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https://github.com/ClickHouse/ClickHouse.git
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165 lines
5.2 KiB
C++
165 lines
5.2 KiB
C++
#include <DB/IO/ReadHelpers.h>
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#include <DB/Interpreters/evaluateConstantExpression.h>
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#include <DB/Interpreters/convertFieldToType.h>
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#include <DB/Parsers/ExpressionListParsers.h>
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#include <DB/DataStreams/ValuesRowInputStream.h>
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#include <DB/DataTypes/DataTypeArray.h>
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#include <DB/Core/FieldVisitors.h>
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#include <DB/Core/Block.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int CANNOT_PARSE_INPUT_ASSERTION_FAILED;
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extern const int CANNOT_PARSE_QUOTED_STRING;
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extern const int CANNOT_PARSE_DATE;
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extern const int CANNOT_PARSE_DATETIME;
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extern const int CANNOT_READ_ARRAY_FROM_TEXT;
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extern const int CANNOT_PARSE_DATE;
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extern const int SYNTAX_ERROR;
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extern const int VALUE_IS_OUT_OF_RANGE_OF_DATA_TYPE;
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}
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ValuesRowInputStream::ValuesRowInputStream(ReadBuffer & istr_, const Context & context_, bool interpret_expressions_)
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: istr(istr_), context(context_), interpret_expressions(interpret_expressions_)
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{
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/// In this format, BOM at beginning of stream cannot be confused with value, so it is safe to skip it.
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skipBOMIfExists(istr);
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}
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bool ValuesRowInputStream::read(Block & block)
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{
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size_t size = block.columns();
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skipWhitespaceIfAny(istr);
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if (istr.eof() || *istr.position() == ';')
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return false;
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/** Как правило, это обычный формат для потокового парсинга.
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* Но в качестве исключения, поддерживается также обработка произвольных выражений вместо значений.
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* Это очень неэффективно. Но если выражений нет, то оверхед отсутствует.
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*/
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ParserExpressionWithOptionalAlias parser(false);
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assertChar('(', istr);
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for (size_t i = 0; i < size; ++i)
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{
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skipWhitespaceIfAny(istr);
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char * prev_istr_position = istr.position();
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size_t prev_istr_bytes = istr.count() - istr.offset();
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auto & col = block.getByPosition(i);
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bool rollback_on_exception = false;
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try
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{
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col.type.get()->deserializeTextQuoted(*col.column.get(), istr);
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rollback_on_exception = true;
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skipWhitespaceIfAny(istr);
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if (i != size - 1)
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assertChar(',', istr);
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else
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assertChar(')', istr);
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}
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catch (const Exception & e)
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{
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if (!interpret_expressions)
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throw;
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/** Обычный потоковый парсер не смог распарсить значение.
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* Попробуем распарсить его SQL-парсером как константное выражение.
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* Это исключительный случай.
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*/
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if (e.code() == ErrorCodes::CANNOT_PARSE_INPUT_ASSERTION_FAILED
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|| e.code() == ErrorCodes::CANNOT_PARSE_QUOTED_STRING
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|| e.code() == ErrorCodes::CANNOT_PARSE_DATE
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|| e.code() == ErrorCodes::CANNOT_PARSE_DATETIME
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|| e.code() == ErrorCodes::CANNOT_READ_ARRAY_FROM_TEXT)
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{
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/// TODO Работоспособность, если выражение не помещается целиком до конца буфера.
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/// Если начало значения уже не лежит в буфере.
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if (istr.count() - istr.offset() != prev_istr_bytes)
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throw;
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if (rollback_on_exception)
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col.column.get()->popBack(1);
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IDataType & type = *block.safeGetByPosition(i).type;
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IParser::Pos pos = prev_istr_position;
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Expected expected = "";
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IParser::Pos max_parsed_pos = pos;
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ASTPtr ast;
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if (!parser.parse(pos, istr.buffer().end(), ast, max_parsed_pos, expected))
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throw Exception("Cannot parse expression of type " + type.getName() + " here: "
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+ String(prev_istr_position, std::min(SHOW_CHARS_ON_SYNTAX_ERROR, istr.buffer().end() - prev_istr_position)),
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ErrorCodes::SYNTAX_ERROR);
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istr.position() = const_cast<char *>(max_parsed_pos);
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std::pair<Field, DataTypePtr> value_raw = evaluateConstantExpression(ast, context);
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Field value = convertFieldToType(value_raw.first, type, value_raw.second.get());
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if (value.isNull())
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{
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/// Check that we are indeed allowed to insert a NULL.
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bool is_null_allowed = false;
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if (type.isNullable())
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is_null_allowed = true;
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else
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{
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/// NOTE: For now we support only one level of null values, i.e.
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/// there are not yet such things as Array(Nullable(Array(Nullable(T))).
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/// Therefore the code below is valid within the current limitations.
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const auto array_type = typeid_cast<const DataTypeArray *>(&type);
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if (array_type != nullptr)
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{
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const auto & nested_type = array_type->getMostNestedType();
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if (nested_type->isNullable())
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is_null_allowed = true;
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}
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}
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if (!is_null_allowed)
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throw Exception{"Expression returns value " + applyVisitor(FieldVisitorToString(), value)
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+ ", that is out of range of type " + type.getName()
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+ ", at: " + String(prev_istr_position, std::min(SHOW_CHARS_ON_SYNTAX_ERROR, istr.buffer().end() - prev_istr_position)),
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ErrorCodes::VALUE_IS_OUT_OF_RANGE_OF_DATA_TYPE};
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}
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col.column->insert(value);
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skipWhitespaceIfAny(istr);
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if (i != size - 1)
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assertChar(',', istr);
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else
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assertChar(')', istr);
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}
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else
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throw;
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}
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}
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skipWhitespaceIfAny(istr);
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if (!istr.eof() && *istr.position() == ',')
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++istr.position();
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return true;
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}
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}
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