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Copy pathxml.go
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184 lines (174 loc) · 4.62 KB
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// Package xml minifies XML1.0 following the specifications at http://www.w3.org/TR/xml/.
package xml // import "github.com/tdewolff/minify/xml"
import (
"io"
"github.com/tdewolff/minify"
"github.com/tdewolff/parse"
"github.com/tdewolff/parse/xml"
)
var (
ltBytes = []byte("<")
gtBytes = []byte(">")
voidBytes = []byte("/>")
ltPIBytes = []byte("<?")
gtPIBytes = []byte("?>")
endBytes = []byte("</")
doctypeBytes = []byte("<!DOCTYPE ")
cdataStartBytes = []byte("<![CDATA[")
cdataEndBytes = []byte("]]>")
isBytes = []byte("=")
spaceBytes = []byte(" ")
)
////////////////////////////////////////////////////////////////
// Minify minifies XML data, it reads from r and writes to w.
func Minify(m minify.Minifier, _ string, w io.Writer, r io.Reader) error {
precededBySpace := true // on true the next text token must not start with a space
attrByteBuffer := make([]byte, 0, 64)
l := xml.NewLexer(r)
tb := NewTokenBuffer(l)
for {
t := *tb.Shift()
if t.TokenType == xml.CDATAToken {
var useCDATA bool
if t.Data, useCDATA = xml.EscapeCDATAVal(&attrByteBuffer, t.Data); !useCDATA {
t.TokenType = xml.TextToken
}
}
switch t.TokenType {
case xml.ErrorToken:
if l.Err() == io.EOF {
return nil
}
return l.Err()
case xml.DOCTYPEToken:
if _, err := w.Write(doctypeBytes); err != nil {
return err
}
if _, err := w.Write(t.Data); err != nil {
return err
}
if _, err := w.Write(gtBytes); err != nil {
return err
}
case xml.CDATAToken:
if _, err := w.Write(cdataStartBytes); err != nil {
return err
}
if _, err := w.Write(t.Data); err != nil {
return err
}
if _, err := w.Write(cdataEndBytes); err != nil {
return err
}
case xml.TextToken:
if t.Data = parse.ReplaceMultipleWhitespace(t.Data); len(t.Data) > 0 {
// whitespace removal; trim left
if t.Data[0] == ' ' && precededBySpace {
t.Data = t.Data[1:]
}
// whitespace removal; trim right
precededBySpace = false
if len(t.Data) == 0 {
precededBySpace = true
} else if t.Data[len(t.Data)-1] == ' ' {
precededBySpace = true
i := 0
for {
next := tb.Peek(i)
// trim if EOF, text token with whitespace begin or block token
if next.TokenType == xml.StartTagToken || next.TokenType == xml.EndTagToken || next.TokenType == xml.ErrorToken {
t.Data = t.Data[:len(t.Data)-1]
precededBySpace = false
break
} else if next.TokenType == xml.TextToken {
// 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]
precededBySpace = false
}
break
}
i++
}
}
if _, err := w.Write(t.Data); err != nil {
return err
}
}
case xml.StartTagToken:
if _, err := w.Write(ltBytes); err != nil {
return err
}
if _, err := w.Write(t.Data); err != nil {
return err
}
case xml.StartTagPIToken:
if _, err := w.Write(ltPIBytes); err != nil {
return err
}
if _, err := w.Write(t.Data); err != nil {
return err
}
case xml.AttributeToken:
if _, err := w.Write(spaceBytes); err != nil {
return err
}
if _, err := w.Write(t.Data); err != nil {
return err
}
if _, err := w.Write(isBytes); err != nil {
return err
}
if len(t.AttrVal) < 2 {
if _, err := w.Write(t.AttrVal); err != nil {
return err
}
} else {
// prefer single or double quotes depending on what occurs more often in value
val := xml.EscapeAttrVal(&attrByteBuffer, t.AttrVal[1:len(t.AttrVal)-1])
if _, err := w.Write(val); err != nil {
return err
}
}
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()
}
if _, err := w.Write(voidBytes); err != nil {
return err
}
} else {
if _, err := w.Write(gtBytes); err != nil {
return err
}
}
case xml.StartTagCloseVoidToken:
if _, err := w.Write(voidBytes); err != nil {
return err
}
case xml.StartTagClosePIToken:
if _, err := w.Write(gtPIBytes); err != nil {
return err
}
case xml.EndTagToken:
if _, err := w.Write(endBytes); err != nil {
return err
}
if _, err := w.Write(t.Data); err != nil {
return err
}
if _, err := w.Write(gtBytes); err != nil {
return err
}
}
}
}