476 lines
10 KiB
Go
476 lines
10 KiB
Go
package xpath
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import (
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"errors"
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"fmt"
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"math"
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"strconv"
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"strings"
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)
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// The XPath function list.
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func predicate(q query) func(NodeNavigator) bool {
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type Predicater interface {
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Test(NodeNavigator) bool
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}
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if p, ok := q.(Predicater); ok {
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return p.Test
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}
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return func(NodeNavigator) bool { return true }
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}
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// positionFunc is a XPath Node Set functions position().
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func positionFunc(q query, t iterator) interface{} {
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var (
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count = 1
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node = t.Current()
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)
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test := predicate(q)
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for node.MoveToPrevious() {
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if test(node) {
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count++
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}
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}
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return float64(count)
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}
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// lastFunc is a XPath Node Set functions last().
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func lastFunc(q query, t iterator) interface{} {
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var (
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count = 0
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node = t.Current()
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)
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node.MoveToFirst()
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test := predicate(q)
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for {
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if test(node) {
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count++
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}
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if !node.MoveToNext() {
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break
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}
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}
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return float64(count)
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}
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// countFunc is a XPath Node Set functions count(node-set).
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func countFunc(q query, t iterator) interface{} {
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var count = 0
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test := predicate(q)
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switch typ := q.Evaluate(t).(type) {
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case query:
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for node := typ.Select(t); node != nil; node = typ.Select(t) {
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if test(node) {
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count++
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}
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}
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}
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return float64(count)
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}
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// sumFunc is a XPath Node Set functions sum(node-set).
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func sumFunc(q query, t iterator) interface{} {
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var sum float64
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switch typ := q.Evaluate(t).(type) {
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case query:
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for node := typ.Select(t); node != nil; node = typ.Select(t) {
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if v, err := strconv.ParseFloat(node.Value(), 64); err == nil {
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sum += v
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}
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}
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case float64:
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sum = typ
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case string:
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v, err := strconv.ParseFloat(typ, 64)
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if err != nil {
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panic(errors.New("sum() function argument type must be a node-set or number"))
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}
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sum = v
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}
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return sum
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}
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func asNumber(t iterator, o interface{}) float64 {
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switch typ := o.(type) {
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case query:
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node := typ.Select(t)
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if node == nil {
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return float64(0)
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}
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if v, err := strconv.ParseFloat(node.Value(), 64); err == nil {
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return v
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}
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case float64:
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return typ
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case string:
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v, err := strconv.ParseFloat(typ, 64)
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if err != nil {
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panic(errors.New("ceiling() function argument type must be a node-set or number"))
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}
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return v
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}
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return 0
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}
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// ceilingFunc is a XPath Node Set functions ceiling(node-set).
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func ceilingFunc(q query, t iterator) interface{} {
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val := asNumber(t, q.Evaluate(t))
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return math.Ceil(val)
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}
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// floorFunc is a XPath Node Set functions floor(node-set).
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func floorFunc(q query, t iterator) interface{} {
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val := asNumber(t, q.Evaluate(t))
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return math.Floor(val)
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}
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// roundFunc is a XPath Node Set functions round(node-set).
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func roundFunc(q query, t iterator) interface{} {
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val := asNumber(t, q.Evaluate(t))
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//return math.Round(val)
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return round(val)
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}
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// nameFunc is a XPath functions name([node-set]).
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func nameFunc(q query, t iterator) interface{} {
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v := q.Select(t)
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if v == nil {
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return ""
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}
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ns := v.Prefix()
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if ns == "" {
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return v.LocalName()
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}
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return ns + ":" + v.LocalName()
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}
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// localNameFunc is a XPath functions local-name([node-set]).
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func localNameFunc(q query, t iterator) interface{} {
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v := q.Select(t)
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if v == nil {
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return ""
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}
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return v.LocalName()
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}
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// namespaceFunc is a XPath functions namespace-uri([node-set]).
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func namespaceFunc(q query, t iterator) interface{} {
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v := q.Select(t)
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if v == nil {
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return ""
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}
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return v.Prefix()
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}
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func asBool(t iterator, v interface{}) bool {
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switch v := v.(type) {
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case nil:
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return false
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case *NodeIterator:
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return v.MoveNext()
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case bool:
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return bool(v)
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case float64:
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return v != 0
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case string:
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return v != ""
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case query:
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return v.Select(t) != nil
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default:
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panic(fmt.Errorf("unexpected type: %T", v))
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}
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}
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func asString(t iterator, v interface{}) string {
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switch v := v.(type) {
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case nil:
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return ""
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case bool:
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if v {
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return "true"
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}
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return "false"
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case float64:
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return strconv.FormatFloat(v, 'g', -1, 64)
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case string:
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return v
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case query:
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node := v.Select(t)
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if node == nil {
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return ""
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}
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return node.Value()
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default:
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panic(fmt.Errorf("unexpected type: %T", v))
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}
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}
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// booleanFunc is a XPath functions boolean([node-set]).
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func booleanFunc(q query, t iterator) interface{} {
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v := q.Evaluate(t)
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return asBool(t, v)
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}
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// numberFunc is a XPath functions number([node-set]).
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func numberFunc(q query, t iterator) interface{} {
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v := q.Evaluate(t)
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return asNumber(t, v)
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}
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// stringFunc is a XPath functions string([node-set]).
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func stringFunc(q query, t iterator) interface{} {
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v := q.Evaluate(t)
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return asString(t, v)
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}
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// startwithFunc is a XPath functions starts-with(string, string).
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func startwithFunc(arg1, arg2 query) func(query, iterator) interface{} {
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return func(q query, t iterator) interface{} {
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var (
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m, n string
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ok bool
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)
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switch typ := arg1.Evaluate(t).(type) {
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case string:
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m = typ
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case query:
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node := typ.Select(t)
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if node == nil {
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return false
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}
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m = node.Value()
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default:
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panic(errors.New("starts-with() function argument type must be string"))
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}
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n, ok = arg2.Evaluate(t).(string)
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if !ok {
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panic(errors.New("starts-with() function argument type must be string"))
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}
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return strings.HasPrefix(m, n)
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}
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}
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// endwithFunc is a XPath functions ends-with(string, string).
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func endwithFunc(arg1, arg2 query) func(query, iterator) interface{} {
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return func(q query, t iterator) interface{} {
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var (
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m, n string
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ok bool
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)
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switch typ := arg1.Evaluate(t).(type) {
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case string:
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m = typ
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case query:
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node := typ.Select(t)
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if node == nil {
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return false
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}
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m = node.Value()
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default:
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panic(errors.New("ends-with() function argument type must be string"))
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}
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n, ok = arg2.Evaluate(t).(string)
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if !ok {
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panic(errors.New("ends-with() function argument type must be string"))
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}
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return strings.HasSuffix(m, n)
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}
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}
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// containsFunc is a XPath functions contains(string or @attr, string).
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func containsFunc(arg1, arg2 query) func(query, iterator) interface{} {
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return func(q query, t iterator) interface{} {
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var (
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m, n string
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ok bool
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)
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switch typ := arg1.Evaluate(t).(type) {
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case string:
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m = typ
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case query:
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node := typ.Select(t)
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if node == nil {
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return false
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}
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m = node.Value()
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default:
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panic(errors.New("contains() function argument type must be string"))
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}
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n, ok = arg2.Evaluate(t).(string)
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if !ok {
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panic(errors.New("contains() function argument type must be string"))
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}
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return strings.Contains(m, n)
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}
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}
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// normalizespaceFunc is XPath functions normalize-space(string?)
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func normalizespaceFunc(q query, t iterator) interface{} {
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var m string
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switch typ := q.Evaluate(t).(type) {
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case string:
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m = typ
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case query:
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node := typ.Select(t)
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if node == nil {
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return false
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}
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m = node.Value()
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}
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return strings.TrimSpace(m)
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}
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// substringFunc is XPath functions substring function returns a part of a given string.
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func substringFunc(arg1, arg2, arg3 query) func(query, iterator) interface{} {
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return func(q query, t iterator) interface{} {
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var m string
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switch typ := arg1.Evaluate(t).(type) {
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case string:
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m = typ
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case query:
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node := typ.Select(t)
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if node == nil {
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return ""
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}
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m = node.Value()
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}
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var start, length float64
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var ok bool
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if start, ok = arg2.Evaluate(t).(float64); !ok {
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panic(errors.New("substring() function first argument type must be int"))
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} else if start < 1 {
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panic(errors.New("substring() function first argument type must be >= 1"))
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}
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start--
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if arg3 != nil {
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if length, ok = arg3.Evaluate(t).(float64); !ok {
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panic(errors.New("substring() function second argument type must be int"))
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}
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}
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if (len(m) - int(start)) < int(length) {
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panic(errors.New("substring() function start and length argument out of range"))
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}
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if length > 0 {
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return m[int(start):int(length+start)]
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}
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return m[int(start):]
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}
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}
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// substringIndFunc is XPath functions substring-before/substring-after function returns a part of a given string.
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func substringIndFunc(arg1, arg2 query, after bool) func(query, iterator) interface{} {
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return func(q query, t iterator) interface{} {
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var str string
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switch v := arg1.Evaluate(t).(type) {
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case string:
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str = v
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case query:
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node := v.Select(t)
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if node == nil {
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return ""
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}
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str = node.Value()
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}
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var word string
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switch v := arg2.Evaluate(t).(type) {
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case string:
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word = v
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case query:
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node := v.Select(t)
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if node == nil {
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return ""
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}
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word = node.Value()
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}
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if word == "" {
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return ""
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}
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i := strings.Index(str, word)
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if i < 0 {
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return ""
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}
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if after {
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return str[i+len(word):]
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}
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return str[:i]
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}
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}
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// stringLengthFunc is XPATH string-length( [string] ) function that returns a number
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// equal to the number of characters in a given string.
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func stringLengthFunc(arg1 query) func(query, iterator) interface{} {
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return func(q query, t iterator) interface{} {
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switch v := arg1.Evaluate(t).(type) {
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case string:
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return float64(len(v))
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case query:
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node := v.Select(t)
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if node == nil {
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break
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}
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return float64(len(node.Value()))
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}
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return float64(0)
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}
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}
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// translateFunc is XPath functions translate() function returns a replaced string.
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func translateFunc(arg1, arg2, arg3 query) func(query, iterator) interface{} {
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return func(q query, t iterator) interface{} {
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str := asString(t, arg1.Evaluate(t))
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src := asString(t, arg2.Evaluate(t))
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dst := asString(t, arg3.Evaluate(t))
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var replace []string
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for i, s := range src {
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d := ""
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if i < len(dst) {
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d = string(dst[i])
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}
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replace = append(replace, string(s), d)
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}
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return strings.NewReplacer(replace...).Replace(str)
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}
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}
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// notFunc is XPATH functions not(expression) function operation.
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func notFunc(q query, t iterator) interface{} {
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switch v := q.Evaluate(t).(type) {
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case bool:
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return !v
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case query:
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node := v.Select(t)
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return node == nil
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default:
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return false
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}
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}
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// concatFunc is the concat function concatenates two or more
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// strings and returns the resulting string.
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// concat( string1 , string2 [, stringn]* )
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func concatFunc(args ...query) func(query, iterator) interface{} {
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return func(q query, t iterator) interface{} {
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var a []string
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for _, v := range args {
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switch v := v.Evaluate(t).(type) {
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case string:
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a = append(a, v)
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case query:
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node := v.Select(t)
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if node != nil {
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a = append(a, node.Value())
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}
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}
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}
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return strings.Join(a, "")
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}
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}
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