aboutsummaryrefslogtreecommitdiffstats
path: root/plumbing/reference.go
blob: eef11e8275abcddd25679961271b5989be099a42 (plain) (blame)
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
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
package plumbing

import (
	"errors"
	"fmt"
	"strings"
)

const (
	refPrefix       = "refs/"
	refHeadPrefix   = refPrefix + "heads/"
	refTagPrefix    = refPrefix + "tags/"
	refRemotePrefix = refPrefix + "remotes/"
	refNotePrefix   = refPrefix + "notes/"
	symrefPrefix    = "ref: "
)

// RefRevParseRules are a set of rules to parse references into short names.
// These are the same rules as used by git in shorten_unambiguous_ref.
// See: https://github.com/git/git/blob/e0aaa1b6532cfce93d87af9bc813fb2e7a7ce9d7/refs.c#L417
var RefRevParseRules = []string{
	"refs/%s",
	"refs/tags/%s",
	"refs/heads/%s",
	"refs/remotes/%s",
	"refs/remotes/%s/HEAD",
}

var (
	ErrReferenceNotFound = errors.New("reference not found")
)

// ReferenceType reference type's
type ReferenceType int8

const (
	InvalidReference  ReferenceType = 0
	HashReference     ReferenceType = 1
	SymbolicReference ReferenceType = 2
)

func (r ReferenceType) String() string {
	switch r {
	case InvalidReference:
		return "invalid-reference"
	case HashReference:
		return "hash-reference"
	case SymbolicReference:
		return "symbolic-reference"
	}

	return ""
}

// ReferenceName reference name's
type ReferenceName string

// NewBranchReferenceName returns a reference name describing a branch based on
// his short name.
func NewBranchReferenceName(name string) ReferenceName {
	return ReferenceName(refHeadPrefix + name)
}

// NewNoteReferenceName returns a reference name describing a note based on his
// short name.
func NewNoteReferenceName(name string) ReferenceName {
	return ReferenceName(refNotePrefix + name)
}

// NewRemoteReferenceName returns a reference name describing a remote branch
// based on his short name and the remote name.
func NewRemoteReferenceName(remote, name string) ReferenceName {
	return ReferenceName(refRemotePrefix + fmt.Sprintf("%s/%s", remote, name))
}

// NewRemoteHEADReferenceName returns a reference name describing a the HEAD
// branch of a remote.
func NewRemoteHEADReferenceName(remote string) ReferenceName {
	return ReferenceName(refRemotePrefix + fmt.Sprintf("%s/%s", remote, HEAD))
}

// NewTagReferenceName returns a reference name describing a tag based on short
// his name.
func NewTagReferenceName(name string) ReferenceName {
	return ReferenceName(refTagPrefix + name)
}

// IsBranch check if a reference is a branch
func (r ReferenceName) IsBranch() bool {
	return strings.HasPrefix(string(r), refHeadPrefix)
}

// IsNote check if a reference is a note
func (r ReferenceName) IsNote() bool {
	return strings.HasPrefix(string(r), refNotePrefix)
}

// IsRemote check if a reference is a remote
func (r ReferenceName) IsRemote() bool {
	return strings.HasPrefix(string(r), refRemotePrefix)
}

// IsTag check if a reference is a tag
func (r ReferenceName) IsTag() bool {
	return strings.HasPrefix(string(r), refTagPrefix)
}

func (r ReferenceName) String() string {
	return string(r)
}

// Short returns the short name of a ReferenceName
func (r ReferenceName) Short() string {
	s := string(r)
	res := s
	for _, format := range RefRevParseRules {
		_, err := fmt.Sscanf(s, format, &res)
		if err == nil {
			continue
		}
	}

	return res
}

const (
	HEAD   ReferenceName = "HEAD"
	Master ReferenceName = "refs/heads/master"
)

// Reference is a representation of git reference
type Reference struct {
	t      ReferenceType
	n      ReferenceName
	h      Hash
	target ReferenceName
}

// NewReferenceFromStrings creates a reference from name and target as string,
// the resulting reference can be a SymbolicReference or a HashReference base
// on the target provided
func NewReferenceFromStrings(name, target string) *Reference {
	n := ReferenceName(name)

	if strings.HasPrefix(target, symrefPrefix) {
		target := ReferenceName(target[len(symrefPrefix):])
		return NewSymbolicReference(n, target)
	}

	return NewHashReference(n, NewHash(target))
}

// NewSymbolicReference creates a new SymbolicReference reference
func NewSymbolicReference(n, target ReferenceName) *Reference {
	return &Reference{
		t:      SymbolicReference,
		n:      n,
		target: target,
	}
}

// NewHashReference creates a new HashReference reference
func NewHashReference(n ReferenceName, h Hash) *Reference {
	return &Reference{
		t: HashReference,
		n: n,
		h: h,
	}
}

// Type returns the type of a reference
func (r *Reference) Type() ReferenceType {
	return r.t
}

// Name returns the name of a reference
func (r *Reference) Name() ReferenceName {
	return r.n
}

// Hash returns the hash of a hash reference
func (r *Reference) Hash() Hash {
	return r.h
}

// Target returns the target of a symbolic reference
func (r *Reference) Target() ReferenceName {
	return r.target
}

// Strings dump a reference as a [2]string
func (r *Reference) Strings() [2]string {
	var o [2]string
	o[0] = r.Name().String()

	switch r.Type() {
	case HashReference:
		o[1] = r.Hash().String()
	case SymbolicReference:
		o[1] = symrefPrefix + r.Target().String()
	}

	return o
}

func (r *Reference) String() string {
	ref := ""
	switch r.Type() {
	case HashReference:
		ref = r.Hash().String()
	case SymbolicReference:
		ref = symrefPrefix + r.Target().String()
	default:
		return ""
	}

	name := r.Name().String()
	var v strings.Builder
	v.Grow(len(ref) + len(name) + 1)
	v.WriteString(ref)
	v.WriteString(" ")
	v.WriteString(name)
	return v.String()
}