92 lines
2.4 KiB
Go
92 lines
2.4 KiB
Go
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/*
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Copyright 2015 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package field
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import (
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"bytes"
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"fmt"
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"strconv"
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)
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// Path represents the path from some root to a particular field.
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type Path struct {
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name string // the name of this field or "" if this is an index
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index string // if name == "", this is a subscript (index or map key) of the previous element
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parent *Path // nil if this is the root element
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}
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// NewPath creates a root Path object.
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func NewPath(name string, moreNames ...string) *Path {
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r := &Path{name: name, parent: nil}
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for _, anotherName := range moreNames {
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r = &Path{name: anotherName, parent: r}
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}
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return r
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}
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// Root returns the root element of this Path.
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func (p *Path) Root() *Path {
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for ; p.parent != nil; p = p.parent {
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// Do nothing.
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}
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return p
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}
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// Child creates a new Path that is a child of the method receiver.
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func (p *Path) Child(name string, moreNames ...string) *Path {
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r := NewPath(name, moreNames...)
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r.Root().parent = p
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return r
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}
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// Index indicates that the previous Path is to be subscripted by an int.
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// This sets the same underlying value as Key.
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func (p *Path) Index(index int) *Path {
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return &Path{index: strconv.Itoa(index), parent: p}
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}
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// Key indicates that the previous Path is to be subscripted by a string.
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// This sets the same underlying value as Index.
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func (p *Path) Key(key string) *Path {
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return &Path{index: key, parent: p}
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}
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// String produces a string representation of the Path.
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func (p *Path) String() string {
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// make a slice to iterate
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elems := []*Path{}
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for ; p != nil; p = p.parent {
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elems = append(elems, p)
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}
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// iterate, but it has to be backwards
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buf := bytes.NewBuffer(nil)
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for i := range elems {
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p := elems[len(elems)-1-i]
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if p.parent != nil && len(p.name) > 0 {
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// This is either the root or it is a subscript.
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buf.WriteString(".")
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}
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if len(p.name) > 0 {
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buf.WriteString(p.name)
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} else {
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fmt.Fprintf(buf, "[%s]", p.index)
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}
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}
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return buf.String()
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}
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