add FindAndCount method (#842)

engine.go

@@ -1453,6 +1453,13 @@ func (engine *Engine) Find(beans interface{}, condiBeans ...interface{}) error {
 	return session.Find(beans, condiBeans...)
 }
 
+// FindAndCount find the results and also return the counts
+func (engine *Engine) FindAndCount(rowsSlicePtr interface{}, condiBean ...interface{}) (int64, error) {
+	session := engine.NewSession()
+	defer session.Close()
+	return session.FindAndCount(rowsSlicePtr, condiBean...)
+}
+
 // Iterate record by record handle records from table, bean's non-empty fields
 // are conditions.
 func (engine *Engine) Iterate(bean interface{}, fun IterFunc) error {

interface.go

@@ -30,6 +30,7 @@ type Interface interface {
 	Exec(string, ...interface{}) (sql.Result, error)
 	Exist(bean ...interface{}) (bool, error)
 	Find(interface{}, ...interface{}) error
+	FindAndCount(interface{}, ...interface{}) (int64, error)
 	Get(interface{}) (bool, error)
 	GroupBy(keys string) *Session
 	ID(interface{}) *Session

session_find.go

@@ -29,6 +29,29 @@ func (session *Session) Find(rowsSlicePtr interface{}, condiBean ...interface{})
 	return session.find(rowsSlicePtr, condiBean...)
 }
 
+// FindAndCount find the results and also return the counts
+func (session *Session) FindAndCount(rowsSlicePtr interface{}, condiBean ...interface{}) (int64, error) {
+	if session.isAutoClose {
+		defer session.Close()
+	}
+
+	session.autoResetStatement = false
+	err := session.find(rowsSlicePtr, condiBean...)
+	if err != nil {
+		return 0, err
+	}
+
+	sliceValue := reflect.Indirect(reflect.ValueOf(rowsSlicePtr))
+	if sliceValue.Kind() != reflect.Slice && sliceValue.Kind() != reflect.Map {
+		return 0, errors.New("needs a pointer to a slice or a map")
+	}
+
+	sliceElementType := sliceValue.Type().Elem()
+	session.autoResetStatement = true
+
+	return session.Count(reflect.New(sliceElementType).Interface())
+}
+
 func (session *Session) find(rowsSlicePtr interface{}, condiBean ...interface{}) error {
 	sliceValue := reflect.Indirect(reflect.ValueOf(rowsSlicePtr))
 	if sliceValue.Kind() != reflect.Slice && sliceValue.Kind() != reflect.Map {

session_find_test.go

@@ -520,3 +520,39 @@ func TestFindMark(t *testing.T) {
 	assert.NoError(t, err)
 	assert.EqualValues(t, 2, len(results))
 }
+
+func TestFindAndCountOneFunc(t *testing.T) {
+	type FindAndCountStruct struct {
+		Id  int64
+		Content string
+		Msg bool `xorm:"bit"`
+	}
+
+	assert.NoError(t, prepareEngine())
+	assertSync(t, new(FindAndCountStruct))
+
+	cnt, err := testEngine.Insert([]FindAndCountStruct{
+		{
+			Content: "111",
+			Msg: false,
+		},
+		{
+			Content: "222",
+			Msg: true,
+		},
+	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 2, cnt)
+
+	var results = make([]FindAndCountStruct, 0, 2)
+	cnt, err = testEngine.FindAndCount(&results)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 2, len(results))
+	assert.EqualValues(t, 2, cnt)
+
+	results = make([]FindAndCountStruct, 0, 1)
+	cnt, err = testEngine.Where("msg = ?", true).FindAndCount(&results)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, len(results))
+	assert.EqualValues(t, 1, cnt)
+}