Fix some mirror bugs (#18649)

* Fix some mirror bugs

* Remove unnecessary code

* Fix lint

* rename stdard url

* Allow more charactors in git ssh protocol url

* improve the detection

* support ipv6 for git url parse

* Fix bug

* Fix template

* Fix bug

* fix template

* Fix tmpl

* Fix tmpl

* Fix parse ssh with interface

* Rename functions name

Co-authored-by: zeripath <art27@cantab.net>

modules/git/url/url.go

@@ -0,0 +1,90 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package url
+
+import (
+	"fmt"
+	stdurl "net/url"
+	"strings"
+)
+
+// ErrWrongURLFormat represents an error with wrong url format
+type ErrWrongURLFormat struct {
+	URL string
+}
+
+func (err ErrWrongURLFormat) Error() string {
+	return fmt.Sprintf("git URL %s format is wrong", err.URL)
+}
+
+// GitURL represents a git URL
+type GitURL struct {
+	*stdurl.URL
+	extraMark int // 0 no extra 1 scp 2 file path with no prefix
+}
+
+// String returns the URL's string
+func (u *GitURL) String() string {
+	switch u.extraMark {
+	case 0:
+		return u.URL.String()
+	case 1:
+		return fmt.Sprintf("%s@%s:%s", u.User.Username(), u.Host, u.Path)
+	case 2:
+		return u.Path
+	default:
+		return ""
+	}
+}
+
+// Parse parse all kinds of git URL
+func Parse(remote string) (*GitURL, error) {
+	if strings.Contains(remote, "://") {
+		u, err := stdurl.Parse(remote)
+		if err != nil {
+			return nil, err
+		}
+		return &GitURL{URL: u}, nil
+	} else if strings.Contains(remote, "@") && strings.Contains(remote, ":") {
+		url := stdurl.URL{
+			Scheme: "ssh",
+		}
+		squareBrackets := false
+		lastIndex := -1
+	FOR:
+		for i := 0; i < len(remote); i++ {
+			switch remote[i] {
+			case '@':
+				url.User = stdurl.User(remote[:i])
+				lastIndex = i + 1
+			case ':':
+				if !squareBrackets {
+					url.Host = strings.ReplaceAll(remote[lastIndex:i], "%25", "%")
+					if len(remote) <= i+1 {
+						return nil, ErrWrongURLFormat{URL: remote}
+					}
+					url.Path = remote[i+1:]
+					break FOR
+				}
+			case '[':
+				squareBrackets = true
+			case ']':
+				squareBrackets = false
+			}
+		}
+		return &GitURL{
+			URL:       &url,
+			extraMark: 1,
+		}, nil
+	}
+
+	return &GitURL{
+		URL: &stdurl.URL{
+			Scheme: "file",
+			Path:   remote,
+		},
+		extraMark: 2,
+	}, nil
+}