Redirects for renamed repos (#807)

* Redirects for renamed repos

* Remove unused phrase from locales

models/repo_redirect.go

@@ -0,0 +1,62 @@
+// Copyright 2017 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 models
+
+import "strings"
+
+// RepoRedirect represents that a repo name should be redirected to another
+type RepoRedirect struct {
+	ID             int64  `xorm:"pk autoincr"`
+	OwnerID        int64  `xorm:"UNIQUE(s)"`
+	LowerName      string `xorm:"UNIQUE(s) INDEX NOT NULL"`
+	RedirectRepoID int64  // repoID to redirect to
+}
+
+// LookupRepoRedirect look up if a repository has a redirect name
+func LookupRepoRedirect(ownerID int64, repoName string) (int64, error) {
+	repoName = strings.ToLower(repoName)
+	redirect := &RepoRedirect{OwnerID: ownerID, LowerName: repoName}
+	if has, err := x.Get(redirect); err != nil {
+		return 0, err
+	} else if !has {
+		return 0, ErrRepoRedirectNotExist{OwnerID: ownerID, RepoName: repoName}
+	}
+	return redirect.RedirectRepoID, nil
+}
+
+// NewRepoRedirect create a new repo redirect
+func NewRepoRedirect(ownerID, repoID int64, oldRepoName, newRepoName string) error {
+	oldRepoName = strings.ToLower(oldRepoName)
+	newRepoName = strings.ToLower(newRepoName)
+	sess := x.NewSession()
+	defer sess.Close()
+
+	if err := sess.Begin(); err != nil {
+		return err
+	}
+
+	if err := deleteRepoRedirect(sess, ownerID, newRepoName); err != nil {
+		sess.Rollback()
+		return err
+	}
+
+	if _, err := sess.Insert(&RepoRedirect{
+		OwnerID:        ownerID,
+		LowerName:      oldRepoName,
+		RedirectRepoID: repoID,
+	}); err != nil {
+		sess.Rollback()
+		return err
+	}
+	return sess.Commit()
+}
+
+// deleteRepoRedirect delete any redirect from the specified repo name to
+// anything else
+func deleteRepoRedirect(e Engine, ownerID int64, repoName string) error {
+	repoName = strings.ToLower(repoName)
+	_, err := e.Delete(&RepoRedirect{OwnerID: ownerID, LowerName: repoName})
+	return err
+}