gotosocial/vendor/github.com/tdewolff/minify/v2/html/html.go
tobi 879b4abde7
[bugfix] Markdown formatting updates (#743)
* add minify dependency specifically for markdown

* rearrange markdown formatting

* update markdown tests
2022-08-07 18:19:16 +02:00

513 lines
17 KiB
Go

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