-
Notifications
You must be signed in to change notification settings - Fork 1.3k
/
path.go
127 lines (111 loc) · 2.65 KB
/
path.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
// Copyright 2016 The OPA Authors. All rights reserved.
// Use of this source code is governed by an Apache2
// license that can be found in the LICENSE file.
package storage
import (
"fmt"
"strconv"
"strings"
"github.com/open-policy-agent/opa/ast"
)
// Path refers to a document in storage.
type Path []string
// ParsePath returns a new path for the given str.
func ParsePath(str string) (path Path, ok bool) {
if len(str) == 0 {
return nil, false
}
if str[0] != '/' {
return nil, false
}
if len(str) == 1 {
return Path{}, true
}
parts := strings.Split(str[1:], "/")
return parts, true
}
// NewPathForRef returns a new path for the given ref.
func NewPathForRef(ref ast.Ref) (path Path, err error) {
if len(ref) == 0 {
return nil, fmt.Errorf("empty reference (indicates error in caller)")
}
if len(ref) == 1 {
return Path{}, nil
}
for _, term := range ref[1:] {
switch v := term.Value.(type) {
case ast.String:
path = append(path, string(v))
case ast.Number:
path = append(path, v.String())
case ast.Boolean, ast.Null:
return nil, notFoundRefError(ref, doesNotExistMsg)
default:
return nil, fmt.Errorf("unresolved reference (indicates error in caller): %v", ref)
}
}
return path, nil
}
// Compare performs lexigraphical comparison on p and other and returns -1 if p
// is less than other, 0 if p is equal to other, or 1 if p is greater than
// other.
func (p Path) Compare(other Path) (cmp int) {
min := len(p)
if len(other) < min {
min = len(other)
}
for i := 0; i < min; i++ {
if cmp := strings.Compare(p[i], other[i]); cmp != 0 {
return cmp
}
}
if len(p) < len(other) {
return -1
}
if len(p) == len(other) {
return 0
}
return 1
}
// Equal returns true if p is the same as other.
func (p Path) Equal(other Path) bool {
return p.Compare(other) == 0
}
// HasPrefix returns true if p starts with other.
func (p Path) HasPrefix(other Path) bool {
if len(other) > len(p) {
return false
}
for i := range other {
if p[i] != other[i] {
return false
}
}
return true
}
// Ref returns a ref that represents p rooted at head.
func (p Path) Ref(head *ast.Term) (ref ast.Ref) {
ref = make(ast.Ref, len(p)+1)
ref[0] = head
for i := range p {
idx, err := strconv.ParseInt(p[i], 10, 64)
if err == nil {
ref[i+1] = ast.IntNumberTerm(int(idx))
} else {
ref[i+1] = ast.StringTerm(p[i])
}
}
return ref
}
func (p Path) String() string {
return "/" + strings.Join(p, "/")
}
// MustParsePath returns a new Path for s. If s cannot be parsed, this function
// will panic. This is mostly for test purposes.
func MustParsePath(s string) Path {
path, ok := ParsePath(s)
if !ok {
panic(s)
}
return path
}