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exp/template/html: change transition functions to return indices

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Formulaic changes to transition functions in preparation for CL 5074041.
This should be completely semantics preserving.

R=nigeltao
CC=golang-dev
https://golang.org/cl/5091041
This commit is contained in:
Mike Samuel 2011-09-19 20:52:14 -07:00
parent 3c3a86ccc7
commit 3a013f1175
3 changed files with 147 additions and 143 deletions
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29
src/pkg/exp/template/html/escape.go
View File

@ -547,22 +547,22 @@ var delimEnds = [...]string{
// escapeText escapes a text template node.
func (e *escaper) escapeText(c context, n *parse.TextNode) context {
s, written := n.Text, 0
var b bytes.Buffer
for len(s) > 0 {
c1, s1 := contextAfterText(c, s)
s, written, i, b := n.Text, 0, 0, new(bytes.Buffer)
for i != len(s) {
c1, nread := contextAfterText(c, s[i:])
i1 := i + nread
if c.state == c1.state && (c.state == stateText || c.state == stateRCDATA) {
i0, i1 := len(n.Text)-len(s), len(n.Text)-len(s1)
for i := i0; i < i1; i++ {
if n.Text[i] == '<' {
b.Write(n.Text[written:i])
for j := i; j < i1; j++ {
if s[j] == '<' {
b.Write(s[written:j])
b.WriteString("&lt;")
written = i + 1
written = j + 1
}
}
}
c, s = c1, s1
c, i = c1, i1
}
if written != 0 && c.state != stateError {
b.Write(n.Text[written:])
e.editTextNode(n, b.Bytes())
@ -572,7 +572,7 @@ func (e *escaper) escapeText(c context, n *parse.TextNode) context {
// contextAfterText starts in context c, consumes some tokens from the front of
// s, then returns the context after those tokens and the unprocessed suffix.
func contextAfterText(c context, s []byte) (context, []byte) {
func contextAfterText(c context, s []byte) (context, int) {
if c.delim == delimNone {
return transitionFunc[c.state](c, s)
}
@ -584,9 +584,10 @@ func contextAfterText(c context, s []byte) (context, []byte) {
// <button onclick="alert(&quot;Hi!&quot;)">
// without having to entity decode token boundaries.
for u := []byte(html.UnescapeString(string(s))); len(u) != 0; {
c, u = transitionFunc[c.state](c, u)
c1, i1 := transitionFunc[c.state](c, u)
c, u = c1, u[i1:]
}
return c, nil
return c, len(s)
}
if c.delim != delimSpaceOrTagEnd {
// Consume any quote.
@ -594,7 +595,7 @@ func contextAfterText(c context, s []byte) (context, []byte) {
}
// On exiting an attribute, we discard all state information
// except the state and element.
return context{state: stateTag, element: c.element}, s[i:]
return context{state: stateTag, element: c.element}, i
}
// editActionNode records a change to an action pipeline for later commit.

29
src/pkg/exp/template/html/html.go
View File

@ -165,43 +165,44 @@ func htmlReplacer(s string, replacementTable []string, badRunes bool) string {
// For example, `<b>&iexcl;Hi!</b> <script>...</script>` -> `&iexcl;Hi! `.
func stripTags(html string) string {
var b bytes.Buffer
s, c := []byte(html), context{}
s, c, i := []byte(html), context{}, 0
// Using the transition funcs helps us avoid mangling
// `<div title="1>2">` or `I <3 Ponies!`.
for len(s) > 0 {
for i != len(s) {
if c.delim == delimNone {
d, t := transitionFunc[c.state](c, s)
d, nread := transitionFunc[c.state](c, s[i:])
i1 := i + nread
if c.state == stateText || c.state == stateRCDATA {
i := len(s) - len(t)
// Emit text up to the start of the tag or comment.
j := i1
if d.state != c.state {
for j := i - 1; j >= 0; j-- {
if s[j] == '<' {
i = j
for j1 := j - 1; j1 >= i; j1-- {
if s[j1] == '<' {
j = j1
break
}
}
}
b.Write(s[:i])
b.Write(s[i:j])
}
c, s = d, t
c, i = d, i1
continue
}
i := bytes.IndexAny(s, delimEnds[c.delim])
if i == -1 {
i1 := i + bytes.IndexAny(s[i:], delimEnds[c.delim])
if i1 < i {
break
}
if c.delim != delimSpaceOrTagEnd {
// Consume any quote.
i++
i1++
}
c, s = context{state: stateTag, element: c.element}, s[i:]
c, i = context{state: stateTag, element: c.element}, i1
}
if c.state == stateText {
if b.Len() == 0 {
return html
}
b.Write(s)
b.Write(s[i:])
}
return b.String()
}

232
src/pkg/exp/template/html/transition.go
View File

@ -14,8 +14,9 @@ import (
// transitionFunc is the array of context transition functions for text nodes.
// A transition function takes a context and template text input, and returns
// the updated context and any unconsumed text.
var transitionFunc = [...]func(context, []byte) (context, []byte){
// the updated context and the number of bytes consumed from the front of the
// input.
var transitionFunc = [...]func(context, []byte) (context, int){
stateText: tText,
stateTag: tTag,
stateAttrName: tAttrName,
@ -46,27 +47,28 @@ var commentStart = []byte("<!--")
var commentEnd = []byte("-->")
// tText is the context transition function for the text state.
func tText(c context, s []byte) (context, []byte) {
func tText(c context, s []byte) (context, int) {
k := 0
for {
i := bytes.IndexByte(s, '<')
if i == -1 || i+1 == len(s) {
return c, nil
i := k + bytes.IndexByte(s[k:], '<')
if i < k || i+1 == len(s) {
return c, len(s)
} else if i+4 <= len(s) && bytes.Equal(commentStart, s[i:i+4]) {
return context{state: stateHTMLCmt}, s[i+4:]
return context{state: stateHTMLCmt}, i + 4
}
i++
if s[i] == '/' {
if i+1 == len(s) {
return c, nil
return c, len(s)
}
i++
}
j, e := eatTagName(s, i)
if j != i {
// We've found an HTML tag.
return context{state: stateTag, element: e}, s[j:]
return context{state: stateTag, element: e}, j
}
s = s[j:]
k = j
}
panic("unreachable")
}
@ -80,21 +82,21 @@ var elementContentType = [...]state{
}
// tTag is the context transition function for the tag state.
func tTag(c context, s []byte) (context, []byte) {
func tTag(c context, s []byte) (context, int) {
// Find the attribute name.
i := eatWhiteSpace(s, 0)
if i == len(s) {
return c, nil
return c, len(s)
}
if s[i] == '>' {
return context{
state: elementContentType[c.element],
element: c.element,
}, s[i+1:]
}, i + 1
}
j, err := eatAttrName(s, i)
if err != nil {
return context{state: stateError, err: err}, nil
return context{state: stateError, err: err}, len(s)
}
state, attr := stateTag, attrNone
if i != j {
@ -112,35 +114,35 @@ func tTag(c context, s []byte) (context, []byte) {
state = stateAfterName
}
}
return context{state: state, element: c.element, attr: attr}, s[j:]
return context{state: state, element: c.element, attr: attr}, j
}
// tAttrName is the context transition function for stateAttrName.
func tAttrName(c context, s []byte) (context, []byte) {
func tAttrName(c context, s []byte) (context, int) {
i, err := eatAttrName(s, 0)
if err != nil {
return context{state: stateError, err: err}, nil
return context{state: stateError, err: err}, len(s)
} else if i == len(s) {
return c, nil
return c, len(s)
}
c.state = stateAfterName
return c, s[i:]
return c, i
}
// tAfterName is the context transition function for stateAfterName.
func tAfterName(c context, s []byte) (context, []byte) {
func tAfterName(c context, s []byte) (context, int) {
// Look for the start of the value.
i := eatWhiteSpace(s, 0)
if i == len(s) {
return c, nil
return c, len(s)
} else if s[i] != '=' {
// Occurs due to tag ending '>', and valueless attribute.
c.state = stateTag
return c, s[i:]
return c, i
}
c.state = stateBeforeValue
// Consume the "=".
return c, s[i+1:]
return c, i + 1
}
var attrStartStates = [...]state{
@ -151,10 +153,10 @@ var attrStartStates = [...]state{
}
// tBeforeValue is the context transition function for stateBeforeValue.
func tBeforeValue(c context, s []byte) (context, []byte) {
func tBeforeValue(c context, s []byte) (context, int) {
i := eatWhiteSpace(s, 0)
if i == len(s) {
return c, nil
return c, len(s)
}
// Find the attribute delimiter.
delim := delimSpaceOrTagEnd
@ -165,16 +167,16 @@ func tBeforeValue(c context, s []byte) (context, []byte) {
delim, i = delimDoubleQuote, i+1
}
c.state, c.delim, c.attr = attrStartStates[c.attr], delim, attrNone
return c, s[i:]
return c, i
}
// tHTMLCmt is the context transition function for stateHTMLCmt.
func tHTMLCmt(c context, s []byte) (context, []byte) {
func tHTMLCmt(c context, s []byte) (context, int) {
i := bytes.Index(s, commentEnd)
if i != -1 {
return context{}, s[i+3:]
return context{}, i + 3
}
return c, nil
return c, len(s)
}
// specialTagEndMarkers maps element types to the character sequence that
@ -188,24 +190,24 @@ var specialTagEndMarkers = [...]string{
// tSpecialTagEnd is the context transition function for raw text and RCDATA
// element states.
func tSpecialTagEnd(c context, s []byte) (context, []byte) {
func tSpecialTagEnd(c context, s []byte) (context, int) {
if c.element != elementNone {
end := specialTagEndMarkers[c.element]
i := strings.Index(strings.ToLower(string(s)), end)
if i != -1 {
return context{state: stateTag}, s[i+len(end):]
return context{state: stateTag}, i + len(end)
}
}
return c, nil
return c, len(s)
}
// tAttr is the context transition function for the attribute state.
func tAttr(c context, s []byte) (context, []byte) {
return c, nil
func tAttr(c context, s []byte) (context, int) {
return c, len(s)
}
// tURL is the context transition function for the URL state.
func tURL(c context, s []byte) (context, []byte) {
func tURL(c context, s []byte) (context, int) {
if bytes.IndexAny(s, "#?") >= 0 {
c.urlPart = urlPartQueryOrFrag
} else if len(s) != eatWhiteSpace(s, 0) && c.urlPart == urlPartNone {
@ -213,20 +215,20 @@ func tURL(c context, s []byte) (context, []byte) {
// attrs: http://www.w3.org/TR/html5/index.html#attributes-1
c.urlPart = urlPartPreQuery
}
return c, nil
return c, len(s)
}
// tJS is the context transition function for the JS state.
func tJS(c context, s []byte) (context, []byte) {
if d, t := tSpecialTagEnd(c, s); t != nil {
return d, t
func tJS(c context, s []byte) (context, int) {
if d, i := tSpecialTagEnd(c, s); i != len(s) {
return d, i
}
i := bytes.IndexAny(s, `"'/`)
if i == -1 {
// Entire input is non string, comment, regexp tokens.
c.jsCtx = nextJSCtx(s, c.jsCtx)
return c, nil
return c, len(s)
}
c.jsCtx = nextJSCtx(s[:i], c.jsCtx)
switch s[i] {
@ -248,18 +250,18 @@ func tJS(c context, s []byte) (context, []byte) {
return context{
state: stateError,
err: errorf(ErrSlashAmbig, 0, "'/' could start div or regexp: %.32q", s[i:]),
}, nil
}, len(s)
}
default:
panic("unreachable")
}
return c, s[i+1:]
return c, i + 1
}
// tJSStr is the context transition function for the JS string states.
func tJSStr(c context, s []byte) (context, []byte) {
if d, t := tSpecialTagEnd(c, s); t != nil {
return d, t
func tJSStr(c context, s []byte) (context, int) {
if d, i := tSpecialTagEnd(c, s); i != len(s) {
return d, i
}
quoteAndEsc := `\"`
@ -267,55 +269,54 @@ func tJSStr(c context, s []byte) (context, []byte) {
quoteAndEsc = `\'`
}
b := s
k := 0
for {
i := bytes.IndexAny(b, quoteAndEsc)
if i == -1 {
return c, nil
i := k + bytes.IndexAny(s[k:], quoteAndEsc)
if i < k {
return c, len(s)
}
if b[i] == '\\' {
if s[i] == '\\' {
i++
if i == len(b) {
if i == len(s) {
return context{
state: stateError,
err: errorf(ErrPartialEscape, 0, "unfinished escape sequence in JS string: %q", s),
}, nil
}, len(s)
}
} else {
c.state, c.jsCtx = stateJS, jsCtxDivOp
return c, b[i+1:]
return c, i + 1
}
b = b[i+1:]
k = i + 1
}
panic("unreachable")
}
// tJSRegexp is the context transition function for the /RegExp/ literal state.
func tJSRegexp(c context, s []byte) (context, []byte) {
if d, t := tSpecialTagEnd(c, s); t != nil {
return d, t
func tJSRegexp(c context, s []byte) (context, int) {
if d, i := tSpecialTagEnd(c, s); i != len(s) {
return d, i
}
b := s
inCharset := false
k, inCharset := 0, false
for {
i := bytes.IndexAny(b, `/[\]`)
if i == -1 {
i := k + bytes.IndexAny(s[k:], `\/[]`)
if i < k {
break
}
switch b[i] {
switch s[i] {
case '/':
if !inCharset {
c.state, c.jsCtx = stateJS, jsCtxDivOp
return c, b[i+1:]
return c, i + 1
}
case '\\':
i++
if i == len(b) {
if i == len(s) {
return context{
state: stateError,
err: errorf(ErrPartialEscape, 0, "unfinished escape sequence in JS regexp: %q", s),
}, nil
}, len(s)
}
case '[':
inCharset = true
@ -324,7 +325,7 @@ func tJSRegexp(c context, s []byte) (context, []byte) {
default:
panic("unreachable")
}
b = b[i+1:]
k = i + 1
}
if inCharset {
@ -333,22 +334,22 @@ func tJSRegexp(c context, s []byte) (context, []byte) {
return context{
state: stateError,
err: errorf(ErrPartialCharset, 0, "unfinished JS regexp charset: %q", s),
}, nil
}, len(s)
}
return c, nil
return c, len(s)
}
var blockCommentEnd = []byte("*/")
// tBlockCmt is the context transition function for /*comment*/ states.
func tBlockCmt(c context, s []byte) (context, []byte) {
if d, t := tSpecialTagEnd(c, s); t != nil {
return d, t
func tBlockCmt(c context, s []byte) (context, int) {
if d, i := tSpecialTagEnd(c, s); i != len(s) {
return d, i
}
i := bytes.Index(s, blockCommentEnd)
if i == -1 {
return c, nil
return c, len(s)
}
switch c.state {
case stateJSBlockCmt:
@ -358,13 +359,13 @@ func tBlockCmt(c context, s []byte) (context, []byte) {
default:
panic(c.state.String())
}
return c, s[i+2:]
return c, i + 2
}
// tLineCmt is the context transition function for //comment states.
func tLineCmt(c context, s []byte) (context, []byte) {
if d, t := tSpecialTagEnd(c, s); t != nil {
return d, t
func tLineCmt(c context, s []byte) (context, int) {
if d, i := tSpecialTagEnd(c, s); i != len(s) {
return d, i
}
var lineTerminators string
var endState state
@ -386,21 +387,21 @@ func tLineCmt(c context, s []byte) (context, []byte) {
i := bytes.IndexAny(s, lineTerminators)
if i == -1 {
return c, nil
return c, len(s)
}
c.state = endState
// Per section 7.4 of EcmaScript 5 : http://es5.github.com/#x7.4
// "However, the LineTerminator at the end of the line is not
// considered to be part of the single-line comment; it is recognised
// separately by the lexical grammar and becomes part of the stream of
// input elements for the syntactic grammar."
return c, s[i:]
// considered to be part of the single-line comment; it is
// recognized separately by the lexical grammar and becomes part
// of the stream of input elements for the syntactic grammar."
return c, i
}
// tCSS is the context transition function for the CSS state.
func tCSS(c context, s []byte) (context, []byte) {
if d, t := tSpecialTagEnd(c, s); t != nil {
return d, t
func tCSS(c context, s []byte) (context, int) {
if d, i := tSpecialTagEnd(c, s); i != len(s) {
return d, i
}
// CSS quoted strings are almost never used except for:
@ -430,55 +431,55 @@ func tCSS(c context, s []byte) (context, []byte) {
// have the attribute name available if our conservative assumption
// proves problematic for real code.
k := 0
for {
i := bytes.IndexAny(s, `("'/`)
if i == -1 {
return c, nil
i := k + bytes.IndexAny(s[k:], `("'/`)
if i < k {
return c, len(s)
}
switch s[i] {
case '(':
// Look for url to the left.
p := bytes.TrimRight(s[:i], "\t\n\f\r ")
if endsWithCSSKeyword(p, "url") {
q := bytes.TrimLeft(s[i+1:], "\t\n\f\r ")
j := len(s) - len(bytes.TrimLeft(s[i+1:], "\t\n\f\r "))
switch {
case len(q) != 0 && q[0] == '"':
c.state, s = stateCSSDqURL, q[1:]
case len(q) != 0 && q[0] == '\'':
c.state, s = stateCSSSqURL, q[1:]
case j != len(s) && s[j] == '"':
c.state, j = stateCSSDqURL, j+1
case j != len(s) && s[j] == '\'':
c.state, j = stateCSSSqURL, j+1
default:
c.state, s = stateCSSURL, q
c.state = stateCSSURL
}
return c, s
return c, j
}
case '/':
if i+1 < len(s) {
switch s[i+1] {
case '/':
c.state = stateCSSLineCmt
return c, s[i+2:]
return c, i + 2
case '*':
c.state = stateCSSBlockCmt
return c, s[i+2:]
return c, i + 2
}
}
case '"':
c.state = stateCSSDqStr
return c, s[i+1:]
return c, i + 1
case '\'':
c.state = stateCSSSqStr
return c, s[i+1:]
return c, i + 1
}
s = s[i+1:]
k = i + 1
}
panic("unreachable")
}
// tCSSStr is the context transition function for the CSS string and URL states.
func tCSSStr(c context, s []byte) (context, []byte) {
if d, t := tSpecialTagEnd(c, s); t != nil {
return d, t
func tCSSStr(c context, s []byte) (context, int) {
if d, i := tSpecialTagEnd(c, s); i != len(s) {
return d, i
}
var endAndEsc string
@ -495,33 +496,34 @@ func tCSSStr(c context, s []byte) (context, []byte) {
panic(c.state.String())
}
b := s
k := 0
for {
i := bytes.IndexAny(b, endAndEsc)
if i == -1 {
return tURL(c, decodeCSS(b))
i := k + bytes.IndexAny(s[k:], endAndEsc)
if i < k {
c, nread := tURL(c, decodeCSS(s[k:]))
return c, k + nread
}
if b[i] == '\\' {
if s[i] == '\\' {
i++
if i == len(b) {
if i == len(s) {
return context{
state: stateError,
err: errorf(ErrPartialEscape, 0, "unfinished escape sequence in CSS string: %q", s),
}, nil
}, len(s)
}
} else {
c.state = stateCSS
return c, b[i+1:]
return c, i + 1
}
c, _ = tURL(c, decodeCSS(b[:i+1]))
b = b[i+1:]
c, _ = tURL(c, decodeCSS(s[:i+1]))
k = i + 1
}
panic("unreachable")
}
// tError is the context transition function for the error state.
func tError(c context, s []byte) (context, []byte) {
return c, nil
func tError(c context, s []byte) (context, int) {
return c, len(s)
}
// eatAttrName returns the largest j such that s[i:j] is an attribute name.