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dex/vendor/github.com/beevik/etree/etree.go

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2017-01-10 04:21:47 +05:30
// Copyright 2015 Brett Vickers.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package etree provides XML services through an Element Tree
// abstraction.
package etree
import (
"bufio"
"bytes"
"encoding/xml"
"errors"
"io"
"os"
"strings"
)
const (
// NoIndent is used with Indent to disable all indenting.
NoIndent = -1
)
// ErrXML is returned when XML parsing fails due to incorrect formatting.
var ErrXML = errors.New("etree: invalid XML format")
// ReadSettings allow for changing the default behavior of the ReadFrom*
// methods.
type ReadSettings struct {
// CharsetReader to be passed to standard xml.Decoder. Default: nil.
CharsetReader func(charset string, input io.Reader) (io.Reader, error)
}
// newReadSettings creates a default ReadSettings record.
func newReadSettings() ReadSettings {
return ReadSettings{}
}
// WriteSettings allow for changing the serialization behavior of the WriteTo*
// methods.
type WriteSettings struct {
// CanonicalEndTags forces the production of XML end tags, even for
// elements that have no child elements. Default: false.
CanonicalEndTags bool
// CanonicalText forces the production of XML character references for
// text data characters &, <, and >. If false, XML character references
// are also produced for " and '. Default: false.
CanonicalText bool
// CanonicalAttrVal forces the production of XML character references for
// attribute value characters &, < and ". If false, XML character
// references are also produced for > and '. Default: false.
CanonicalAttrVal bool
}
// newWriteSettings creates a default WriteSettings record.
func newWriteSettings() WriteSettings {
return WriteSettings{
CanonicalEndTags: false,
CanonicalText: false,
CanonicalAttrVal: false,
}
}
// A Token is an empty interface that represents an Element, CharData,
// Comment, Directive, or ProcInst.
type Token interface {
Parent() *Element
dup(parent *Element) Token
setParent(parent *Element)
writeTo(w *bufio.Writer, s *WriteSettings)
}
// A Document is a container holding a complete XML hierarchy. Its embedded
// element contains zero or more children, one of which is usually the root
// element. The embedded element may include other children such as
// processing instructions or BOM CharData tokens.
type Document struct {
Element
ReadSettings ReadSettings
WriteSettings WriteSettings
}
// An Element represents an XML element, its attributes, and its child tokens.
type Element struct {
Space, Tag string // namespace and tag
Attr []Attr // key-value attribute pairs
Child []Token // child tokens (elements, comments, etc.)
parent *Element // parent element
}
// An Attr represents a key-value attribute of an XML element.
type Attr struct {
Space, Key string // The attribute's namespace and key
Value string // The attribute value string
}
// CharData represents character data within XML.
type CharData struct {
Data string
parent *Element
whitespace bool
}
// A Comment represents an XML comment.
type Comment struct {
Data string
parent *Element
}
// A Directive represents an XML directive.
type Directive struct {
Data string
parent *Element
}
// A ProcInst represents an XML processing instruction.
type ProcInst struct {
Target string
Inst string
parent *Element
}
// NewDocument creates an XML document without a root element.
func NewDocument() *Document {
return &Document{
Element{Child: make([]Token, 0)},
newReadSettings(),
newWriteSettings(),
}
}
// Copy returns a recursive, deep copy of the document.
func (d *Document) Copy() *Document {
return &Document{*(d.dup(nil).(*Element)), d.ReadSettings, d.WriteSettings}
}
// Root returns the root element of the document, or nil if there is no root
// element.
func (d *Document) Root() *Element {
for _, t := range d.Child {
if c, ok := t.(*Element); ok {
return c
}
}
return nil
}
// SetRoot replaces the document's root element with e. If the document
// already has a root when this function is called, then the document's
// original root is unbound first. If the element e is bound to another
// document (or to another element within a document), then it is unbound
// first.
func (d *Document) SetRoot(e *Element) {
if e.parent != nil {
e.parent.RemoveChild(e)
}
e.setParent(&d.Element)
for i, t := range d.Child {
if _, ok := t.(*Element); ok {
t.setParent(nil)
d.Child[i] = e
return
}
}
d.Child = append(d.Child, e)
}
// ReadFrom reads XML from the reader r into the document d. It returns the
// number of bytes read and any error encountered.
func (d *Document) ReadFrom(r io.Reader) (n int64, err error) {
return d.Element.readFrom(r, d.ReadSettings.CharsetReader)
}
// ReadFromFile reads XML from the string s into the document d.
func (d *Document) ReadFromFile(filename string) error {
f, err := os.Open(filename)
if err != nil {
return err
}
defer f.Close()
_, err = d.ReadFrom(f)
return err
}
// ReadFromBytes reads XML from the byte slice b into the document d.
func (d *Document) ReadFromBytes(b []byte) error {
_, err := d.ReadFrom(bytes.NewReader(b))
return err
}
// ReadFromString reads XML from the string s into the document d.
func (d *Document) ReadFromString(s string) error {
_, err := d.ReadFrom(strings.NewReader(s))
return err
}
// WriteTo serializes an XML document into the writer w. It
// returns the number of bytes written and any error encountered.
func (d *Document) WriteTo(w io.Writer) (n int64, err error) {
cw := newCountWriter(w)
b := bufio.NewWriter(cw)
for _, c := range d.Child {
c.writeTo(b, &d.WriteSettings)
}
err, n = b.Flush(), cw.bytes
return
}
// WriteToFile serializes an XML document into the file named
// filename.
func (d *Document) WriteToFile(filename string) error {
f, err := os.Create(filename)
if err != nil {
return err
}
defer f.Close()
_, err = d.WriteTo(f)
return err
}
// WriteToBytes serializes the XML document into a slice of
// bytes.
func (d *Document) WriteToBytes() (b []byte, err error) {
var buf bytes.Buffer
if _, err = d.WriteTo(&buf); err != nil {
return
}
return buf.Bytes(), nil
}
// WriteToString serializes the XML document into a string.
func (d *Document) WriteToString() (s string, err error) {
var b []byte
if b, err = d.WriteToBytes(); err != nil {
return
}
return string(b), nil
}
type indentFunc func(depth int) string
// Indent modifies the document's element tree by inserting CharData entities
// containing carriage returns and indentation. The amount of indentation per
// depth level is given as spaces. Pass etree.NoIndent for spaces if you want
// no indentation at all.
func (d *Document) Indent(spaces int) {
var indent indentFunc
switch {
case spaces < 0:
indent = func(depth int) string { return "" }
default:
indent = func(depth int) string { return crIndent(depth*spaces, crsp) }
}
d.Element.indent(0, indent)
}
// IndentTabs modifies the document's element tree by inserting CharData
// entities containing carriage returns and tabs for indentation. One tab is
// used per indentation level.
func (d *Document) IndentTabs() {
indent := func(depth int) string { return crIndent(depth, crtab) }
d.Element.indent(0, indent)
}
// NewElement creates an unparented element with the specified tag. The tag
// may be prefixed by a namespace and a colon.
func NewElement(tag string) *Element {
space, stag := spaceDecompose(tag)
return newElement(space, stag, nil)
}
// newElement is a helper function that creates an element and binds it to
// a parent element if possible.
func newElement(space, tag string, parent *Element) *Element {
e := &Element{
Space: space,
Tag: tag,
Attr: make([]Attr, 0),
Child: make([]Token, 0),
parent: parent,
}
if parent != nil {
parent.addChild(e)
}
return e
}
// Copy creates a recursive, deep copy of the element and all its attributes
// and children. The returned element has no parent but can be parented to a
// another element using AddElement, or to a document using SetRoot.
func (e *Element) Copy() *Element {
var parent *Element
return e.dup(parent).(*Element)
}
// Text returns the characters immediately following the element's
// opening tag.
func (e *Element) Text() string {
if len(e.Child) == 0 {
return ""
}
if cd, ok := e.Child[0].(*CharData); ok {
return cd.Data
}
return ""
}
// SetText replaces an element's subsidiary CharData text with a new string.
func (e *Element) SetText(text string) {
if len(e.Child) > 0 {
if cd, ok := e.Child[0].(*CharData); ok {
cd.Data = text
return
}
}
cd := newCharData(text, false, e)
copy(e.Child[1:], e.Child[0:])
e.Child[0] = cd
}
// CreateElement creates an element with the specified tag and adds it as the
// last child element of the element e. The tag may be prefixed by a namespace
// and a colon.
func (e *Element) CreateElement(tag string) *Element {
space, stag := spaceDecompose(tag)
return newElement(space, stag, e)
}
// AddChild adds the token t as the last child of element e. If token t was
// already the child of another element, it is first removed from its current
// parent element.
func (e *Element) AddChild(t Token) {
if t.Parent() != nil {
t.Parent().RemoveChild(t)
}
t.setParent(e)
e.addChild(t)
}
// InsertChild inserts the token t before e's existing child token ex. If ex
// is nil (or if ex is not a child of e), then t is added to the end of e's
// child token list. If token t was already the child of another element, it
// is first removed from its current parent element.
func (e *Element) InsertChild(ex Token, t Token) {
if t.Parent() != nil {
t.Parent().RemoveChild(t)
}
t.setParent(e)
for i, c := range e.Child {
if c == ex {
e.Child = append(e.Child, nil)
copy(e.Child[i+1:], e.Child[i:])
e.Child[i] = t
return
}
}
e.addChild(t)
}
// RemoveChild attempts to remove the token t from element e's list of
// children. If the token t is a child of e, then it is returned. Otherwise,
// nil is returned.
func (e *Element) RemoveChild(t Token) Token {
for i, c := range e.Child {
if c == t {
e.Child = append(e.Child[:i], e.Child[i+1:]...)
c.setParent(nil)
return t
}
}
return nil
}
// ReadFrom reads XML from the reader r and stores the result as a new child
// of element e.
func (e *Element) readFrom(ri io.Reader, charsetReader func(charset string, input io.Reader) (io.Reader, error)) (n int64, err error) {
r := newCountReader(ri)
dec := xml.NewDecoder(r)
dec.CharsetReader = charsetReader
var stack stack
stack.push(e)
for {
t, err := dec.RawToken()
switch {
case err == io.EOF:
return r.bytes, nil
case err != nil:
return r.bytes, err
case stack.empty():
return r.bytes, ErrXML
}
top := stack.peek().(*Element)
switch t := t.(type) {
case xml.StartElement:
e := newElement(t.Name.Space, t.Name.Local, top)
for _, a := range t.Attr {
e.createAttr(a.Name.Space, a.Name.Local, a.Value)
}
stack.push(e)
case xml.EndElement:
stack.pop()
case xml.CharData:
data := string(t)
newCharData(data, isWhitespace(data), top)
case xml.Comment:
newComment(string(t), top)
case xml.Directive:
newDirective(string(t), top)
case xml.ProcInst:
newProcInst(t.Target, string(t.Inst), top)
}
}
}
// SelectAttr finds an element attribute matching the requested key and
// returns it if found. The key may be prefixed by a namespace and a colon.
func (e *Element) SelectAttr(key string) *Attr {
space, skey := spaceDecompose(key)
for i, a := range e.Attr {
if spaceMatch(space, a.Space) && skey == a.Key {
return &e.Attr[i]
}
}
return nil
}
// SelectAttrValue finds an element attribute matching the requested key and
// returns its value if found. The key may be prefixed by a namespace and a
// colon. If the key is not found, the dflt value is returned instead.
func (e *Element) SelectAttrValue(key, dflt string) string {
space, skey := spaceDecompose(key)
for _, a := range e.Attr {
if spaceMatch(space, a.Space) && skey == a.Key {
return a.Value
}
}
return dflt
}
// ChildElements returns all elements that are children of element e.
func (e *Element) ChildElements() []*Element {
var elements []*Element
for _, t := range e.Child {
if c, ok := t.(*Element); ok {
elements = append(elements, c)
}
}
return elements
}
// SelectElement returns the first child element with the given tag. The tag
// may be prefixed by a namespace and a colon.
func (e *Element) SelectElement(tag string) *Element {
space, stag := spaceDecompose(tag)
for _, t := range e.Child {
if c, ok := t.(*Element); ok && spaceMatch(space, c.Space) && stag == c.Tag {
return c
}
}
return nil
}
// SelectElements returns a slice of all child elements with the given tag.
// The tag may be prefixed by a namespace and a colon.
func (e *Element) SelectElements(tag string) []*Element {
space, stag := spaceDecompose(tag)
var elements []*Element
for _, t := range e.Child {
if c, ok := t.(*Element); ok && spaceMatch(space, c.Space) && stag == c.Tag {
elements = append(elements, c)
}
}
return elements
}
// FindElement returns the first element matched by the XPath-like path
// string. Panics if an invalid path string is supplied.
func (e *Element) FindElement(path string) *Element {
return e.FindElementPath(MustCompilePath(path))
}
// FindElementPath returns the first element matched by the XPath-like path
// string.
func (e *Element) FindElementPath(path Path) *Element {
p := newPather()
elements := p.traverse(e, path)
switch {
case len(elements) > 0:
return elements[0]
default:
return nil
}
}
// FindElements returns a slice of elements matched by the XPath-like path
// string. Panics if an invalid path string is supplied.
func (e *Element) FindElements(path string) []*Element {
return e.FindElementsPath(MustCompilePath(path))
}
// FindElementsPath returns a slice of elements matched by the Path object.
func (e *Element) FindElementsPath(path Path) []*Element {
p := newPather()
return p.traverse(e, path)
}
// indent recursively inserts proper indentation between an
// XML element's child tokens.
func (e *Element) indent(depth int, indent indentFunc) {
e.stripIndent()
n := len(e.Child)
if n == 0 {
return
}
oldChild := e.Child
e.Child = make([]Token, 0, n*2+1)
isCharData, firstNonCharData := false, true
for _, c := range oldChild {
// Insert CR+indent before child if it's not character data.
// Exceptions: when it's the first non-character-data child, or when
// the child is at root depth.
_, isCharData = c.(*CharData)
if !isCharData {
if !firstNonCharData || depth > 0 {
newCharData(indent(depth), true, e)
}
firstNonCharData = false
}
e.addChild(c)
// Recursively process child elements.
if ce, ok := c.(*Element); ok {
ce.indent(depth+1, indent)
}
}
// Insert CR+indent before the last child.
if !isCharData {
if !firstNonCharData || depth > 0 {
newCharData(indent(depth-1), true, e)
}
}
}
// stripIndent removes any previously inserted indentation.
func (e *Element) stripIndent() {
// Count the number of non-indent child tokens
n := len(e.Child)
for _, c := range e.Child {
if cd, ok := c.(*CharData); ok && cd.whitespace {
n--
}
}
if n == len(e.Child) {
return
}
// Strip out indent CharData
newChild := make([]Token, n)
j := 0
for _, c := range e.Child {
if cd, ok := c.(*CharData); ok && cd.whitespace {
continue
}
newChild[j] = c
j++
}
e.Child = newChild
}
// dup duplicates the element.
func (e *Element) dup(parent *Element) Token {
ne := &Element{
Space: e.Space,
Tag: e.Tag,
Attr: make([]Attr, len(e.Attr)),
Child: make([]Token, len(e.Child)),
parent: parent,
}
for i, t := range e.Child {
ne.Child[i] = t.dup(ne)
}
for i, a := range e.Attr {
ne.Attr[i] = a
}
return ne
}
// Parent returns the element token's parent element, or nil if it has no
// parent.
func (e *Element) Parent() *Element {
return e.parent
}
// setParent replaces the element token's parent.
func (e *Element) setParent(parent *Element) {
e.parent = parent
}
// writeTo serializes the element to the writer w.
func (e *Element) writeTo(w *bufio.Writer, s *WriteSettings) {
w.WriteByte('<')
if e.Space != "" {
w.WriteString(e.Space)
w.WriteByte(':')
}
w.WriteString(e.Tag)
for _, a := range e.Attr {
w.WriteByte(' ')
a.writeTo(w, s)
}
if len(e.Child) > 0 {
w.WriteString(">")
for _, c := range e.Child {
c.writeTo(w, s)
}
w.Write([]byte{'<', '/'})
if e.Space != "" {
w.WriteString(e.Space)
w.WriteByte(':')
}
w.WriteString(e.Tag)
w.WriteByte('>')
} else {
if s.CanonicalEndTags {
w.Write([]byte{'>', '<', '/'})
if e.Space != "" {
w.WriteString(e.Space)
w.WriteByte(':')
}
w.WriteString(e.Tag)
w.WriteByte('>')
} else {
w.Write([]byte{'/', '>'})
}
}
}
// addChild adds a child token to the element e.
func (e *Element) addChild(t Token) {
e.Child = append(e.Child, t)
}
// CreateAttr creates an attribute and adds it to element e. The key may be
// prefixed by a namespace and a colon. If an attribute with the key already
// exists, its value is replaced.
func (e *Element) CreateAttr(key, value string) *Attr {
space, skey := spaceDecompose(key)
return e.createAttr(space, skey, value)
}
// createAttr is a helper function that creates attributes.
func (e *Element) createAttr(space, key, value string) *Attr {
for i, a := range e.Attr {
if space == a.Space && key == a.Key {
e.Attr[i].Value = value
return &e.Attr[i]
}
}
a := Attr{space, key, value}
e.Attr = append(e.Attr, a)
return &e.Attr[len(e.Attr)-1]
}
// RemoveAttr removes and returns the first attribute of the element whose key
// matches the given key. The key may be prefixed by a namespace and a colon.
// If an equal attribute does not exist, nil is returned.
func (e *Element) RemoveAttr(key string) *Attr {
space, skey := spaceDecompose(key)
for i, a := range e.Attr {
if space == a.Space && skey == a.Key {
e.Attr = append(e.Attr[0:i], e.Attr[i+1:]...)
return &a
}
}
return nil
}
var xmlReplacerNormal = strings.NewReplacer(
"&", "&amp;",
"<", "&lt;",
">", "&gt;",
"'", "&apos;",
`"`, "&quot;",
)
var xmlReplacerCanonicalText = strings.NewReplacer(
"&", "&amp;",
"<", "&lt;",
">", "&gt;",
"\r", "&#xD;",
)
var xmlReplacerCanonicalAttrVal = strings.NewReplacer(
"&", "&amp;",
"<", "&lt;",
`"`, "&quot;",
"\t", "&#x9;",
"\n", "&#xA;",
"\r", "&#xD;",
)
// writeTo serializes the attribute to the writer.
func (a *Attr) writeTo(w *bufio.Writer, s *WriteSettings) {
if a.Space != "" {
w.WriteString(a.Space)
w.WriteByte(':')
}
w.WriteString(a.Key)
w.WriteString(`="`)
var r *strings.Replacer
if s.CanonicalAttrVal {
r = xmlReplacerCanonicalAttrVal
} else {
r = xmlReplacerNormal
}
w.WriteString(r.Replace(a.Value))
w.WriteByte('"')
}
// NewCharData creates a parentless XML character data entity.
func NewCharData(data string) *CharData {
return newCharData(data, false, nil)
}
// newCharData creates an XML character data entity and binds it to a parent
// element. If parent is nil, the CharData token remains unbound.
func newCharData(data string, whitespace bool, parent *Element) *CharData {
c := &CharData{
Data: data,
whitespace: whitespace,
parent: parent,
}
if parent != nil {
parent.addChild(c)
}
return c
}
// CreateCharData creates an XML character data entity and adds it as a child
// of element e.
func (e *Element) CreateCharData(data string) *CharData {
return newCharData(data, false, e)
}
// dup duplicates the character data.
func (c *CharData) dup(parent *Element) Token {
return &CharData{
Data: c.Data,
whitespace: c.whitespace,
parent: parent,
}
}
// Parent returns the character data token's parent element, or nil if it has
// no parent.
func (c *CharData) Parent() *Element {
return c.parent
}
// setParent replaces the character data token's parent.
func (c *CharData) setParent(parent *Element) {
c.parent = parent
}
// writeTo serializes the character data entity to the writer.
func (c *CharData) writeTo(w *bufio.Writer, s *WriteSettings) {
var r *strings.Replacer
if s.CanonicalText {
r = xmlReplacerCanonicalText
} else {
r = xmlReplacerNormal
}
w.WriteString(r.Replace(c.Data))
}
// NewComment creates a parentless XML comment.
func NewComment(comment string) *Comment {
return newComment(comment, nil)
}
// NewComment creates an XML comment and binds it to a parent element. If
// parent is nil, the Comment remains unbound.
func newComment(comment string, parent *Element) *Comment {
c := &Comment{
Data: comment,
parent: parent,
}
if parent != nil {
parent.addChild(c)
}
return c
}
// CreateComment creates an XML comment and adds it as a child of element e.
func (e *Element) CreateComment(comment string) *Comment {
return newComment(comment, e)
}
// dup duplicates the comment.
func (c *Comment) dup(parent *Element) Token {
return &Comment{
Data: c.Data,
parent: parent,
}
}
// Parent returns comment token's parent element, or nil if it has no parent.
func (c *Comment) Parent() *Element {
return c.parent
}
// setParent replaces the comment token's parent.
func (c *Comment) setParent(parent *Element) {
c.parent = parent
}
// writeTo serialies the comment to the writer.
func (c *Comment) writeTo(w *bufio.Writer, s *WriteSettings) {
w.WriteString("<!--")
w.WriteString(c.Data)
w.WriteString("-->")
}
// NewDirective creates a parentless XML directive.
func NewDirective(data string) *Directive {
return newDirective(data, nil)
}
// newDirective creates an XML directive and binds it to a parent element. If
// parent is nil, the Directive remains unbound.
func newDirective(data string, parent *Element) *Directive {
d := &Directive{
Data: data,
parent: parent,
}
if parent != nil {
parent.addChild(d)
}
return d
}
// CreateDirective creates an XML directive and adds it as the last child of
// element e.
func (e *Element) CreateDirective(data string) *Directive {
return newDirective(data, e)
}
// dup duplicates the directive.
func (d *Directive) dup(parent *Element) Token {
return &Directive{
Data: d.Data,
parent: parent,
}
}
// Parent returns directive token's parent element, or nil if it has no
// parent.
func (d *Directive) Parent() *Element {
return d.parent
}
// setParent replaces the directive token's parent.
func (d *Directive) setParent(parent *Element) {
d.parent = parent
}
// writeTo serializes the XML directive to the writer.
func (d *Directive) writeTo(w *bufio.Writer, s *WriteSettings) {
w.WriteString("<!")
w.WriteString(d.Data)
w.WriteString(">")
}
// NewProcInst creates a parentless XML processing instruction.
func NewProcInst(target, inst string) *ProcInst {
return newProcInst(target, inst, nil)
}
// newProcInst creates an XML processing instruction and binds it to a parent
// element. If parent is nil, the ProcInst remains unbound.
func newProcInst(target, inst string, parent *Element) *ProcInst {
p := &ProcInst{
Target: target,
Inst: inst,
parent: parent,
}
if parent != nil {
parent.addChild(p)
}
return p
}
// CreateProcInst creates a processing instruction and adds it as a child of
// element e.
func (e *Element) CreateProcInst(target, inst string) *ProcInst {
return newProcInst(target, inst, e)
}
// dup duplicates the procinst.
func (p *ProcInst) dup(parent *Element) Token {
return &ProcInst{
Target: p.Target,
Inst: p.Inst,
parent: parent,
}
}
// Parent returns processing instruction token's parent element, or nil if it
// has no parent.
func (p *ProcInst) Parent() *Element {
return p.parent
}
// setParent replaces the processing instruction token's parent.
func (p *ProcInst) setParent(parent *Element) {
p.parent = parent
}
// writeTo serializes the processing instruction to the writer.
func (p *ProcInst) writeTo(w *bufio.Writer, s *WriteSettings) {
w.WriteString("<?")
w.WriteString(p.Target)
if p.Inst != "" {
w.WriteByte(' ')
w.WriteString(p.Inst)
}
w.WriteString("?>")
}