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74 lines
2.7 KiB
C++
74 lines
2.7 KiB
C++
#pragma once
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#include <Core/Block.h>
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#include <Formats/FormatSettings.h>
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#include <Processors/Formats/IRowInputFormat.h>
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#include <Common/HashTable/HashMap.h>
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namespace DB
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{
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class ReadBuffer;
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class BSONEachRowRowInputFormat final : public IRowInputFormat
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{
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public:
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BSONEachRowRowInputFormat(
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ReadBuffer & in_, const Block & header_, Params params_, const FormatSettings & format_settings_, bool yield_strings_);
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String getName() const override { return "BSONEachRowRowInputFormat"; }
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void resetParser() override { }
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private:
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void readPrefix() override { }
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void readSuffix() override { }
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bool readRow(MutableColumns & columns, RowReadExtension & ext) override;
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bool allowSyncAfterError() const override { return true; }
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void syncAfterError() override { }
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const String & columnName(size_t i) const;
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size_t columnIndex(const StringRef & name, size_t key_index);
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StringRef readColumnName(ReadBuffer & buf);
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void readField(size_t index, MutableColumns & columns);
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void readBSONObject(MutableColumns & columns);
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const FormatSettings format_settings;
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/// Buffer for the read from the stream field name. Used when you have to copy it.
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/// Also, if processing of Nested data is in progress, it holds the common prefix
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/// of the nested column names (so that appending the field name to it produces
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/// the full column name)
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String current_column_name;
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/// If processing Nested data, holds the length of the common prefix
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/// of the names of related nested columns. For example, for a table
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/// created as follows
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/// CREATE TABLE t (n Nested (i Int32, s String))
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/// the nested column names are 'n.i' and 'n.s' and the nested prefix is 'n.'
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size_t nested_prefix_length = 0;
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/// Set of columns for which the values were read. The rest will be filled with default values.
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std::vector<UInt8> read_columns;
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/// Set of columns which already met in row. Exception is thrown if there are more than one column with the same name.
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std::vector<UInt8> seen_columns;
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/// These sets may be different, because if null_as_default=1 read_columns[i] will be false and seen_columns[i] will be true
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/// for row like {..., "non-nullable column name" : null, ...}
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/// Hash table match `field name -> position in the block`. NOTE You can use perfect hash map.
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using NameMap = HashMap<StringRef, size_t, StringRefHash>;
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NameMap name_map;
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/// Cached search results for previous row (keyed as index in JSON object) - used as a hint.
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std::vector<NameMap::LookupResult> prev_positions;
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/// This flag is needed to know if data is in square brackets.
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bool data_in_square_brackets = false;
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bool allow_new_rows = true;
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bool yield_strings;
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};
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}
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