encoding: move asn1, csv, gob, json, xml into encoding

This is Go 1 package renaming CL #1.
This one merely moves the source; the import strings will be
changed after the next weekly release.

The only edits are in Makefiles.

R=r, rsc
CC=golang-dev
https://golang.org/cl/5331060

src/pkg/encoding/xml/marshal.go

@@ -0,0 +1,304 @@
+// 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"
+	"io"
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+const (
+	// A generic XML header suitable for use with the output of Marshal and
+	// MarshalIndent.  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"
+)
+
+// A Marshaler can produce well-formatted XML representing its internal state.
+// It is used by both Marshal and MarshalIndent.
+type Marshaler interface {
+	MarshalXML() ([]byte, error)
+}
+
+type printer struct {
+	*bufio.Writer
+}
+
+// Marshal writes an XML-formatted representation of v to w.
+//
+// If v implements Marshaler, then Marshal calls its MarshalXML method.
+// Otherwise, Marshal uses the following procedure to create the XML.
+//
+// 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 an XMLName field, if the data is a struct
+//     - the value of an 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 '???'.
+//
+// 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 "attr" becomes an attribute 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.
+//
+// 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.  For example:
+//
+//	type Result struct {
+//		XMLName   xml.Name `xml:"result"`
+//		FirstName string   `xml:"person>name>first"`
+//		LastName  string   `xml:"person>name>last"`
+//		Age       int      `xml:"person>age"`
+//	}
+//
+//	xml.Marshal(w, &Result{FirstName: "John", LastName: "Doe", Age: 42})
+//
+// would be marshalled as:
+//
+//	<result>
+//		<person>
+//			<name>
+//				<first>John</first>
+//				<last>Doe</last>
+//			</name>
+//			<age>42</age>
+//		</person>
+//	</result>
+//
+// Marshal will return an error if asked to marshal a channel, function, or map.
+func Marshal(w io.Writer, v interface{}) (err error) {
+	p := &printer{bufio.NewWriter(w)}
+	err = p.marshalValue(reflect.ValueOf(v), "???")
+	p.Flush()
+	return err
+}
+
+func (p *printer) marshalValue(val reflect.Value, name string) error {
+	if !val.IsValid() {
+		return nil
+	}
+
+	kind := val.Kind()
+	typ := val.Type()
+
+	// Try Marshaler
+	if typ.NumMethod() > 0 {
+		if marshaler, ok := val.Interface().(Marshaler); ok {
+			bytes, err := marshaler.MarshalXML()
+			if err != nil {
+				return err
+			}
+			p.Write(bytes)
+			return nil
+		}
+	}
+
+	// Drill into pointers/interfaces
+	if kind == reflect.Ptr || kind == reflect.Interface {
+		if val.IsNil() {
+			return nil
+		}
+		return p.marshalValue(val.Elem(), name)
+	}
+
+	// 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), name); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+
+	// Find XML name
+	xmlns := ""
+	if kind == reflect.Struct {
+		if f, ok := typ.FieldByName("XMLName"); ok {
+			if tag := f.Tag.Get("xml"); tag != "" {
+				if i := strings.Index(tag, " "); i >= 0 {
+					xmlns, name = tag[:i], tag[i+1:]
+				} else {
+					name = tag
+				}
+			} else if v, ok := val.FieldByIndex(f.Index).Interface().(Name); ok && v.Local != "" {
+				xmlns, name = v.Space, v.Local
+			}
+		}
+	}
+
+	p.WriteByte('<')
+	p.WriteString(name)
+
+	// Attributes
+	if kind == reflect.Struct {
+		if len(xmlns) > 0 {
+			p.WriteString(` xmlns="`)
+			Escape(p, []byte(xmlns))
+			p.WriteByte('"')
+		}
+
+		for i, n := 0, typ.NumField(); i < n; i++ {
+			if f := typ.Field(i); f.PkgPath == "" && f.Tag.Get("xml") == "attr" {
+				if f.Type.Kind() == reflect.String {
+					if str := val.Field(i).String(); str != "" {
+						p.WriteByte(' ')
+						p.WriteString(strings.ToLower(f.Name))
+						p.WriteString(`="`)
+						Escape(p, []byte(str))
+						p.WriteByte('"')
+					}
+				}
+			}
+		}
+	}
+	p.WriteByte('>')
+
+	switch k := val.Kind(); k {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		p.WriteString(strconv.Itoa64(val.Int()))
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		p.WriteString(strconv.Uitoa64(val.Uint()))
+	case reflect.Float32, reflect.Float64:
+		p.WriteString(strconv.Ftoa64(val.Float(), 'g', -1))
+	case reflect.String:
+		Escape(p, []byte(val.String()))
+	case reflect.Bool:
+		p.WriteString(strconv.Btoa(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
+		bytes := val.Interface().([]byte)
+		Escape(p, bytes)
+	case reflect.Struct:
+		s := parentStack{printer: p}
+		for i, n := 0, val.NumField(); i < n; i++ {
+			if f := typ.Field(i); f.Name != "XMLName" && f.PkgPath == "" {
+				name := f.Name
+				vf := val.Field(i)
+				switch tag := f.Tag.Get("xml"); tag {
+				case "":
+					s.trim(nil)
+				case "chardata":
+					if tk := f.Type.Kind(); tk == reflect.String {
+						Escape(p, []byte(vf.String()))
+					} else if tk == reflect.Slice {
+						if elem, ok := vf.Interface().([]byte); ok {
+							Escape(p, elem)
+						}
+					}
+					continue
+				case "innerxml":
+					iface := vf.Interface()
+					switch raw := iface.(type) {
+					case []byte:
+						p.Write(raw)
+						continue
+					case string:
+						p.WriteString(raw)
+						continue
+					}
+				case "attr":
+					continue
+				default:
+					parents := strings.Split(tag, ">")
+					if len(parents) == 1 {
+						parents, name = nil, tag
+					} else {
+						parents, name = parents[:len(parents)-1], parents[len(parents)-1]
+						if parents[0] == "" {
+							parents[0] = f.Name
+						}
+					}
+
+					s.trim(parents)
+					if !(vf.Kind() == reflect.Ptr || vf.Kind() == reflect.Interface) || !vf.IsNil() {
+						s.push(parents[len(s.stack):])
+					}
+				}
+
+				if err := p.marshalValue(vf, name); err != nil {
+					return err
+				}
+			}
+		}
+		s.trim(nil)
+	default:
+		return &UnsupportedTypeError{typ}
+	}
+
+	p.WriteByte('<')
+	p.WriteByte('/')
+	p.WriteString(name)
+	p.WriteByte('>')
+
+	return nil
+}
+
+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.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.WriteString("<")
+		s.WriteString(parents[i])
+		s.WriteByte('>')
+	}
+	s.stack = append(s.stack, parents...)
+}
+
+// A MarshalXMLError is returned when Marshal or MarshalIndent encounter 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()
+}