enh: add tag filter operator

source/libs/executor/inc/indexoperator.h

+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "filter.h"
+#include "tglobal.h"
+
+// construct tag filter operator later
+int32_t doFilterTag(const SNode *pFilterNode, SArray *resutl);

source/libs/executor/src/indexoperator.c

+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "indexoperator.h"
+#include "executorimpl.h"
+// construct tag filter operator later
+static void destroyTagFilterOperatorInfo(void *param) {
+  STagFilterOperatorInfo *pInfo = (STagFilterOperatorInfo *)param;
+}
+int32_t doFilterTag(const SNode *pFilterNode, SArray *resutl) {
+  if (pFilterNode == NULL) {
+    return TSDB_CODE_SUCCESS;
+  }
+
+  SFilterInfo *filter = NULL;
+
+  // todo move to the initialization function
+  int32_t code = filterInitFromNode((SNode *)pFilterNode, &filter, 0);
+  return code;
+}