exp/template/html: define isComment helper

Non semantics-changing refactoring in preparation for comment elision.

R=nigeltao
CC=golang-dev
https://golang.org/cl/5071043

diff --git a/src/pkg/exp/template/html/context.go b/src/pkg/exp/template/html/context.go
index f7802d04b3155ccf72a094ce561997aa6d4d6f82..57d44938ca66169305fb71a06f1beb5b0d0e307f 100644 (file)
--- a/src/pkg/exp/template/html/context.go
+++ b/src/pkg/exp/template/html/context.go
@@ -89,8 +89,8 @@ const (
        // stateBeforeValue occurs after the equals sign but before the value.
        // It occurs between the ^'s in ` name =^ ^value`.
        stateBeforeValue
-       // stateComment occurs inside an <!-- HTML comment -->.
-       stateComment
+       // stateHTMLCmt occurs inside an <!-- HTML comment -->.
+       stateHTMLCmt
        // stateRCDATA occurs inside an RCDATA element (<textarea> or <title>)
        // as described at http://dev.w3.org/html5/spec/syntax.html#elements-0
        stateRCDATA
@@ -137,7 +137,7 @@ var stateNames = [...]string{
        stateAttrName:    "stateAttrName",
        stateAfterName:   "stateAfterName",
        stateBeforeValue: "stateBeforeValue",
-       stateComment:     "stateComment",
+       stateHTMLCmt:     "stateHTMLCmt",
        stateRCDATA:      "stateRCDATA",
        stateAttr:        "stateAttr",
        stateURL:         "stateURL",
@@ -165,6 +165,16 @@ func (s state) String() string {
        return fmt.Sprintf("illegal state %d", int(s))
 }
 
+// isComment is true for any state that contains content meant for template
+// authors & maintainers, not for end-users or machines.
+func isComment(s state) bool {
+       switch s {
+       case stateHTMLCmt, stateJSBlockCmt, stateJSLineCmt, stateCSSBlockCmt, stateCSSLineCmt:
+               return true
+       }
+       return false
+}
+
 // delim is the delimiter that will end the current HTML attribute.
 type delim uint8
 

diff --git a/src/pkg/exp/template/html/escape.go b/src/pkg/exp/template/html/escape.go
index a8f3dfc17ddec65c8fe89acd4d5f440dabc0596a..e307fc9ae42333ee17c19ba4dcb2434aba5803c9 100644 (file)
--- a/src/pkg/exp/template/html/escape.go
+++ b/src/pkg/exp/template/html/escape.go
@@ -187,11 +187,6 @@ func (e *escaper) escapeAction(c context, n *parse.ActionNode) context {
                s = append(s, "exp_template_html_jsstrescaper")
        case stateJSRegexp:
                s = append(s, "exp_template_html_jsregexpescaper")
-       case stateComment, stateJSBlockCmt, stateJSLineCmt, stateCSSBlockCmt, stateCSSLineCmt:
-               return context{
-                       state: stateError,
-                       err:   errorf(ErrInsideComment, n.Line, "%s appears inside a comment", n),
-               }
        case stateCSS:
                s = append(s, "exp_template_html_cssvaluefilter")
        case stateText:
@@ -204,6 +199,12 @@ func (e *escaper) escapeAction(c context, n *parse.ActionNode) context {
                c.state = stateAttrName
                s = append(s, "exp_template_html_htmlnamefilter")
        default:
+               if isComment(c.state) {
+                       return context{
+                               state: stateError,
+                               err:   errorf(ErrInsideComment, n.Line, "%s appears inside a comment", n),
+                       }
+               }
                panic("unexpected state " + c.state.String())
        }
        switch c.delim {

diff --git a/src/pkg/exp/template/html/escape_test.go b/src/pkg/exp/template/html/escape_test.go
index 5202aa34a13fa915799c955a43e8a64af8da04be..47927e753ecbbc2b14166b1ef195c89768ddaa16 100644 (file)
--- a/src/pkg/exp/template/html/escape_test.go
+++ b/src/pkg/exp/template/html/escape_test.go
@@ -1123,15 +1123,15 @@ func TestEscapeText(t *testing.T) {
                },
                {
                        `<!-- foo`,
-                       context{state: stateComment},
+                       context{state: stateHTMLCmt},
                },
                {
                        `<!-->`,
-                       context{state: stateComment},
+                       context{state: stateHTMLCmt},
                },
                {
                        `<!--->`,
-                       context{state: stateComment},
+                       context{state: stateHTMLCmt},
                },
                {
                        `<!-- foo -->`,
@@ -1167,7 +1167,7 @@ func TestEscapeText(t *testing.T) {
                },
                {
                        `<script>foo</script><!--`,
-                       context{state: stateComment},
+                       context{state: stateHTMLCmt},
                },
                {
                        `<script>document.write("<p>foo</p>");`,

diff --git a/src/pkg/exp/template/html/transition.go b/src/pkg/exp/template/html/transition.go
index 6b10561caa4856373abd6e2d170014238099dcfa..7c7f845b175838df9b5b36a588e0ab2b28e1dddc 100644 (file)
--- a/src/pkg/exp/template/html/transition.go
+++ b/src/pkg/exp/template/html/transition.go
@@ -21,7 +21,7 @@ var transitionFunc = [...]func(context, []byte) (context, []byte){
        stateAttrName:    tAttrName,
        stateAfterName:   tAfterName,
        stateBeforeValue: tBeforeValue,
-       stateComment:     tComment,
+       stateHTMLCmt:     tHTMLCmt,
        stateRCDATA:      tSpecialTagEnd,
        stateAttr:        tAttr,
        stateURL:         tURL,
@@ -52,7 +52,7 @@ func tText(c context, s []byte) (context, []byte) {
                if i == -1 || i+1 == len(s) {
                        return c, nil
                } else if i+4 <= len(s) && bytes.Equal(commentStart, s[i:i+4]) {
-                       return context{state: stateComment}, s[i+4:]
+                       return context{state: stateHTMLCmt}, s[i+4:]
                }
                i++
                if s[i] == '/' {
@@ -168,8 +168,8 @@ func tBeforeValue(c context, s []byte) (context, []byte) {
        return c, s[i:]
 }
 
-// tComment is the context transition function for stateComment.
-func tComment(c context, s []byte) (context, []byte) {
+// tHTMLCmt is the context transition function for stateHTMLCmt.
+func tHTMLCmt(c context, s []byte) (context, []byte) {
        i := bytes.Index(s, commentEnd)
        if i != -1 {
                return context{}, s[i+3:]