enh: support drop user notify

common/const.go

@@ -148,4 +148,9 @@ const ReqIDKey = "taos_req_id"
 const (
 	TAOS_NOTIFY_PASSVER       = 0
 	TAOS_NOTIFY_WHITELIST_VER = 1
+	TAOS_NOTIFY_USER_DROPPED  = 2
+)
+
+const (
+	TAOS_CONN_MODE_BI = 0
 )

wrapper/notify_test.go

@@ -70,4 +70,25 @@ func TestNotify(t *testing.T) {
 			t.Error("wait for notify callback timeout")
 		}
 	}
+	{
+		notify := make(chan struct{}, 1)
+		handler := cgo.NewHandle(notify)
+		errCode := TaosSetNotifyCB(conn2, handler, common.TAOS_NOTIFY_USER_DROPPED)
+		if errCode != 0 {
+			errStr := TaosErrorStr(nil)
+			t.Error(errCode, errStr)
+		}
+		err = exec(conn, "drop USER t_notify")
+		assert.NoError(t, err)
+		timeout, cancel = context.WithTimeout(context.Background(), time.Second*5)
+		defer cancel()
+		now := time.Now()
+		select {
+		case _ = <-notify:
+			fmt.Println(time.Now().Sub(now))
+			t.Log("user dropped")
+		case <-timeout.Done():
+			t.Error("wait for notify callback timeout")
+		}
+	}
 }

wrapper/notifycb.go

@@ -20,13 +20,17 @@ func NotifyCallback(p unsafe.Pointer, ext unsafe.Pointer, notifyType C.int) {
 		// channel may be closed
 		recover()
 	}()
-	if int(notifyType) == common.TAOS_NOTIFY_PASSVER {
+	switch int(notifyType) {
+	case common.TAOS_NOTIFY_PASSVER:
 		version := int32(*(*C.int32_t)(ext))
 		c := (*(*cgo.Handle)(p)).Value().(chan int32)
 		c <- version
-	} else if int(notifyType) == common.TAOS_NOTIFY_WHITELIST_VER {
+	case common.TAOS_NOTIFY_WHITELIST_VER:
 		version := int64(*(*C.int64_t)(ext))
 		c := (*(*cgo.Handle)(p)).Value().(chan int64)
 		c <- version
+	case common.TAOS_NOTIFY_USER_DROPPED:
+		c := (*(*cgo.Handle)(p)).Value().(chan struct{})
+		c <- struct{}{}
 	}
 }

wrapper/whitelist.go

@@ -21,8 +21,6 @@ import (
 	"github.com/taosdata/driver-go/v3/wrapper/cgo"
 )
 
-const TAOS_NOTIFY_WHITELIST_VER = 1
-
 // typedef void (*__taos_async_whitelist_fn_t)(void *param, int code, TAOS *taos, int numOfWhiteLists, uint64_t* pWhiteLists);
 
 // TaosFetchWhitelistA DLL_EXPORT void taos_fetch_whitelist_a(TAOS *taos, __taos_async_whitelist_fn_t fp, void *param);