Merge db.Iterate and IterateObjects (#21641)

These two functions are similiar, merge them.

models/db/iterate_test.go

@@ -0,0 +1,44 @@
+// 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 db_test
+
+import (
+	"context"
+	"testing"
+
+	"code.gitea.io/gitea/models/db"
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unittest"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIterate(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	xe := unittest.GetXORMEngine()
+	assert.NoError(t, xe.Sync(&repo_model.RepoUnit{}))
+
+	var repoCnt int
+	err := db.Iterate(db.DefaultContext, nil, func(ctx context.Context, repo *repo_model.RepoUnit) error {
+		repoCnt++
+		return nil
+	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 79, repoCnt)
+
+	err = db.Iterate(db.DefaultContext, nil, func(ctx context.Context, repoUnit *repo_model.RepoUnit) error {
+		reopUnit2 := repo_model.RepoUnit{ID: repoUnit.ID}
+		has, err := db.GetByBean(ctx, &reopUnit2)
+		if err != nil {
+			return err
+		} else if !has {
+			return db.ErrNotExist{Resource: "repo_unit", ID: repoUnit.ID}
+		}
+		assert.EqualValues(t, repoUnit.RepoID, repoUnit.RepoID)
+		assert.EqualValues(t, repoUnit.CreatedUnix, repoUnit.CreatedUnix)
+		return nil
+	})
+	assert.NoError(t, err)
+}