ob_expr_assign.cpp

/**
 * 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.
 */

#define USING_LOG_PREFIX SQL_ENG

#include "sql/engine/expr/ob_expr_assign.h"
#include "lib/ob_name_def.h"
#include "share/object/ob_obj_cast.h"
#include "sql/session/ob_sql_session_info.h"
#include "sql/engine/ob_exec_context.h"

namespace oceanbase {
using namespace common;
namespace sql {

ObExprAssign::ObExprAssign(ObIAllocator& alloc) : ObFuncExprOperator(alloc, T_OP_ASSIGN, N_ASSIGN, 2, NOT_ROW_DIMENSION)
{}

ObExprAssign::~ObExprAssign()
{}

int ObExprAssign::calc_result2(ObObj& result, const ObObj& key, const ObObj& value, ObExprCtx& expr_ctx) const
{
  EXPR_DEFINE_CAST_CTX(expr_ctx, CM_NONE);
  return calc(result, key, value, expr_ctx.my_session_, cast_ctx);
}

int ObExprAssign::calc(
    ObObj& result, const ObObj& key, const ObObj& value, sql::ObSQLSessionInfo* my_session_, ObCastCtx& cast_ctx)
{
  int ret = OB_SUCCESS;
  if (OB_UNLIKELY(ObStringTC != key.get_type_class())) {
    LOG_WARN("Key must be string type", K(ret), K(key));
    ret = OB_INVALID_ARGUMENT;
  } else if (NULL == my_session_) {
    LOG_WARN("Session is NULL", K(ret));
    ret = OB_INVALID_ARGUMENT;
  } else {
    ObSessionVariable sess_var;
    if (ob_is_temporal_type(value.get_type())) {
      // In mysql, treat datetime type as blob. use varchar instead in ob.
      ObObj obj_tmp;
      const ObObj* obj_res = NULL;
      if (OB_FAIL(ObObjCaster::to_type(ObVarcharType, cast_ctx, value, obj_tmp, obj_res))) {
        LOG_WARN("failed to cast object to ObVarcharType ", K(ret), K(value), K(obj_res));
      } else if (OB_ISNULL(obj_res)) {
        LOG_WARN("null pointer", K(ret), K(value), K(obj_res));
        ret = OB_ERR_UNEXPECTED;
      } else {
        sess_var.value_ = *obj_res;
        sess_var.meta_.set_varchar();
        sess_var.meta_.set_collation_level(CS_LEVEL_IMPLICIT);
        sess_var.meta_.set_collation_type(ObCharset::get_default_collation(ObCharset::get_default_charset()));
      }
    } else if (OB_UNLIKELY(value.is_null())) {
      sess_var.value_.set_null();
      sess_var.meta_.set_collation_level(CS_LEVEL_IMPLICIT);
      sess_var.meta_.set_collation_type(CS_TYPE_BINARY);
    } else {
      sess_var.value_ = value;
      sess_var.meta_.set_type(value.get_type());
      sess_var.meta_.set_scale(value.get_scale());
      sess_var.meta_.set_collation_level(CS_LEVEL_IMPLICIT);
      sess_var.meta_.set_collation_type(value.get_collation_type());
    }
    if (OB_SUCC(ret)) {
      ObString str = key.get_varchar();
      if (OB_FAIL(my_session_->replace_user_variable(str, sess_var))) {
        LOG_WARN("failed replace user var", K(ret), K(str), K(value));
      } else {
        result = sess_var.value_;
        result.set_meta_type(sess_var.meta_);
      }
    }
  }
  return ret;
}

int ObExprAssign::calc_result_type2(
    ObExprResType& type, ObExprResType& key, ObExprResType& value, common::ObExprTypeCtx& type_ctx) const
{
  int ret = OB_SUCCESS;
  UNUSED(type_ctx);
  UNUSED(key);
  ObObjType val_type = value.get_type();
  if (ob_is_temporal_type(val_type)) {
    type.set_varchar();
    type.set_collation_level(common::CS_LEVEL_IMPLICIT);
    type.set_collation_type(common::ObCharset::get_default_collation(common::ObCharset::get_default_charset()));
  } else if (ob_is_bit_tc(val_type)) {
    type.set_uint64();
    value.set_calc_type(ObUInt64Type);
  } else if (OB_UNLIKELY(value.is_null())) {
    type.set_varchar();
    type.set_collation_level(common::CS_LEVEL_IMPLICIT);
    type.set_collation_type(common::CS_TYPE_BINARY);
  } else {
    type.set_type(val_type);
    type.set_collation_level(common::CS_LEVEL_IMPLICIT);
    type.set_collation_type(value.get_collation_type());
  }
  type.set_precision(value.get_precision());
  type.set_scale(value.get_scale());
  // set length
  if (ob_is_string_type(type.get_type())) {
    type.set_full_length(common::MAX_BUFFER_SIZE, value.get_length_semantics());
  }

  const ObSQLSessionInfo* session = dynamic_cast<const ObSQLSessionInfo*>(type_ctx.get_session());
  if (OB_ISNULL(session)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("cast basic session to sql session failed", K(ret));
  } else if (session->use_static_typing_engine()) {
    value.set_calc_meta(type.get_obj_meta());
    value.set_calc_accuracy(type.get_accuracy());
    value.set_calc_collation_type(type.get_collation_type());
    value.set_calc_collation_level(type.get_collation_level());
    key.set_calc_type(ObVarcharType);
    key.set_calc_collation_type(ObCharset::get_system_collation());
  }
  return ret;
}

int calc_assign_expr(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& res_datum)
{
  int ret = OB_SUCCESS;
  ObDatum* key_res = NULL;
  ObDatum* val_res = NULL;
  ObSQLSessionInfo* session = ctx.exec_ctx_.get_my_session();
  if (OB_ISNULL(session)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("session is NULL", K(ret));
  } else if (OB_FAIL(expr.args_[0]->eval(ctx, key_res)) || OB_FAIL(expr.args_[1]->eval(ctx, val_res))) {
    LOG_WARN("eval arg failed", K(ret));
  } else {
    ObObj obj;
    ObObjMeta obj_meta;
    ObSessionVariable sess_var;
    if (val_res->is_null()) {
      obj.set_null();
      obj_meta.set_null();
      // same as old engine. but why...
      obj_meta.set_collation_level(CS_LEVEL_IMPLICIT);
      obj_meta.set_collation_type(ObCharset::get_default_collation(ObCharset::get_default_charset()));
    } else {
      obj_meta.set_type(expr.datum_meta_.type_);
      obj_meta.set_scale(expr.datum_meta_.scale_);
      obj_meta.set_collation_type(expr.datum_meta_.cs_type_);
      obj_meta.set_collation_level(common::CS_LEVEL_IMPLICIT);
      if (OB_FAIL(val_res->to_obj(obj, obj_meta))) {
        LOG_WARN("to_obj failed", K(ret), K(expr), K(obj_meta));
      }
    }
    if (OB_SUCC(ret)) {
      sess_var.value_ = obj;
      sess_var.meta_ = obj_meta;
    }
    if (OB_SUCC(ret) && OB_FAIL(session->replace_user_variable(key_res->get_string(), sess_var))) {
      LOG_WARN("replace user val failed", K(ret), K(key_res->get_string()));
    } else {
      res_datum.set_datum(*val_res);
    }
  }
  return ret;
}

int ObExprAssign::cg_expr(ObExprCGCtx& expr_cg_ctx, const ObRawExpr& raw_expr, ObExpr& rt_expr) const
{
  int ret = OB_SUCCESS;
  UNUSED(expr_cg_ctx);
  UNUSED(raw_expr);
  rt_expr.eval_func_ = calc_assign_expr;
  return ret;
}

}  // namespace sql
}  // namespace oceanbase