Some repository refactors (#17950)

* some repository refactors

* remove unnecessary code

* Fix test

* Remove unnecessary banner

models/repo/redirect.go

@@ -0,0 +1,82 @@
+// 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 repo
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"code.gitea.io/gitea/models/db"
+)
+
+// ErrRedirectNotExist represents a "RedirectNotExist" kind of error.
+type ErrRedirectNotExist struct {
+	OwnerID  int64
+	RepoName string
+}
+
+// IsErrRedirectNotExist check if an error is an ErrRepoRedirectNotExist.
+func IsErrRedirectNotExist(err error) bool {
+	_, ok := err.(ErrRedirectNotExist)
+	return ok
+}
+
+func (err ErrRedirectNotExist) Error() string {
+	return fmt.Sprintf("repository redirect does not exist [uid: %d, name: %s]", err.OwnerID, err.RepoName)
+}
+
+// Redirect represents that a repo name should be redirected to another
+type Redirect 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
+}
+
+// TableName represents real table name in database
+func (Redirect) TableName() string {
+	return "repo_redirect"
+}
+
+func init() {
+	db.RegisterModel(new(Redirect))
+}
+
+// LookupRedirect look up if a repository has a redirect name
+func LookupRedirect(ownerID int64, repoName string) (int64, error) {
+	repoName = strings.ToLower(repoName)
+	redirect := &Redirect{OwnerID: ownerID, LowerName: repoName}
+	if has, err := db.GetEngine(db.DefaultContext).Get(redirect); err != nil {
+		return 0, err
+	} else if !has {
+		return 0, ErrRedirectNotExist{OwnerID: ownerID, RepoName: repoName}
+	}
+	return redirect.RedirectRepoID, nil
+}
+
+// NewRedirect create a new repo redirect
+func NewRedirect(ctx context.Context, ownerID, repoID int64, oldRepoName, newRepoName string) error {
+	oldRepoName = strings.ToLower(oldRepoName)
+	newRepoName = strings.ToLower(newRepoName)
+
+	if err := DeleteRedirect(ctx, ownerID, newRepoName); err != nil {
+		return err
+	}
+
+	return db.Insert(ctx, &Redirect{
+		OwnerID:        ownerID,
+		LowerName:      oldRepoName,
+		RedirectRepoID: repoID,
+	})
+}
+
+// DeleteRedirect delete any redirect from the specified repo name to
+// anything else
+func DeleteRedirect(ctx context.Context, ownerID int64, repoName string) error {
+	repoName = strings.ToLower(repoName)
+	_, err := db.GetEngine(ctx).Delete(&Redirect{OwnerID: ownerID, LowerName: repoName})
+	return err
+}