init push

src/sql/engine/expr/ob_expr_get_sys_var.h

@@ -0,0 +1,51 @@
+/**
+ * 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.
+ */
+
+#ifndef _OB_EXPR_GET_SYS_VAR_H
+#define _OB_EXPR_GET_SYS_VAR_H 1
+#include "sql/engine/expr/ob_expr_operator.h"
+#include "sql/session/ob_sql_session_info.h"
+
+namespace oceanbase {
+namespace sql {
+// get_sys_var(name, scope)
+class ObExprGetSysVar : public ObFuncExprOperator {
+  public:
+  static const ObExprOperatorType op_type_;
+  ObExprGetSysVar();
+  explicit ObExprGetSysVar(common::ObIAllocator& alloc);
+  virtual ~ObExprGetSysVar();
+  virtual int calc_result_type2(
+      ObExprResType& type, ObExprResType& type1, ObExprResType& type2, common::ObExprTypeCtx& type_ctx) const;
+  virtual int calc_result2(
+      common::ObObj& result, const common::ObObj& name, const common::ObObj& scope, common::ObExprCtx& expr_ctx) const;
+  // for engine 3.0
+  virtual int cg_expr(ObExprCGCtx& expr_cg_ctx, const ObRawExpr& raw_expr, ObExpr& rt_expr) const override;
+  static int calc_get_sys_val_expr(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& res_datum);
+
+  private:
+  static int calc_(common::ObObj& result, const common::ObString& var_name, const int64_t var_scope,
+      ObSQLSessionInfo* session, ObExecContext* exec_ctx, common::ObIAllocator& alloc);
+  static int get_session_var(common::ObObj& result, const common::ObString& var_name, common::ObIAllocator& alloc,
+      ObSQLSessionInfo* session, ObExecContext* exec_ctx);
+  static int get_sys_var_disp_obj(common::ObIAllocator& allocator, const ObSQLSessionInfo& session,
+      const common::ObString& var_name, common::ObObj& disp_obj);
+
+  private:
+  // disallow copy
+  DISALLOW_COPY_AND_ASSIGN(ObExprGetSysVar);
+};
+
+}  // end namespace sql
+}  // end namespace oceanbase
+
+#endif /* _OB_EXPR_GET_SYS_VAR_H */