1 files changed, 129 insertions, 0 deletions
diff --git a/modules/git/tag.go b/modules/git/tag.go
new file mode 100644
index 0000000..04f50e8
--- /dev/null
+++ b/modules/git/tag.go
@@ -0,0 +1,129 @@
+// Copyright 2015 The Gogs Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package git
+
+import (
+	"bytes"
+	"sort"
+	"strings"
+
+	api "code.gitea.io/gitea/modules/structs"
+	"code.gitea.io/gitea/modules/util"
+)
+
+const (
+	beginpgp = "\n-----BEGIN PGP SIGNATURE-----\n"
+	endpgp   = "\n-----END PGP SIGNATURE-----"
+	beginssh = "\n-----BEGIN SSH SIGNATURE-----\n"
+	endssh   = "\n-----END SSH SIGNATURE-----"
+)
+
+// Tag represents a Git tag.
+type Tag struct {
+	Name                 string
+	ID                   ObjectID
+	Object               ObjectID // The id of this commit object
+	Type                 string
+	Tagger               *Signature
+	Message              string
+	Signature            *ObjectSignature
+	ArchiveDownloadCount *api.TagArchiveDownloadCount
+}
+
+// Commit return the commit of the tag reference
+func (tag *Tag) Commit(gitRepo *Repository) (*Commit, error) {
+	return gitRepo.getCommit(tag.Object)
+}
+
+// Parse commit information from the (uncompressed) raw
+// data from the commit object.
+// \n\n separate headers from message
+func parseTagData(objectFormat ObjectFormat, data []byte) (*Tag, error) {
+	tag := new(Tag)
+	tag.ID = objectFormat.EmptyObjectID()
+	tag.Object = objectFormat.EmptyObjectID()
+	tag.Tagger = &Signature{}
+	// we now have the contents of the commit object. Let's investigate...
+	nextline := 0
+l:
+	for {
+		eol := bytes.IndexByte(data[nextline:], '\n')
+		switch {
+		case eol > 0:
+			line := data[nextline : nextline+eol]
+			spacepos := bytes.IndexByte(line, ' ')
+			reftype := line[:spacepos]
+			switch string(reftype) {
+			case "object":
+				id, err := NewIDFromString(string(line[spacepos+1:]))
+				if err != nil {
+					return nil, err
+				}
+				tag.Object = id
+			case "type":
+				// A commit can have one or more parents
+				tag.Type = string(line[spacepos+1:])
+			case "tagger":
+				tag.Tagger = parseSignatureFromCommitLine(util.UnsafeBytesToString(line[spacepos+1:]))
+			}
+			nextline += eol + 1
+		case eol == 0:
+			tag.Message = string(data[nextline+1:])
+			break l
+		default:
+			break l
+		}
+	}
+
+	extractTagSignature := func(signatureBeginMark, signatureEndMark string) (bool, *ObjectSignature, string) {
+		idx := strings.LastIndex(tag.Message, signatureBeginMark)
+		if idx == -1 {
+			return false, nil, ""
+		}
+
+		endSigIdx := strings.Index(tag.Message[idx:], signatureEndMark)
+		if endSigIdx == -1 {
+			return false, nil, ""
+		}
+
+		return true, &ObjectSignature{
+			Signature: tag.Message[idx+1 : idx+endSigIdx+len(signatureEndMark)],
+			Payload:   string(data[:bytes.LastIndex(data, []byte(signatureBeginMark))+1]),
+		}, tag.Message[:idx+1]
+	}
+
+	// Try to find an OpenPGP signature
+	found, sig, message := extractTagSignature(beginpgp, endpgp)
+	if !found {
+		// If not found, try an SSH one
+		found, sig, message = extractTagSignature(beginssh, endssh)
+	}
+	// If either is found, update the tag Signature and Message
+	if found {
+		tag.Signature = sig
+		tag.Message = message
+	}
+
+	return tag, nil
+}
+
+type tagSorter []*Tag
+
+func (ts tagSorter) Len() int {
+	return len([]*Tag(ts))
+}
+
+func (ts tagSorter) Less(i, j int) bool {
+	return []*Tag(ts)[i].Tagger.When.After([]*Tag(ts)[j].Tagger.When)
+}
+
+func (ts tagSorter) Swap(i, j int) {
+	[]*Tag(ts)[i], []*Tag(ts)[j] = []*Tag(ts)[j], []*Tag(ts)[i]
+}
+
+// sortTagsByTime
+func sortTagsByTime(tags []*Tag) {
+	sorter := tagSorter(tags)
+	sort.Sort(sorter)
+}