119 lines
2.8 KiB
Go
119 lines
2.8 KiB
Go
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/*
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Copyright 2018 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 fieldpath
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import (
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"fmt"
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"strings"
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"sigs.k8s.io/structured-merge-diff/v4/value"
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)
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// Path describes how to select a potentially deeply-nested child field given a
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// containing object.
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type Path []PathElement
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func (fp Path) String() string {
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strs := make([]string, len(fp))
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for i := range fp {
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strs[i] = fp[i].String()
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}
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return strings.Join(strs, "")
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}
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// Equals returns true if the two paths are equivalent.
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func (fp Path) Equals(fp2 Path) bool {
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if len(fp) != len(fp2) {
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return false
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}
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for i := range fp {
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if !fp[i].Equals(fp2[i]) {
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return false
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}
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}
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return true
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}
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// Less provides a lexical order for Paths.
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func (fp Path) Compare(rhs Path) int {
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i := 0
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for {
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if i >= len(fp) && i >= len(rhs) {
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// Paths are the same length and all items are equal.
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return 0
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}
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if i >= len(fp) {
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// LHS is shorter.
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return -1
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}
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if i >= len(rhs) {
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// RHS is shorter.
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return 1
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}
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if c := fp[i].Compare(rhs[i]); c != 0 {
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return c
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}
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// The items are equal; continue.
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i++
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}
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}
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func (fp Path) Copy() Path {
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new := make(Path, len(fp))
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copy(new, fp)
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return new
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}
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// MakePath constructs a Path. The parts may be PathElements, ints, strings.
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func MakePath(parts ...interface{}) (Path, error) {
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var fp Path
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for _, p := range parts {
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switch t := p.(type) {
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case PathElement:
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fp = append(fp, t)
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case int:
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// TODO: Understand schema and object and convert this to the
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// FieldSpecifier below if appropriate.
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fp = append(fp, PathElement{Index: &t})
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case string:
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fp = append(fp, PathElement{FieldName: &t})
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case *value.FieldList:
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if len(*t) == 0 {
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return nil, fmt.Errorf("associative list key type path elements must have at least one key (got zero)")
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}
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fp = append(fp, PathElement{Key: t})
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case value.Value:
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// TODO: understand schema and verify that this is a set type
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// TODO: make a copy of t
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fp = append(fp, PathElement{Value: &t})
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default:
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return nil, fmt.Errorf("unable to make %#v into a path element", p)
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}
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}
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return fp, nil
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}
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// MakePathOrDie panics if parts can't be turned into a path. Good for things
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// that are known at complie time.
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func MakePathOrDie(parts ...interface{}) Path {
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fp, err := MakePath(parts...)
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if err != nil {
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panic(err)
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}
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return fp
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}
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