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91 lines
2.4 KiB
91 lines
2.4 KiB
/* |
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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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