ClickHouse/src/TableFunctions/TableFunctionInput.cpp

74 lines
2.4 KiB
C++

#include <TableFunctions/TableFunctionInput.h>
#include <TableFunctions/TableFunctionFactory.h>
#include <TableFunctions/parseColumnsListForTableFunction.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTLiteral.h>
#include <Common/Exception.h>
#include <Storages/StorageInput.h>
#include <Storages/checkAndGetLiteralArgument.h>
#include <DataTypes/DataTypeFactory.h>
#include <Interpreters/evaluateConstantExpression.h>
#include "registerTableFunctions.h"
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
extern const int CANNOT_EXTRACT_TABLE_STRUCTURE;
}
void TableFunctionInput::parseArguments(const ASTPtr & ast_function, ContextPtr context)
{
const auto * function = ast_function->as<ASTFunction>();
if (!function->arguments)
throw Exception("Table function '" + getName() + "' must have arguments", ErrorCodes::LOGICAL_ERROR);
auto args = function->arguments->children;
if (args.empty())
{
structure = "auto";
return;
}
if (args.size() != 1)
throw Exception("Table function '" + getName() + "' requires exactly 1 argument: structure",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
structure = checkAndGetLiteralArgument<String>(evaluateConstantExpressionOrIdentifierAsLiteral(args[0], context), "structure");
}
ColumnsDescription TableFunctionInput::getActualTableStructure(ContextPtr context) const
{
if (structure == "auto")
{
if (structure_hint.empty())
throw Exception(
ErrorCodes::CANNOT_EXTRACT_TABLE_STRUCTURE,
"Table function '{}' was used without structure argument but structure could not be determined automatically. Please, "
"provide structure manually",
getName());
return structure_hint;
}
return parseColumnsListFromString(structure, context);
}
StoragePtr TableFunctionInput::executeImpl(const ASTPtr & /*ast_function*/, ContextPtr context, const std::string & table_name, ColumnsDescription /*cached_columns*/) const
{
auto storage = std::make_shared<StorageInput>(StorageID(getDatabaseName(), table_name), getActualTableStructure(context));
storage->startup();
return storage;
}
void registerTableFunctionInput(TableFunctionFactory & factory)
{
factory.registerFunction<TableFunctionInput>();
}
}