1 files changed, 222 insertions, 114 deletions

diff --git a/libgo/go/html/token.go b/libgo/go/html/token.go
index ad03241..d266b3a 100644
--- a/libgo/go/html/token.go
+++ b/libgo/go/html/token.go
@@ -27,6 +27,8 @@ const (
 	SelfClosingTagToken
 	// A CommentToken looks like <!--x-->.
 	CommentToken
+	// A DoctypeToken looks like <!DOCTYPE x>
+	DoctypeToken
 )
 
 // String returns a string representation of the TokenType.
@@ -44,6 +46,8 @@ func (t TokenType) String() string {
 		return "SelfClosingTag"
 	case CommentToken:
 		return "Comment"
+	case DoctypeToken:
+		return "Doctype"
 	}
 	return "Invalid(" + strconv.Itoa(int(t)) + ")"
 }
@@ -56,9 +60,9 @@ type Attribute struct {
 }
 
 // A Token consists of a TokenType and some Data (tag name for start and end
-// tags, content for text and comments). A tag Token may also contain a slice
-// of Attributes. Data is unescaped for all Tokens (it looks like "a<b" rather
-// than "a&lt;b").
+// tags, content for text, comments and doctypes). A tag Token may also contain
+// a slice of Attributes. Data is unescaped for all Tokens (it looks like "a<b"
+// rather than "a&lt;b").
 type Token struct {
 	Type TokenType
 	Data string
@@ -97,6 +101,8 @@ func (t Token) String() string {
 		return "<" + t.tagString() + "/>"
 	case CommentToken:
 		return "<!--" + EscapeString(t.Data) + "-->"
+	case DoctypeToken:
+		return "<!DOCTYPE " + EscapeString(t.Data) + ">"
 	}
 	return "Invalid(" + strconv.Itoa(int(t.Type)) + ")"
 }
@@ -109,9 +115,15 @@ type Tokenizer struct {
 
 	// r is the source of the HTML text.
 	r io.Reader
-	// tt is the TokenType of the most recently read token. If tt == Error
-	// then err is the error associated with trying to read that token.
-	tt  TokenType
+	// tt is the TokenType of the most recently read token.
+	tt TokenType
+	// err is the first error encountered during tokenization. It is possible
+	// for tt != Error && err != nil to hold: this means that Next returned a
+	// valid token but the subsequent Next call will return an error token.
+	// For example, if the HTML text input was just "plain", then the first
+	// Next call would set z.err to os.EOF but return a TextToken, and all
+	// subsequent Next calls would return an ErrorToken.
+	// err is never reset. Once it becomes non-nil, it stays non-nil.
 	err os.Error
 	// buf[p0:p1] holds the raw data of the most recent token.
 	// buf[p1:] is buffered input that will yield future tokens.
@@ -137,7 +149,9 @@ func (z *Tokenizer) Raw() []byte {
 // readByte returns the next byte from the input stream, doing a buffered read
 // from z.r into z.buf if necessary. z.buf[z.p0:z.p1] remains a contiguous byte
 // slice that holds all the bytes read so far for the current token.
-func (z *Tokenizer) readByte() (byte, os.Error) {
+// It sets z.err if the underlying reader returns an error.
+// Pre-condition: z.err == nil.
+func (z *Tokenizer) readByte() byte {
 	if z.p1 >= len(z.buf) {
 		// Our buffer is exhausted and we have to read from z.r.
 		// We copy z.buf[z.p0:z.p1] to the beginning of z.buf. If the length
@@ -149,139 +163,168 @@ func (z *Tokenizer) readByte() (byte, os.Error) {
 		if 2*d > c {
 			buf1 = make([]byte, d, 2*c)
 		} else {
-			buf1 = z.buf[0:d]
+			buf1 = z.buf[:d]
 		}
 		copy(buf1, z.buf[z.p0:z.p1])
-		z.p0, z.p1, z.buf = 0, d, buf1[0:d]
+		z.p0, z.p1, z.buf = 0, d, buf1[:d]
 		// Now that we have copied the live bytes to the start of the buffer,
 		// we read from z.r into the remainder.
 		n, err := z.r.Read(buf1[d:cap(buf1)])
 		if err != nil {
-			return 0, err
+			z.err = err
+			return 0
 		}
-		z.buf = buf1[0 : d+n]
+		z.buf = buf1[:d+n]
 	}
 	x := z.buf[z.p1]
 	z.p1++
-	return x, nil
+	return x
 }
 
-// readTo keeps reading bytes until x is found.
-func (z *Tokenizer) readTo(x uint8) os.Error {
+// readTo keeps reading bytes until x is found or a read error occurs. If an
+// error does occur, z.err is set to that error.
+// Pre-condition: z.err == nil.
+func (z *Tokenizer) readTo(x uint8) {
 	for {
-		c, err := z.readByte()
-		if err != nil {
-			return err
+		c := z.readByte()
+		if z.err != nil {
+			return
 		}
 		switch c {
 		case x:
-			return nil
+			return
 		case '\\':
-			_, err = z.readByte()
-			if err != nil {
-				return err
+			z.readByte()
+			if z.err != nil {
+				return
 			}
 		}
 	}
-	panic("unreachable")
 }
 
-// nextMarkupDeclaration returns the next TokenType starting with "<!".
-func (z *Tokenizer) nextMarkupDeclaration() (TokenType, os.Error) {
-	// TODO: check for <!DOCTYPE ... >, don't just assume that it's a comment.
-	for i := 0; i < 2; i++ {
-		c, err := z.readByte()
-		if err != nil {
-			return TextToken, err
-		}
-		if c != '-' {
-			return z.nextText(), nil
-		}
-	}
+// nextComment reads the next token starting with "<!--".
+// The opening "<!--" has already been consumed.
+// Pre-condition: z.tt == TextToken && z.err == nil && z.p0 + 4 <= z.p1.
+func (z *Tokenizer) nextComment() {
 	// <!--> is a valid comment.
 	for dashCount := 2; ; {
-		c, err := z.readByte()
-		if err != nil {
-			return TextToken, err
+		c := z.readByte()
+		if z.err != nil {
+			return
 		}
 		switch c {
 		case '-':
 			dashCount++
 		case '>':
 			if dashCount >= 2 {
-				return CommentToken, nil
+				z.tt = CommentToken
+				return
 			}
-			fallthrough
+			dashCount = 0
 		default:
 			dashCount = 0
 		}
 	}
-	panic("unreachable")
 }
 
-// nextTag returns the next TokenType starting from the tag open state.
-func (z *Tokenizer) nextTag() (tt TokenType, err os.Error) {
-	c, err := z.readByte()
-	if err != nil {
-		return ErrorToken, err
+// nextMarkupDeclaration reads the next token starting with "<!".
+// It might be a "<!--comment-->", a "<!DOCTYPE foo>", or "<!malformed text".
+// The opening "<!" has already been consumed.
+// Pre-condition: z.tt == TextToken && z.err == nil && z.p0 + 2 <= z.p1.
+func (z *Tokenizer) nextMarkupDeclaration() {
+	var c [2]byte
+	for i := 0; i < 2; i++ {
+		c[i] = z.readByte()
+		if z.err != nil {
+			return
+		}
+	}
+	if c[0] == '-' && c[1] == '-' {
+		z.nextComment()
+		return
+	}
+	z.p1 -= 2
+	const s = "DOCTYPE "
+	for i := 0; ; i++ {
+		c := z.readByte()
+		if z.err != nil {
+			return
+		}
+		// Capitalize c.
+		if 'a' <= c && c <= 'z' {
+			c = 'A' + (c - 'a')
+		}
+		if i < len(s) && c != s[i] {
+			z.nextText()
+			return
+		}
+		if c == '>' {
+			if i >= len(s) {
+				z.tt = DoctypeToken
+			}
+			return
+		}
+	}
+}
+
+// nextTag reads the next token starting with "<". It might be a "<startTag>",
+// an "</endTag>", a "<!markup declaration>", or "<malformed text".
+// The opening "<" has already been consumed.
+// Pre-condition: z.tt == TextToken && z.err == nil && z.p0 + 1 <= z.p1.
+func (z *Tokenizer) nextTag() {
+	c := z.readByte()
+	if z.err != nil {
+		return
 	}
 	switch {
 	case c == '/':
-		tt = EndTagToken
+		z.tt = EndTagToken
 	// Lower-cased characters are more common in tag names, so we check for them first.
 	case 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z':
-		tt = StartTagToken
+		z.tt = StartTagToken
 	case c == '!':
-		return z.nextMarkupDeclaration()
+		z.nextMarkupDeclaration()
+		return
 	case c == '?':
-		return ErrorToken, os.NewError("html: TODO(nigeltao): implement XML processing instructions")
+		z.tt, z.err = ErrorToken, os.NewError("html: TODO: implement XML processing instructions")
+		return
 	default:
-		return ErrorToken, os.NewError("html: TODO(nigeltao): handle malformed tags")
+		z.tt, z.err = ErrorToken, os.NewError("html: TODO: handle malformed tags")
+		return
 	}
 	for {
-		c, err := z.readByte()
-		if err != nil {
-			return TextToken, err
+		c := z.readByte()
+		if z.err != nil {
+			return
 		}
 		switch c {
-		case '"':
-			err = z.readTo('"')
-			if err != nil {
-				return TextToken, err
-			}
-		case '\'':
-			err = z.readTo('\'')
-			if err != nil {
-				return TextToken, err
+		case '"', '\'':
+			z.readTo(c)
+			if z.err != nil {
+				return
 			}
 		case '>':
-			if z.buf[z.p1-2] == '/' && tt == StartTagToken {
-				return SelfClosingTagToken, nil
+			if z.buf[z.p1-2] == '/' && z.tt == StartTagToken {
+				z.tt = SelfClosingTagToken
 			}
-			return tt, nil
+			return
 		}
 	}
-	panic("unreachable")
 }
 
 // nextText reads all text up until an '<'.
-func (z *Tokenizer) nextText() TokenType {
+// Pre-condition: z.tt == TextToken && z.err == nil && z.p0 + 1 <= z.p1.
+func (z *Tokenizer) nextText() {
 	for {
-		c, err := z.readByte()
-		if err != nil {
-			z.tt, z.err = ErrorToken, err
-			if err == os.EOF {
-				z.tt = TextToken
-			}
-			return z.tt
+		c := z.readByte()
+		if z.err != nil {
+			return
 		}
 		if c == '<' {
 			z.p1--
-			z.tt = TextToken
-			return z.tt
+			return
 		}
 	}
-	panic("unreachable")
 }
 
 // Next scans the next token and returns its type.
@@ -292,19 +335,22 @@ func (z *Tokenizer) Next() TokenType {
 			return z.tt
 		}
 		z.p0 = z.p1
-		c, err := z.readByte()
-		if err != nil {
-			z.tt, z.err = ErrorToken, err
+		c := z.readByte()
+		if z.err != nil {
+			z.tt = ErrorToken
 			return z.tt
 		}
-		if c == '<' {
-			z.tt, z.err = z.nextTag()
+		// We assume that the next token is text unless proven otherwise.
+		z.tt = TextToken
+		if c != '<' {
+			z.nextText()
+		} else {
+			z.nextTag()
 			if z.tt == CommentToken && !z.ReturnComments {
 				continue
 			}
-			return z.tt
 		}
-		return z.nextText()
+		return z.tt
 	}
 	panic("unreachable")
 }
@@ -331,20 +377,65 @@ func (z *Tokenizer) trim(i int) int {
 	return k
 }
 
-// lower finds the largest alphabetic [0-9A-Za-z]* word at the start of z.buf[i:]
-// and returns that word lower-cased, as well as the trimmed cursor location
-// after that word.
-func (z *Tokenizer) lower(i int) ([]byte, int) {
+// tagName finds the tag name at the start of z.buf[i:] and returns that name
+// lower-cased, as well as the trimmed cursor location afterwards.
+func (z *Tokenizer) tagName(i int) ([]byte, int) {
+	i0 := i
+loop:
+	for ; i < z.p1; i++ {
+		c := z.buf[i]
+		switch c {
+		case ' ', '\n', '\t', '\f', '/', '>':
+			break loop
+		}
+		if 'A' <= c && c <= 'Z' {
+			z.buf[i] = c + 'a' - 'A'
+		}
+	}
+	return z.buf[i0:i], z.trim(i)
+}
+
+// unquotedAttrVal finds the unquoted attribute value at the start of z.buf[i:]
+// and returns that value, as well as the trimmed cursor location afterwards.
+func (z *Tokenizer) unquotedAttrVal(i int) ([]byte, int) {
+	i0 := i
+loop:
+	for ; i < z.p1; i++ {
+		switch z.buf[i] {
+		case ' ', '\n', '\t', '\f', '>':
+			break loop
+		case '&':
+			// TODO: unescape the entity.
+		}
+	}
+	return z.buf[i0:i], z.trim(i)
+}
+
+// attrName finds the largest attribute name at the start
+// of z.buf[i:] and returns it lower-cased, as well
+// as the trimmed cursor location after that name.
+//
+// http://dev.w3.org/html5/spec/Overview.html#syntax-attribute-name
+// TODO: unicode characters
+func (z *Tokenizer) attrName(i int) ([]byte, int) {
+	for z.buf[i] == '/' {
+		i++
+		if z.buf[i] == '>' {
+			return nil, z.trim(i)
+		}
+	}
 	i0 := i
 loop:
 	for ; i < z.p1; i++ {
 		c := z.buf[i]
+		switch c {
+		case '>', '/', '=':
+			break loop
+		}
 		switch {
-		case '0' <= c && c <= '9':
-			// No-op.
 		case 'A' <= c && c <= 'Z':
 			z.buf[i] = c + 'a' - 'A'
-		case 'a' <= c && c <= 'z':
+		case c > ' ' && c < 0x7f:
 			// No-op.
 		default:
 			break loop
@@ -353,25 +444,29 @@ loop:
 	return z.buf[i0:i], z.trim(i)
 }
 
-// Text returns the unescaped text of a TextToken or a CommentToken.
-// The contents of the returned slice may change on the next call to Next.
+// Text returns the unescaped text of a text, comment or doctype token. The
+// contents of the returned slice may change on the next call to Next.
 func (z *Tokenizer) Text() []byte {
+	var i0, i1 int
 	switch z.tt {
 	case TextToken:
-		s := unescape(z.Raw())
-		z.p0 = z.p1
-		return s
+		i0 = z.p0
+		i1 = z.p1
 	case CommentToken:
-		// We trim the "<!--" from the left and the "-->" from the right.
+		// Trim the "<!--" from the left and the "-->" from the right.
 		// "<!-->" is a valid comment, so the adjusted endpoints might overlap.
-		i0 := z.p0 + 4
-		i1 := z.p1 - 3
-		z.p0 = z.p1
-		var s []byte
-		if i0 < i1 {
-			s = unescape(z.buf[i0:i1])
-		}
-		return s
+		i0 = z.p0 + 4
+		i1 = z.p1 - 3
+	case DoctypeToken:
+		// Trim the "<!DOCTYPE " from the left and the ">" from the right.
+		i0 = z.p0 + 10
+		i1 = z.p1 - 1
+	default:
+		return nil
+	}
+	z.p0 = z.p1
+	if i0 < i1 {
+		return unescape(z.buf[i0:i1])
 	}
 	return nil
 }
@@ -388,7 +483,7 @@ func (z *Tokenizer) TagName() (name []byte, hasAttr bool) {
 	if z.buf[i] == '/' {
 		i++
 	}
-	name, z.p0 = z.lower(i)
+	name, z.p0 = z.tagName(i)
 	hasAttr = z.p0 != z.p1
 	return
 }
@@ -397,27 +492,40 @@ func (z *Tokenizer) TagName() (name []byte, hasAttr bool) {
 // attribute for the current tag token and whether there are more attributes.
 // The contents of the returned slices may change on the next call to Next.
 func (z *Tokenizer) TagAttr() (key, val []byte, moreAttr bool) {
-	key, i := z.lower(z.p0)
-	// Get past the "=\"".
-	if i == z.p1 || z.buf[i] != '=' {
+	key, i := z.attrName(z.p0)
+	// Check for an empty attribute value.
+	if i == z.p1 {
+		z.p0 = i
+		return
+	}
+	// Get past the equals and quote characters.
+	if z.buf[i] != '=' {
+		z.p0, moreAttr = i, true
 		return
 	}
 	i = z.trim(i + 1)
-	if i == z.p1 || z.buf[i] != '"' {
+	if i == z.p1 {
+		z.p0 = i
+		return
+	}
+	closeQuote := z.buf[i]
+	if closeQuote != '\'' && closeQuote != '"' {
+		val, z.p0 = z.unquotedAttrVal(i)
+		moreAttr = z.p0 != z.p1
 		return
 	}
 	i = z.trim(i + 1)
-	// Copy and unescape everything up to the closing '"'.
+	// Copy and unescape everything up to the closing quote.
 	dst, src := i, i
 loop:
 	for src < z.p1 {
 		c := z.buf[src]
 		switch c {
-		case '"':
+		case closeQuote:
 			src++
 			break loop
 		case '&':
-			dst, src = unescapeEntity(z.buf, dst, src)
+			dst, src = unescapeEntity(z.buf, dst, src, true)
 		case '\\':
 			if src == z.p1 {
 				z.buf[dst] = '\\'
@@ -441,7 +549,7 @@ loop:
 func (z *Tokenizer) Token() Token {
 	t := Token{Type: z.tt}
 	switch z.tt {
-	case TextToken, CommentToken:
+	case TextToken, CommentToken, DoctypeToken:
 		t.Data = string(z.Text())
 	case StartTagToken, EndTagToken, SelfClosingTagToken:
 		var attr []Attribute