825 lines
16 KiB
Go
825 lines
16 KiB
Go
package xpath
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import (
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"bytes"
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"fmt"
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"hash/fnv"
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"reflect"
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)
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type iterator interface {
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Current() NodeNavigator
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}
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// An XPath query interface.
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type query interface {
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// Select traversing iterator returns a query matched node NodeNavigator.
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Select(iterator) NodeNavigator
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// Evaluate evaluates query and returns values of the current query.
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Evaluate(iterator) interface{}
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Clone() query
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}
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// contextQuery is returns current node on the iterator object query.
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type contextQuery struct {
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count int
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Root bool // Moving to root-level node in the current context iterator.
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}
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func (c *contextQuery) Select(t iterator) (n NodeNavigator) {
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if c.count == 0 {
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c.count++
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n = t.Current().Copy()
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if c.Root {
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n.MoveToRoot()
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}
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}
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return n
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}
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func (c *contextQuery) Evaluate(iterator) interface{} {
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c.count = 0
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return c
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}
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func (c *contextQuery) Clone() query {
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return &contextQuery{count: 0, Root: c.Root}
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}
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// ancestorQuery is an XPath ancestor node query.(ancestor::*|ancestor-self::*)
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type ancestorQuery struct {
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iterator func() NodeNavigator
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Self bool
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Input query
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Predicate func(NodeNavigator) bool
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}
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func (a *ancestorQuery) Select(t iterator) NodeNavigator {
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for {
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if a.iterator == nil {
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node := a.Input.Select(t)
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if node == nil {
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return nil
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}
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first := true
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a.iterator = func() NodeNavigator {
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if first && a.Self {
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first = false
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if a.Predicate(node) {
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return node
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}
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}
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for node.MoveToParent() {
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if !a.Predicate(node) {
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continue
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}
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return node
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}
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return nil
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}
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}
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if node := a.iterator(); node != nil {
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return node
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}
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a.iterator = nil
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}
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}
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func (a *ancestorQuery) Evaluate(t iterator) interface{} {
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a.Input.Evaluate(t)
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a.iterator = nil
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return a
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}
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func (a *ancestorQuery) Test(n NodeNavigator) bool {
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return a.Predicate(n)
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}
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func (a *ancestorQuery) Clone() query {
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return &ancestorQuery{Self: a.Self, Input: a.Input.Clone(), Predicate: a.Predicate}
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}
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// attributeQuery is an XPath attribute node query.(@*)
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type attributeQuery struct {
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iterator func() NodeNavigator
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Input query
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Predicate func(NodeNavigator) bool
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}
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func (a *attributeQuery) Select(t iterator) NodeNavigator {
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for {
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if a.iterator == nil {
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node := a.Input.Select(t)
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if node == nil {
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return nil
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}
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node = node.Copy()
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a.iterator = func() NodeNavigator {
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for {
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onAttr := node.MoveToNextAttribute()
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if !onAttr {
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return nil
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}
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if a.Predicate(node) {
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return node
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}
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}
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}
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}
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if node := a.iterator(); node != nil {
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return node
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}
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a.iterator = nil
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}
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}
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func (a *attributeQuery) Evaluate(t iterator) interface{} {
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a.Input.Evaluate(t)
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a.iterator = nil
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return a
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}
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func (a *attributeQuery) Test(n NodeNavigator) bool {
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return a.Predicate(n)
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}
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func (a *attributeQuery) Clone() query {
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return &attributeQuery{Input: a.Input.Clone(), Predicate: a.Predicate}
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}
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// childQuery is an XPath child node query.(child::*)
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type childQuery struct {
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posit int
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iterator func() NodeNavigator
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Input query
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Predicate func(NodeNavigator) bool
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}
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func (c *childQuery) Select(t iterator) NodeNavigator {
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for {
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if c.iterator == nil {
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c.posit = 0
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node := c.Input.Select(t)
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if node == nil {
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return nil
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}
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node = node.Copy()
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first := true
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c.iterator = func() NodeNavigator {
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for {
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if (first && !node.MoveToChild()) || (!first && !node.MoveToNext()) {
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return nil
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}
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first = false
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if c.Predicate(node) {
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return node
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}
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}
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}
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}
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if node := c.iterator(); node != nil {
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c.posit++
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return node
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}
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c.iterator = nil
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}
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}
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func (c *childQuery) Evaluate(t iterator) interface{} {
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c.Input.Evaluate(t)
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c.iterator = nil
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return c
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}
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func (c *childQuery) Test(n NodeNavigator) bool {
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return c.Predicate(n)
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}
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func (c *childQuery) Clone() query {
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return &childQuery{Input: c.Input.Clone(), Predicate: c.Predicate}
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}
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// position returns a position of current NodeNavigator.
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func (c *childQuery) position() int {
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return c.posit
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}
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// descendantQuery is an XPath descendant node query.(descendant::* | descendant-or-self::*)
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type descendantQuery struct {
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iterator func() NodeNavigator
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posit int
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Self bool
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Input query
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Predicate func(NodeNavigator) bool
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}
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func (d *descendantQuery) Select(t iterator) NodeNavigator {
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for {
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if d.iterator == nil {
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d.posit = 0
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node := d.Input.Select(t)
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if node == nil {
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return nil
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}
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node = node.Copy()
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level := 0
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first := true
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d.iterator = func() NodeNavigator {
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if first && d.Self {
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first = false
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if d.Predicate(node) {
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return node
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}
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}
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for {
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if node.MoveToChild() {
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level++
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} else {
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for {
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if level == 0 {
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return nil
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}
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if node.MoveToNext() {
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break
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}
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node.MoveToParent()
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level--
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}
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}
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if d.Predicate(node) {
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return node
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}
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}
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}
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}
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if node := d.iterator(); node != nil {
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d.posit++
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return node
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}
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d.iterator = nil
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}
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}
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func (d *descendantQuery) Evaluate(t iterator) interface{} {
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d.Input.Evaluate(t)
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d.iterator = nil
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return d
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}
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func (d *descendantQuery) Test(n NodeNavigator) bool {
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return d.Predicate(n)
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}
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// position returns a position of current NodeNavigator.
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func (d *descendantQuery) position() int {
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return d.posit
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}
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func (d *descendantQuery) Clone() query {
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return &descendantQuery{Self: d.Self, Input: d.Input.Clone(), Predicate: d.Predicate}
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}
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// followingQuery is an XPath following node query.(following::*|following-sibling::*)
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type followingQuery struct {
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iterator func() NodeNavigator
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Input query
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Sibling bool // The matching sibling node of current node.
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Predicate func(NodeNavigator) bool
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}
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func (f *followingQuery) Select(t iterator) NodeNavigator {
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for {
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if f.iterator == nil {
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node := f.Input.Select(t)
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if node == nil {
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return nil
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}
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node = node.Copy()
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if f.Sibling {
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f.iterator = func() NodeNavigator {
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for {
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if !node.MoveToNext() {
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return nil
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}
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if f.Predicate(node) {
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return node
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}
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}
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}
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} else {
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var q query // descendant query
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f.iterator = func() NodeNavigator {
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for {
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if q == nil {
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for !node.MoveToNext() {
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if !node.MoveToParent() {
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return nil
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}
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}
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q = &descendantQuery{
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Self: true,
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Input: &contextQuery{},
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Predicate: f.Predicate,
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}
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t.Current().MoveTo(node)
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}
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if node := q.Select(t); node != nil {
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return node
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}
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q = nil
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}
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}
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}
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}
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if node := f.iterator(); node != nil {
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return node
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}
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f.iterator = nil
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}
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}
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func (f *followingQuery) Evaluate(t iterator) interface{} {
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f.Input.Evaluate(t)
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return f
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}
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func (f *followingQuery) Test(n NodeNavigator) bool {
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return f.Predicate(n)
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}
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func (f *followingQuery) Clone() query {
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return &followingQuery{Input: f.Input.Clone(), Sibling: f.Sibling, Predicate: f.Predicate}
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}
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// precedingQuery is an XPath preceding node query.(preceding::*)
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type precedingQuery struct {
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iterator func() NodeNavigator
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Input query
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Sibling bool // The matching sibling node of current node.
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Predicate func(NodeNavigator) bool
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}
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func (p *precedingQuery) Select(t iterator) NodeNavigator {
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for {
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if p.iterator == nil {
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node := p.Input.Select(t)
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if node == nil {
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return nil
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}
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node = node.Copy()
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if p.Sibling {
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p.iterator = func() NodeNavigator {
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for {
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for !node.MoveToPrevious() {
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return nil
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}
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if p.Predicate(node) {
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return node
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}
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}
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}
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} else {
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var q query
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p.iterator = func() NodeNavigator {
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for {
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if q == nil {
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for !node.MoveToPrevious() {
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if !node.MoveToParent() {
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return nil
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}
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}
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q = &descendantQuery{
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Self: true,
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Input: &contextQuery{},
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Predicate: p.Predicate,
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}
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t.Current().MoveTo(node)
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}
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if node := q.Select(t); node != nil {
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return node
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}
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q = nil
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}
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}
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}
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}
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if node := p.iterator(); node != nil {
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return node
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}
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p.iterator = nil
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}
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}
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func (p *precedingQuery) Evaluate(t iterator) interface{} {
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p.Input.Evaluate(t)
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return p
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}
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func (p *precedingQuery) Test(n NodeNavigator) bool {
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return p.Predicate(n)
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}
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func (p *precedingQuery) Clone() query {
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return &precedingQuery{Input: p.Input.Clone(), Sibling: p.Sibling, Predicate: p.Predicate}
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}
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// parentQuery is an XPath parent node query.(parent::*)
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type parentQuery struct {
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Input query
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Predicate func(NodeNavigator) bool
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}
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func (p *parentQuery) Select(t iterator) NodeNavigator {
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for {
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node := p.Input.Select(t)
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if node == nil {
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return nil
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}
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node = node.Copy()
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if node.MoveToParent() && p.Predicate(node) {
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return node
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}
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}
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}
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func (p *parentQuery) Evaluate(t iterator) interface{} {
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p.Input.Evaluate(t)
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return p
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}
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func (p *parentQuery) Clone() query {
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return &parentQuery{Input: p.Input.Clone(), Predicate: p.Predicate}
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}
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func (p *parentQuery) Test(n NodeNavigator) bool {
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return p.Predicate(n)
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}
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// selfQuery is an Self node query.(self::*)
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type selfQuery struct {
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Input query
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Predicate func(NodeNavigator) bool
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}
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func (s *selfQuery) Select(t iterator) NodeNavigator {
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for {
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node := s.Input.Select(t)
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if node == nil {
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return nil
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}
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if s.Predicate(node) {
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return node
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}
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}
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}
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func (s *selfQuery) Evaluate(t iterator) interface{} {
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s.Input.Evaluate(t)
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return s
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}
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func (s *selfQuery) Test(n NodeNavigator) bool {
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return s.Predicate(n)
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}
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func (s *selfQuery) Clone() query {
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return &selfQuery{Input: s.Input.Clone(), Predicate: s.Predicate}
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}
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// filterQuery is an XPath query for predicate filter.
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type filterQuery struct {
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Input query
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Predicate query
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}
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func (f *filterQuery) do(t iterator) bool {
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val := reflect.ValueOf(f.Predicate.Evaluate(t))
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switch val.Kind() {
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case reflect.Bool:
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return val.Bool()
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case reflect.String:
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return len(val.String()) > 0
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case reflect.Float64:
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pt := float64(getNodePosition(f.Input))
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return int(val.Float()) == int(pt)
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default:
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if q, ok := f.Predicate.(query); ok {
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return q.Select(t) != nil
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}
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}
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return false
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}
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func (f *filterQuery) Select(t iterator) NodeNavigator {
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for {
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node := f.Input.Select(t)
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if node == nil {
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return node
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}
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node = node.Copy()
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//fmt.Println(node.LocalName())
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t.Current().MoveTo(node)
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if f.do(t) {
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return node
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}
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}
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}
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func (f *filterQuery) Evaluate(t iterator) interface{} {
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f.Input.Evaluate(t)
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return f
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}
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func (f *filterQuery) Clone() query {
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return &filterQuery{Input: f.Input.Clone(), Predicate: f.Predicate.Clone()}
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}
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// functionQuery is an XPath function that call a function to returns
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// value of current NodeNavigator node.
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type functionQuery struct {
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Input query // Node Set
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Func func(query, iterator) interface{} // The xpath function.
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}
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func (f *functionQuery) Select(t iterator) NodeNavigator {
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return nil
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}
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// Evaluate call a specified function that will returns the
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// following value type: number,string,boolean.
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func (f *functionQuery) Evaluate(t iterator) interface{} {
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return f.Func(f.Input, t)
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}
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func (f *functionQuery) Clone() query {
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return &functionQuery{Input: f.Input.Clone(), Func: f.Func}
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}
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// constantQuery is an XPath constant operand.
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type constantQuery struct {
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Val interface{}
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}
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func (c *constantQuery) Select(t iterator) NodeNavigator {
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return nil
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}
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func (c *constantQuery) Evaluate(t iterator) interface{} {
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return c.Val
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}
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func (c *constantQuery) Clone() query {
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return c
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}
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// logicalQuery is an XPath logical expression.
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type logicalQuery struct {
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Left, Right query
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Do func(iterator, interface{}, interface{}) interface{}
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}
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func (l *logicalQuery) Select(t iterator) NodeNavigator {
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// When a XPath expr is logical expression.
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node := t.Current().Copy()
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val := l.Evaluate(t)
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switch val.(type) {
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case bool:
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if val.(bool) == true {
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return node
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}
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}
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return nil
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}
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func (l *logicalQuery) Evaluate(t iterator) interface{} {
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m := l.Left.Evaluate(t)
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n := l.Right.Evaluate(t)
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return l.Do(t, m, n)
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}
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func (l *logicalQuery) Clone() query {
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return &logicalQuery{Left: l.Left.Clone(), Right: l.Right.Clone(), Do: l.Do}
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}
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// numericQuery is an XPath numeric operator expression.
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type numericQuery struct {
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Left, Right query
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Do func(interface{}, interface{}) interface{}
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}
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func (n *numericQuery) Select(t iterator) NodeNavigator {
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return nil
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}
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func (n *numericQuery) Evaluate(t iterator) interface{} {
|
|
m := n.Left.Evaluate(t)
|
|
k := n.Right.Evaluate(t)
|
|
return n.Do(m, k)
|
|
}
|
|
|
|
func (n *numericQuery) Clone() query {
|
|
return &numericQuery{Left: n.Left.Clone(), Right: n.Right.Clone(), Do: n.Do}
|
|
}
|
|
|
|
type booleanQuery struct {
|
|
IsOr bool
|
|
Left, Right query
|
|
iterator func() NodeNavigator
|
|
}
|
|
|
|
func (b *booleanQuery) Select(t iterator) NodeNavigator {
|
|
if b.iterator == nil {
|
|
var list []NodeNavigator
|
|
i := 0
|
|
root := t.Current().Copy()
|
|
if b.IsOr {
|
|
for {
|
|
node := b.Left.Select(t)
|
|
if node == nil {
|
|
break
|
|
}
|
|
node = node.Copy()
|
|
list = append(list, node)
|
|
}
|
|
t.Current().MoveTo(root)
|
|
for {
|
|
node := b.Right.Select(t)
|
|
if node == nil {
|
|
break
|
|
}
|
|
node = node.Copy()
|
|
list = append(list, node)
|
|
}
|
|
} else {
|
|
var m []NodeNavigator
|
|
var n []NodeNavigator
|
|
for {
|
|
node := b.Left.Select(t)
|
|
if node == nil {
|
|
break
|
|
}
|
|
node = node.Copy()
|
|
list = append(m, node)
|
|
}
|
|
t.Current().MoveTo(root)
|
|
for {
|
|
node := b.Right.Select(t)
|
|
if node == nil {
|
|
break
|
|
}
|
|
node = node.Copy()
|
|
list = append(n, node)
|
|
}
|
|
for _, k := range m {
|
|
for _, j := range n {
|
|
if k == j {
|
|
list = append(list, k)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
b.iterator = func() NodeNavigator {
|
|
if i >= len(list) {
|
|
return nil
|
|
}
|
|
node := list[i]
|
|
i++
|
|
return node
|
|
}
|
|
}
|
|
return b.iterator()
|
|
}
|
|
|
|
func (b *booleanQuery) Evaluate(t iterator) interface{} {
|
|
m := b.Left.Evaluate(t)
|
|
left := asBool(t, m)
|
|
if b.IsOr && left {
|
|
return true
|
|
} else if !b.IsOr && !left {
|
|
return false
|
|
}
|
|
m = b.Right.Evaluate(t)
|
|
return asBool(t, m)
|
|
}
|
|
|
|
func (b *booleanQuery) Clone() query {
|
|
return &booleanQuery{IsOr: b.IsOr, Left: b.Left.Clone(), Right: b.Right.Clone()}
|
|
}
|
|
|
|
type unionQuery struct {
|
|
Left, Right query
|
|
iterator func() NodeNavigator
|
|
}
|
|
|
|
func (u *unionQuery) Select(t iterator) NodeNavigator {
|
|
if u.iterator == nil {
|
|
var m = make(map[uint64]NodeNavigator)
|
|
root := t.Current().Copy()
|
|
for {
|
|
node := u.Left.Select(t)
|
|
if node == nil {
|
|
break
|
|
}
|
|
code := getHashCode(node.Copy())
|
|
if _, ok := m[code]; !ok {
|
|
m[code] = node.Copy()
|
|
}
|
|
}
|
|
t.Current().MoveTo(root)
|
|
for {
|
|
node := u.Right.Select(t)
|
|
if node == nil {
|
|
break
|
|
}
|
|
code := getHashCode(node.Copy())
|
|
if _, ok := m[code]; !ok {
|
|
m[code] = node.Copy()
|
|
}
|
|
}
|
|
list := make([]NodeNavigator, len(m))
|
|
var i int
|
|
for _, v := range m {
|
|
list[i] = v
|
|
i++
|
|
}
|
|
i = 0
|
|
u.iterator = func() NodeNavigator {
|
|
if i >= len(list) {
|
|
return nil
|
|
}
|
|
node := list[i]
|
|
i++
|
|
return node
|
|
}
|
|
}
|
|
return u.iterator()
|
|
}
|
|
|
|
func (u *unionQuery) Evaluate(t iterator) interface{} {
|
|
u.iterator = nil
|
|
u.Left.Evaluate(t)
|
|
u.Right.Evaluate(t)
|
|
return u
|
|
}
|
|
|
|
func (u *unionQuery) Clone() query {
|
|
return &unionQuery{Left: u.Left.Clone(), Right: u.Right.Clone()}
|
|
}
|
|
|
|
func getHashCode(n NodeNavigator) uint64 {
|
|
var sb bytes.Buffer
|
|
switch n.NodeType() {
|
|
case AttributeNode, TextNode, CommentNode:
|
|
sb.WriteString(fmt.Sprintf("%s=%s", n.LocalName(), n.Value()))
|
|
if n.MoveToParent() {
|
|
sb.WriteString(n.LocalName())
|
|
}
|
|
case ElementNode:
|
|
sb.WriteString(n.Prefix() + n.LocalName())
|
|
d := 1
|
|
for n.MoveToPrevious() {
|
|
d++
|
|
}
|
|
sb.WriteString(fmt.Sprintf("-%d", d))
|
|
|
|
for n.MoveToParent() {
|
|
d = 1
|
|
for n.MoveToPrevious() {
|
|
d++
|
|
}
|
|
sb.WriteString(fmt.Sprintf("-%d", d))
|
|
}
|
|
}
|
|
h := fnv.New64a()
|
|
h.Write([]byte(sb.String()))
|
|
return h.Sum64()
|
|
}
|
|
|
|
func getNodePosition(q query) int {
|
|
type Position interface {
|
|
position() int
|
|
}
|
|
if count, ok := q.(Position); ok {
|
|
return count.position()
|
|
}
|
|
return 1
|
|
}
|