feat: First implement

tag_reader.go

@@ -0,0 +1,65 @@
+package chglog
+
+import (
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+
+	gitcmd "github.com/tsuyoshiwada/go-gitcmd"
+)
+
+type tagReader struct {
+	client gitcmd.Client
+	format string
+	reTag  *regexp.Regexp
+}
+
+func newTagReader(client gitcmd.Client) *tagReader {
+	return &tagReader{
+		client: client,
+		reTag:  regexp.MustCompile("tag: ([\\w\\.\\-_]+),?"),
+	}
+}
+
+func (r *tagReader) ReadAll() ([]*Tag, error) {
+	out, err := r.client.Exec(
+		"log",
+		"--tags",
+		"--simplify-by-decoration",
+		"--pretty=%D\t%at",
+	)
+
+	tags := []*Tag{}
+
+	if err != nil {
+		return tags, err
+	}
+
+	lines := strings.Split(out, "\n")
+
+	for _, line := range lines {
+		if line == "" {
+			continue
+		}
+
+		tokens := strings.Split(line, "\t")
+
+		res := r.reTag.FindAllStringSubmatch(tokens[0], -1)
+		if len(res) == 0 {
+			continue
+		}
+
+		ts, err := strconv.Atoi(tokens[1])
+		if err != nil {
+			continue
+		}
+
+		tags = append(tags, &Tag{
+			Name: res[0][1],
+			Date: time.Unix(int64(ts), 0),
+		})
+	}
+
+	return tags, nil
+}