Refactor mail notification (#5110)

* mail notification implement interface

* fix file comment year

* use NullNotifier as parent struct of notifiers

modules/notification/base/null.go

@@ -0,0 +1,108 @@
+// Copyright 2019 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 base
+
+import (
+	"code.gitea.io/git"
+	"code.gitea.io/gitea/models"
+)
+
+// NullNotifier implements a blank notifier
+type NullNotifier struct {
+}
+
+var (
+	_ Notifier = &NullNotifier{}
+)
+
+// Run places a place holder function
+func (*NullNotifier) Run() {
+}
+
+// NotifyCreateIssueComment places a place holder function
+func (*NullNotifier) NotifyCreateIssueComment(doer *models.User, repo *models.Repository,
+	issue *models.Issue, comment *models.Comment) {
+}
+
+// NotifyNewIssue places a place holder function
+func (*NullNotifier) NotifyNewIssue(issue *models.Issue) {
+}
+
+// NotifyIssueChangeStatus places a place holder function
+func (*NullNotifier) NotifyIssueChangeStatus(doer *models.User, issue *models.Issue, isClosed bool) {
+}
+
+// NotifyNewPullRequest places a place holder function
+func (*NullNotifier) NotifyNewPullRequest(pr *models.PullRequest) {
+}
+
+// NotifyPullRequestReview places a place holder function
+func (*NullNotifier) NotifyPullRequestReview(pr *models.PullRequest, r *models.Review, comment *models.Comment) {
+}
+
+// NotifyMergePullRequest places a place holder function
+func (*NullNotifier) NotifyMergePullRequest(pr *models.PullRequest, doer *models.User, baseRepo *git.Repository) {
+}
+
+// NotifyUpdateComment places a place holder function
+func (*NullNotifier) NotifyUpdateComment(doer *models.User, c *models.Comment, oldContent string) {
+}
+
+// NotifyDeleteComment places a place holder function
+func (*NullNotifier) NotifyDeleteComment(doer *models.User, c *models.Comment) {
+}
+
+// NotifyDeleteRepository places a place holder function
+func (*NullNotifier) NotifyDeleteRepository(doer *models.User, repo *models.Repository) {
+}
+
+// NotifyForkRepository places a place holder function
+func (*NullNotifier) NotifyForkRepository(doer *models.User, oldRepo, repo *models.Repository) {
+}
+
+// NotifyNewRelease places a place holder function
+func (*NullNotifier) NotifyNewRelease(rel *models.Release) {
+}
+
+// NotifyUpdateRelease places a place holder function
+func (*NullNotifier) NotifyUpdateRelease(doer *models.User, rel *models.Release) {
+}
+
+// NotifyDeleteRelease places a place holder function
+func (*NullNotifier) NotifyDeleteRelease(doer *models.User, rel *models.Release) {
+}
+
+// NotifyIssueChangeMilestone places a place holder function
+func (*NullNotifier) NotifyIssueChangeMilestone(doer *models.User, issue *models.Issue) {
+}
+
+// NotifyIssueChangeContent places a place holder function
+func (*NullNotifier) NotifyIssueChangeContent(doer *models.User, issue *models.Issue, oldContent string) {
+}
+
+// NotifyIssueChangeAssignee places a place holder function
+func (*NullNotifier) NotifyIssueChangeAssignee(doer *models.User, issue *models.Issue, removed bool) {
+}
+
+// NotifyIssueClearLabels places a place holder function
+func (*NullNotifier) NotifyIssueClearLabels(doer *models.User, issue *models.Issue) {
+}
+
+// NotifyIssueChangeTitle places a place holder function
+func (*NullNotifier) NotifyIssueChangeTitle(doer *models.User, issue *models.Issue, oldTitle string) {
+}
+
+// NotifyIssueChangeLabels places a place holder function
+func (*NullNotifier) NotifyIssueChangeLabels(doer *models.User, issue *models.Issue,
+	addedLabels []*models.Label, removedLabels []*models.Label) {
+}
+
+// NotifyCreateRepository places a place holder function
+func (*NullNotifier) NotifyCreateRepository(doer *models.User, u *models.User, repo *models.Repository) {
+}
+
+// NotifyMigrateRepository places a place holder function
+func (*NullNotifier) NotifyMigrateRepository(doer *models.User, u *models.User, repo *models.Repository) {
+}