add ModelHandler feature for package gdb

database/gdb/gdb_model.go

@@ -53,6 +53,9 @@ type Model struct {
 	onDuplicateEx interface{}    // onDuplicateEx is used for excluding some columns ON "DUPLICATE KEY UPDATE" statement.
 }
 
+// ModelHandler is a function that handles given Model and returns a new Model that is custom modified.
+type ModelHandler func(m *Model) *Model
+
 // whereHolder is the holder for where condition preparing.
 type whereHolder struct {
 	operator int           // Operator for this holder.
@@ -297,3 +300,13 @@ func (m *Model) Args(args ...interface{}) *Model {
 	model.extraArgs = append(model.extraArgs, args)
 	return model
 }
+
+// Handler calls each of `handlers` on current Model and returns a new Model.
+// ModelHandler is a function that handles given Model and returns a new Model that is custom modified.
+func (m *Model) Handler(handlers ...ModelHandler) *Model {
+	model := m.getModel()
+	for _, handler := range handlers {
+		model = handler(model)
+	}
+	return model
+}

database/gdb/gdb_z_mysql_model_test.go

@@ -3729,3 +3729,27 @@ func Test_Model_Raw(t *testing.T) {
 		t.Assert(count, 6)
 	})
 }
+
+func Test_Model_Handler(t *testing.T) {
+	table := createInitTable()
+	defer dropTable(table)
+
+	gtest.C(t, func(t *gtest.T) {
+		m := db.Model(table).Safe().Handler(
+			func(m *gdb.Model) *gdb.Model {
+				return m.Page(0, 3)
+			},
+			func(m *gdb.Model) *gdb.Model {
+				return m.Where("id", g.Slice{1, 2, 3, 4, 5, 6})
+			},
+			func(m *gdb.Model) *gdb.Model {
+				return m.OrderDesc("id")
+			},
+		)
+		all, err := m.All()
+		t.AssertNil(err)
+		t.Assert(len(all), 3)
+		t.Assert(all[0]["id"], 6)
+		t.Assert(all[2]["id"], 4)
+	})
+}

os/glog/glog_z_unit_chaining_test.go

@@ -145,6 +145,8 @@ func Test_StackWithFilter(t *testing.T) {
 		t.Assert(gstr.Count(content, defaultLevelPrefixes[LEVEL_ERRO]), 1)
 		t.Assert(gstr.Count(content, "1 2 3"), 1)
 		t.Assert(gstr.Count(content, "Stack"), 0)
+		fmt.Println("Content:")
+		fmt.Println(content)
 	})
 }