diff options
Diffstat (limited to 'vendor/github.com/hashicorp/hcl/hcl/strconv/quote.go')
| -rw-r--r-- | vendor/github.com/hashicorp/hcl/hcl/strconv/quote.go | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/hcl/hcl/strconv/quote.go b/vendor/github.com/hashicorp/hcl/hcl/strconv/quote.go new file mode 100644 index 0000000..e87ac63 --- /dev/null +++ b/vendor/github.com/hashicorp/hcl/hcl/strconv/quote.go @@ -0,0 +1,245 @@ +package strconv + +import ( + "errors" + "unicode/utf8" +) + +// ErrSyntax indicates that a value does not have the right syntax for the target type. +var ErrSyntax = errors.New("invalid syntax") + +// Unquote interprets s as a single-quoted, double-quoted, +// or backquoted Go string literal, returning the string value +// that s quotes. (If s is single-quoted, it would be a Go +// character literal; Unquote returns the corresponding +// one-character string.) +func Unquote(s string) (t string, err error) { + n := len(s) + if n < 2 { + return "", ErrSyntax + } + quote := s[0] + if quote != s[n-1] { + return "", ErrSyntax + } + s = s[1 : n-1] + + if quote != '"' { + return "", ErrSyntax + } + if contains(s, '\n') { + return "", ErrSyntax + } + + // Is it trivial? Avoid allocation. + if !contains(s, '\\') && !contains(s, quote) && !contains(s, '$') { + switch quote { + case '"': + return s, nil + case '\'': + r, size := utf8.DecodeRuneInString(s) + if size == len(s) && (r != utf8.RuneError || size != 1) { + return s, nil + } + } + } + + var runeTmp [utf8.UTFMax]byte + buf := make([]byte, 0, 3*len(s)/2) // Try to avoid more allocations. + for len(s) > 0 { + // If we're starting a '${}' then let it through un-unquoted. + // Specifically: we don't unquote any characters within the `${}` + // section, except for escaped quotes, which we handle specifically. + if s[0] == '$' && len(s) > 1 && s[1] == '{' { + buf = append(buf, '$', '{') + s = s[2:] + + // Continue reading until we find the closing brace, copying as-is + braces := 1 + for len(s) > 0 && braces > 0 { + r, size := utf8.DecodeRuneInString(s) + if r == utf8.RuneError { + return "", ErrSyntax + } + + s = s[size:] + + // We special case escaped double quotes in interpolations, converting + // them to straight double quotes. + if r == '\\' { + if q, _ := utf8.DecodeRuneInString(s); q == '"' { + continue + } + } + + n := utf8.EncodeRune(runeTmp[:], r) + buf = append(buf, runeTmp[:n]...) + + switch r { + case '{': + braces++ + case '}': + braces-- + } + } + if braces != 0 { + return "", ErrSyntax + } + if len(s) == 0 { + // If there's no string left, we're done! + break + } else { + // If there's more left, we need to pop back up to the top of the loop + // in case there's another interpolation in this string. + continue + } + } + + c, multibyte, ss, err := unquoteChar(s, quote) + if err != nil { + return "", err + } + s = ss + if c < utf8.RuneSelf || !multibyte { + buf = append(buf, byte(c)) + } else { + n := utf8.EncodeRune(runeTmp[:], c) + buf = append(buf, runeTmp[:n]...) + } + if quote == '\'' && len(s) != 0 { + // single-quoted must be single character + return "", ErrSyntax + } + } + return string(buf), nil +} + +// contains reports whether the string contains the byte c. +func contains(s string, c byte) bool { + for i := 0; i < len(s); i++ { + if s[i] == c { + return true + } + } + return false +} + +func unhex(b byte) (v rune, ok bool) { + c := rune(b) + switch { + case '0' <= c && c <= '9': + return c - '0', true + case 'a' <= c && c <= 'f': + return c - 'a' + 10, true + case 'A' <= c && c <= 'F': + return c - 'A' + 10, true + } + return +} + +func unquoteChar(s string, quote byte) (value rune, multibyte bool, tail string, err error) { + // easy cases + switch c := s[0]; { + case c == quote && (quote == '\'' || quote == '"'): + err = ErrSyntax + return + case c >= utf8.RuneSelf: + r, size := utf8.DecodeRuneInString(s) + return r, true, s[size:], nil + case c != '\\': + return rune(s[0]), false, s[1:], nil + } + + // hard case: c is backslash + if len(s) <= 1 { + err = ErrSyntax + return + } + c := s[1] + s = s[2:] + + switch c { + case 'a': + value = '\a' + case 'b': + value = '\b' + case 'f': + value = '\f' + case 'n': + value = '\n' + case 'r': + value = '\r' + case 't': + value = '\t' + case 'v': + value = '\v' + case 'x', 'u', 'U': + n := 0 + switch c { + case 'x': + n = 2 + case 'u': + n = 4 + case 'U': + n = 8 + } + var v rune + if len(s) < n { + err = ErrSyntax + return + } + for j := 0; j < n; j++ { + x, ok := unhex(s[j]) + if !ok { + err = ErrSyntax + return + } + v = v<<4 | x + } + s = s[n:] + if c == 'x' { + // single-byte string, possibly not UTF-8 + value = v + break + } + if v > utf8.MaxRune { + err = ErrSyntax + return + } + value = v + multibyte = true + case '0', '1', '2', '3', '4', '5', '6', '7': + v := rune(c) - '0' + if len(s) < 2 { + err = ErrSyntax + return + } + for j := 0; j < 2; j++ { // one digit already; two more + x := rune(s[j]) - '0' + if x < 0 || x > 7 { + err = ErrSyntax + return + } + v = (v << 3) | x + } + s = s[2:] + if v > 255 { + err = ErrSyntax + return + } + value = v + case '\\': + value = '\\' + case '\'', '"': + if c != quote { + err = ErrSyntax + return + } + value = rune(c) + default: + err = ErrSyntax + return + } + tail = s + return +} |