html: a first step at parsing foreign content (MathML, SVG).

Nodes now have a Namespace field. Pass adoption01.dat, test 12: <a><svg><tr><input></a> | <html> | <head> | <body> | <a> | <svg svg> | <svg tr> | <svg input> The other adoption01.dat tests already passed. R=andybalholm CC=golang-dev https://golang.org/cl/5467075

html: a first step at parsing foreign content (MathML, SVG).
b9064fb1 · Nigel Tao · 0643aace · b9064fb1 · b9064fb1 · b9064fb1
Commit b9064fb1 authored Dec 13, 2011 by Nigel Tao
5 changed files
--- a/src/pkg/html/Makefile
+++ b/src/pkg/html/Makefile
@@ -11,6 +11,7 @@ GOFILES=\
 	doctype.go\
 	entity.go\
 	escape.go\
+	foreign.go\
 	node.go\
 	parse.go\
 	render.go\

--- a/src/pkg/html/foreign.go
+++ b/src/pkg/html/foreign.go
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package html
+
+// Section 12.2.5.5.
+var breakout = map[string]bool{
+	"b":          true,
+	"big":        true,
+	"blockquote": true,
+	"body":       true,
+	"br":         true,
+	"center":     true,
+	"code":       true,
+	"dd":         true,
+	"div":        true,
+	"dl":         true,
+	"dt":         true,
+	"em":         true,
+	"embed":      true,
+	"font":       true,
+	"h1":         true,
+	"h2":         true,
+	"h3":         true,
+	"h4":         true,
+	"h5":         true,
+	"h6":         true,
+	"head":       true,
+	"hr":         true,
+	"i":          true,
+	"img":        true,
+	"li":         true,
+	"listing":    true,
+	"menu":       true,
+	"meta":       true,
+	"nobr":       true,
+	"ol":         true,
+	"p":          true,
+	"pre":        true,
+	"ruby":       true,
+	"s":          true,
+	"small":      true,
+	"span":       true,
+	"strong":     true,
+	"strike":     true,
+	"sub":        true,
+	"sup":        true,
+	"table":      true,
+	"tt":         true,
+	"u":          true,
+	"ul":         true,
+	"var":        true,
+}
+
+// TODO: add look-up tables for MathML and SVG adjustments.
--- a/src/pkg/html/node.go
+++ b/src/pkg/html/node.go
@@ -24,14 +24,15 @@ var scopeMarker = Node{Type: scopeMarkerNode}

 // A Node consists of a NodeType and some Data (tag name for element nodes,
 // content for text) and are part of a tree of Nodes. Element nodes may also
-// contain a slice of Attributes. Data is unescaped, so that it looks like
-// "a<b" rather than "a&lt;b".
+// have a Namespace and contain a slice of Attributes. Data is unescaped, so
+// that it looks like "a<b" rather than "a&lt;b".
 type Node struct {
-	Parent *Node
-	Child  []*Node
-	Type   NodeType
-	Data   string
-	Attr   []Attribute
+	Parent    *Node
+	Child     []*Node
+	Type      NodeType
+	Data      string
+	Namespace string
+	Attr      []Attribute
 }

 // Add adds a node as a child of n.

--- a/src/pkg/html/parse.go
+++ b/src/pkg/html/parse.go
@@ -192,9 +192,10 @@ func (p *parser) addText(text string) {
 // addElement calls addChild with an element node.
 func (p *parser) addElement(tag string, attr []Attribute) {
 	p.addChild(&Node{
-		Type: ElementNode,
-		Data: tag,
-		Attr: attr,
+		Type:      ElementNode,
+		Data:      tag,
+		Namespace: p.top().Namespace,
+		Attr:      attr,
 	})
 }

@@ -318,7 +319,10 @@ func (p *parser) resetInsertionMode() {
 		case "html":
 			p.im = beforeHeadIM
 		default:
-			continue
+			if p.top().Namespace == "" {
+				continue
+			}
+			p.im = inForeignContentIM
 		}
 		return
 	}
@@ -792,6 +796,21 @@ func inBodyIM(p *parser) bool {
 			p.reconstructActiveFormattingElements()
 			p.framesetOK = false
 			p.addElement(p.tok.Data, p.tok.Attr)
+		case "math", "svg":
+			p.reconstructActiveFormattingElements()
+			namespace := ""
+			if p.tok.Data == "math" {
+				// TODO: adjust MathML attributes.
+				namespace = "mathml"
+			} else {
+				// TODO: adjust SVG attributes.
+				namespace = "svg"
+			}
+			// TODO: adjust foreign attributes.
+			p.addElement(p.tok.Data, p.tok.Attr)
+			p.top().Namespace = namespace
+			p.im = inForeignContentIM
+			return true
 		case "caption", "col", "colgroup", "frame", "head", "tbody", "td", "tfoot", "th", "thead", "tr":
 			// Ignore the token.
 		default:
@@ -1557,6 +1576,39 @@ func afterAfterFramesetIM(p *parser) bool {
 	return true
 }

+// TODO: fix up the other IM's section numbers to match the latest spec.
+
+// Section 12.2.5.5.
+func inForeignContentIM(p *parser) bool {
+	switch p.tok.Type {
+	case CommentToken:
+		p.addChild(&Node{
+			Type: CommentNode,
+			Data: p.tok.Data,
+		})
+	case StartTagToken:
+		if breakout[p.tok.Data] {
+			// TODO.
+		}
+		switch p.top().Namespace {
+		case "mathml":
+			// TODO: adjust MathML attributes.
+		case "svg":
+			// TODO: adjust SVG tag names.
+			// TODO: adjust SVG attributes.
+		default:
+			panic("html: bad parser state: unexpected namespace")
+		}
+		// TODO: adjust foreign attributes.
+		p.addElement(p.tok.Data, p.tok.Attr)
+	case EndTagToken:
+		// TODO.
+	default:
+		// Ignore the token.
+	}
+	return true
+}
+
 func (p *parser) parse() error {
 	// Iterate until EOF. Any other error will cause an early return.
 	consumed := true

--- a/src/pkg/html/parse_test.go
+++ b/src/pkg/html/parse_test.go
@@ -98,7 +98,11 @@ func dumpLevel(w io.Writer, n *Node, level int) error {
 	case DocumentNode:
 		return errors.New("unexpected DocumentNode")
 	case ElementNode:
-		fmt.Fprintf(w, "<%s>", n.Data)
+		if n.Namespace != "" {
+			fmt.Fprintf(w, "<%s %s>", n.Namespace, n.Data)
+		} else {
+			fmt.Fprintf(w, "<%s>", n.Data)
+		}
 		for _, a := range n.Attr {
 			io.WriteString(w, "\n")
 			dumpIndent(w, level+1)
@@ -161,6 +165,7 @@ func TestParser(t *testing.T) {
 		n int
 	}{
 		// TODO(nigeltao): Process all the test cases from all the .dat files.
+		{"adoption01.dat", -1},
 		{"doctype01.dat", -1},
 		{"tests1.dat", -1},
 		{"tests2.dat", -1},