mirror of
https://github.com/go-sylixos/elvish.git
synced 2024-12-15 03:37:52 +08:00
ae9e6d1565
- Fix the handling of actual occurrences of U+FFFD. - Fix an existing bug of QuoteVariableName("$\n").
141 lines
3.4 KiB
Go
141 lines
3.4 KiB
Go
package parse
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import (
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"bytes"
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"unicode"
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"unicode/utf8"
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)
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// Quote returns a valid Elvish expression that evaluates to the given string.
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// If s is a valid bareword, it is returned as is; otherwise it is quoted,
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// preferring the use of single quotes.
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func Quote(s string) string {
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s, _ = QuoteAs(s, Bareword)
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return s
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}
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// QuoteVariableName is like Quote, but quotes s if it contains any character
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// that may not appear unquoted in variable names.
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func QuoteVariableName(s string) string {
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if s == "" {
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return "''"
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}
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// Keep track of whether it is a valid (unquoted) variable name.
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bare := true
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for _, r := range s {
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if r == unicode.ReplacementChar || !unicode.IsPrint(r) {
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// Contains invalid UTF-8 sequence or unprintable character; force
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// double quote.
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return quoteDouble(s)
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}
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if !allowedInVariableName(r) {
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bare = false
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}
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}
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if bare {
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return s
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}
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return quoteSingle(s)
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}
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// QuoteAs returns a representation of s in Elvish syntax, preferring the syntax
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// specified by q, which must be one of Bareword, SingleQuoted, or DoubleQuoted.
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// It returns the quoted string and the actual quoting.
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func QuoteAs(s string, q PrimaryType) (string, PrimaryType) {
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if q == DoubleQuoted {
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// Everything can be quoted using double quotes, return directly.
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return quoteDouble(s), DoubleQuoted
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}
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if s == "" {
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return "''", SingleQuoted
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}
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// Keep track of whether it is a valid bareword.
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bare := s[0] != '~'
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for _, r := range s {
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if r == unicode.ReplacementChar || !unicode.IsPrint(r) {
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// Contains invalid UTF-8 sequence or unprintable character; force
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// double quote.
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return quoteDouble(s), DoubleQuoted
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}
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if !allowedInBareword(r, strictExpr) {
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bare = false
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}
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}
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if q == Bareword && bare {
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return s, Bareword
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}
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return quoteSingle(s), SingleQuoted
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}
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func quoteSingle(s string) string {
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var buf bytes.Buffer
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buf.WriteByte('\'')
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for _, r := range s {
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buf.WriteRune(r)
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if r == '\'' {
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buf.WriteByte('\'')
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}
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}
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buf.WriteByte('\'')
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return buf.String()
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}
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// rtohex is optimized for the common cases encountered when encoding Elvish strings and should be
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// more efficient than using fmt.Sprintf("%x").
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func rtohex(r rune, w int) []byte {
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bytes := make([]byte, w)
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for i := w - 1; i >= 0; i-- {
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d := byte(r % 16)
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r /= 16
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if d <= 9 {
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bytes[i] = '0' + d
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} else {
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bytes[i] = 'a' + d - 10
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}
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}
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return bytes
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}
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func quoteDouble(s string) string {
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var buf bytes.Buffer
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buf.WriteByte('"')
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for s != "" {
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r, w := utf8.DecodeRuneInString(s)
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if r == utf8.RuneError && w == 1 {
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// An invalid UTF-8 sequence was seen -- encode first byte as a hex literal.
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buf.WriteByte('\\')
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buf.WriteByte('x')
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buf.Write(rtohex(rune(s[0]), 2))
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} else if e, ok := doubleUnescape[r]; ok {
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// This handles the escaping of " and \ too.
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buf.WriteByte('\\')
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buf.WriteRune(e)
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} else if unicode.IsPrint(r) && r != utf8.RuneError {
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// RuneError is technically printable, but don't print it directly
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// to avoid confusion.
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buf.WriteRune(r)
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} else if r <= 0x7f {
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// Unprintable characters in the ASCII range can be escaped with \x
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// since they are one byte in UTF-8.
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buf.WriteByte('\\')
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buf.WriteByte('x')
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buf.Write(rtohex(r, 2))
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} else if r <= 0xffff {
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buf.WriteByte('\\')
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buf.WriteByte('u')
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buf.Write(rtohex(r, 4))
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} else {
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buf.WriteByte('\\')
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buf.WriteByte('U')
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buf.Write(rtohex(r, 8))
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}
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s = s[w:]
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}
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buf.WriteByte('"')
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return buf.String()
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}
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