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
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
package version
import (
"fmt"
"regexp"
"strings"
)
// Constraint represents a single constraint for a version, such as
// ">= 1.0".
type Constraint struct {
f constraintFunc
check *Version
original string
}
// Constraints is a slice of constraints. We make a custom type so that
// we can add methods to it.
type Constraints []*Constraint
type constraintFunc func(v, c *Version) bool
var constraintOperators map[string]constraintFunc
var constraintRegexp *regexp.Regexp
func init() {
constraintOperators = map[string]constraintFunc{
"": constraintEqual,
"=": constraintEqual,
"!=": constraintNotEqual,
">": constraintGreaterThan,
"<": constraintLessThan,
">=": constraintGreaterThanEqual,
"<=": constraintLessThanEqual,
"~>": constraintPessimistic,
}
ops := make([]string, 0, len(constraintOperators))
for k := range constraintOperators {
ops = append(ops, regexp.QuoteMeta(k))
}
constraintRegexp = regexp.MustCompile(fmt.Sprintf(
`^\s*(%s)\s*(%s)\s*$`,
strings.Join(ops, "|"),
VersionRegexpRaw))
}
// NewConstraint will parse one or more constraints from the given
// constraint string. The string must be a comma-separated list of
// constraints.
func NewConstraint(v string) (Constraints, error) {
vs := strings.Split(v, ",")
result := make([]*Constraint, len(vs))
for i, single := range vs {
c, err := parseSingle(single)
if err != nil {
return nil, err
}
result[i] = c
}
return Constraints(result), nil
}
// Check tests if a version satisfies all the constraints.
func (cs Constraints) Check(v *Version) bool {
for _, c := range cs {
if !c.Check(v) {
return false
}
}
return true
}
// Returns the string format of the constraints
func (cs Constraints) String() string {
csStr := make([]string, len(cs))
for i, c := range cs {
csStr[i] = c.String()
}
return strings.Join(csStr, ",")
}
// Check tests if a constraint is validated by the given version.
func (c *Constraint) Check(v *Version) bool {
return c.f(v, c.check)
}
func (c *Constraint) String() string {
return c.original
}
func parseSingle(v string) (*Constraint, error) {
matches := constraintRegexp.FindStringSubmatch(v)
if matches == nil {
return nil, fmt.Errorf("Malformed constraint: %s", v)
}
check, err := NewVersion(matches[2])
if err != nil {
return nil, err
}
return &Constraint{
f: constraintOperators[matches[1]],
check: check,
original: v,
}, nil
}
//-------------------------------------------------------------------
// Constraint functions
//-------------------------------------------------------------------
func constraintEqual(v, c *Version) bool {
return v.Equal(c)
}
func constraintNotEqual(v, c *Version) bool {
return !v.Equal(c)
}
func constraintGreaterThan(v, c *Version) bool {
return v.Compare(c) == 1
}
func constraintLessThan(v, c *Version) bool {
return v.Compare(c) == -1
}
func constraintGreaterThanEqual(v, c *Version) bool {
return v.Compare(c) >= 0
}
func constraintLessThanEqual(v, c *Version) bool {
return v.Compare(c) <= 0
}
func constraintPessimistic(v, c *Version) bool {
// If the version being checked is naturally less than the constraint, then there
// is no way for the version to be valid against the constraint
if v.LessThan(c) {
return false
}
// We'll use this more than once, so grab the length now so it's a little cleaner
// to write the later checks
cs := len(c.segments)
// If the version being checked has less specificity than the constraint, then there
// is no way for the version to be valid against the constraint
if cs > len(v.segments) {
return false
}
// Check the segments in the constraint against those in the version. If the version
// being checked, at any point, does not have the same values in each index of the
// constraints segments, then it cannot be valid against the constraint.
for i := 0; i < c.si-1; i++ {
if v.segments[i] != c.segments[i] {
return false
}
}
// Check the last part of the segment in the constraint. If the version segment at
// this index is less than the constraints segment at this index, then it cannot
// be valid against the constraint
if c.segments[cs-1] > v.segments[cs-1] {
return false
}
// If nothing has rejected the version by now, it's valid
return true
}
|