138 lines
2.9 KiB
Go
138 lines
2.9 KiB
Go
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package html
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import (
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"github.com/tdewolff/parse/v2"
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"github.com/tdewolff/parse/v2/html"
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)
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// Token is a single token unit with an attribute value (if given) and hash of the data.
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type Token struct {
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html.TokenType
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Hash Hash
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Data []byte
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Text []byte
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AttrVal []byte
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Traits traits
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Offset int
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}
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// TokenBuffer is a buffer that allows for token look-ahead.
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type TokenBuffer struct {
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r *parse.Input
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l *html.Lexer
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buf []Token
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pos int
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attrBuffer []*Token
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}
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// NewTokenBuffer returns a new TokenBuffer.
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func NewTokenBuffer(r *parse.Input, l *html.Lexer) *TokenBuffer {
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return &TokenBuffer{
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r: r,
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l: l,
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buf: make([]Token, 0, 8),
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}
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}
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func (z *TokenBuffer) read(t *Token) {
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t.Offset = z.r.Offset()
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t.TokenType, t.Data = z.l.Next()
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t.Text = z.l.Text()
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if t.TokenType == html.AttributeToken {
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t.Offset += 1 + len(t.Text) + 1
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t.AttrVal = z.l.AttrVal()
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if len(t.AttrVal) > 1 && (t.AttrVal[0] == '"' || t.AttrVal[0] == '\'') {
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t.Offset++
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t.AttrVal = t.AttrVal[1 : len(t.AttrVal)-1] // quotes will be readded in attribute loop if necessary
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}
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t.Hash = ToHash(t.Text)
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t.Traits = attrMap[t.Hash]
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} else if t.TokenType == html.StartTagToken || t.TokenType == html.EndTagToken {
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t.AttrVal = nil
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t.Hash = ToHash(t.Text)
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t.Traits = tagMap[t.Hash] // zero if not exist
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} else {
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t.AttrVal = nil
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t.Hash = 0
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t.Traits = 0
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}
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}
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// Peek returns the ith element and possibly does an allocation.
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// Peeking past an error will panic.
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func (z *TokenBuffer) Peek(pos int) *Token {
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pos += z.pos
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if pos >= len(z.buf) {
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if len(z.buf) > 0 && z.buf[len(z.buf)-1].TokenType == html.ErrorToken {
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return &z.buf[len(z.buf)-1]
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}
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c := cap(z.buf)
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d := len(z.buf) - z.pos
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p := pos - z.pos + 1 // required peek length
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var buf []Token
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if 2*p > c {
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buf = make([]Token, 0, 2*c+p)
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} else {
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buf = z.buf
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}
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copy(buf[:d], z.buf[z.pos:])
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buf = buf[:p]
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pos -= z.pos
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for i := d; i < p; i++ {
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z.read(&buf[i])
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if buf[i].TokenType == html.ErrorToken {
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buf = buf[:i+1]
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pos = i
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break
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}
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}
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z.pos, z.buf = 0, buf
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}
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return &z.buf[pos]
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}
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// Shift returns the first element and advances position.
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func (z *TokenBuffer) Shift() *Token {
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if z.pos >= len(z.buf) {
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t := &z.buf[:1][0]
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z.read(t)
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return t
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}
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t := &z.buf[z.pos]
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z.pos++
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return t
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}
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// Attributes extracts the gives attribute hashes from a tag.
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// It returns in the same order pointers to the requested token data or nil.
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func (z *TokenBuffer) Attributes(hashes ...Hash) []*Token {
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n := 0
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for {
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if t := z.Peek(n); t.TokenType != html.AttributeToken {
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break
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}
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n++
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}
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if len(hashes) > cap(z.attrBuffer) {
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z.attrBuffer = make([]*Token, len(hashes))
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} else {
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z.attrBuffer = z.attrBuffer[:len(hashes)]
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for i := range z.attrBuffer {
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z.attrBuffer[i] = nil
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}
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}
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for i := z.pos; i < z.pos+n; i++ {
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attr := &z.buf[i]
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for j, hash := range hashes {
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if hash == attr.Hash {
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z.attrBuffer[j] = attr
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}
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}
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}
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return z.attrBuffer
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}
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