521 lines
17 KiB
Go
521 lines
17 KiB
Go
// Package html minifies HTML5 following the specifications at http://www.w3.org/TR/html5/syntax.html.
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package html
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import (
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"bytes"
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"io"
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"github.com/tdewolff/minify/v2"
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"github.com/tdewolff/parse/v2"
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"github.com/tdewolff/parse/v2/buffer"
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"github.com/tdewolff/parse/v2/html"
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)
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var (
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gtBytes = []byte(">")
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isBytes = []byte("=")
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spaceBytes = []byte(" ")
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doctypeBytes = []byte("<!doctype html>")
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jsMimeBytes = []byte("application/javascript")
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cssMimeBytes = []byte("text/css")
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htmlMimeBytes = []byte("text/html")
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svgMimeBytes = []byte("image/svg+xml")
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formMimeBytes = []byte("application/x-www-form-urlencoded")
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mathMimeBytes = []byte("application/mathml+xml")
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dataSchemeBytes = []byte("data:")
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jsSchemeBytes = []byte("javascript:")
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httpBytes = []byte("http")
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radioBytes = []byte("radio")
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onBytes = []byte("on")
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textBytes = []byte("text")
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noneBytes = []byte("none")
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submitBytes = []byte("submit")
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allBytes = []byte("all")
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rectBytes = []byte("rect")
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dataBytes = []byte("data")
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getBytes = []byte("get")
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autoBytes = []byte("auto")
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oneBytes = []byte("one")
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inlineParams = map[string]string{"inline": "1"}
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)
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////////////////////////////////////////////////////////////////
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var GoTemplateDelims = [2]string{"{{", "}}"}
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var HandlebarsTemplateDelims = [2]string{"{{", "}}"}
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var MustacheTemplateDelims = [2]string{"{{", "}}"}
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var EJSTemplateDelims = [2]string{"<%", "%>"}
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var ASPTemplateDelims = [2]string{"<%", "%>"}
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var PHPTemplateDelims = [2]string{"<?", "?>"}
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// Minifier is an HTML minifier.
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type Minifier struct {
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KeepComments bool
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KeepConditionalComments bool
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KeepDefaultAttrVals bool
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KeepDocumentTags bool
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KeepEndTags bool
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KeepQuotes bool
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KeepWhitespace bool
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TemplateDelims [2]string
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}
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// Minify minifies HTML data, it reads from r and writes to w.
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func Minify(m *minify.M, w io.Writer, r io.Reader, params map[string]string) error {
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return (&Minifier{}).Minify(m, w, r, params)
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}
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// Minify minifies HTML data, it reads from r and writes to w.
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func (o *Minifier) Minify(m *minify.M, w io.Writer, r io.Reader, _ map[string]string) error {
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var rawTagHash Hash
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var rawTagMediatype []byte
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omitSpace := true // if true the next leading space is omitted
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inPre := false
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attrMinifyBuffer := buffer.NewWriter(make([]byte, 0, 64))
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attrByteBuffer := make([]byte, 0, 64)
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z := parse.NewInput(r)
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defer z.Restore()
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l := html.NewTemplateLexer(z, o.TemplateDelims)
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tb := NewTokenBuffer(z, l)
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for {
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t := *tb.Shift()
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switch t.TokenType {
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case html.ErrorToken:
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if _, err := w.Write(nil); err != nil {
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return err
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}
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if l.Err() == io.EOF {
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return nil
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}
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return l.Err()
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case html.DoctypeToken:
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w.Write(doctypeBytes)
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case html.CommentToken:
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if o.KeepComments {
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w.Write(t.Data)
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} else if o.KeepConditionalComments && 6 < len(t.Text) && (bytes.HasPrefix(t.Text, []byte("[if ")) || bytes.HasSuffix(t.Text, []byte("[endif]")) || bytes.HasSuffix(t.Text, []byte("[endif]--"))) {
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// [if ...] is always 7 or more characters, [endif] is only encountered for downlevel-revealed
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// see https://msdn.microsoft.com/en-us/library/ms537512(v=vs.85).aspx#syntax
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if bytes.HasPrefix(t.Data, []byte("<!--[if ")) && bytes.HasSuffix(t.Data, []byte("<![endif]-->")) { // downlevel-hidden
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begin := bytes.IndexByte(t.Data, '>') + 1
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end := len(t.Data) - len("<![endif]-->")
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if begin < end {
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w.Write(t.Data[:begin])
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if err := o.Minify(m, w, buffer.NewReader(t.Data[begin:end]), nil); err != nil {
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return minify.UpdateErrorPosition(err, z, t.Offset)
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}
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w.Write(t.Data[end:])
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} else {
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w.Write(t.Data) // malformed
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}
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} else {
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w.Write(t.Data) // downlevel-revealed or short downlevel-hidden
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}
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} else if 1 < len(t.Text) && t.Text[0] == '#' {
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// SSI tags
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w.Write(t.Data)
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}
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case html.SvgToken:
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if err := m.MinifyMimetype(svgMimeBytes, w, buffer.NewReader(t.Data), nil); err != nil {
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if err != minify.ErrNotExist {
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return minify.UpdateErrorPosition(err, z, t.Offset)
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}
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w.Write(t.Data)
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}
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case html.MathToken:
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if err := m.MinifyMimetype(mathMimeBytes, w, buffer.NewReader(t.Data), nil); err != nil {
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if err != minify.ErrNotExist {
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return minify.UpdateErrorPosition(err, z, t.Offset)
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}
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w.Write(t.Data)
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}
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case html.TextToken:
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if t.HasTemplate {
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w.Write(t.Data)
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} else if rawTagHash != 0 {
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if rawTagHash == Style || rawTagHash == Script || rawTagHash == Iframe {
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var mimetype []byte
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var params map[string]string
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if rawTagHash == Iframe {
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mimetype = htmlMimeBytes
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} else if 0 < len(rawTagMediatype) {
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mimetype, params = parse.Mediatype(rawTagMediatype)
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} else if rawTagHash == Script {
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mimetype = jsMimeBytes
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} else if rawTagHash == Style {
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mimetype = cssMimeBytes
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}
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if err := m.MinifyMimetype(mimetype, w, buffer.NewReader(t.Data), params); err != nil {
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if err != minify.ErrNotExist {
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return minify.UpdateErrorPosition(err, z, t.Offset)
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}
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w.Write(t.Data)
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}
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} else {
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w.Write(t.Data)
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}
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} else if inPre {
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w.Write(t.Data)
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} else {
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t.Data = parse.ReplaceMultipleWhitespaceAndEntities(t.Data, EntitiesMap, TextRevEntitiesMap)
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// whitespace removal; trim left
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if omitSpace && parse.IsWhitespace(t.Data[0]) {
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t.Data = t.Data[1:]
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}
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// whitespace removal; trim right
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omitSpace = false
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if len(t.Data) == 0 {
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omitSpace = true
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} else if parse.IsWhitespace(t.Data[len(t.Data)-1]) {
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omitSpace = true
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i := 0
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for {
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next := tb.Peek(i)
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// trim if EOF, text token with leading whitespace or block token
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if next.TokenType == html.ErrorToken {
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t.Data = t.Data[:len(t.Data)-1]
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omitSpace = false
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break
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} else if next.TokenType == html.TextToken && !parse.IsAllWhitespace(next.Data) {
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// stop looking when text encountered
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break
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} else if next.TokenType == html.StartTagToken || next.TokenType == html.EndTagToken {
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if o.KeepWhitespace {
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break
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}
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// remove when followed by a block tag
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if next.Traits&blockTag != 0 {
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t.Data = t.Data[:len(t.Data)-1]
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omitSpace = false
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break
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} else if next.TokenType == html.StartTagToken {
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break
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}
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}
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i++
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}
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}
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w.Write(t.Data)
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}
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case html.StartTagToken, html.EndTagToken:
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rawTagHash = 0
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hasAttributes := false
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if t.TokenType == html.StartTagToken {
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if next := tb.Peek(0); next.TokenType == html.AttributeToken {
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hasAttributes = true
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}
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if t.Traits&rawTag != 0 {
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// ignore empty script and style tags
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if !hasAttributes && (t.Hash == Script || t.Hash == Style) {
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if next := tb.Peek(1); next.TokenType == html.EndTagToken {
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tb.Shift()
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tb.Shift()
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break
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}
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}
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rawTagHash = t.Hash
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rawTagMediatype = nil
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// do not minify content of <style amp-boilerplate>
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if hasAttributes && t.Hash == Style {
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if attrs := tb.Attributes(Amp_Boilerplate); attrs[0] != nil {
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rawTagHash = 0
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}
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}
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}
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} else if t.Hash == Template {
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omitSpace = true // EndTagToken
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}
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if t.Hash == Pre {
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inPre = t.TokenType == html.StartTagToken
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}
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// remove superfluous tags, except for html, head and body tags when KeepDocumentTags is set
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if !hasAttributes && (!o.KeepDocumentTags && (t.Hash == Html || t.Hash == Head || t.Hash == Body) || t.Hash == Colgroup) {
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break
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} else if t.TokenType == html.EndTagToken {
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omitEndTag := false
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if !o.KeepEndTags {
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if t.Hash == Thead || t.Hash == Tbody || t.Hash == Tfoot || t.Hash == Tr || t.Hash == Th ||
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t.Hash == Td || t.Hash == Option || t.Hash == Dd || t.Hash == Dt || t.Hash == Li ||
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t.Hash == Rb || t.Hash == Rt || t.Hash == Rtc || t.Hash == Rp {
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omitEndTag = true // omit end tags
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} else if t.Hash == P {
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i := 0
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for {
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next := tb.Peek(i)
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i++
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// continue if text token is empty or whitespace
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if next.TokenType == html.TextToken && parse.IsAllWhitespace(next.Data) {
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continue
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}
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if next.TokenType == html.ErrorToken || next.TokenType == html.EndTagToken && next.Traits&keepPTag == 0 || next.TokenType == html.StartTagToken && next.Traits&omitPTag != 0 {
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omitEndTag = true // omit p end tag
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}
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break
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}
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} else if t.Hash == Optgroup {
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i := 0
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for {
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next := tb.Peek(i)
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i++
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// continue if text token
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if next.TokenType == html.TextToken {
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continue
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}
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if next.TokenType == html.ErrorToken || next.Hash != Option {
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omitEndTag = true // omit optgroup end tag
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}
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break
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}
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}
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}
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if !omitEndTag {
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if o.KeepWhitespace || t.Traits&objectTag != 0 {
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omitSpace = false
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} else if t.Traits&blockTag != 0 {
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omitSpace = true // omit spaces after block elements
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}
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if 3+len(t.Text) < len(t.Data) {
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t.Data[2+len(t.Text)] = '>'
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t.Data = t.Data[:3+len(t.Text)]
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}
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w.Write(t.Data)
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}
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// skip text in select and optgroup tags
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if t.Hash == Option || t.Hash == Optgroup {
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if next := tb.Peek(0); next.TokenType == html.TextToken {
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tb.Shift()
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}
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}
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break
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}
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if o.KeepWhitespace || t.Traits&objectTag != 0 {
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omitSpace = false
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} else if t.Traits&blockTag != 0 {
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omitSpace = true // omit spaces after block elements
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}
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w.Write(t.Data)
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if hasAttributes {
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if t.Hash == Meta {
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attrs := tb.Attributes(Content, Http_Equiv, Charset, Name)
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if content := attrs[0]; content != nil {
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if httpEquiv := attrs[1]; httpEquiv != nil {
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httpEquiv.AttrVal = parse.TrimWhitespace(httpEquiv.AttrVal)
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if charset := attrs[2]; charset == nil && parse.EqualFold(httpEquiv.AttrVal, []byte("content-type")) {
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content.AttrVal = minify.Mediatype(content.AttrVal)
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if bytes.Equal(content.AttrVal, []byte("text/html;charset=utf-8")) {
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httpEquiv.Text = nil
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content.Text = []byte("charset")
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content.Hash = Charset
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content.AttrVal = []byte("utf-8")
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}
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}
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}
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if name := attrs[3]; name != nil {
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name.AttrVal = parse.TrimWhitespace(name.AttrVal)
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if parse.EqualFold(name.AttrVal, []byte("keywords")) {
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content.AttrVal = bytes.ReplaceAll(content.AttrVal, []byte(", "), []byte(","))
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} else if parse.EqualFold(name.AttrVal, []byte("viewport")) {
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content.AttrVal = bytes.ReplaceAll(content.AttrVal, []byte(" "), []byte(""))
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for i := 0; i < len(content.AttrVal); i++ {
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if content.AttrVal[i] == '=' && i+2 < len(content.AttrVal) {
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i++
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if n := parse.Number(content.AttrVal[i:]); 0 < n {
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minNum := minify.Number(content.AttrVal[i:i+n], -1)
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if len(minNum) < n {
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copy(content.AttrVal[i:i+len(minNum)], minNum)
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copy(content.AttrVal[i+len(minNum):], content.AttrVal[i+n:])
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content.AttrVal = content.AttrVal[:len(content.AttrVal)+len(minNum)-n]
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}
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i += len(minNum)
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}
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i-- // mitigate for-loop increase
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}
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}
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}
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}
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}
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} else if t.Hash == Script {
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attrs := tb.Attributes(Src, Charset)
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if attrs[0] != nil && attrs[1] != nil {
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attrs[1].Text = nil
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}
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} else if t.Hash == Input {
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attrs := tb.Attributes(Type, Value)
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if t, value := attrs[0], attrs[1]; t != nil && value != nil {
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isRadio := parse.EqualFold(t.AttrVal, radioBytes)
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if !isRadio && len(value.AttrVal) == 0 {
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value.Text = nil
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} else if isRadio && parse.EqualFold(value.AttrVal, onBytes) {
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value.Text = nil
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}
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}
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} else if t.Hash == A {
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attrs := tb.Attributes(Id, Name)
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if id, name := attrs[0], attrs[1]; id != nil && name != nil {
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if bytes.Equal(id.AttrVal, name.AttrVal) {
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name.Text = nil
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}
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}
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}
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// write attributes
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for {
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attr := *tb.Shift()
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if attr.TokenType != html.AttributeToken {
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break
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} else if attr.Text == nil {
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continue // removed attribute
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} else if attr.HasTemplate {
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w.Write(attr.Data)
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continue // don't minify attributes that contain templates
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}
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val := attr.AttrVal
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if attr.Traits&trimAttr != 0 {
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val = parse.ReplaceMultipleWhitespaceAndEntities(val, EntitiesMap, nil)
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val = parse.TrimWhitespace(val)
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} else {
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val = parse.ReplaceEntities(val, EntitiesMap, nil)
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}
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if t.Traits != 0 {
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if len(val) == 0 && (attr.Hash == Class ||
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attr.Hash == Dir ||
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attr.Hash == Id ||
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attr.Hash == Name ||
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attr.Hash == Action && t.Hash == Form) {
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continue // omit empty attribute values
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}
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if rawTagHash != 0 && attr.Hash == Type {
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rawTagMediatype = parse.Copy(val)
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}
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if attr.Hash == Enctype ||
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attr.Hash == Formenctype ||
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attr.Hash == Accept ||
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attr.Hash == Type && (t.Hash == A || t.Hash == Link || t.Hash == Embed || t.Hash == Object || t.Hash == Source || t.Hash == Script) {
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val = minify.Mediatype(val)
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}
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// default attribute values can be omitted
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if !o.KeepDefaultAttrVals && (attr.Hash == Type && (t.Hash == Script && jsMimetypes[string(parse.ToLower(parse.Copy(val)))] ||
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t.Hash == Style && parse.EqualFold(val, cssMimeBytes) ||
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t.Hash == Link && parse.EqualFold(val, cssMimeBytes) ||
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t.Hash == Input && parse.EqualFold(val, textBytes) ||
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t.Hash == Button && parse.EqualFold(val, submitBytes)) ||
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attr.Hash == Method && parse.EqualFold(val, getBytes) ||
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attr.Hash == Enctype && parse.EqualFold(val, formMimeBytes) ||
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attr.Hash == Colspan && bytes.Equal(val, oneBytes) ||
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attr.Hash == Rowspan && bytes.Equal(val, oneBytes) ||
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attr.Hash == Shape && parse.EqualFold(val, rectBytes) ||
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attr.Hash == Span && bytes.Equal(val, oneBytes) ||
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attr.Hash == Media && t.Hash == Style && parse.EqualFold(val, allBytes)) {
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continue
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}
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if attr.Hash == Style {
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// CSS minifier for attribute inline code
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val = parse.TrimWhitespace(val)
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attrMinifyBuffer.Reset()
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if err := m.MinifyMimetype(cssMimeBytes, attrMinifyBuffer, buffer.NewReader(val), inlineParams); err == nil {
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val = attrMinifyBuffer.Bytes()
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} else if err != minify.ErrNotExist {
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return minify.UpdateErrorPosition(err, z, attr.Offset)
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}
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if len(val) == 0 {
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continue
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}
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} else if 2 < len(attr.Text) && attr.Text[0] == 'o' && attr.Text[1] == 'n' {
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// JS minifier for attribute inline code
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val = parse.TrimWhitespace(val)
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if 11 <= len(val) && parse.EqualFold(val[:11], jsSchemeBytes) {
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val = val[11:]
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}
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attrMinifyBuffer.Reset()
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if err := m.MinifyMimetype(jsMimeBytes, attrMinifyBuffer, buffer.NewReader(val), inlineParams); err == nil {
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val = attrMinifyBuffer.Bytes()
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} else if err != minify.ErrNotExist {
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return minify.UpdateErrorPosition(err, z, attr.Offset)
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}
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if len(val) == 0 {
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continue
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}
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} else if attr.Traits&urlAttr != 0 { // anchors are already handled
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val = parse.TrimWhitespace(val)
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if 5 < len(val) {
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if parse.EqualFold(val[:4], httpBytes) {
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if val[4] == ':' {
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if m.URL != nil && m.URL.Scheme == "http" {
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val = val[5:]
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} else {
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parse.ToLower(val[:4])
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}
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} else if (val[4] == 's' || val[4] == 'S') && val[5] == ':' {
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if m.URL != nil && m.URL.Scheme == "https" {
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val = val[6:]
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} else {
|
|
parse.ToLower(val[:5])
|
|
}
|
|
}
|
|
} else if parse.EqualFold(val[:5], dataSchemeBytes) {
|
|
val = minify.DataURI(m, val)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
w.Write(spaceBytes)
|
|
w.Write(attr.Text)
|
|
if 0 < len(val) && attr.Traits&booleanAttr == 0 {
|
|
w.Write(isBytes)
|
|
|
|
// use double quotes for RDFa attributes
|
|
isXML := attr.Hash == Vocab || attr.Hash == Typeof || attr.Hash == Property || attr.Hash == Resource || attr.Hash == Prefix || attr.Hash == Content || attr.Hash == About || attr.Hash == Rev || attr.Hash == Datatype || attr.Hash == Inlist
|
|
|
|
// no quotes if possible, else prefer single or double depending on which occurs more often in value
|
|
var quote byte
|
|
|
|
if 0 < len(attr.Data) && (attr.Data[len(attr.Data)-1] == '\'' || attr.Data[len(attr.Data)-1] == '"') {
|
|
quote = attr.Data[len(attr.Data)-1]
|
|
}
|
|
val = html.EscapeAttrVal(&attrByteBuffer, val, quote, o.KeepQuotes, isXML)
|
|
w.Write(val)
|
|
}
|
|
}
|
|
} else {
|
|
_ = tb.Shift() // StartTagClose
|
|
}
|
|
w.Write(gtBytes)
|
|
|
|
// skip text in select and optgroup tags
|
|
if t.Hash == Select || t.Hash == Optgroup {
|
|
if next := tb.Peek(0); next.TokenType == html.TextToken {
|
|
tb.Shift()
|
|
}
|
|
}
|
|
|
|
// keep space after phrasing tags (<i>, <span>, ...) FontAwesome etc.
|
|
if t.TokenType == html.StartTagToken && t.Traits == normalTag {
|
|
if next := tb.Peek(0); next.Hash == t.Hash && next.TokenType == html.EndTagToken {
|
|
omitSpace = false
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|