exp/html: add parseImpliedToken method to parser

This method will allow us to be explicit about what we're doing when we insert an implied token, and avoid repeating the logic involved in multiple places. R=nigeltao CC=golang-dev https://golang.org/cl/6060048

exp/html: add parseImpliedToken method to parser
This method will allow us to be explicit about what we're doing when we insert an implied token, and avoid repeating the logic involved in multiple places. R=nigeltao CC=golang-dev https://golang.org/cl/6060048
c88ca590 · Andrew Balholm · Nigel Tao · e03dd509 · c88ca590
Commit c88ca590 authored Apr 19, 2012 by Andrew Balholm Committed by Nigel Tao Apr 19, 2012
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Showing with 47 additions and 37 deletions

parse.go src/pkg/exp/html/parse.go +47 -37

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--- a/src/pkg/exp/html/parse.go
+++ b/src/pkg/exp/html/parse.go
@@ -295,23 +295,12 @@ func (p *parser) reconstructActiveFormattingElements() {
 	}
 }

-// read reads the next token. This is usually from the tokenizer, but it may
-// be the synthesized end tag implied by a self-closing tag.
+// read reads the next token from the tokenizer.
 func (p *parser) read() error {
-	if p.hasSelfClosingToken {
-		p.hasSelfClosingToken = false
-		p.tok.Type = EndTagToken
-		p.tok.Attr = nil
-		return nil
-	}
 	p.tokenizer.Next()
 	p.tok = p.tokenizer.Token()
-	switch p.tok.Type {
-	case ErrorToken:
+	if p.tok.Type == ErrorToken {
 		return p.tokenizer.Err()
-	case SelfClosingTagToken:
-		p.hasSelfClosingToken = true
-		p.tok.Type = StartTagToken
 	}
 	return nil
 }
@@ -426,7 +415,8 @@ func beforeHTMLIM(p *parser) bool {
 	case EndTagToken:
 		switch p.tok.Data {
 		case "head", "body", "html", "br":
-			// Drop down to creating an implied <html> tag.
+			p.parseImpliedToken(StartTagToken, "html", nil)
+			return false
 		default:
 			// Ignore the token.
 			return true
@@ -438,9 +428,7 @@ func beforeHTMLIM(p *parser) bool {
 		})
 		return true
 	}
-	// Create an implied <html> tag.
-	p.addElement("html", nil)
-	p.im = beforeHeadIM
+	p.parseImpliedToken(StartTagToken, "html", nil)
 	return false
 }

@@ -466,7 +454,8 @@ func beforeHeadIM(p *parser) bool {
 	case EndTagToken:
 		switch p.tok.Data {
 		case "head", "body", "html", "br":
-			// Drop down to adding an implied <head> tag.
+			p.parseImpliedToken(StartTagToken, "head", nil)
+			return false
 		default:
 			// Ignore the token.
 			return true
@@ -482,9 +471,7 @@ func beforeHeadIM(p *parser) bool {
 		return true
 	}

-	p.addElement("head", nil)
-	p.head = p.top()
-	p.im = inHeadIM
+	p.parseImpliedToken(StartTagToken, "head", nil)
 	return false
 }

@@ -1767,29 +1754,52 @@ func (p *parser) inForeignContent() bool {
 	return true
 }

-func (p *parser) parse() error {
-	// Iterate until EOF. Any other error will cause an early return.
-	consumed := true
-	for {
-		if consumed {
-			if err := p.read(); err != nil {
-				if err == io.EOF {
-					break
-				}
-				return err
-			}
-		}
+// parseImpliedToken parses a token as though it had appeared in the parser's
+// input.
+func (p *parser) parseImpliedToken(t TokenType, data string, attr []Attribute) {
+	realToken, selfClosing := p.tok, p.hasSelfClosingToken
+	p.tok = Token{
+		Type: t,
+		Data: data,
+		Attr: attr,
+	}
+	p.hasSelfClosingToken = false
+	p.parseCurrentToken()
+	p.tok, p.hasSelfClosingToken = realToken, selfClosing
+}
+
+// parseCurrentToken runs the current token through the parsing routines
+// until it is consumed.
+func (p *parser) parseCurrentToken() {
+	if p.tok.Type == SelfClosingTagToken {
+		p.hasSelfClosingToken = true
+		p.tok.Type = StartTagToken
+	}
+
+	consumed := false
+	for !consumed {
 		if p.inForeignContent() {
 			consumed = parseForeignContent(p)
 		} else {
 			consumed = p.im(p)
 		}
 	}
-	// Loop until the final token (the ErrorToken signifying EOF) is consumed.
-	for {
-		if consumed = p.im(p); consumed {
-			break
+
+	if p.hasSelfClosingToken {
+		p.hasSelfClosingToken = false
+		p.parseImpliedToken(EndTagToken, p.tok.Data, nil)
+	}
+}
+
+func (p *parser) parse() error {
+	// Iterate until EOF. Any other error will cause an early return.
+	var err error
+	for err != io.EOF {
+		err = p.read()
+		if err != nil && err != io.EOF {
+			return err
 		}
+		p.parseCurrentToken()
 	}
 	return nil
 }