revision.go RawHistoryFolder

1// SPDX-License-Identifier: AGPL-3.0-or-later
2
3package domain
4
5import "strings"
6
7// RevisionCandidateKind identifies the lookup needed to resolve a revision.
8type RevisionCandidateKind uint8
9
10const (
11	RevisionCandidateHead RevisionCandidateKind = iota
12	RevisionCandidateObject
13	RevisionCandidateRef
14	RevisionCandidateAbbrevID
15)
16
17// RevisionCandidate is one lookup to try when resolving a revision.
18// Name is HEAD, an object id, a full ref name, or an abbreviated object id.
19type RevisionCandidate struct {
20	Kind RevisionCandidateKind
21	Name string
22}
23
24// Candidates returns the resolution order. HEAD is special; full object ids
25// are objects before refs, so a ref cannot redirect an existing object link.
26// Otherwise branches beat tags. Full ref names and abbreviated ids are tried
27// as written only after the branch and tag forms.
28func (r Revision) Candidates() []RevisionCandidate {
29	s := r.String()
30	if r.IsHead() || s == "HEAD" {
31		return []RevisionCandidate{{Kind: RevisionCandidateHead, Name: "HEAD"}}
32	}
33	refs := []RevisionCandidate{
34		{Kind: RevisionCandidateRef, Name: "refs/heads/" + s},
35		{Kind: RevisionCandidateRef, Name: "refs/tags/" + s},
36	}
37	switch {
38	case r.IsObjectID():
39		return append([]RevisionCandidate{{Kind: RevisionCandidateObject, Name: s}}, refs...)
40	case strings.HasPrefix(s, "refs/"):
41		return append(refs, RevisionCandidate{Kind: RevisionCandidateRef, Name: s})
42	case r.IsAbbrevID():
43		return append(refs, RevisionCandidate{Kind: RevisionCandidateAbbrevID, Name: s})
44	}
45	return refs
46}
47
48// ResolvedRef returns the full ref name for a ref candidate, or empty otherwise.
49func (c RevisionCandidate) ResolvedRef() string {
50	if c.Kind == RevisionCandidateRef {
51		return c.Name
52	}
53	return ""
54}