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path: root/src/pkg/html/token.go
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Diffstat (limited to 'src/pkg/html/token.go')
-rw-r--r--src/pkg/html/token.go509
1 files changed, 0 insertions, 509 deletions
diff --git a/src/pkg/html/token.go b/src/pkg/html/token.go
deleted file mode 100644
index 23c95ece6..000000000
--- a/src/pkg/html/token.go
+++ /dev/null
@@ -1,509 +0,0 @@
-// Copyright 2010 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
-
-import (
- "bytes"
- "io"
- "os"
- "strconv"
-)
-
-// A TokenType is the type of a Token.
-type TokenType int
-
-const (
- // ErrorToken means that an error occurred during tokenization.
- ErrorToken TokenType = iota
- // TextToken means a text node.
- TextToken
- // A StartTagToken looks like <a>.
- StartTagToken
- // An EndTagToken looks like </a>.
- EndTagToken
- // A SelfClosingTagToken tag looks like <br/>.
- SelfClosingTagToken
- // A CommentToken looks like <!--x-->.
- CommentToken
-)
-
-// String returns a string representation of the TokenType.
-func (t TokenType) String() string {
- switch t {
- case ErrorToken:
- return "Error"
- case TextToken:
- return "Text"
- case StartTagToken:
- return "StartTag"
- case EndTagToken:
- return "EndTag"
- case SelfClosingTagToken:
- return "SelfClosingTag"
- case CommentToken:
- return "Comment"
- }
- return "Invalid(" + strconv.Itoa(int(t)) + ")"
-}
-
-// An Attribute is an attribute key-value pair. Key is alphabetic (and hence
-// does not contain escapable characters like '&', '<' or '>'), and Val is
-// unescaped (it looks like "a<b" rather than "a&lt;b").
-type Attribute struct {
- Key, Val string
-}
-
-// 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").
-type Token struct {
- Type TokenType
- Data string
- Attr []Attribute
-}
-
-// tagString returns a string representation of a tag Token's Data and Attr.
-func (t Token) tagString() string {
- if len(t.Attr) == 0 {
- return t.Data
- }
- buf := bytes.NewBuffer(nil)
- buf.WriteString(t.Data)
- for _, a := range t.Attr {
- buf.WriteByte(' ')
- buf.WriteString(a.Key)
- buf.WriteString(`="`)
- escape(buf, a.Val)
- buf.WriteByte('"')
- }
- return buf.String()
-}
-
-// String returns a string representation of the Token.
-func (t Token) String() string {
- switch t.Type {
- case ErrorToken:
- return ""
- case TextToken:
- return EscapeString(t.Data)
- case StartTagToken:
- return "<" + t.tagString() + ">"
- case EndTagToken:
- return "</" + t.tagString() + ">"
- case SelfClosingTagToken:
- return "<" + t.tagString() + "/>"
- case CommentToken:
- return "<!--" + EscapeString(t.Data) + "-->"
- }
- return "Invalid(" + strconv.Itoa(int(t.Type)) + ")"
-}
-
-// A Tokenizer returns a stream of HTML Tokens.
-type Tokenizer struct {
- // If ReturnComments is set, Next returns comment tokens;
- // otherwise it skips over comments (default).
- ReturnComments bool
-
- // 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
- 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.
- p0, p1 int
- buf []byte
-}
-
-// Error returns the error associated with the most recent ErrorToken token.
-// This is typically os.EOF, meaning the end of tokenization.
-func (z *Tokenizer) Error() os.Error {
- if z.tt != ErrorToken {
- return nil
- }
- return z.err
-}
-
-// Raw returns the unmodified text of the current token. Calling Next, Token,
-// Text, TagName or TagAttr may change the contents of the returned slice.
-func (z *Tokenizer) Raw() []byte {
- return z.buf[z.p0:z.p1]
-}
-
-// 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) {
- 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
- // z.p1 - z.p0 is more than half the capacity of z.buf, then we
- // allocate a new buffer before the copy.
- c := cap(z.buf)
- d := z.p1 - z.p0
- var buf1 []byte
- if 2*d > c {
- buf1 = make([]byte, d, 2*c)
- } else {
- buf1 = z.buf[0:d]
- }
- copy(buf1, z.buf[z.p0:z.p1])
- z.p0, z.p1, z.buf = 0, d, buf1[0: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.buf = buf1[0 : d+n]
- }
- x := z.buf[z.p1]
- z.p1++
- return x, nil
-}
-
-// readTo keeps reading bytes until x is found.
-func (z *Tokenizer) readTo(x uint8) os.Error {
- for {
- c, err := z.readByte()
- if err != nil {
- return err
- }
- switch c {
- case x:
- return nil
- case '\\':
- _, err = z.readByte()
- if err != nil {
- return err
- }
- }
- }
- 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
- }
- }
- // <!--> is a valid comment.
- for dashCount := 2; ; {
- c, err := z.readByte()
- if err != nil {
- return TextToken, err
- }
- switch c {
- case '-':
- dashCount++
- case '>':
- if dashCount >= 2 {
- return CommentToken, nil
- }
- fallthrough
- 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
- }
- switch {
- case c == '/':
- 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
- case c == '!':
- return z.nextMarkupDeclaration()
- case c == '?':
- return ErrorToken, os.NewError("html: TODO(nigeltao): implement XML processing instructions")
- default:
- return ErrorToken, os.NewError("html: TODO(nigeltao): handle malformed tags")
- }
- for {
- c, err := z.readByte()
- if err != nil {
- return TextToken, err
- }
- switch c {
- case '"':
- err = z.readTo('"')
- if err != nil {
- return TextToken, err
- }
- case '\'':
- err = z.readTo('\'')
- if err != nil {
- return TextToken, err
- }
- case '>':
- if z.buf[z.p1-2] == '/' && tt == StartTagToken {
- return SelfClosingTagToken, nil
- }
- return tt, nil
- }
- }
- panic("unreachable")
-}
-
-// nextText reads all text up until an '<'.
-func (z *Tokenizer) nextText() TokenType {
- for {
- c, err := z.readByte()
- if err != nil {
- z.tt, z.err = ErrorToken, err
- if err == os.EOF {
- z.tt = TextToken
- }
- return z.tt
- }
- if c == '<' {
- z.p1--
- z.tt = TextToken
- return z.tt
- }
- }
- panic("unreachable")
-}
-
-// Next scans the next token and returns its type.
-func (z *Tokenizer) Next() TokenType {
- for {
- if z.err != nil {
- z.tt = ErrorToken
- return z.tt
- }
- z.p0 = z.p1
- c, err := z.readByte()
- if err != nil {
- z.tt, z.err = ErrorToken, err
- return z.tt
- }
- if c == '<' {
- z.tt, z.err = z.nextTag()
- if z.tt == CommentToken && !z.ReturnComments {
- continue
- }
- return z.tt
- }
- return z.nextText()
- }
- panic("unreachable")
-}
-
-// trim returns the largest j such that z.buf[i:j] contains only white space,
-// or only white space plus the final ">" or "/>" of the raw data.
-func (z *Tokenizer) trim(i int) int {
- k := z.p1
- for ; i < k; i++ {
- switch z.buf[i] {
- case ' ', '\n', '\t', '\f':
- continue
- case '>':
- if i == k-1 {
- return k
- }
- case '/':
- if i == k-2 {
- return k
- }
- }
- return i
- }
- return k
-}
-
-// word finds the largest alphabetic [0-9A-Za-z]* word at the start
-// of z.buf[i:] and returns that word (optionally lower-cased), as
-// well as the trimmed cursor location after that word.
-func (z *Tokenizer) word(i int, lower bool) ([]byte, int) {
- i0 := i
-loop:
- for ; i < z.p1; i++ {
- c := z.buf[i]
- switch {
- case '0' <= c && c <= '9':
- // No-op.
- case 'A' <= c && c <= 'Z':
- if lower {
- z.buf[i] = c + 'a' - 'A'
- }
- case 'a' <= c && c <= 'z':
- // No-op.
- default:
- break loop
- }
- }
- 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 word.
-//
-// http://dev.w3.org/html5/spec/Overview.html#syntax-attribute-name
-// TODO: unicode characters
-func (z *Tokenizer) attrName(i int) ([]byte, int) {
- i0 := i
-loop:
- for ; i < z.p1; i++ {
- c := z.buf[i]
- switch c {
- case '<', '>', '"', '\'', '/', '=':
- break loop
- }
- switch {
- case 'A' <= c && c <= 'Z':
- z.buf[i] = c + 'a' - 'A'
- case c > ' ' && c < 0x7f:
- // No-op.
- default:
- break 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.
-func (z *Tokenizer) Text() []byte {
- switch z.tt {
- case TextToken:
- s := unescape(z.Raw())
- z.p0 = z.p1
- return s
- case CommentToken:
- // We 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
- }
- return nil
-}
-
-// TagName returns the lower-cased name of a tag token (the `img` out of
-// `<IMG SRC="foo">`) and whether the tag has attributes.
-// The contents of the returned slice may change on the next call to Next.
-func (z *Tokenizer) TagName() (name []byte, hasAttr bool) {
- i := z.p0 + 1
- if i >= z.p1 {
- z.p0 = z.p1
- return nil, false
- }
- if z.buf[i] == '/' {
- i++
- }
- name, z.p0 = z.word(i, true)
- hasAttr = z.p0 != z.p1
- return
-}
-
-// TagAttr returns the lower-cased key and unescaped value of the next unparsed
-// 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.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.p0 = i
- return
- }
- closeQuote := z.buf[i]
- if closeQuote != '\'' && closeQuote != '"' {
- val, z.p0 = z.word(i, false)
- moreAttr = z.p0 != z.p1
- return
- }
- i = z.trim(i + 1)
- // 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 closeQuote:
- src++
- break loop
- case '&':
- dst, src = unescapeEntity(z.buf, dst, src)
- case '\\':
- if src == z.p1 {
- z.buf[dst] = '\\'
- dst++
- } else {
- z.buf[dst] = z.buf[src+1]
- dst, src = dst+1, src+2
- }
- default:
- z.buf[dst] = c
- dst, src = dst+1, src+1
- }
- }
- val, z.p0 = z.buf[i:dst], z.trim(src)
- moreAttr = z.p0 != z.p1
- return
-}
-
-// Token returns the next Token. The result's Data and Attr values remain valid
-// after subsequent Next calls.
-func (z *Tokenizer) Token() Token {
- t := Token{Type: z.tt}
- switch z.tt {
- case TextToken, CommentToken:
- t.Data = string(z.Text())
- case StartTagToken, EndTagToken, SelfClosingTagToken:
- var attr []Attribute
- name, moreAttr := z.TagName()
- for moreAttr {
- var key, val []byte
- key, val, moreAttr = z.TagAttr()
- attr = append(attr, Attribute{string(key), string(val)})
- }
- t.Data = string(name)
- t.Attr = attr
- }
- return t
-}
-
-// NewTokenizer returns a new HTML Tokenizer for the given Reader.
-// The input is assumed to be UTF-8 encoded.
-func NewTokenizer(r io.Reader) *Tokenizer {
- return &Tokenizer{
- r: r,
- buf: make([]byte, 0, 4096),
- }
-}
generated by cgit v1.2.3 (git 2.46.0) at 2025-10-11 15:30:15 +0000