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go/src/infra/libs/git/user.go

Index: go/src/infra/libs/git/user.go
diff --git a/go/src/infra/libs/git/user.go b/go/src/infra/libs/git/user.go
new file mode 100644
index 0000000000000000000000000000000000000000..1e1d2dd74c2ce69f35e3ac3cef48b50574dcd024
--- /dev/null
+++ b/go/src/infra/libs/git/user.go
@@ -0,0 +1,68 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package git
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+	"time"
+)
+
+// Types ///////////////////////////////////////////////////////////////////////
+
+// User represents an author/committer line in a Commit
+type User struct {
+	Name  string
+	Email string
+	Time  time.Time
+}
+
+// Constructors ////////////////////////////////////////////////////////////////
+
+func MakeUserFromCommitLine(lineType, line string) (User, error) {
+	fields := userRegex.FindStringSubmatch(line)
+	if len(fields) == 0 {
+		return User{}, fmt.Errorf("Incompatible user line: %#v", line)
+	}
+	if fields[1] != lineType {
+		return User{}, fmt.Errorf("Expected to parse %s but got %s instead", lineType, fields[1])
+	}
+	t, err := time.Parse("-0700", fields[5])
+	if err != nil {
+		return User{}, err
+	}
+
+	timecode, err := strconv.ParseInt(fields[4], 10, 64)
+	if err != nil {
+		return User{}, err
+	}
+
+	return User{
+		Name:  fields[2],
+		Email: fields[3],
+		Time:  time.Unix(timecode, 0).In(t.Location()),
+	}, nil
+}
+
+// Member functions ////////////////////////////////////////////////////////////
+
+// RawString returns a `git hash-object` compatible string for this User
+func (u *User) RawString() string {
+	return fmt.Sprintf("%s <%s> %d %s", u.Name, u.Email, u.Time.Unix(),
+		u.Time.Format("-0700"))
+}
+
+// Private /////////////////////////////////////////////////////////////////////
+
+// author|committer SP <user_name> SP '<' <user_email> '>' SP timecode +0000
+// I would use named groups, but the interface to access them is terrible
+// in the regexp package...
+var userRegex = regexp.MustCompile(
+	`^(author|committer) ` +
+		`([^<]*) ` + // user_name
+		`<([^>]*)> ` + // user_email
+		`(\d*) ` + // timecode
+		`([+-]\d{4})$`) //timezone