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#pragma once
#include <Core/Block.h>
#include <Formats/FormatSettings.h>
#include <Formats/BSONTypes.h>
#include <Processors/Formats/IRowInputFormat.h>
#include <Processors/Formats/ISchemaReader.h>
#include <Common/HashTable/HashMap.h>
namespace DB
{
/*
* Class for parsing data in BSON format.
* Each row is parsed as a separate BSON document.
* Each column is parsed as a single field with column name as a key.
* It uses the following correspondence between BSON types and ClickHouse types:
*
* BSON Type | ClickHouse Type
* \x01 double | Float32/Float64
* \x02 string | String/FixedString
* \x03 document | Map/Named Tuple
* \x04 array | Array/Tuple
* \x05 binary, \x00 binary subtype | String/FixedString
* \x05 binary, \x02 old binary subtype | String/FixedString
* \x05 binary, \x03 old uuid subtype | UUID
* \x05 binary, \x04 uuid subtype | UUID
* \x07 ObjectId | String
* \x08 boolean | Bool
* \x09 datetime | DateTime64
* \x0A null value | NULL
* \x0D JavaScript code | String
* \x0E symbol | String/FixedString
* \x10 int32 | Int32/Decimal32
* \x12 int64 | Int64/Decimal64/DateTime64
* \x11 uint64 | UInt64
*
* Other BSON types are not supported.
* Also, we perform conversion between different integer types
* (for example, you can insert BSON int32 value into ClickHouse UInt8)
* Big integers and decimals Int128/UInt128/Int256/UInt256/Decimal128/Decimal256
* can be parsed from BSON Binary value with \x00 binary subtype. In this case
* we validate that the size of binary data equals the size of expected value.
*
* Note: this format will not work on Big-Endian platforms.
*/
class ReadBuffer;
class BSONEachRowRowInputFormat final : public IRowInputFormat
{
public:
BSONEachRowRowInputFormat(
ReadBuffer & in_, const Block & header_, Params params_, const FormatSettings & format_settings_);
String getName() const override { return "BSONEachRowRowInputFormat"; }
void resetParser() override;
private:
void readPrefix() override { }
void readSuffix() override { }
bool readRow(MutableColumns & columns, RowReadExtension & ext) override;
bool allowSyncAfterError() const override { return true; }
void syncAfterError() override;
bool supportsCountRows() const override { return true; }
size_t countRows(size_t max_block_size) override;
size_t columnIndex(const StringRef & name, size_t key_index);
using ColumnReader = std::function<void(StringRef name, BSONType type)>;
bool readField(IColumn & column, const DataTypePtr & data_type, BSONType bson_type);
void skipUnknownField(BSONType type, const String & key_name);
void readTuple(IColumn & column, const DataTypePtr & data_type, BSONType bson_type);
void readArray(IColumn & column, const DataTypePtr & data_type, BSONType bson_type);
void readMap(IColumn & column, const DataTypePtr & data_type, BSONType bson_type);
const FormatSettings format_settings;
/// Buffer for the read from the stream field name. Used when you have to copy it.
String current_key_name;
/// Set of columns for which the values were read. The rest will be filled with default values.
std::vector<UInt8> read_columns;
/// Set of columns which already met in row. Exception is thrown if there are more than one column with the same name.
std::vector<UInt8> seen_columns;
/// These sets may be different, because if null_as_default=1 read_columns[i] will be false and seen_columns[i] will be true
/// for row like {..., "non-nullable column name" : null, ...}
/// Hash table match `field name -> position in the block`.
Block::NameMap name_map;
/// Cached search results for previous row (keyed as index in JSON object) - used as a hint.
std::vector<Block::NameMap::const_iterator> prev_positions;
DataTypes types;
size_t current_document_start;
BSONSizeT current_document_size;
};
class BSONEachRowSchemaReader : public IRowWithNamesSchemaReader
{
public:
BSONEachRowSchemaReader(ReadBuffer & in_, const FormatSettings & settings_);
private:
NamesAndTypesList readRowAndGetNamesAndDataTypes(bool & eof) override;
void transformTypesIfNeeded(DataTypePtr & type, DataTypePtr & new_type) override;
NamesAndTypesList getDataTypesFromBSONDocument(bool skip_unsupported_types);
DataTypePtr getDataTypeFromBSONField(BSONType type, bool skip_unsupported_types, bool & skip);
};
}
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