Imported Upstream version 1upstream/1

1 files changed, 447 insertions, 0 deletions

diff --git a/src/pkg/encoding/xml/marshal.go b/src/pkg/encoding/xml/marshal.go
new file mode 100644
index 000000000..6c3170bdd
--- /dev/null
+++ b/src/pkg/encoding/xml/marshal.go
@@ -0,0 +1,447 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xml
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"reflect"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const (
+	// A generic XML header suitable for use with the output of Marshal.
+	// This is not automatically added to any output of this package,
+	// it is provided as a convenience.
+	Header = `<?xml version="1.0" encoding="UTF-8"?>` + "\n"
+)
+
+// Marshal returns the XML encoding of v.
+//
+// Marshal handles an array or slice by marshalling each of the elements.
+// Marshal handles a pointer by marshalling the value it points at or, if the
+// pointer is nil, by writing nothing.  Marshal handles an interface value by
+// marshalling the value it contains or, if the interface value is nil, by
+// writing nothing.  Marshal handles all other data by writing one or more XML
+// elements containing the data.
+//
+// The name for the XML elements is taken from, in order of preference:
+//     - the tag on the XMLName field, if the data is a struct
+//     - the value of the XMLName field of type xml.Name
+//     - the tag of the struct field used to obtain the data
+//     - the name of the struct field used to obtain the data
+//     - the name of the marshalled type
+//
+// The XML element for a struct contains marshalled elements for each of the
+// exported fields of the struct, with these exceptions:
+//     - the XMLName field, described above, is omitted.
+//     - a field with tag "-" is omitted.
+//     - a field with tag "name,attr" becomes an attribute with
+//       the given name in the XML element.
+//     - a field with tag ",attr" becomes an attribute with the
+//       field name in the in the XML element.
+//     - a field with tag ",chardata" is written as character data,
+//       not as an XML element.
+//     - a field with tag ",innerxml" is written verbatim, not subject
+//       to the usual marshalling procedure.
+//     - a field with tag ",comment" is written as an XML comment, not
+//       subject to the usual marshalling procedure. It must not contain
+//       the "--" string within it.
+//     - a field with a tag including the "omitempty" option is omitted
+//       if the field value is empty. The empty values are false, 0, any
+//       nil pointer or interface value, and any array, slice, map, or
+//       string of length zero.
+//     - a non-pointer anonymous struct field is handled as if the
+//       fields of its value were part of the outer struct.
+//
+// If a field uses a tag "a>b>c", then the element c will be nested inside
+// parent elements a and b.  Fields that appear next to each other that name
+// the same parent will be enclosed in one XML element.
+//
+// See MarshalIndent for an example.
+//
+// Marshal will return an error if asked to marshal a channel, function, or map.
+func Marshal(v interface{}) ([]byte, error) {
+	var b bytes.Buffer
+	if err := NewEncoder(&b).Encode(v); err != nil {
+		return nil, err
+	}
+	return b.Bytes(), nil
+}
+
+// MarshalIndent works like Marshal, but each XML element begins on a new
+// indented line that starts with prefix and is followed by one or more
+// copies of indent according to the nesting depth.
+func MarshalIndent(v interface{}, prefix, indent string) ([]byte, error) {
+	var b bytes.Buffer
+	enc := NewEncoder(&b)
+	enc.prefix = prefix
+	enc.indent = indent
+	err := enc.marshalValue(reflect.ValueOf(v), nil)
+	enc.Flush()
+	if err != nil {
+		return nil, err
+	}
+	return b.Bytes(), nil
+}
+
+// An Encoder writes XML data to an output stream.
+type Encoder struct {
+	printer
+}
+
+// NewEncoder returns a new encoder that writes to w.
+func NewEncoder(w io.Writer) *Encoder {
+	return &Encoder{printer{Writer: bufio.NewWriter(w)}}
+}
+
+// Encode writes the XML encoding of v to the stream.
+//
+// See the documentation for Marshal for details about the conversion
+// of Go values to XML.
+func (enc *Encoder) Encode(v interface{}) error {
+	err := enc.marshalValue(reflect.ValueOf(v), nil)
+	enc.Flush()
+	return err
+}
+
+type printer struct {
+	*bufio.Writer
+	indent     string
+	prefix     string
+	depth      int
+	indentedIn bool
+}
+
+// marshalValue writes one or more XML elements representing val.
+// If val was obtained from a struct field, finfo must have its details.
+func (p *printer) marshalValue(val reflect.Value, finfo *fieldInfo) error {
+	if !val.IsValid() {
+		return nil
+	}
+	if finfo != nil && finfo.flags&fOmitEmpty != 0 && isEmptyValue(val) {
+		return nil
+	}
+
+	kind := val.Kind()
+	typ := val.Type()
+
+	// Drill into pointers/interfaces
+	if kind == reflect.Ptr || kind == reflect.Interface {
+		if val.IsNil() {
+			return nil
+		}
+		return p.marshalValue(val.Elem(), finfo)
+	}
+
+	// Slices and arrays iterate over the elements. They do not have an enclosing tag.
+	if (kind == reflect.Slice || kind == reflect.Array) && typ.Elem().Kind() != reflect.Uint8 {
+		for i, n := 0, val.Len(); i < n; i++ {
+			if err := p.marshalValue(val.Index(i), finfo); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+
+	tinfo, err := getTypeInfo(typ)
+	if err != nil {
+		return err
+	}
+
+	// Precedence for the XML element name is:
+	// 1. XMLName field in underlying struct;
+	// 2. field name/tag in the struct field; and
+	// 3. type name
+	var xmlns, name string
+	if tinfo.xmlname != nil {
+		xmlname := tinfo.xmlname
+		if xmlname.name != "" {
+			xmlns, name = xmlname.xmlns, xmlname.name
+		} else if v, ok := val.FieldByIndex(xmlname.idx).Interface().(Name); ok && v.Local != "" {
+			xmlns, name = v.Space, v.Local
+		}
+	}
+	if name == "" && finfo != nil {
+		xmlns, name = finfo.xmlns, finfo.name
+	}
+	if name == "" {
+		name = typ.Name()
+		if name == "" {
+			return &UnsupportedTypeError{typ}
+		}
+	}
+
+	p.writeIndent(1)
+	p.WriteByte('<')
+	p.WriteString(name)
+
+	if xmlns != "" {
+		p.WriteString(` xmlns="`)
+		// TODO: EscapeString, to avoid the allocation.
+		Escape(p, []byte(xmlns))
+		p.WriteByte('"')
+	}
+
+	// Attributes
+	for i := range tinfo.fields {
+		finfo := &tinfo.fields[i]
+		if finfo.flags&fAttr == 0 {
+			continue
+		}
+		fv := val.FieldByIndex(finfo.idx)
+		if finfo.flags&fOmitEmpty != 0 && isEmptyValue(fv) {
+			continue
+		}
+		p.WriteByte(' ')
+		p.WriteString(finfo.name)
+		p.WriteString(`="`)
+		if err := p.marshalSimple(fv.Type(), fv); err != nil {
+			return err
+		}
+		p.WriteByte('"')
+	}
+	p.WriteByte('>')
+
+	if val.Kind() == reflect.Struct {
+		err = p.marshalStruct(tinfo, val)
+	} else {
+		err = p.marshalSimple(typ, val)
+	}
+	if err != nil {
+		return err
+	}
+
+	p.writeIndent(-1)
+	p.WriteByte('<')
+	p.WriteByte('/')
+	p.WriteString(name)
+	p.WriteByte('>')
+
+	return nil
+}
+
+var timeType = reflect.TypeOf(time.Time{})
+
+func (p *printer) marshalSimple(typ reflect.Type, val reflect.Value) error {
+	// Normally we don't see structs, but this can happen for an attribute.
+	if val.Type() == timeType {
+		p.WriteString(val.Interface().(time.Time).Format(time.RFC3339Nano))
+		return nil
+	}
+	switch val.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		p.WriteString(strconv.FormatInt(val.Int(), 10))
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		p.WriteString(strconv.FormatUint(val.Uint(), 10))
+	case reflect.Float32, reflect.Float64:
+		p.WriteString(strconv.FormatFloat(val.Float(), 'g', -1, 64))
+	case reflect.String:
+		// TODO: Add EscapeString.
+		Escape(p, []byte(val.String()))
+	case reflect.Bool:
+		p.WriteString(strconv.FormatBool(val.Bool()))
+	case reflect.Array:
+		// will be [...]byte
+		bytes := make([]byte, val.Len())
+		for i := range bytes {
+			bytes[i] = val.Index(i).Interface().(byte)
+		}
+		Escape(p, bytes)
+	case reflect.Slice:
+		// will be []byte
+		Escape(p, val.Bytes())
+	default:
+		return &UnsupportedTypeError{typ}
+	}
+	return nil
+}
+
+var ddBytes = []byte("--")
+
+func (p *printer) marshalStruct(tinfo *typeInfo, val reflect.Value) error {
+	if val.Type() == timeType {
+		p.WriteString(val.Interface().(time.Time).Format(time.RFC3339Nano))
+		return nil
+	}
+	s := parentStack{printer: p}
+	for i := range tinfo.fields {
+		finfo := &tinfo.fields[i]
+		if finfo.flags&(fAttr|fAny) != 0 {
+			continue
+		}
+		vf := val.FieldByIndex(finfo.idx)
+		switch finfo.flags & fMode {
+		case fCharData:
+			switch vf.Kind() {
+			case reflect.String:
+				Escape(p, []byte(vf.String()))
+			case reflect.Slice:
+				if elem, ok := vf.Interface().([]byte); ok {
+					Escape(p, elem)
+				}
+			}
+			continue
+
+		case fComment:
+			k := vf.Kind()
+			if !(k == reflect.String || k == reflect.Slice && vf.Type().Elem().Kind() == reflect.Uint8) {
+				return fmt.Errorf("xml: bad type for comment field of %s", val.Type())
+			}
+			if vf.Len() == 0 {
+				continue
+			}
+			p.writeIndent(0)
+			p.WriteString("<!--")
+			dashDash := false
+			dashLast := false
+			switch k {
+			case reflect.String:
+				s := vf.String()
+				dashDash = strings.Index(s, "--") >= 0
+				dashLast = s[len(s)-1] == '-'
+				if !dashDash {
+					p.WriteString(s)
+				}
+			case reflect.Slice:
+				b := vf.Bytes()
+				dashDash = bytes.Index(b, ddBytes) >= 0
+				dashLast = b[len(b)-1] == '-'
+				if !dashDash {
+					p.Write(b)
+				}
+			default:
+				panic("can't happen")
+			}
+			if dashDash {
+				return fmt.Errorf(`xml: comments must not contain "--"`)
+			}
+			if dashLast {
+				// "--->" is invalid grammar. Make it "- -->"
+				p.WriteByte(' ')
+			}
+			p.WriteString("-->")
+			continue
+
+		case fInnerXml:
+			iface := vf.Interface()
+			switch raw := iface.(type) {
+			case []byte:
+				p.Write(raw)
+				continue
+			case string:
+				p.WriteString(raw)
+				continue
+			}
+
+		case fElement:
+			s.trim(finfo.parents)
+			if len(finfo.parents) > len(s.stack) {
+				if vf.Kind() != reflect.Ptr && vf.Kind() != reflect.Interface || !vf.IsNil() {
+					s.push(finfo.parents[len(s.stack):])
+				}
+			}
+		}
+		if err := p.marshalValue(vf, finfo); err != nil {
+			return err
+		}
+	}
+	s.trim(nil)
+	return nil
+}
+
+func (p *printer) writeIndent(depthDelta int) {
+	if len(p.prefix) == 0 && len(p.indent) == 0 {
+		return
+	}
+	if depthDelta < 0 {
+		p.depth--
+		if p.indentedIn {
+			p.indentedIn = false
+			return
+		}
+		p.indentedIn = false
+	}
+	p.WriteByte('\n')
+	if len(p.prefix) > 0 {
+		p.WriteString(p.prefix)
+	}
+	if len(p.indent) > 0 {
+		for i := 0; i < p.depth; i++ {
+			p.WriteString(p.indent)
+		}
+	}
+	if depthDelta > 0 {
+		p.depth++
+		p.indentedIn = true
+	}
+}
+
+type parentStack struct {
+	*printer
+	stack []string
+}
+
+// trim updates the XML context to match the longest common prefix of the stack
+// and the given parents.  A closing tag will be written for every parent
+// popped.  Passing a zero slice or nil will close all the elements.
+func (s *parentStack) trim(parents []string) {
+	split := 0
+	for ; split < len(parents) && split < len(s.stack); split++ {
+		if parents[split] != s.stack[split] {
+			break
+		}
+	}
+	for i := len(s.stack) - 1; i >= split; i-- {
+		s.writeIndent(-1)
+		s.WriteString("</")
+		s.WriteString(s.stack[i])
+		s.WriteByte('>')
+	}
+	s.stack = parents[:split]
+}
+
+// push adds parent elements to the stack and writes open tags.
+func (s *parentStack) push(parents []string) {
+	for i := 0; i < len(parents); i++ {
+		s.writeIndent(1)
+		s.WriteByte('<')
+		s.WriteString(parents[i])
+		s.WriteByte('>')
+	}
+	s.stack = append(s.stack, parents...)
+}
+
+// A MarshalXMLError is returned when Marshal encounters a type
+// that cannot be converted into XML.
+type UnsupportedTypeError struct {
+	Type reflect.Type
+}
+
+func (e *UnsupportedTypeError) Error() string {
+	return "xml: unsupported type: " + e.Type.String()
+}
+
+func isEmptyValue(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
+		return v.Len() == 0
+	case reflect.Bool:
+		return !v.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Interface, reflect.Ptr:
+		return v.IsNil()
+	}
+	return false
+}