First commit

vendor/github.com/tdewolff/minify/xml/xml.go

@@ -0,0 +1,193 @@
+// 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 (
+	isBytes    = []byte("=")
+	spaceBytes = []byte(" ")
+	voidBytes  = []byte("/>")
+)
+
+////////////////////////////////////////////////////////////////
+
+// DefaultMinifier is the default minifier.
+var DefaultMinifier = &Minifier{}
+
+// 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 DefaultMinifier.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)
+
+	l := xml.NewLexer(r)
+	defer l.Restore()
+
+	tb := NewTokenBuffer(l)
+	for {
+		t := *tb.Shift()
+		if t.TokenType == xml.CDATAToken {
+			if text, useText := xml.EscapeCDATAVal(&attrByteBuffer, t.Text); useText {
+				t.TokenType = xml.TextToken
+				t.Data = text
+			}
+		}
+		switch t.TokenType {
+		case xml.ErrorToken:
+			if l.Err() == io.EOF {
+				return nil
+			}
+			return l.Err()
+		case xml.DOCTYPEToken:
+			if _, err := w.Write(t.Data); err != nil {
+				return err
+			}
+		case xml.CDATAToken:
+			if _, err := w.Write(t.Data); err != nil {
+				return err
+			}
+			if len(t.Text) > 0 && parse.IsWhitespace(t.Text[len(t.Text)-1]) {
+				omitSpace = true
+			}
+		case xml.TextToken:
+			t.Data = parse.ReplaceMultipleWhitespace(t.Data)
+
+			// whitespace removal; trim left
+			if omitSpace && (t.Data[0] == ' ' || t.Data[0] == '\n') {
+				t.Data = t.Data[1:]
+			}
+
+			// whitespace removal; trim right
+			omitSpace = false
+			if len(t.Data) == 0 {
+				omitSpace = true
+			} else if t.Data[len(t.Data)-1] == ' ' || t.Data[len(t.Data)-1] == '\n' {
+				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++
+				}
+			}
+
+			if _, err := w.Write(t.Data); err != nil {
+				return err
+			}
+		case xml.StartTagToken:
+			if o.KeepWhitespace {
+				omitSpace = false
+			}
+			if _, err := w.Write(t.Data); err != nil {
+				return err
+			}
+		case xml.StartTagPIToken:
+			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.Text); 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(t.Text); err != nil {
+					return err
+				}
+			}
+		case xml.StartTagCloseVoidToken:
+			if _, err := w.Write(t.Text); err != nil {
+				return err
+			}
+		case xml.StartTagClosePIToken:
+			if _, err := w.Write(t.Text); err != nil {
+				return err
+			}
+		case xml.EndTagToken:
+			if o.KeepWhitespace {
+				omitSpace = false
+			}
+			if len(t.Data) > 3+len(t.Text) {
+				t.Data[2+len(t.Text)] = '>'
+				t.Data = t.Data[:3+len(t.Text)]
+			}
+			if _, err := w.Write(t.Data); err != nil {
+				return err
+			}
+		}
+	}
+}