-byte characters must not be split across encoded-words.
+		// See RFC 2047, section 5.3.
+		_, runeLen = utf8.DecodeRuneInString(s[i:])
+
+		if currentLen+runeLen <= maxBase64Len {
+			currentLen += runeLen
+		} else {
+			io.WriteString(w, s[last:i])
+			w.Close()
+			e.splitWord(buf, charset)
+			last = i
+			currentLen = runeLen
+		}
+	}
+	io.WriteString(w, s[last:])
+	w.Close()
+}
+
+// qEncode encodes s using Q encoding and writes it to buf. It splits the
+// encoded-words when necessary.
+func (e WordEncoder) qEncode(buf *strings.Builder, charset, s string) {
+	// We only split encoded-words when the charset is UTF-8.
+	if !isUTF8(charset) {
+		writeQString(buf, s)
+		return
+	}
+
+	var currentLen, runeLen int
+	for i := 0; i < len(s); i += runeLen {
+		b := s[i]
+		// Multi-byte characters must not be split across encoded-words.
+		// See RFC 2047, section 5.3.
+		var encLen int
+		if b >= ' ' && b <= '~' && b != '=' && b != '?' && b != '_' {
+			runeLen, encLen = 1, 1
+		} else {
+			_, runeLen = utf8.DecodeRuneInString(s[i:])
+			encLen = 3 * runeLen
+		}
+
+		if currentLen+encLen > maxContentLen {
+			e.splitWord(buf, charset)
+			currentLen = 0
+		}
+		writeQString(buf, s[i:i+runeLen])
+		currentLen += encLen
+	}
+}
+
+// writeQString encodes s using Q encoding and writes it to buf.
+func writeQString(buf *strings.Builder, s string) {
+	for i := 0; i < len(s); i++ {
+		switch b := s[i]; {
+		case b == ' ':
+			buf.WriteByte('_')
+		case b >= '!' && b <= '~' && b != '=' && b != '?' && b != '_':
+			buf.WriteByte(b)
+		default:
+			buf.WriteByte('=')
+			buf.WriteByte(upperhex[b>>4])
+			buf.WriteByte(upperhex[b&0x0f])
+		}
+	}
+}
+
+// openWord writes the beginning of an encoded-word into buf.
+func (e WordEncoder) openWord(buf *strings.Builder, charset string) {
+	buf.WriteString("=?")
+	buf.WriteString(charset)
+	buf.WriteByte('?')
+	buf.WriteByte(byte(e))
+	buf.WriteByte('?')
+}
+
+// closeWord writes the end of an encoded-word into buf.
+func closeWord(buf *strings.Builder) {
+	buf.WriteString("?=")
+}
+
+// splitWord closes the current encoded-word and opens a new one.
+func (e WordEncoder) splitWord(buf *strings.Builder, charset string) {
+	closeWord(buf)
+	buf.WriteByte(' ')
+	e.openWord(buf, charset)
+}
+
+func isUTF8(charset string) bool {
+	return strings.EqualFold(charset, "UTF-8")
+}
+
+const upperhex = "0123456789ABCDEF"
+
+// A WordDecoder decodes MIME headers containing RFC 2047 encoded-words.
+type WordDecoder struct {
+	// CharsetReader, if non-nil, defines a function to generate
+	// charset-conversion readers, converting from the provided
+	// charset into UTF-8.
+	// Charsets are always lower-case. utf-8, iso-8859-1 and us-ascii charsets
+	// are handled by default.
+	// One of the CharsetReader's result values must be non-nil.
+	CharsetReader func(charset string, input io.Reader) (io.Reader, error)
+}
+
+// Decode decodes an RFC 2047 encoded-word.
+func (d *WordDecoder) Decode(word string) (string, error) {
+	// See https://tools.ietf.org/html/rfc2047#section-2 for details.
+	// Our decoder is permissive, we accept empty encoded-text.
+	if len(word) < 8 || !strings.HasPrefix(word, "=?") || !strings.HasSuffix(word, "?=") || strings.Count(word, "?") != 4 {
+		return "", errInvalidWord
+	}
+	word = word[2 : len(word)-2]
+
+	// split word "UTF-8?q?text" into "UTF-8", 'q', and "text"
+	charset, text, _ := strings.Cut(word, "?")
+	if charset == "" {
+		return "", errInvalidWord
+	}
+	encoding, text, _ := strings.Cut(text, "?")
+	if len(encoding) != 1 {
+		return "", errInvalidWord
+	}
+
+	content, err := decode(encoding[0], text)
+	if err != nil {
+		return "", err
+	}
+
+	var buf strings.Builder
+	if err := d.convert(&buf, charset, content); err != nil {
+		return "", err
+	}
+	return buf.String(), nil
+}
+
+// DecodeHeader decodes all encoded-words of the given string. It returns an
+// error if and only if CharsetReader of d returns an error.
+func (d *WordDecoder) DecodeHeader(header string) (string, error) {
+	// If there is no encoded-word, returns before creating a buffer.
+	i := strings.Index(header, "=?")
+	if i == -1 {
+		return header, nil
+	}
+
+	var buf strings.Builder
+
+	buf.WriteString(header[:i])
+	header = header[i:]
+
+	betweenWords := false
+	for {
+		start := strings.Index(header, "=?")
+		if start == -1 {
+			break
+		}
+		cur := start + len("=?")
+
+		i := strings.Index(header[cur:], "?")
+		if i == -1 {
+			break
+		}
+		charset := header[cur : cur+i]
+		cur += i + len("?")
+
+		if len(header) < cur+len("Q??=") {
+			break
+		}
+		encoding := header[cur]
+		cur++
+
+		if header[cur] != '?' {
+			break
+		}
+		cur++
+
+		j := strings.Index(header[cur:], "?=")
+		if j == -1 {
+			break
+		}
+		text := header[cur : cur+j]
+		end := cur + j + len("?=")
+
+		content, err := decode(encoding, text)
+		if err != nil {
+			betweenWords = false
+			buf.WriteString(header[:start+2])
+			header = header[start+2:]
+			continue
+		}
+
+		// Write characters before the encoded-word. White-space and newline
+		// characters separating two encoded-words must be deleted.
+		if start > 0 && (!betweenWords || hasNonWhitespace(header[:start])) {
+			buf.WriteString(header[:start])
+		}
+
+		if err := d.convert(&buf, charset, content); err != nil {
+			return "", err
+		}
+
+		header = header[end:]
+		betweenWords = true
+	}
+
+	if len(header) > 0 {
+		buf.WriteString(header)
+	}
+
+	return buf.String(), nil
+}
+
+func decode(encoding byte, text string) ([]byte, error) {
+	switch encoding {
+	case 'B', 'b':
+		return base64.StdEncoding.DecodeString(text)
+	case 'Q', 'q':
+		return qDecode(text)
+	default:
+		return nil, errInvalidWord
+	}
+}
+
+func (d *WordDecoder) convert(buf *strings.Builder, charset string, content []byte) error {
+	switch {
+	case strings.EqualFold("utf-8", charset):
+		buf.Write(content)
+	case strings.EqualFold("iso-8859-1", charset):
+		for _, c := range content {
+			buf.WriteRune(rune(c))
+		}
+	case strings.EqualFold("us-ascii", charset):
+		for _, c := range content {
+			if c >= utf8.RuneSelf {
+				buf.WriteRune(unicode.ReplacementChar)
+			} else {
+				buf.WriteByte(c)
+			}
+		}
+	default:
+		if d.CharsetReader == nil {
+			return fmt.Errorf("mime: unhandled charset %q", charset)
+		}
+		r, err := d.CharsetReader(strings.ToLower(charset), bytes.NewReader(content))
+		if err != nil {
+			return err
+		}
+		if _, err = io.Copy(buf, r); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// hasNonWhitespace reports whether s (assumed to be ASCII) contains at least
+// one byte of non-whitespace.
+func hasNonWhitespace(s string) bool {
+	for _, b := range s {
+		switch b {
+		// Encoded-words can only be separated by linear white spaces which does
+		// not include vertical tabs (\v).
+		case ' ', '\t', '\n', '\r':
+		default:
+			return true
+		}
+	}
+	return false
+}
+
+// qDecode decodes a Q encoded string.
+func qDecode(s string) ([]byte, error) {
+	dec := make([]byte, len(s))
+	n := 0
+	for i := 0; i < len(s); i++ {
+		switch c := s[i]; {
+		case c == '_':
+			dec[n] = ' '
+		case c == '=':
+			if i+2 >= len(s) {
+				return nil, errInvalidWord
+			}
+			b, err := readHexByte(s[i+1], s[i+2])
+			if err != nil {
+				return nil, err
+			}
+			dec[n] = b
+			i += 2
+		case (c <= '~' && c >= ' ') || c == '\n' || c == '\r' || c == '\t':
+			dec[n] = c
+		default:
+			return nil, errInvalidWord
+		}
+		n++
+	}
+
+	return dec[:n], nil
+}
+
+// readHexByte returns the byte from its quoted-printable representation.
+func readHexByte(a, b byte) (byte, error) {
+	var hb, lb byte
+	var err error
+	if hb, err = fromHex(a); err != nil {
+		return 0, err
+	}
+	if lb, err = fromHex(b); err != nil {
+		return 0, err
+	}
+	return hb<<4 | lb, nil
+}
+
+func fromHex(b byte) (byte, error) {
+	switch {
+	case b >= '0' && b <= '9':
+		return b - '0', nil
+	case b >= 'A' && b <= 'F':
+		return b - 'A' + 10, nil
+	// Accept badly encoded bytes.
+	case b >= 'a' && b <= 'f':
+		return b - 'a' + 10, nil
+	}
+	return 0, fmt.Errorf("mime: invalid hex byte %#02x", b)
+}
diff --git a/contrib/go/_std_1.18/src/mime/grammar.go b/contrib/go/_std_1.18/src/mime/grammar.go
new file mode 100644
index 0000000000..6a6f71dbd4
--- /dev/null
+++ b/contrib/go/_std_1.18/src/mime/grammar.go
@@ -0,0 +1,32 @@
+// Copyright 2010 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 (
+	"strings"
+)
+
+// isTSpecial reports whether rune is in 'tspecials' as defined by RFC
+// 1521 and RFC 2045.
+func isTSpecial(r rune) bool {
+	return strings.ContainsRune(`()<>@,;:\"/[]?=`, r)
+}
+
+// isTokenChar reports whether rune is in 'token' as defined by RFC
+// 1521 and RFC 2045.
+func isTokenChar(r rune) bool {
+	// token := 1*<any (US-ASCII) CHAR except SPACE, CTLs,
+	//             or tspecials>
+	return r > 0x20 && r < 0x7f && !isTSpecial(r)
+}
+
+// isToken reports whether s is a 'token' as defined by RFC 1521
+// and RFC 2045.
+func isToken(s string) bool {
+	if s == "" {
+		return false
+	}
+	return strings.IndexFunc(s, isNotTokenChar) < 0
+}
diff --git a/contrib/go/_std_1.18/src/mime/mediatype.go b/contrib/go/_std_1.18/src/mime/mediatype.go
new file mode 100644
index 0000000000..6c1b095065
--- /dev/null
+++ b/contrib/go/_std_1.18/src/mime/mediatype.go
@@ -0,0 +1,410 @@
+// Copyright 2010 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 (
+	"errors"
+	"fmt"
+	"sort"
+	"strings"
+	"unicode"
+)
+
+// FormatMediaType serializes mediatype t and the parameters
+// param as a media type conforming to RFC 2045 and RFC 2616.
+// The type and parameter names are written in lower-case.
+// When any of the arguments result in a standard violation then
+// FormatMediaType returns the empty string.
+func FormatMediaType(t string, param map[string]string) string {
+	var b strings.Builder
+	if major, sub, ok := strings.Cut(t, "/"); !ok {
+		if !isToken(t) {
+			return ""
+		}
+		b.WriteString(strings.ToLower(t))
+	} else {
+		if !isToken(major) || !isToken(sub) {
+			return ""
+		}
+		b.WriteString(strings.ToLower(major))
+		b.WriteByte('/')
+		b.WriteString(strings.ToLower(sub))
+	}
+
+	attrs := make([]string, 0, len(param))
+	for a := range param {
+		attrs = append(attrs, a)
+	}
+	sort.Strings(attrs)
+
+	for _, attribute := range attrs {
+		value := param[attribute]
+		b.WriteByte(';')
+		b.WriteByte(' ')
+		if !isToken(attribute) {
+			return ""
+		}
+		b.WriteString(strings.ToLower(attribute))
+
+		needEnc := needsEncoding(value)
+		if needEnc {
+			// RFC 2231 section 4
+			b.WriteByte('*')
+		}
+		b.WriteByte('=')
+
+		if needEnc {
+			b.WriteString("utf-8''")
+
+			offset := 0
+			for index := 0; index < len(value); index++ {
+				ch := value[index]
+				// {RFC 2231 section 7}
+				// attribute-char := <any (US-ASCII) CHAR except SPACE, CTLs, "*", "'", "%", or tspecials>
+				if ch <= ' ' || ch >= 0x7F ||
+					ch == '*' || ch == '\'' || ch == '%' ||
+					isTSpecial(rune(ch)) {
+
+					b.WriteString(value[offset:index])
+					offset = index + 1
+
+					b.WriteByte('%')
+					b.WriteByte(upperhex[ch>>4])
+					b.WriteByte(upperhex[ch&0x0F])
+				}
+			}
+			b.WriteString(value[offset:])
+			continue
+		}
+
+		if isToken(value) {
+			b.WriteString(value)
+			continue
+		}
+
+		b.WriteByte('"')
+		offset := 0
+		for index := 0; index < len(value); index++ {
+			character := value[index]
+			if character == '"' || character == '\\' {
+				b.WriteString(value[offset:index])
+				offset = index
+				b.WriteByte('\\')
+			}
+		}
+		b.WriteString(value[offset:])
+		b.WriteByte('"')
+	}
+	return b.String()
+}
+
+func checkMediaTypeDisposition(s string) error {
+	typ, rest := consumeToken(s)
+	if typ == "" {
+		return errors.New("mime: no media type")
+	}
+	if rest == "" {
+		return nil
+	}
+	if !strings.HasPrefix(rest, "/") {
+		return errors.New("mime: expected slash after first token")
+	}
+	subtype, rest := consumeToken(rest[1:])
+	if subtype == "" {
+		return errors.New("mime: expected token after slash")
+	}
+	if rest != "" {
+		return errors.New("mime: unexpected content after media subtype")
+	}
+	return nil
+}
+
+// ErrInvalidMediaParameter is returned by ParseMediaType if
+// the media type value was found but there was an error parsing
+// the optional parameters
+var ErrInvalidMediaParameter = errors.New("mime: invalid media parameter")
+
+// ParseMediaType parses a media type value and any optional
+// parameters, per RFC 1521.  Media types are the values in
+// Content-Type and Content-Disposition headers (RFC 2183).
+// On success, ParseMediaType returns the media type converted
+// to lowercase and trimmed of white space and a non-nil map.
+// If there is an error parsing the optional parameter,
+// the media type will be returned along with the error
+// ErrInvalidMediaParameter.
+// The returned map, params, maps from the lowercase
+// attribute to the attribute value with its case preserved.
+func ParseMediaType(v string) (mediatype string, params map[string]string, err error) {
+	base, _, _ := strings.Cut(v, ";")
+	mediatype = strings.TrimSpace(strings.ToLower(base))
+
+	err = checkMediaTypeDisposition(mediatype)
+	if err != nil {
+		return "", nil, err
+	}
+
+	params = make(map[string]string)
+
+	// Map of base parameter name -> parameter name -> value
+	// for parameters containing a '*' character.
+	// Lazily initialized.
+	var continuation map[string]map[string]string
+
+	v = v[len(base):]
+	for len(v) > 0 {
+		v = strings.TrimLeftFunc(v, unicode.IsSpace)
+		if len(v) == 0 {
+			break
+		}
+		key, value, rest := consumeMediaParam(v)
+		if key == "" {
+			if strings.TrimSpace(rest) == ";" {
+				// Ignore trailing semicolons.
+				// Not an error.
+				break
+			}
+			// Parse error.
+			return mediatype, nil, ErrInvalidMediaParameter
+		}
+
+		pmap := params
+		if baseName, _, ok := strings.Cut(key, "*"); ok {
+			if continuation == nil {
+				continuation = make(map[string]map[string]string)
+			}
+			var ok bool
+			if pmap, ok = continuation[baseName]; !ok {
+				continuation[baseName] = make(map[string]string)
+				pmap = continuation[baseName]
+			}
+		}
+		if _, exists := pmap[key]; exists {
+			// Duplicate parameter name is bogus.
+			return "", nil, errors.New("mime: duplicate parameter name")
+		}
+		pmap[key] = value
+		v = rest
+	}
+
+	// Stitch together any continuations or things with stars
+	// (i.e. RFC 2231 things with stars: "foo*0" or "foo*")
+	var buf strings.Builder
+	for key, pieceMap := range continuation {
+		singlePartKey := key + "*"
+		if v, ok := pieceMap[singlePartKey]; ok {
+			if decv, ok := decode2231Enc(v); ok {
+				params[key] = decv
+			}
+			continue
+		}
+
+		buf.Reset()
+		valid := false
+		for n := 0; ; n++ {
+			simplePart := fmt.Sprintf("%s*%d", key, n)
+			if v, ok := pieceMap[simplePart]; ok {
+				valid = true
+				buf.WriteString(v)
+				continue
+			}
+			encodedPart := simplePart + "*"
+			v, ok := pieceMap[encodedPart]
+			if !ok {
+				break
+			}
+			valid = true
+			if n == 0 {
+				if decv, ok := decode2231Enc(v); ok {
+					buf.WriteString(decv)
+				}
+			} else {
+				decv, _ := percentHexUnescape(v)
+				buf.WriteString(decv)
+			}
+		}
+		if valid {
+			params[key] = buf.String()
+		}
+	}
+
+	return
+}
+
+func decode2231Enc(v string) (string, bool) {
+	sv := strings.SplitN(v, "'", 3)
+	if len(sv) != 3 {
+		return "", false
+	}
+	// TODO: ignoring lang in sv[1] for now. If anybody needs it we'll
+	// need to decide how to expose it in the API. But I'm not sure
+	// anybody uses it in practice.
+	charset := strings.ToLower(sv[0])
+	if len(charset) == 0 {
+		return "", false
+	}
+	if charset != "us-ascii" && charset != "utf-8" {
+		// TODO: unsupported encoding
+		return "", false
+	}
+	encv, err := percentHexUnescape(sv[2])
+	if err != nil {
+		return "", false
+	}
+	return encv, true
+}
+
+func isNotTokenChar(r rune) bool {
+	return !isTokenChar(r)
+}
+
+// consumeToken consumes a token from the beginning of provided
+// string, per RFC 2045 section 5.1 (referenced from 2183), and return
+// the token consumed and the rest of the string. Returns ("", v) on
+// failure to consume at least one character.
+func consumeToken(v string) (token, rest string) {
+	notPos := strings.IndexFunc(v, isNotTokenChar)
+	if notPos == -1 {
+		return v, ""
+	}
+	if notPos == 0 {
+		return "", v
+	}
+	return v[0:notPos], v[notPos:]
+}
+
+// consumeValue consumes a "value" per RFC 2045, where a value is
+// either a 'token' or a 'quoted-string'.  On success, consumeValue
+// returns the value consumed (and de-quoted/escaped, if a
+// quoted-string) and the rest of the string. On failure, returns
+// ("", v).
+func consumeValue(v string) (value, rest string) {
+	if v == "" {
+		return
+	}
+	if v[0] != '"' {
+		return consumeToken(v)
+	}
+
+	// parse a quoted-string
+	buffer := new(strings.Builder)
+	for i := 1; i < len(v); i++ {
+		r := v[i]
+		if r == '"' {
+			return buffer.String(), v[i+1:]
+		}
+		// When MSIE sends a full file path (in "intranet mode"), it does not
+		// escape backslashes: "C:\dev\go\foo.txt", not "C:\\dev\\go\\foo.txt".
+		//
+		// No known MIME generators emit unnecessary backslash escapes
+		// for simple token characters like numbers and letters.
+		//
+		// If we see an unnecessary backslash escape, assume it is from MSIE
+		// and intended as a literal backslash. This makes Go servers deal better
+		// with MSIE without affecting the way they handle conforming MIME
+		// generators.
+		if r == '\\' && i+1 < len(v) && isTSpecial(rune(v[i+1])) {
+			buffer.WriteByte(v[i+1])
+			i++
+			continue
+		}
+		if r == '\r' || r == '\n' {
+			return "", v
+		}
+		buffer.WriteByte(v[i])
+	}
+	// Did not find end quote.
+	return "", v
+}
+
+func consumeMediaParam(v string) (param, value, rest string) {
+	rest = strings.TrimLeftFunc(v, unicode.IsSpace)
+	if !strings.HasPrefix(rest, ";") {
+		return "", "", v
+	}
+
+	rest = rest[1:] // consume semicolon
+	rest = strings.TrimLeftFunc(rest, unicode.IsSpace)
+	param, rest = consumeToken(rest)
+	param = strings.ToLower(param)
+	if param == "" {
+		return "", "", v
+	}
+
+	rest = strings.TrimLeftFunc(rest, unicode.IsSpace)
+	if !strings.HasPrefix(rest, "=") {
+		return "", "", v
+	}
+	rest = rest[1:] // consume equals sign
+	rest = strings.TrimLeftFunc(rest, unicode.IsSpace)
+	value, rest2 := consumeValue(rest)
+	if value == "" && rest2 == rest {
+		return "", "", v
+	}
+	rest = rest2
+	return param, value, rest
+}
+
+func percentHexUnescape(s string) (string, error) {
+	// Count %, check that they're well-formed.
+	percents := 0
+	for i := 0; i < len(s); {
+		if s[i] != '%' {
+			i++
+			continue
+		}
+		percents++
+		if i+2 >= len(s) || !ishex(s[i+1]) || !ishex(s[i+2]) {
+			s = s[i:]
+			if len(s) > 3 {
+				s = s[0:3]
+			}
+			return "", fmt.Errorf("mime: bogus characters after %%: %q", s)
+		}
+		i += 3
+	}
+	if percents == 0 {
+		return s, nil
+	}
+
+	t := make([]byte, len(s)-2*percents)
+	j := 0
+	for i := 0; i < len(s); {
+		switch s[i] {
+		case '%':
+			t[j] = unhex(s[i+1])<<4 | unhex(s[i+2])
+			j++
+			i += 3
+		default:
+			t[j] = s[i]
+			j++
+			i++
+		}
+	}
+	return string(t), nil
+}
+
+func ishex(c byte) bool {
+	switch {
+	case '0' <= c && c <= '9':
+		return true
+	case 'a' <= c && c <= 'f':
+		return true
+	case 'A' <= c && c <= 'F':
+		return true
+	}
+	return false
+}
+
+func unhex(c byte) byte {
+	switch {
+	case '0' <= c && c <= '9':
+		return c - '0'
+	case 'a' <= c && c <= 'f':
+		return c - 'a' + 10
+	case 'A' <= c && c <= 'F':
+		return c - 'A' + 10
+	}
+	return 0
+}
diff --git a/contrib/go/_std_1.18/src/mime/multipart/formdata.go b/contrib/go/_std_1.18/src/mime/multipart/formdata.go
new file mode 100644
index 0000000000..fca5f9e15f
--- /dev/null
+++ b/contrib/go/_std_1.18/src/mime/multipart/formdata.go
@@ -0,0 +1,182 @@
+// Copyright 2011 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 multipart
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"math"
+	"net/textproto"
+	"os"
+)
+
+// ErrMessageTooLarge is returned by ReadForm if the message form
+// data is too large to be processed.
+var ErrMessageTooLarge = errors.New("multipart: message too large")
+
+// TODO(adg,bradfitz): find a way to unify the DoS-prevention strategy here
+// with that of the http package's ParseForm.
+
+// ReadForm parses an entire multipart message whose parts have
+// a Content-Disposition of "form-data".
+// It stores up to maxMemory bytes + 10MB (reserved for non-file parts)
+// in memory. File parts which can't be stored in memory will be stored on
+// disk in temporary files.
+// It returns ErrMessageTooLarge if all non-file parts can't be stored in
+// memory.
+func (r *Reader) ReadForm(maxMemory int64) (*Form, error) {
+	return r.readForm(maxMemory)
+}
+
+func (r *Reader) readForm(maxMemory int64) (_ *Form, err error) {
+	form := &Form{make(map[string][]string), make(map[string][]*FileHeader)}
+	defer func() {
+		if err != nil {
+			form.RemoveAll()
+		}
+	}()
+
+	// Reserve an additional 10 MB for non-file parts.
+	maxValueBytes := maxMemory + int64(10<<20)
+	if maxValueBytes <= 0 {
+		if maxMemory < 0 {
+			maxValueBytes = 0
+		} else {
+			maxValueBytes = math.MaxInt64
+		}
+	}
+	for {
+		p, err := r.NextPart()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, err
+		}
+
+		name := p.FormName()
+		if name == "" {
+			continue
+		}
+		filename := p.FileName()
+
+		var b bytes.Buffer
+
+		if filename == "" {
+			// value, store as string in memory
+			n, err := io.CopyN(&b, p, maxValueBytes+1)
+			if err != nil && err != io.EOF {
+				return nil, err
+			}
+			maxValueBytes -= n
+			if maxValueBytes < 0 {
+				return nil, ErrMessageTooLarge
+			}
+			form.Value[name] = append(form.Value[name], b.String())
+			continue
+		}
+
+		// file, store in memory or on disk
+		fh := &FileHeader{
+			Filename: filename,
+			Header:   p.Header,
+		}
+		n, err := io.CopyN(&b, p, maxMemory+1)
+		if err != nil && err != io.EOF {
+			return nil, err
+		}
+		if n > maxMemory {
+			// too big, write to disk and flush buffer
+			file, err := os.CreateTemp("", "multipart-")
+			if err != nil {
+				return nil, err
+			}
+			size, err := io.Copy(file, io.MultiReader(&b, p))
+			if cerr := file.Close(); err == nil {
+				err = cerr
+			}
+			if err != nil {
+				os.Remove(file.Name())
+				return nil, err
+			}
+			fh.tmpfile = file.Name()
+			fh.Size = size
+		} else {
+			fh.content = b.Bytes()
+			fh.Size = int64(len(fh.content))
+			maxMemory -= n
+			maxValueBytes -= n
+		}
+		form.File[name] = append(form.File[name], fh)
+	}
+
+	return form, nil
+}
+
+// Form is a parsed multipart form.
+// Its File parts are stored either in memory or on disk,
+// and are accessible via the *FileHeader's Open method.
+// Its Value parts are stored as strings.
+// Both are keyed by field name.
+type Form struct {
+	Value map[string][]string
+	File  map[string][]*FileHeader
+}
+
+// RemoveAll removes any temporary files associated with a Form.
+func (f *Form) RemoveAll() error {
+	var err error
+	for _, fhs := range f.File {
+		for _, fh := range fhs {
+			if fh.tmpfile != "" {
+				e := os.Remove(fh.tmpfile)
+				if e != nil && err == nil {
+					err = e
+				}
+			}
+		}
+	}
+	return err
+}
+
+// A FileHeader describes a file part of a multipart request.
+type FileHeader struct {
+	Filename string
+	Header   textproto.MIMEHeader
+	Size     int64
+
+	content []byte
+	tmpfile string
+}
+
+// Open opens and returns the FileHeader's associated File.
+func (fh *FileHeader) Open() (File, error) {
+	if b := fh.content; b != nil {
+		r := io.NewSectionReader(bytes.NewReader(b), 0, int64(len(b)))
+		return sectionReadCloser{r}, nil
+	}
+	return os.Open(fh.tmpfile)
+}
+
+// File is an interface to access the file part of a multipart message.
+// Its contents may be either stored in memory or on disk.
+// If stored on disk, the File's underlying concrete type will be an *os.File.
+type File interface {
+	io.Reader
+	io.ReaderAt
+	io.Seeker
+	io.Closer
+}
+
+// helper types to turn a []byte into a File
+
+type sectionReadCloser struct {
+	*io.SectionReader
+}
+
+func (rc sectionReadCloser) Close() error {
+	return nil
+}
diff --git a/contrib/go/_std_1.18/src/mime/multipart/multipart.go b/contrib/go/_std_1.18/src/mime/multipart/multipart.go
new file mode 100644
index 0000000000..81bf722d4e
--- /dev/null
+++ b/contrib/go/_std_1.18/src/mime/multipart/multipart.go
@@ -0,0 +1,429 @@
+// Copyright 2010 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 multipart implements MIME multipart parsing, as defined in RFC
+2046.
+
+The implementation is sufficient for HTTP (RFC 2388) and the multipart
+bodies generated by popular browsers.
+*/
+package multipart
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"mime"
+	"mime/quotedprintable"
+	"net/textproto"
+	"path/filepath"
+	"strings"
+)
+
+var emptyParams = make(map[string]string)
+
+// This constant needs to be at least 76 for this package to work correctly.
+// This is because \r\n--separator_of_len_70- would fill the buffer and it
+// wouldn't be safe to consume a single byte from it.
+const peekBufferSize = 4096
+
+// A Part represents a single part in a multipart body.
+type Part struct {
+	// The headers of the body, if any, with the keys canonicalized
+	// in the same fashion that the Go http.Request headers are.
+	// For example, "foo-bar" changes case to "Foo-Bar"
+	Header textproto.MIMEHeader
+
+	mr *Reader
+
+	disposition       string
+	dispositionParams map[string]string
+
+	// r is either a reader directly reading from mr, or it's a
+	// wrapper around such a reader, decoding the
+	// Content-Transfer-Encoding
+	r io.Reader
+
+	n       int   // known data bytes waiting in mr.bufReader
+	total   int64 // total data bytes read already
+	err     error // error to return when n == 0
+	readErr error // read error observed from mr.bufReader
+}
+
+// FormName returns the name parameter if p has a Content-Disposition
+// of type "form-data".  Otherwise it returns the empty string.
+func (p *Part) FormName() string {
+	// See https://tools.ietf.org/html/rfc2183 section 2 for EBNF
+	// of Content-Disposition value format.
+	if p.dispositionParams == nil {
+		p.parseContentDisposition()
+	}
+	if p.disposition != "form-data" {
+		return ""
+	}
+	return p.dispositionParams["name"]
+}
+
+// FileName returns the filename parameter of the Part's Content-Disposition
+// header. If not empty, the filename is passed through filepath.Base (which is
+// platform dependent) before being returned.
+func (p *Part) FileName() string {
+	if p.dispositionParams == nil {
+		p.parseContentDisposition()
+	}
+	filename := p.dispositionParams["filename"]
+	if filename == "" {
+		return ""
+	}
+	// RFC 7578, Section 4.2 requires that if a filename is provided, the
+	// directory path information must not be used.
+	return filepath.Base(filename)
+}
+
+func (p *Part) parseContentDisposition() {
+	v := p.Header.Get("Content-Disposition")
+	var err error
+	p.disposition, p.dispositionParams, err = mime.ParseMediaType(v)
+	if err != nil {
+		p.dispositionParams = emptyParams
+	}
+}
+
+// NewReader creates a new multipart Reader reading from r using the
+// given MIME boundary.
+//
+// The boundary is usually obtained from the "boundary" parameter of
+// the message's "Content-Type" header. Use mime.ParseMediaType to
+// parse such headers.
+func NewReader(r io.Reader, boundary string) *Reader {
+	b := []byte("\r\n--" + boundary + "--")
+	return &Reader{
+		bufReader:        bufio.NewReaderSize(&stickyErrorReader{r: r}, peekBufferSize),
+		nl:               b[:2],
+		nlDashBoundary:   b[:len(b)-2],
+		dashBoundaryDash: b[2:],
+		dashBoundary:     b[2 : len(b)-2],
+	}
+}
+
+// stickyErrorReader is an io.Reader which never calls Read on its
+// underlying Reader once an error has been seen. (the io.Reader
+// interface's contract promises nothing about the return values of
+// Read calls after an error, yet this package does do multiple Reads
+// after error)
+type stickyErrorReader struct {
+	r   io.Reader
+	err error
+}
+
+func (r *stickyErrorReader) Read(p []byte) (n int, _ error) {
+	if r.err != nil {
+		return 0, r.err
+	}
+	n, r.err = r.r.Read(p)
+	return n, r.err
+}
+
+func newPart(mr *Reader, rawPart bool) (*Part, error) {
+	bp := &Part{
+		Header: make(map[string][]string),
+		mr:     mr,
+	}
+	if err := bp.populateHeaders(); err != nil {
+		return nil, err
+	}
+	bp.r = partReader{bp}
+
+	// rawPart is used to switch between Part.NextPart and Part.NextRawPart.
+	if !rawPart {
+		const cte = "Content-Transfer-Encoding"
+		if strings.EqualFold(bp.Header.Get(cte), "quoted-printable") {
+			bp.Header.Del(cte)
+			bp.r = quotedprintable.NewReader(bp.r)
+		}
+	}
+	return bp, nil
+}
+
+func (bp *Part) populateHeaders() error {
+	r := textproto.NewReader(bp.mr.bufReader)
+	header, err := r.ReadMIMEHeader()
+	if err == nil {
+		bp.Header = header
+	}
+	return err
+}
+
+// Read reads the body of a part, after its headers and before the
+// next part (if any) begins.
+func (p *Part) Read(d []byte) (n int, err error) {
+	return p.r.Read(d)
+}
+
+// partReader implements io.Reader by reading raw bytes directly from the
+// wrapped *Part, without doing any Transfer-Encoding decoding.
+type partReader struct {
+	p *Part
+}
+
+func (pr partReader) Read(d []byte) (int, error) {
+	p := pr.p
+	br := p.mr.bufReader
+
+	// Read into buffer until we identify some data to return,
+	// or we find a reason to stop (boundary or read error).
+	for p.n == 0 && p.err == nil {
+		peek, _ := br.Peek(br.Buffered())
+		p.n, p.err = scanUntilBoundary(peek, p.mr.dashBoundary, p.mr.nlDashBoundary, p.total, p.readErr)
+		if p.n == 0 && p.err == nil {
+			// Force buffered I/O to read more into buffer.
+			_, p.readErr = br.Peek(len(peek) + 1)
+			if p.readErr == io.EOF {
+				p.readErr = io.ErrUnexpectedEOF
+			}
+		}
+	}
+
+	// Read out from "data to return" part of buffer.
+	if p.n == 0 {
+		return 0, p.err
+	}
+	n := len(d)
+	if n > p.n {
+		n = p.n
+	}
+	n, _ = br.Read(d[:n])
+	p.total += int64(n)
+	p.n -= n
+	if p.n == 0 {
+		return n, p.err
+	}
+	return n, nil
+}
+
+// scanUntilBoundary scans buf to identify how much of it can be safely
+// returned as part of the Part body.
+// dashBoundary is "--boundary".
+// nlDashBoundary is "\r\n--boundary" or "\n--boundary", depending on what mode we are in.
+// The comments below (and the name) assume "\n--boundary", but either is accepted.
+// total is the number of bytes read out so far. If total == 0, then a leading "--boundary" is recognized.
+// readErr is the read error, if any, that followed reading the bytes in buf.
+// scanUntilBoundary returns the number of data bytes from buf that can be
+// returned as part of the Part body and also the error to return (if any)
+// once those data bytes are done.
+func scanUntilBoundary(buf, dashBoundary, nlDashBoundary []byte, total int64, readErr error) (int, error) {
+	if total == 0 {
+		// At beginning of body, allow dashBoundary.
+		if bytes.HasPrefix(buf, dashBoundary) {
+			switch matchAfterPrefix(buf, dashBoundary, readErr) {
+			case -1:
+				return len(dashBoundary), nil
+			case 0:
+				return 0, nil
+			case +1:
+				return 0, io.EOF
+			}
+		}
+		if bytes.HasPrefix(dashBoundary, buf) {
+			return 0, readErr
+		}
+	}
+
+	// Search for "\n--boundary".
+	if i := bytes.Index(buf, nlDashBoundary); i >= 0 {
+		switch matchAfterPrefix(buf[i:], nlDashBoundary, readErr) {
+		case -1:
+			return i + len(nlDashBoundary), nil
+		case 0:
+			return i, nil
+		case +1:
+			return i, io.EOF
+		}
+	}
+	if bytes.HasPrefix(nlDashBoundary, buf) {
+		return 0, readErr
+	}
+
+	// Otherwise, anything up to the final \n is not part of the boundary
+	// and so must be part of the body.
+	// Also if the section from the final \n onward is not a prefix of the boundary,
+	// it too must be part of the body.
+	i := bytes.LastIndexByte(buf, nlDashBoundary[0])
+	if i >= 0 && bytes.HasPrefix(nlDashBoundary, buf[i:]) {
+		return i, nil
+	}
+	return len(buf), readErr
+}
+
+// matchAfterPrefix checks whether buf should be considered to match the boundary.
+// The prefix is "--boundary" or "\r\n--boundary" or "\n--boundary",
+// and the caller has verified already that bytes.HasPrefix(buf, prefix) is true.
+//
+// matchAfterPrefix returns +1 if the buffer does match the boundary,
+// meaning the prefix is followed by a dash, space, tab, cr, nl, or end of input.
+// It returns -1 if the buffer definitely does NOT match the boundary,
+// meaning the prefix is followed by some other character.
+// For example, "--foobar" does not match "--foo".
+// It returns 0 more input needs to be read to make the decision,
+// meaning that len(buf) == len(prefix) and readErr == nil.
+func matchAfterPrefix(buf, prefix []byte, readErr error) int {
+	if len(buf) == len(prefix) {
+		if readErr != nil {
+			return +1
+		}
+		return 0
+	}
+	c := buf[len(prefix)]
+	if c == ' ' || c == '\t' || c == '\r' || c == '\n' || c == '-' {
+		return +1
+	}
+	return -1
+}
+
+func (p *Part) Close() error {
+	io.Copy(io.Discard, p)
+	return nil
+}
+
+// Reader is an iterator over parts in a MIME multipart body.
+// Reader's underlying parser consumes its input as needed. Seeking
+// isn't supported.
+type Reader struct {
+	bufReader *bufio.Reader
+
+	currentPart *Part
+	partsRead   int
+
+	nl               []byte // "\r\n" or "\n" (set after seeing first boundary line)
+	nlDashBoundary   []byte // nl + "--boundary"
+	dashBoundaryDash []byte // "--boundary--"
+	dashBoundary     []byte // "--boundary"
+}
+
+// NextPart returns the next part in the multipart or an error.
+// When there are no more parts, the error io.EOF is returned.
+//
+// As a special case, if the "Content-Transfer-Encoding" header
+// has a value of "quoted-printable", that header is instead
+// hidden and the body is transparently decoded during Read calls.
+func (r *Reader) NextPart() (*Part, error) {
+	return r.nextPart(false)
+}
+
+// NextRawPart returns the next part in the multipart or an error.
+// When there are no more parts, the error io.EOF is returned.
+//
+// Unlike NextPart, it does not have special handling for
+// "Content-Transfer-Encoding: quoted-printable".
+func (r *Reader) NextRawPart() (*Part, error) {
+	return r.nextPart(true)
+}
+
+func (r *Reader) nextPart(rawPart bool) (*Part, error) {
+	if r.currentPart != nil {
+		r.currentPart.Close()
+	}
+	if string(r.dashBoundary) == "--" {
+		return nil, fmt.Errorf("multipart: boundary is empty")
+	}
+	expectNewPart := false
+	for {
+		line, err := r.bufReader.ReadSlice('\n')
+
+		if err == io.EOF && r.isFinalBoundary(line) {
+			// If the buffer ends in "--boundary--" without the
+			// trailing "\r\n", ReadSlice will return an error
+			// (since it's missing the '\n'), but this is a valid
+			// multipart EOF so we need to return io.EOF instead of
+			// a fmt-wrapped one.
+			return nil, io.EOF
+		}
+		if err != nil {
+			return nil, fmt.Errorf("multipart: NextPart: %v", err)
+		}
+
+		if r.isBoundaryDelimiterLine(line) {
+			r.partsRead++
+			bp, err := newPart(r, rawPart)
+			if err != nil {
+				return nil, err
+			}
+			r.currentPart = bp
+			return bp, nil
+		}
+
+		if r.isFinalBoundary(line) {
+			// Expected EOF
+			return nil, io.EOF
+		}
+
+		if expectNewPart {
+			return nil, fmt.Errorf("multipart: expecting a new Part; got line %q", string(line))
+		}
+
+		if r.partsRead == 0 {
+			// skip line
+			continue
+		}
+
+		// Consume the "\n" or "\r\n" separator between the
+		// body of the previous part and the boundary line we
+		// now expect will follow. (either a new part or the
+		// end boundary)
+		if bytes.Equal(line, r.nl) {
+			expectNewPart = true
+			continue
+		}
+
+		return nil, fmt.Errorf("multipart: unexpected line in Next(): %q", line)
+	}
+}
+
+// isFinalBoundary reports whether line is the final boundary line
+// indicating that all parts are over.
+// It matches `^--boundary--[ \t]*(\r\n)?$`
+func (mr *Reader) isFinalBoundary(line []byte) bool {
+	if !bytes.HasPrefix(line, mr.dashBoundaryDash) {
+		return false
+	}
+	rest := line[len(mr.dashBoundaryDash):]
+	rest = skipLWSPChar(rest)
+	return len(rest) == 0 || bytes.Equal(rest, mr.nl)
+}
+
+func (mr *Reader) isBoundaryDelimiterLine(line []byte) (ret bool) {
+	// https://tools.ietf.org/html/rfc2046#section-5.1
+	//   The boundary delimiter line is then defined as a line
+	//   consisting entirely of two hyphen characters ("-",
+	//   decimal value 45) followed by the boundary parameter
+	//   value from the Content-Type header field, optional linear
+	//   whitespace, and a terminating CRLF.
+	if !bytes.HasPrefix(line, mr.dashBoundary) {
+		return false
+	}
+	rest := line[len(mr.dashBoundary):]
+	rest = skipLWSPChar(rest)
+
+	// On the first part, see our lines are ending in \n instead of \r\n
+	// and switch into that mode if so. This is a violation of the spec,
+	// but occurs in practice.
+	if mr.partsRead == 0 && len(rest) == 1 && rest[0] == '\n' {
+		mr.nl = mr.nl[1:]
+		mr.nlDashBoundary = mr.nlDashBoundary[1:]
+	}
+	return bytes.Equal(rest, mr.nl)
+}
+
+// skipLWSPChar returns b with leading spaces and tabs removed.
+// RFC 822 defines:
+//    LWSP-char = SPACE / HTAB
+func skipLWSPChar(b []byte) []byte {
+	for len(b) > 0 && (b[0] == ' ' || b[0] == '\t') {
+		b = b[1:]
+	}
+	return b
+}
diff --git a/contrib/go/_std_1.18/src/mime/multipart/writer.go b/contrib/go/_std_1.18/src/mime/multipart/writer.go
new file mode 100644
index 0000000000..d1ff151a7d
--- /dev/null
+++ b/contrib/go/_std_1.18/src/mime/multipart/writer.go
@@ -0,0 +1,201 @@
+// Copyright 2011 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 multipart
+
+import (
+	"bytes"
+	"crypto/rand"
+	"errors"
+	"fmt"
+	"io"
+	"net/textproto"
+	"sort"
+	"strings"
+)
+
+// A Writer generates multipart messages.
+type Writer struct {
+	w        io.Writer
+	boundary string
+	lastpart *part
+}
+
+// NewWriter returns a new multipart Writer with a random boundary,
+// writing to w.
+func NewWriter(w io.Writer) *Writer {
+	return &Writer{
+		w:        w,
+		boundary: randomBoundary(),
+	}
+}
+
+// Boundary returns the Writer's boundary.
+func (w *Writer) Boundary() string {
+	return w.boundary
+}
+
+// SetBoundary overrides the Writer's default randomly-generated
+// boundary separator with an explicit value.
+//
+// SetBoundary must be called before any parts are created, may only
+// contain certain ASCII characters, and must be non-empty and
+// at most 70 bytes long.
+func (w *Writer) SetBoundary(boundary string) error {
+	if w.lastpart != nil {
+		return errors.New("mime: SetBoundary called after write")
+	}
+	// rfc2046#section-5.1.1
+	if len(boundary) < 1 || len(boundary) > 70 {
+		return errors.New("mime: invalid boundary length")
+	}
+	end := len(boundary) - 1
+	for i, b := range boundary {
+		if 'A' <= b && b <= 'Z' || 'a' <= b && b <= 'z' || '0' <= b && b <= '9' {
+			continue
+		}
+		switch b {
+		case '\'', '(', ')', '+', '_', ',', '-', '.', '/', ':', '=', '?':
+			continue
+		case ' ':
+			if i != end {
+				continue
+			}
+		}
+		return errors.New("mime: invalid boundary character")
+	}
+	w.boundary = boundary
+	return nil
+}
+
+// FormDataContentType returns the Content-Type for an HTTP
+// multipart/form-data with this Writer's Boundary.
+func (w *Writer) FormDataContentType() string {
+	b := w.boundary
+	// We must quote the boundary if it contains any of the
+	// tspecials characters defined by RFC 2045, or space.
+	if strings.ContainsAny(b, `()<>@,;:\"/[]?= `) {
+		b = `"` + b + `"`
+	}
+	return "multipart/form-data; boundary=" + b
+}
+
+func randomBoundary() string {
+	var buf [30]byte
+	_, err := io.ReadFull(rand.Reader, buf[:])
+	if err != nil {
+		panic(err)
+	}
+	return fmt.Sprintf("%x", buf[:])
+}
+
+// CreatePart creates a new multipart section with the provided
+// header. The body of the part should be written to the returned
+// Writer. After calling CreatePart, any previous part may no longer
+// be written to.
+func (w *Writer) CreatePart(header textproto.MIMEHeader) (io.Writer, error) {
+	if w.lastpart != nil {
+		if err := w.lastpart.close(); err != nil {
+			return nil, err
+		}
+	}
+	var b bytes.Buffer
+	if w.lastpart != nil {
+		fmt.Fprintf(&b, "\r\n--%s\r\n", w.boundary)
+	} else {
+		fmt.Fprintf(&b, "--%s\r\n", w.boundary)
+	}
+
+	keys := make([]string, 0, len(header))
+	for k := range header {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	for _, k := range keys {
+		for _, v := range header[k] {
+			fmt.Fprintf(&b, "%s: %s\r\n", k, v)
+		}
+	}
+	fmt.Fprintf(&b, "\r\n")
+	_, err := io.Copy(w.w, &b)
+	if err != nil {
+		return nil, err
+	}
+	p := &part{
+		mw: w,
+	}
+	w.lastpart = p
+	return p, nil
+}
+
+var quoteEscaper = strings.NewReplacer("\\", "\\\\", `"`, "\\\"")
+
+func escapeQuotes(s string) string {
+	return quoteEscaper.Replace(s)
+}
+
+// CreateFormFile is a convenience wrapper around CreatePart. It creates
+// a new form-data header with the provided field name and file name.
+func (w *Writer) CreateFormFile(fieldname, filename string) (io.Writer, error) {
+	h := make(textproto.MIMEHeader)
+	h.Set("Content-Disposition",
+		fmt.Sprintf(`form-data; name="%s"; filename="%s"`,
+			escapeQuotes(fieldname), escapeQuotes(filename)))
+	h.Set("Content-Type", "application/octet-stream")
+	return w.CreatePart(h)
+}
+
+// CreateFormField calls CreatePart with a header using the
+// given field name.
+func (w *Writer) CreateFormField(fieldname string) (io.Writer, error) {
+	h := make(textproto.MIMEHeader)
+	h.Set("Content-Disposition",
+		fmt.Sprintf(`form-data; name="%s"`, escapeQuotes(fieldname)))
+	return w.CreatePart(h)
+}
+
+// WriteField calls CreateFormField and then writes the given value.
+func (w *Writer) WriteField(fieldname, value string) error {
+	p, err := w.CreateFormField(fieldname)
+	if err != nil {
+		return err
+	}
+	_, err = p.Write([]byte(value))
+	return err
+}
+
+// Close finishes the multipart message and writes the trailing
+// boundary end line to the output.
+func (w *Writer) Close() error {
+	if w.lastpart != nil {
+		if err := w.lastpart.close(); err != nil {
+			return err
+		}
+		w.lastpart = nil
+	}
+	_, err := fmt.Fprintf(w.w, "\r\n--%s--\r\n", w.boundary)
+	return err
+}
+
+type part struct {
+	mw     *Writer
+	closed bool
+	we     error // last error that occurred writing
+}
+
+func (p *part) close() error {
+	p.closed = true
+	return p.we
+}
+
+func (p *part) Write(d []byte) (n int, err error) {
+	if p.closed {
+		return 0, errors.New("multipart: can't write to finished part")
+	}
+	n, err = p.mw.w.Write(d)
+	if err != nil {
+		p.we = err
+	}
+	return
+}
diff --git a/contrib/go/_std_1.18/src/mime/quotedprintable/reader.go b/contrib/go/_std_1.18/src/mime/quotedprintable/reader.go
new file mode 100644
index 0000000000..4239625402
--- /dev/null
+++ b/contrib/go/_std_1.18/src/mime/quotedprintable/reader.go
@@ -0,0 +1,139 @@
+// Copyright 2012 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 quotedprintable implements quoted-printable encoding as specified by
+// RFC 2045.
+package quotedprintable
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+)
+
+// Reader is a quoted-printable decoder.
+type Reader struct {
+	br   *bufio.Reader
+	rerr error  // last read error
+	line []byte // to be consumed before more of br
+}
+
+// NewReader returns a quoted-printable reader, decoding from r.
+func NewReader(r io.Reader) *Reader {
+	return &Reader{
+		br: bufio.NewReader(r),
+	}
+}
+
+func fromHex(b byte) (byte, error) {
+	switch {
+	case b >= '0' && b <= '9':
+		return b - '0', nil
+	case b >= 'A' && b <= 'F':
+		return b - 'A' + 10, nil
+	// Accept badly encoded bytes.
+	case b >= 'a' && b <= 'f':
+		return b - 'a' + 10, nil
+	}
+	return 0, fmt.Errorf("quotedprintable: invalid hex byte 0x%02x", b)
+}
+
+func readHexByte(v []byte) (b byte, err error) {
+	if len(v) < 2 {
+		return 0, io.ErrUnexpectedEOF
+	}
+	var hb, lb byte
+	if hb, err = fromHex(v[0]); err != nil {
+		return 0, err
+	}
+	if lb, err = fromHex(v[1]); err != nil {
+		return 0, err
+	}
+	return hb<<4 | lb, nil
+}
+
+func isQPDiscardWhitespace(r rune) bool {
+	switch r {
+	case '\n', '\r', ' ', '\t':
+		return true
+	}
+	return false
+}
+
+var (
+	crlf       = []byte("\r\n")
+	lf         = []byte("\n")
+	softSuffix = []byte("=")
+)
+
+// Read reads and decodes quoted-printable data from the underlying reader.
+func (r *Reader) Read(p []byte) (n int, err error) {
+	// Deviations from RFC 2045:
+	// 1. in addition to "=\r\n", "=\n" is also treated as soft line break.
+	// 2. it will pass through a '\r' or '\n' not preceded by '=', consistent
+	//    with other broken QP encoders & decoders.
+	// 3. it accepts soft line-break (=) at end of message (issue 15486); i.e.
+	//    the final byte read from the underlying reader is allowed to be '=',
+	//    and it will be silently ignored.
+	// 4. it takes = as literal = if not followed by two hex digits
+	//    but not at end of line (issue 13219).
+	for len(p) > 0 {
+		if len(r.line) == 0 {
+			if r.rerr != nil {
+				return n, r.rerr
+			}
+			r.line, r.rerr = r.br.ReadSlice('\n')
+
+			// Does the line end in CRLF instead of just LF?
+			hasLF := bytes.HasSuffix(r.line, lf)
+			hasCR := bytes.HasSuffix(r.line, crlf)
+			wholeLine := r.line
+			r.line = bytes.TrimRightFunc(wholeLine, isQPDiscardWhitespace)
+			if bytes.HasSuffix(r.line, softSuffix) {
+				rightStripped := wholeLine[len(r.line):]
+				r.line = r.line[:len(r.line)-1]
+				if !bytes.HasPrefix(rightStripped, lf) && !bytes.HasPrefix(rightStripped, crlf) &&
+					!(len(rightStripped) == 0 && len(r.line) > 0 && r.rerr == io.EOF) {
+					r.rerr = fmt.Errorf("quotedprintable: invalid bytes after =: %q", rightStripped)
+				}
+			} else if hasLF {
+				if hasCR {
+					r.line = append(r.line, '\r', '\n')
+				} else {
+					r.line = append(r.line, '\n')
+				}
+			}
+			continue
+		}
+		b := r.line[0]
+
+		switch {
+		case b == '=':
+			b, err = readHexByte(r.line[1:])
+			if err != nil {
+				if len(r.line) >= 2 && r.line[1] != '\r' && r.line[1] != '\n' {
+					// Take the = as a literal =.
+					b = '='
+					break
+				}
+				return n, err
+			}
+			r.line = r.line[2:] // 2 of the 3; other 1 is done below
+		case b == '\t' || b == '\r' || b == '\n':
+			break
+		case b >= 0x80:
+			// As an extension to RFC 2045, we accept
+			// values >= 0x80 without complaint. Issue 22597.
+			break
+		case b < ' ' || b > '~':
+			return n, fmt.Errorf("quotedprintable: invalid unescaped byte 0x%02x in body", b)
+		}
+		p[0] = b
+		p = p[1:]
+		r.line = r.line[1:]
+		n++
+	}
+	return n, nil
+}
diff --git a/contrib/go/_std_1.18/src/mime/quotedprintable/writer.go b/contrib/go/_std_1.18/src/mime/quotedprintable/writer.go
new file mode 100644
index 0000000000..16ea0bf7d6
--- /dev/null
+++ b/contrib/go/_std_1.18/src/mime/quotedprintable/writer.go
@@ -0,0 +1,172 @@
+// 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 quotedprintable
+
+import "io"
+
+const lineMaxLen = 76
+
+// A Writer is a quoted-printable writer that implements io.WriteCloser.
+type Writer struct {
+	// Binary mode treats the writer's input as pure binary and processes end of
+	// line bytes as binary data.
+	Binary bool
+
+	w    io.Writer
+	i    int
+	line [78]byte
+	cr   bool
+}
+
+// NewWriter returns a new Writer that writes to w.
+func NewWriter(w io.Writer) *Writer {
+	return &Writer{w: w}
+}
+
+// Write encodes p using quoted-printable encoding and writes it to the
+// underlying io.Writer. It limits line length to 76 characters. The encoded
+// bytes are not necessarily flushed until the Writer is closed.
+func (w *Writer) Write(p []byte) (n int, err error) {
+	for i, b := range p {
+		switch {
+		// Simple writes are done in batch.
+		case b >= '!' && b <= '~' && b != '=':
+			continue
+		case isWhitespace(b) || !w.Binary && (b == '\n' || b == '\r'):
+			continue
+		}
+
+		if i > n {
+			if err := w.write(p[n:i]); err != nil {
+				return n, err
+			}
+			n = i
+		}
+
+		if err := w.encode(b); err != nil {
+			return n, err
+		}
+		n++
+	}
+
+	if n == len(p) {
+		return n, nil
+	}
+
+	if err := w.write(p[n:]); err != nil {
+		return n, err
+	}
+
+	return len(p), nil
+}
+
+// Close closes the Writer, flushing any unwritten data to the underlying
+// io.Writer, but does not close the underlying io.Writer.
+func (w *Writer) Close() error {
+	if err := w.checkLastByte(); err != nil {
+		return err
+	}
+
+	return w.flush()
+}
+
+// write limits text encoded in quoted-printable to 76 characters per line.
+func (w *Writer) write(p []byte) error {
+	for _, b := range p {
+		if b == '\n' || b == '\r' {
+			// If the previous byte was \r, the CRLF has already been inserted.
+			if w.cr && b == '\n' {
+				w.cr = false
+				continue
+			}
+
+			if b == '\r' {
+				w.cr = true
+			}
+
+			if err := w.checkLastByte(); err != nil {
+				return err
+			}
+			if err := w.insertCRLF(); err != nil {
+				return err
+			}
+			continue
+		}
+
+		if w.i == lineMaxLen-1 {
+			if err := w.insertSoftLineBreak(); err != nil {
+				return err
+			}
+		}
+
+		w.line[w.i] = b
+		w.i++
+		w.cr = false
+	}
+
+	return nil
+}
+
+func (w *Writer) encode(b byte) error {
+	if lineMaxLen-1-w.i < 3 {
+		if err := w.insertSoftLineBreak(); err != nil {
+			return err
+		}
+	}
+
+	w.line[w.i] = '='
+	w.line[w.i+1] = upperhex[b>>4]
+	w.line[w.i+2] = upperhex[b&0x0f]
+	w.i += 3
+
+	return nil
+}
+
+const upperhex = "0123456789ABCDEF"
+
+// checkLastByte encodes the last buffered byte if it is a space or a tab.
+func (w *Writer) checkLastByte() error {
+	if w.i == 0 {
+		return nil
+	}
+
+	b := w.line[w.i-1]
+	if isWhitespace(b) {
+		w.i--
+		if err := w.encode(b); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (w *Writer) insertSoftLineBreak() error {
+	w.line[w.i] = '='
+	w.i++
+
+	return w.insertCRLF()
+}
+
+func (w *Writer) insertCRLF() error {
+	w.line[w.i] = '\r'
+	w.line[w.i+1] = '\n'
+	w.i += 2
+
+	return w.flush()
+}
+
+func (w *Writer) flush() error {
+	if _, err := w.w.Write(w.line[:w.i]); err != nil {
+		return err
+	}
+
+	w.i = 0
+	return nil
+}
+
+func isWhitespace(b byte) bool {
+	return b == ' ' || b == '\t'
+}
diff --git a/contrib/go/_std_1.18/src/mime/type.go b/contrib/go/_std_1.18/src/mime/type.go
new file mode 100644
index 0000000000..bdb8bb319a
--- /dev/null
+++ b/contrib/go/_std_1.18/src/mime/type.go
@@ -0,0 +1,202 @@
+// Copyright 2010 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 implements parts of the MIME spec.
+package mime
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+	"sync"
+)
+
+var (
+	mimeTypes      sync.Map // map[string]string; ".Z" => "application/x-compress"
+	mimeTypesLower sync.Map // map[string]string; ".z" => "application/x-compress"
+
+	// extensions maps from MIME type to list of lowercase file
+	// extensions: "image/jpeg" => [".jpg", ".jpeg"]
+	extensionsMu sync.Mutex // Guards stores (but not loads) on extensions.
+	extensions   sync.Map   // map[string][]string; slice values are append-only.
+)
+
+func clearSyncMap(m *sync.Map) {
+	m.Range(func(k, _ any) bool {
+		m.Delete(k)
+		return true
+	})
+}
+
+// setMimeTypes is used by initMime's non-test path, and by tests.
+func setMimeTypes(lowerExt, mixExt map[string]string) {
+	clearSyncMap(&mimeTypes)
+	clearSyncMap(&mimeTypesLower)
+	clearSyncMap(&extensions)
+
+	for k, v := range lowerExt {
+		mimeTypesLower.Store(k, v)
+	}
+	for k, v := range mixExt {
+		mimeTypes.Store(k, v)
+	}
+
+	extensionsMu.Lock()
+	defer extensionsMu.Unlock()
+	for k, v := range lowerExt {
+		justType, _, err := ParseMediaType(v)
+		if err != nil {
+			panic(err)
+		}
+		var exts []string
+		if ei, ok := extensions.Load(justType); ok {
+			exts = ei.([]string)
+		}
+		extensions.Store(justType, append(exts, k))
+	}
+}
+
+var builtinTypesLower = map[string]string{
+	".avif": "image/avif",
+	".css":  "text/css; charset=utf-8",
+	".gif":  "image/gif",
+	".htm":  "text/html; charset=utf-8",
+	".html": "text/html; charset=utf-8",
+	".jpeg": "image/jpeg",
+	".jpg":  "image/jpeg",
+	".js":   "text/javascript; charset=utf-8",
+	".json": "application/json",
+	".mjs":  "text/javascript; charset=utf-8",
+	".pdf":  "application/pdf",
+	".png":  "image/png",
+	".svg":  "image/svg+xml",
+	".wasm": "application/wasm",
+	".webp": "image/webp",
+	".xml":  "text/xml; charset=utf-8",
+}
+
+var once sync.Once // guards initMime
+
+var testInitMime, osInitMime func()
+
+func initMime() {
+	if fn := testInitMime; fn != nil {
+		fn()
+	} else {
+		setMimeTypes(builtinTypesLower, builtinTypesLower)
+		osInitMime()
+	}
+}
+
+// TypeByExtension returns the MIME type associated with the file extension ext.
+// The extension ext should begin with a leading dot, as in ".html".
+// When ext has no associated type, TypeByExtension returns "".
+//
+// Extensions are looked up first case-sensitively, then case-insensitively.
+//
+// The built-in table is small but on unix it is augmented by the local
+// system's MIME-info database or mime.types file(s) if available under one or
+// more of these names:
+//
+//   /usr/local/share/mime/globs2
+//   /usr/share/mime/globs2
+//   /etc/mime.types
+//   /etc/apache2/mime.types
+//   /etc/apache/mime.types
+//
+// On Windows, MIME types are extracted from the registry.
+//
+// Text types have the charset parameter set to "utf-8" by default.
+func TypeByExtension(ext string) string {
+	once.Do(initMime)
+
+	// Case-sensitive lookup.
+	if v, ok := mimeTypes.Load(ext); ok {
+		return v.(string)
+	}
+
+	// Case-insensitive lookup.
+	// Optimistically assume a short ASCII extension and be
+	// allocation-free in that case.
+	var buf [10]byte
+	lower := buf[:0]
+	const utf8RuneSelf = 0x80 // from utf8 package, but not importing it.
+	for i := 0; i < len(ext); i++ {
+		c := ext[i]
+		if c >= utf8RuneSelf {
+			// Slow path.
+			si, _ := mimeTypesLower.Load(strings.ToLower(ext))
+			s, _ := si.(string)
+			return s
+		}
+		if 'A' <= c && c <= 'Z' {
+			lower = append(lower, c+('a'-'A'))
+		} else {
+			lower = append(lower, c)
+		}
+	}
+	si, _ := mimeTypesLower.Load(string(lower))
+	s, _ := si.(string)
+	return s
+}
+
+// ExtensionsByType returns the extensions known to be associated with the MIME
+// type typ. The returned extensions will each begin with a leading dot, as in
+// ".html". When typ has no associated extensions, ExtensionsByType returns an
+// nil slice.
+func ExtensionsByType(typ string) ([]string, error) {
+	justType, _, err := ParseMediaType(typ)
+	if err != nil {
+		return nil, err
+	}
+
+	once.Do(initMime)
+	s, ok := extensions.Load(justType)
+	if !ok {
+		return nil, nil
+	}
+	ret := append([]string(nil), s.([]string)...)
+	sort.Strings(ret)
+	return ret, nil
+}
+
+// AddExtensionType sets the MIME type associated with
+// the extension ext to typ. The extension should begin with
+// a leading dot, as in ".html".
+func AddExtensionType(ext, typ string) error {
+	if !strings.HasPrefix(ext, ".") {
+		return fmt.Errorf("mime: extension %q missing leading dot", ext)
+	}
+	once.Do(initMime)
+	return setExtensionType(ext, typ)
+}
+
+func setExtensionType(extension, mimeType string) error {
+	justType, param, err := ParseMediaType(mimeType)
+	if err != nil {
+		return err
+	}
+	if strings.HasPrefix(mimeType, "text/") && param["charset"] == "" {
+		param["charset"] = "utf-8"
+		mimeType = FormatMediaType(mimeType, param)
+	}
+	extLower := strings.ToLower(extension)
+
+	mimeTypes.Store(extension, mimeType)
+	mimeTypesLower.Store(extLower, mimeType)
+
+	extensionsMu.Lock()
+	defer extensionsMu.Unlock()
+	var exts []string
+	if ei, ok := extensions.Load(justType); ok {
+		exts = ei.([]string)
+	}
+	for _, v := range exts {
+		if v == extLower {
+			return nil
+		}
+	}
+	extensions.Store(justType, append(exts, extLower))
+	return nil
+}
diff --git a/contrib/go/_std_1.18/src/mime/type_unix.go b/contrib/go/_std_1.18/src/mime/type_unix.go
new file mode 100644
index 0000000000..3abc1fa10e
--- /dev/null
+++ b/contrib/go/_std_1.18/src/mime/type_unix.go
@@ -0,0 +1,114 @@
+// Copyright 2010 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.
+
+//go:build aix || darwin || dragonfly || freebsd || (js && wasm) || linux || netbsd || openbsd || solaris
+
+package mime
+
+import (
+	"bufio"
+	"os"
+	"strings"
+)
+
+func init() {
+	osInitMime = initMimeUnix
+}
+
+// See https://specifications.freedesktop.org/shared-mime-info-spec/shared-mime-info-spec-0.21.html
+// for the FreeDesktop Shared MIME-info Database specification.
+var mimeGlobs = []string{
+	"/usr/local/share/mime/globs2",
+	"/usr/share/mime/globs2",
+}
+
+// Common locations for mime.types files on unix.
+var typeFiles = []string{
+	"/etc/mime.types",
+	"/etc/apache2/mime.types",
+	"/etc/apache/mime.types",
+	"/etc/httpd/conf/mime.types",
+}
+
+func loadMimeGlobsFile(filename string) error {
+	f, err := os.Open(filename)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		// Each line should be of format: weight:mimetype:*.ext
+		fields := strings.Split(scanner.Text(), ":")
+		if len(fields) < 3 || len(fields[0]) < 1 || len(fields[2]) < 2 {
+			continue
+		} else if fields[0][0] == '#' || fields[2][0] != '*' {
+			continue
+		}
+
+		extension := fields[2][1:]
+		if _, ok := mimeTypes.Load(extension); ok {
+			// We've already seen this extension.
+			// The file is in weight order, so we keep
+			// the first entry that we see.
+			continue
+		}
+
+		setExtensionType(extension, fields[1])
+	}
+	if err := scanner.Err(); err != nil {
+		panic(err)
+	}
+	return nil
+}
+
+func loadMimeFile(filename string) {
+	f, err := os.Open(filename)
+	if err != nil {
+		return
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		fields := strings.Fields(scanner.Text())
+		if len(fields) <= 1 || fields[0][0] == '#' {
+			continue
+		}
+		mimeType := fields[0]
+		for _, ext := range fields[1:] {
+			if ext[0] == '#' {
+				break
+			}
+			setExtensionType("."+ext, mimeType)
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		panic(err)
+	}
+}
+
+func initMimeUnix() {
+	for _, filename := range mimeGlobs {
+		if err := loadMimeGlobsFile(filename); err == nil {
+			return // Stop checking more files if mimetype database is found.
+		}
+	}
+
+	// Fallback if no system-generated mimetype database exists.
+	for _, filename := range typeFiles {
+		loadMimeFile(filename)
+	}
+}
+
+func initMimeForTests() map[string]string {
+	mimeGlobs = []string{""}
+	typeFiles = []string{"testdata/test.types"}
+	return map[string]string{
+		".T1":  "application/test",
+		".t2":  "text/test; charset=utf-8",
+		".png": "image/png",
+	}
+}