/
regexp.go
143 lines (115 loc) · 5.14 KB
/
regexp.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
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
package reference
import "regexp"
var (
// alphaNumericRegexp defines the alpha numeric atom, typically a
// component of names. This only allows lower case characters and digits.
alphaNumericRegexp = match(`[a-z0-9]+`)
// separatorRegexp defines the separators allowed to be embedded in name
// components. This allow one period, one or two underscore and multiple
// dashes.
separatorRegexp = match(`(?:[._]|__|[-]*)`)
// nameComponentRegexp restricts registry path component names to start
// with at least one letter or number, with following parts able to be
// separated by one period, one or two underscore and multiple dashes.
nameComponentRegexp = expression(
alphaNumericRegexp,
optional(repeated(separatorRegexp, alphaNumericRegexp)))
// domainComponentRegexp restricts the registry domain component of a
// repository name to start with a component as defined by DomainRegexp
// and followed by an optional port.
domainComponentRegexp = match(`(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])`)
// DomainRegexp defines the structure of potential domain components
// that may be part of image names. This is purposely a subset of what is
// allowed by DNS to ensure backwards compatibility with Docker image
// names.
DomainRegexp = expression(
domainComponentRegexp,
optional(repeated(literal(`.`), domainComponentRegexp)),
optional(literal(`:`), match(`[0-9]+`)))
// TagRegexp matches valid tag names. From docker/docker:graph/tags.go.
TagRegexp = match(`[\w][\w.-]{0,127}`)
// anchoredTagRegexp matches valid tag names, anchored at the start and
// end of the matched string.
anchoredTagRegexp = anchored(TagRegexp)
// DigestRegexp matches valid digests.
DigestRegexp = match(`[A-Za-z][A-Za-z0-9]*(?:[-_+.][A-Za-z][A-Za-z0-9]*)*[:][[:xdigit:]]{32,}`)
// anchoredDigestRegexp matches valid digests, anchored at the start and
// end of the matched string.
anchoredDigestRegexp = anchored(DigestRegexp)
// NameRegexp is the format for the name component of references. The
// regexp has capturing groups for the domain and name part omitting
// the separating forward slash from either.
NameRegexp = expression(
optional(DomainRegexp, literal(`/`)),
nameComponentRegexp,
optional(repeated(literal(`/`), nameComponentRegexp)))
// anchoredNameRegexp is used to parse a name value, capturing the
// domain and trailing components.
anchoredNameRegexp = anchored(
optional(capture(DomainRegexp), literal(`/`)),
capture(nameComponentRegexp,
optional(repeated(literal(`/`), nameComponentRegexp))))
// ReferenceRegexp is the full supported format of a reference. The regexp
// is anchored and has capturing groups for name, tag, and digest
// components.
ReferenceRegexp = anchored(capture(NameRegexp),
optional(literal(":"), capture(TagRegexp)),
optional(literal("@"), capture(DigestRegexp)))
// IdentifierRegexp is the format for string identifier used as a
// content addressable identifier using sha256. These identifiers
// are like digests without the algorithm, since sha256 is used.
IdentifierRegexp = match(`([a-f0-9]{64})`)
// ShortIdentifierRegexp is the format used to represent a prefix
// of an identifier. A prefix may be used to match a sha256 identifier
// within a list of trusted identifiers.
ShortIdentifierRegexp = match(`([a-f0-9]{6,64})`)
// anchoredIdentifierRegexp is used to check or match an
// identifier value, anchored at start and end of string.
anchoredIdentifierRegexp = anchored(IdentifierRegexp)
// anchoredShortIdentifierRegexp is used to check if a value
// is a possible identifier prefix, anchored at start and end
// of string.
anchoredShortIdentifierRegexp = anchored(ShortIdentifierRegexp)
)
// match compiles the string to a regular expression.
var match = regexp.MustCompile
// literal compiles s into a literal regular expression, escaping any regexp
// reserved characters.
func literal(s string) *regexp.Regexp {
re := match(regexp.QuoteMeta(s))
if _, complete := re.LiteralPrefix(); !complete {
panic("must be a literal")
}
return re
}
// expression defines a full expression, where each regular expression must
// follow the previous.
func expression(res ...*regexp.Regexp) *regexp.Regexp {
var s string
for _, re := range res {
s += re.String()
}
return match(s)
}
// optional wraps the expression in a non-capturing group and makes the
// production optional.
func optional(res ...*regexp.Regexp) *regexp.Regexp {
return match(group(expression(res...)).String() + `?`)
}
// repeated wraps the regexp in a non-capturing group to get one or more
// matches.
func repeated(res ...*regexp.Regexp) *regexp.Regexp {
return match(group(expression(res...)).String() + `+`)
}
// group wraps the regexp in a non-capturing group.
func group(res ...*regexp.Regexp) *regexp.Regexp {
return match(`(?:` + expression(res...).String() + `)`)
}
// capture wraps the expression in a capturing group.
func capture(res ...*regexp.Regexp) *regexp.Regexp {
return match(`(` + expression(res...).String() + `)`)
}
// anchored anchors the regular expression by adding start and end delimiters.
func anchored(res ...*regexp.Regexp) *regexp.Regexp {
return match(`^` + expression(res...).String() + `$`)
}