support json type

src/sql/engine/expr/ob_expr_json_length.h

@@ -0,0 +1,53 @@
+/**
+ * Copyright (c) 2021 OceanBase
+ * OceanBase CE is licensed under Mulan PubL v2.
+ * You can use this software according to the terms and conditions of the Mulan PubL v2.
+ * You may obtain a copy of Mulan PubL v2 at:
+ *          http://license.coscl.org.cn/MulanPubL-2.0
+ * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
+ * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
+ * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
+ * See the Mulan PubL v2 for more details.
+ */
+
+// This file contains implementation for json_length.
+#ifndef OCEANBASE_SQL_OB_EXPR_JSON_LENGTH_H_
+#define OCEANBASE_SQL_OB_EXPR_JSON_LENGTH_H_
+
+#include "sql/engine/expr/ob_expr_operator.h"
+#include "lib/json_type/ob_json_path.h"
+
+using namespace oceanbase::common;
+
+namespace oceanbase
+{
+namespace sql
+{
+class ObExprJsonLength : public ObFuncExprOperator
+{
+public:
+  explicit ObExprJsonLength(common::ObIAllocator &alloc);
+  virtual ~ObExprJsonLength();
+  virtual int calc_result_typeN(ObExprResType& type,
+                                ObExprResType* types_stack,
+                                int64_t param_num,
+                                ObExprTypeCtx& type_ctx) const override;
+  virtual int calc_resultN(common::ObObj &result,
+                           const common::ObObj *objs,
+                           int64_t param_num,
+                           common::ObExprCtx &expr_ctx) const;
+  template <typename T>
+  static int calc(const T &data1, ObObjType type1, ObCollationType cs_type, const T *data2, 
+                  ObObjType type2, ObIAllocator *allocator, T &res,
+                  ObJsonPathCache* path_cache);
+  static int eval_json_length(const ObExpr &expr, ObEvalCtx &ctx, ObDatum &res);
+  virtual int cg_expr(ObExprCGCtx &expr_cg_ctx, const ObRawExpr &raw_expr,
+                      ObExpr &rt_expr) const override;
+  virtual bool need_rt_ctx() const override { return true; }
+private:
+  DISALLOW_COPY_AND_ASSIGN(ObExprJsonLength);
+};
+
+} // sql
+} // oceanbase
+#endif // OCEANBASE_SQL_OB_EXPR_JSON_LENGTH_H_