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// Package xml minifies XML1.0 following the specifications at http://www.w3.org/TR/xml/.
package xml
import (
"io"
"github.com/tdewolff/minify/v2"
"github.com/tdewolff/parse/v2"
"github.com/tdewolff/parse/v2/xml"
)
var (
isBytes = []byte("=")
spaceBytes = []byte(" ")
voidBytes = []byte("/>")
)
////////////////////////////////////////////////////////////////
// Minifier is an XML minifier.
type Minifier struct {
KeepWhitespace bool
}
// Minify minifies XML 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 XML 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 {
omitSpace := true // on true the next text token must not start with a space
attrByteBuffer := make([]byte, 0, 64)
z := parse.NewInput(r)
defer z.Restore()
l := xml.NewLexer(z)
tb := NewTokenBuffer(l)
for {
t := *tb.Shift()
if t.TokenType == xml.CDATAToken {
// convert CDATA to regular text if smaller
if len(t.Text) == 0 {
continue
} else if text, useText := xml.EscapeCDATAVal(&attrByteBuffer, t.Text); useText {
t.Data = text
}
}
switch t.TokenType {
case xml.ErrorToken:
if _, err := w.Write(nil); err != nil {
return err
}
if l.Err() == io.EOF {
return nil
}
return l.Err()
case xml.DOCTYPEToken:
w.Write(t.Data)
case xml.CDATAToken:
w.Write(t.Data)
if len(t.Text) > 0 && parse.IsWhitespace(t.Text[len(t.Text)-1]) {
omitSpace = true
}
case xml.TextToken:
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 whitespace begin or block token
if next.TokenType == xml.ErrorToken {
t.Data = t.Data[:len(t.Data)-1]
omitSpace = false
break
} else if next.TokenType == xml.TextToken {
// this only happens when a comment, doctype, cdata startpi tag 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 == xml.CDATAToken {
if len(next.Text) > 0 && parse.IsWhitespace(next.Text[0]) {
t.Data = t.Data[:len(t.Data)-1]
omitSpace = false
}
break
} else if next.TokenType == xml.StartTagToken || next.TokenType == xml.EndTagToken {
if !o.KeepWhitespace {
t.Data = t.Data[:len(t.Data)-1]
omitSpace = false
}
break
}
i++
}
}
w.Write(t.Data)
case xml.StartTagToken:
w.Write(t.Data)
if o.KeepWhitespace {
omitSpace = false
}
case xml.StartTagPIToken:
w.Write(t.Data)
case xml.AttributeToken:
w.Write(spaceBytes)
w.Write(t.Text)
w.Write(isBytes)
if len(t.AttrVal) < 2 || t.AttrVal[0] != '"' || t.AttrVal[len(t.AttrVal)-1] != '"' {
w.Write(t.AttrVal)
} else {
val := t.AttrVal[1 : len(t.AttrVal)-1]
val = parse.ReplaceEntities(val, EntitiesMap, nil)
val = xml.EscapeAttrVal(&attrByteBuffer, val) // prefer single or double quotes depending on what occurs more often in value
w.Write(val)
}
case xml.StartTagCloseToken:
next := tb.Peek(0)
skipExtra := false
if next.TokenType == xml.TextToken && parse.IsAllWhitespace(next.Data) {
next = tb.Peek(1)
skipExtra = true
}
if next.TokenType == xml.EndTagToken {
// collapse empty tags to single void tag
tb.Shift()
if skipExtra {
tb.Shift()
}
w.Write(voidBytes)
} else {
w.Write(t.Data)
}
case xml.StartTagCloseVoidToken:
w.Write(t.Data)
case xml.StartTagClosePIToken:
w.Write(t.Data)
case xml.EndTagToken:
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)
if o.KeepWhitespace {
omitSpace = false
}
}
}
}
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