exp/template/html: change transition functions to return indices
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
diff --git a/src/pkg/exp/template/html/escape.go b/src/pkg/exp/template/html/escape.go
index b859751..6490c5f 100644
--- a/src/pkg/exp/template/html/escape.go
+++ b/src/pkg/exp/template/html/escape.go
@@ -547,22 +547,22 @@
// 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("<")
- 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 @@
// 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 @@
// <button onclick="alert("Hi!")">
// 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 @@
}
// 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.
diff --git a/src/pkg/exp/template/html/html.go b/src/pkg/exp/template/html/html.go
index 7b5fab0..27ef652 100644
--- a/src/pkg/exp/template/html/html.go
+++ b/src/pkg/exp/template/html/html.go
@@ -165,43 +165,44 @@
// For example, `<b>¡Hi!</b> <script>...</script>` -> `¡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()
}
diff --git a/src/pkg/exp/template/html/transition.go b/src/pkg/exp/template/html/transition.go
index 7c7f845..0274d9e 100644
--- a/src/pkg/exp/template/html/transition.go
+++ b/src/pkg/exp/template/html/transition.go
@@ -14,8 +14,9 @@
// 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 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 @@
}
// 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 @@
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 @@
}
// 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 @@
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 @@
// 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 @@
// 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 @@
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 @@
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 @@
default:
panic("unreachable")
}
- b = b[i+1:]
+ k = i + 1
}
if inCharset {
@@ -333,22 +334,22 @@
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 @@
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 @@
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 @@
// 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 @@
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.
