Some repository refactors (#17950)

* some repository refactors

* remove unnecessary code

* Fix test

* Remove unnecessary banner

models/repo/repo.go

@@ -25,6 +25,20 @@ import (
 	"code.gitea.io/gitea/modules/util"
 )
 
+var (
+	reservedRepoNames    = []string{".", ".."}
+	reservedRepoPatterns = []string{"*.git", "*.wiki", "*.rss", "*.atom"}
+)
+
+// IsUsableRepoName returns true when repository is usable
+func IsUsableRepoName(name string) error {
+	if db.AlphaDashDotPattern.MatchString(name) {
+		// Note: usually this error is normally caught up earlier in the UI
+		return db.ErrNameCharsNotAllowed{Name: name}
+	}
+	return db.IsUsableName(reservedRepoNames, reservedRepoPatterns, name)
+}
+
 // TrustModelType defines the types of trust model for this repository
 type TrustModelType int
 
@@ -734,3 +748,25 @@ func GetPublicRepositoryCount(u *user_model.User) (int64, error) {
 func GetPrivateRepositoryCount(u *user_model.User) (int64, error) {
 	return getPrivateRepositoryCount(db.GetEngine(db.DefaultContext), u)
 }
+
+// IterateRepository iterate repositories
+func IterateRepository(f func(repo *Repository) error) error {
+	var start int
+	batchSize := setting.Database.IterateBufferSize
+	for {
+		repos := make([]*Repository, 0, batchSize)
+		if err := db.GetEngine(db.DefaultContext).Limit(batchSize, start).Find(&repos); err != nil {
+			return err
+		}
+		if len(repos) == 0 {
+			return nil
+		}
+		start += len(repos)
+
+		for _, repo := range repos {
+			if err := f(repo); err != nil {
+				return err
+			}
+		}
+	}
+}