Beispiel #1
0
func (i *inputBytes) context(pos int) syntax.EmptyOp {
	r1, r2 := endOfText, endOfText
	if pos > 0 && pos <= len(i.str) {
		r1, _ = utf8.DecodeLastRune(i.str[:pos])
	}
	if pos < len(i.str) {
		r2, _ = utf8.DecodeRune(i.str[pos:])
	}
	return syntax.EmptyOpContext(r1, r2)
}
// lastIndexFunc is the same as LastIndexFunc except that if
// truth==false, the sense of the predicate function is
// inverted.
func lastIndexFunc(s []byte, f func(r int) bool, truth bool) int {
	for i := len(s); i > 0; {
		rune, size := utf8.DecodeLastRune(s[0:i])
		i -= size
		if f(rune) == truth {
			return i
		}
	}
	return -1
}
Beispiel #3
0
// UnreadRune unreads the last rune returned by ReadRune.
// If the most recent read or write operation on the buffer was
// not a ReadRune, UnreadRune returns an error.  (In this regard
// it is stricter than UnreadByte, which will unread the last byte
// from any read operation.)
func (b *Buffer) UnreadRune() error {
	if b.lastRead != opReadRune {
		return errors.New("bytes.Buffer: UnreadRune: previous operation was not ReadRune")
	}
	b.lastRead = opInvalid
	if b.off > 0 {
		_, n := utf8.DecodeLastRune(b.buf[0:b.off])
		b.off -= n
	}
	return nil
}
// LastIndexAny interprets s as a sequence of UTF-8-encoded Unicode code
// points.  It returns the byte index of the last occurrence in s of any of
// the Unicode code points in chars.  It returns -1 if chars is empty or if
// there is no code point in common.
func LastIndexAny(s []byte, chars string) int {
	if len(chars) > 0 {
		for i := len(s); i > 0; {
			rune, size := utf8.DecodeLastRune(s[0:i])
			i -= size
			for _, m := range chars {
				if rune == m {
					return i
				}
			}
		}
	}
	return -1
}
Beispiel #5
0
// endsWithCSSKeyword returns whether b ends with an ident that
// case-insensitively matches the lower-case kw.
func endsWithCSSKeyword(b []byte, kw string) bool {
	i := len(b) - len(kw)
	if i < 0 {
		// Too short.
		return false
	}
	if i != 0 {
		r, _ := utf8.DecodeLastRune(b[:i])
		if isCSSNmchar(r) {
			// Too long.
			return false
		}
	}
	// Many CSS keywords, such as "!important" can have characters encoded,
	// but the URI production does not allow that according to
	// http://www.w3.org/TR/css3-syntax/#TOK-URI
	// This does not attempt to recognize encoded keywords. For example,
	// given "\75\72\6c" and "url" this return false.
	return string(bytes.ToLower(b[i:])) == kw
}
Beispiel #6
0
// jsValEscaper escapes its inputs to a JS Expression (section 11.14) that has
// nether side-effects nor free variables outside (NaN, Infinity).
func jsValEscaper(args ...interface{}) string {
	var a interface{}
	if len(args) == 1 {
		a = args[0]
		switch t := a.(type) {
		case JS:
			return string(t)
		case JSStr:
			// TODO: normalize quotes.
			return `"` + string(t) + `"`
		case json.Marshaler:
			// Do not treat as a Stringer.
		case fmt.Stringer:
			a = t.String()
		}
	} else {
		a = fmt.Sprint(args...)
	}
	// TODO: detect cycles before calling Marshal which loops infinitely on
	// cyclic data. This may be an unnacceptable DoS risk.

	b, err := json.Marshal(a)
	if err != nil {
		// Put a space before comment so that if it is flush against
		// a division operator it is not turned into a line comment:
		//     x/{{y}}
		// turning into
		//     x//* error marshalling y:
		//          second line of error message */null
		return fmt.Sprintf(" /* %s */null ", strings.Replace(err.Error(), "*/", "* /", -1))
	}

	// TODO: maybe post-process output to prevent it from containing
	// "<!--", "-->", "<![CDATA[", "]]>", or "</script"
	// in case custom marshallers produce output containing those.

	// TODO: Maybe abbreviate \u00ab to \xab to produce more compact output.
	if len(b) == 0 {
		// In, `x=y/{{.}}*z` a json.Marshaler that produces "" should
		// not cause the output `x=y/*z`.
		return " null "
	}
	first, _ := utf8.DecodeRune(b)
	last, _ := utf8.DecodeLastRune(b)
	var buf bytes.Buffer
	// Prevent IdentifierNames and NumericLiterals from running into
	// keywords: in, instanceof, typeof, void
	pad := isJSIdentPart(first) || isJSIdentPart(last)
	if pad {
		buf.WriteByte(' ')
	}
	written := 0
	// Make sure that json.Marshal escapes codepoints U+2028 & U+2029
	// so it falls within the subset of JSON which is valid JS.
	for i := 0; i < len(b); {
		rune, n := utf8.DecodeRune(b[i:])
		repl := ""
		if rune == 0x2028 {
			repl = `\u2028`
		} else if rune == 0x2029 {
			repl = `\u2029`
		}
		if repl != "" {
			buf.Write(b[written:i])
			buf.WriteString(repl)
			written = i + n
		}
		i += n
	}
	if buf.Len() != 0 {
		buf.Write(b[written:])
		if pad {
			buf.WriteByte(' ')
		}
		b = buf.Bytes()
	}
	return string(b)
}