refactor: do some internal refactor.

source/client/src/clientMain.c

@@ -563,7 +563,31 @@ const char *taos_get_server_info(TAOS *taos) {
 }
 
 void taos_query_a(TAOS *taos, const char *sql, __taos_async_fn_t fp, void *param) {
-  // TODO
+  if (taos == NULL || sql == NULL) {
+    fp(param, NULL, TSDB_CODE_INVALID_PARA);
+    return;
+  }
+
+  SRequestObj* pRequest = NULL;
+  int32_t      retryNum = 0;
+  int32_t      code = 0;
+
+  while (retryNum++ < REQUEST_MAX_TRY_TIMES) {
+//    pRequest = launchQuery(pTscObj, sql, sqlLen);
+    if (pRequest == NULL || TSDB_CODE_SUCCESS == pRequest->code || !NEED_CLIENT_HANDLE_ERROR(pRequest->code)) {
+      break;
+    }
+
+    code = refreshMeta(taos, pRequest);
+    if (code) {
+      pRequest->code = code;
+      break;
+    }
+
+    destroyRequest(pRequest);
+  }
+
+  fp(param, pRequest, code);
 }
 
 void taos_fetch_rows_a(TAOS_RES *res, __taos_async_fn_t fp, void *param) {

source/client/test/clientTests.cpp

@@ -41,6 +41,11 @@ void showDB(TAOS* pConn) {
     printf("%s\n", str);
   }
 }
+
+void queryCallback(void *param, TAOS_RES *, int code) {
+  printf("this is a callback\n");
+
+}
 }  // namespace
 
 int main(int argc, char** argv) {
@@ -692,8 +697,6 @@ TEST(testCase, projection_query_stables) {
   taos_close(pConn);
 }
 
-#endif
-
 TEST(testCase, agg_query_tables) {
   TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
   ASSERT_NE(pConn, nullptr);
@@ -735,4 +738,27 @@ TEST(testCase, agg_query_tables) {
   taos_close(pConn);
 }
 
+# endif
+
+TEST(testCase, agg_query_tables) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  ASSERT_NE(pConn, nullptr);
+
+  taos_query_a(pConn, "use abc1", NULL, NULL);
+  getchar();
+
+  taos_close(pConn);
+//  if (taos_errno(pRes) != 0) {
+//    printf("failed to use db, reason:%s\n", taos_errstr(pRes));
+//    taos_free_result(pRes);
+//    ASSERT_TRUE(false);
+//  }
+//  taos_free_result(pRes);
+//
+//  pRes = taos_query(pConn, "select tbname from st1");
+//  if (taos_errno(pRes) != 0) {
+//    printf("failed to select from table, reas");
+//  }
+}
+
 #pragma GCC diagnostic pop