ClickHouse/dbms/src/AggregateFunctions/parseAggregateFunctionParameters.cpp

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#include <AggregateFunctions/parseAggregateFunctionParameters.h>
#include <Parsers/ExpressionListParsers.h>
#include <Parsers/parseQuery.h>
#include <Common/typeid_cast.h>
namespace DB
{
namespace ErrorCodes
{
extern const int BAD_ARGUMENTS;
extern const int PARAMETERS_TO_AGGREGATE_FUNCTIONS_MUST_BE_LITERALS;
}
Array getAggregateFunctionParametersArray(const ASTPtr & expression_list, const std::string & error_context)
{
const ASTs & parameters = typeid_cast<const ASTExpressionList &>(*expression_list).children;
if (parameters.empty())
throw Exception("Parameters list to aggregate functions cannot be empty", ErrorCodes::BAD_ARGUMENTS);
Array params_row(parameters.size());
for (size_t i = 0; i < parameters.size(); ++i)
{
const ASTLiteral * lit = typeid_cast<const ASTLiteral *>(parameters[i].get());
if (!lit)
{
throw Exception("Parameters to aggregate functions must be literals" + (error_context.empty() ? "" : " (in " + error_context +")"),
ErrorCodes::PARAMETERS_TO_AGGREGATE_FUNCTIONS_MUST_BE_LITERALS);
}
params_row[i] = lit->value;
}
return params_row;
}
void getAggregateFunctionNameAndParametersArray(
const std::string & aggregate_function_name_with_params,
std::string & aggregate_function_name,
Array & aggregate_function_parameters,
const std::string & error_context)
{
if (aggregate_function_name_with_params.back() != ')')
{
aggregate_function_name = aggregate_function_name_with_params;
aggregate_function_parameters = Array();
return;
}
size_t pos = aggregate_function_name_with_params.find('(');
if (pos == std::string::npos || pos + 2 >= aggregate_function_name_with_params.size())
throw Exception(aggregate_function_name_with_params + " doesn't look like aggregate function name in " + error_context + ".",
ErrorCodes::BAD_ARGUMENTS);
aggregate_function_name = aggregate_function_name_with_params.substr(0, pos);
std::string parameters_str = aggregate_function_name_with_params.substr(pos + 1, aggregate_function_name_with_params.size() - pos - 2);
if (aggregate_function_name.empty())
throw Exception(aggregate_function_name_with_params + " doesn't look like aggregate function name in " + error_context + ".",
ErrorCodes::BAD_ARGUMENTS);
ParserExpressionList params_parser(false);
ASTPtr args_ast = parseQuery(params_parser,
parameters_str.data(), parameters_str.data() + parameters_str.size(),
"parameters of aggregate function in " + error_context);
ASTExpressionList & args_list = typeid_cast<ASTExpressionList &>(*args_ast);
if (args_list.children.empty())
throw Exception("Incorrect list of parameters to aggregate function "
+ aggregate_function_name, ErrorCodes::BAD_ARGUMENTS);
aggregate_function_parameters = getAggregateFunctionParametersArray(args_ast);
}
}