127 lines
4.5 KiB
C++
127 lines
4.5 KiB
C++
/**
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* Copyright (c) 2021 OceanBase
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* OceanBase CE is licensed under Mulan PubL v2.
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* You can use this software according to the terms and conditions of the Mulan PubL v2.
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* You may obtain a copy of Mulan PubL v2 at:
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* http://license.coscl.org.cn/MulanPubL-2.0
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* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
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* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
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* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
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* See the Mulan PubL v2 for more details.
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*/
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#define USING_LOG_PREFIX SQL_ENG
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#include "sql/engine/expr/ob_expr_randstr.h"
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#include "sql/engine/ob_exec_context.h"
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namespace oceanbase
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{
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using namespace common;
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namespace sql
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{
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ObExprRandstr::ObExprRandstr(common::ObIAllocator &alloc)
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: ObFuncExprOperator(alloc, T_FUN_SYS_RANDSTR, "randstr", 2, NOT_VALID_FOR_GENERATED_COL, NOT_ROW_DIMENSION)
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{
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}
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ObExprRandstr::~ObExprRandstr()
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{
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}
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int ObExprRandstr::calc_result_type2(ObExprResType &type,
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ObExprResType &len,
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ObExprResType &seed,
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common::ObExprTypeCtx &type_ctx) const
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{
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UNUSED(type_ctx);
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int ret = OB_SUCCESS;
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len.set_calc_type(ObIntType);
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seed.set_calc_type(ObIntType);
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if (lib::is_mysql_mode()) {
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int64_t mbmaxlen = 0;
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if (OB_FAIL(ObCharset::get_mbmaxlen_by_coll(
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common::ObCharset::get_default_collation(common::ObCharset::get_default_charset()), mbmaxlen))) {
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ret = OB_ERR_UNEXPECTED;
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SQL_RESV_LOG(WARN, "fail to get mbmaxlen");
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} else if (0 == mbmaxlen){
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ret = OB_ERR_UNEXPECTED;
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LOG_WARN("mb maxlen invalid");
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} else {
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type.set_type(ObVarcharType);
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// must divide by mbmaxlen,
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// otherwise create table as select would fail with randstr() function
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type.set_length(OB_MAX_VARCHAR_LENGTH / mbmaxlen);
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}
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} else {
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type.set_collation_type(type_ctx.get_coll_type());
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type.set_collation_level(CS_LEVEL_IMPLICIT);
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type.set_length_semantics(LS_CHAR);
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type.set_type(ObVarcharType);
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type.set_length(OB_MAX_ORACLE_VARCHAR_LENGTH);
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}
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type.set_collation_level(common::CS_LEVEL_IMPLICIT);
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type.set_collation_type(common::ObCharset::get_default_collation(common::ObCharset::get_default_charset()));
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return ret;
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}
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int ObExprRandstr::calc_random_str(const ObExpr &expr,
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ObEvalCtx &ctx,
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ObDatum &res_datum)
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{
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int ret = OB_SUCCESS;
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int64_t max_size = 0;
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if (OB_UNLIKELY(2 != expr.arg_cnt_)) {
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ret = OB_ERR_UNEXPECTED;
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LOG_WARN("unexpected arg_cnt", K(ret), K(expr.arg_cnt_));
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} else if (OB_FAIL(expr.eval_param_value(ctx))) {
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LOG_WARN("expr.eval_param_value failed", K(ret));
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} else if (OB_FAIL(ctx.exec_ctx_.get_my_session()->get_max_allowed_packet(max_size))) {
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LOG_WARN("get max length failed", K(ret));
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} else {
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int64_t rand_res = 0;
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ObDatum &len = expr.locate_param_datum(ctx, 0);
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ObDatum &seed = expr.locate_param_datum(ctx, 1);
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if (len.is_null() || seed.is_null()) {
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res_datum.set_null();
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} else if (OB_UNLIKELY(len.get_int() < 0)) {
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res_datum.set_null();
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} else if (OB_UNLIKELY(len.get_int() > max_size)) {
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res_datum.set_null();
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LOG_USER_WARN(OB_ERR_FUNC_RESULT_TOO_LARGE, "randstr", static_cast<int>(max_size));
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} else {
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ObString output;
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ObExprStrResAlloc expr_res_alloc(expr, ctx);
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int64_t len_val = len.get_int();
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int64_t seed_val = seed.get_int();
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char *buf = static_cast<char *>(expr_res_alloc.alloc(len_val));
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if (OB_ISNULL(buf)) {
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ret = OB_ALLOCATE_MEMORY_FAILED;
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LOG_WARN("fail alloc memory", K(ret), K(len_val));
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} else {
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static const char dict[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
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for (int64_t i = 0; i < len_val && OB_SUCC(ret); ++i) {
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// LCG, Linear Congruential Method for Generating Pseudo Random Number
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seed_val = (seed_val * 1103515245 + 12345) & ((1U << 31) - 1);
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buf[i] = dict[seed_val % (sizeof(dict) - 1)];
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}
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output.assign_ptr(buf, static_cast<int32_t>(len_val));
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res_datum.set_string(output);
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}
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}
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}
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return ret;
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}
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int ObExprRandstr::cg_expr(ObExprCGCtx &expr_cg_ctx, const ObRawExpr &raw_expr,
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ObExpr &rt_expr) const
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{
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int ret = OB_SUCCESS;
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UNUSED(expr_cg_ctx);
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UNUSED(raw_expr);
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rt_expr.eval_func_ = ObExprRandstr::calc_random_str;
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return ret;
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}
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} /* namespace sql */
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} /* namespace oceanbase */
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