Files
scylladb/alternator/serialization.hh
Botond Dénes 2b0bc11f2e service/paging: use position_in_partition instead of clustering_key for last row
The former allows for expressing more positions, like a position
before/after a clustering key. This practically enables the coordinator
side paging logic, for a query to be stopped at a tombstone (which can
have said positions).
2022-06-23 13:36:20 +03:00

94 lines
3.4 KiB
C++

/*
* Copyright 2019-present ScyllaDB
*/
/*
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#pragma once
#include <string>
#include <string_view>
#include <optional>
#include "types.hh"
#include "schema_fwd.hh"
#include "keys.hh"
#include "utils/rjson.hh"
#include "utils/big_decimal.hh"
class position_in_partition;
namespace alternator {
enum class alternator_type : int8_t {
S, B, BOOL, N, NOT_SUPPORTED_YET
};
struct type_info {
alternator_type atype;
data_type dtype;
};
struct type_representation {
std::string ident;
data_type dtype;
};
inline constexpr std::string_view scylla_paging_region(":scylla:paging:region");
inline constexpr std::string_view scylla_paging_weight(":scylla:paging:weight");
type_info type_info_from_string(std::string_view type);
type_representation represent_type(alternator_type atype);
bytes serialize_item(const rjson::value& item);
rjson::value deserialize_item(bytes_view bv);
std::string type_to_string(data_type type);
bytes get_key_column_value(const rjson::value& item, const column_definition& column);
bytes get_key_from_typed_value(const rjson::value& key_typed_value, const column_definition& column);
rjson::value json_key_column_value(bytes_view cell, const column_definition& column);
partition_key pk_from_json(const rjson::value& item, schema_ptr schema);
clustering_key ck_from_json(const rjson::value& item, schema_ptr schema);
position_in_partition pos_from_json(const rjson::value& item, schema_ptr schema);
// If v encodes a number (i.e., it is a {"N": [...]}, returns an object representing it. Otherwise,
// raises ValidationException with diagnostic.
big_decimal unwrap_number(const rjson::value& v, std::string_view diagnostic);
// try_unwrap_number is like unwrap_number, but returns an unset optional
// when the given v does not encode a number.
std::optional<big_decimal> try_unwrap_number(const rjson::value& v);
// Check if a given JSON object encodes a set (i.e., it is a {"SS": [...]}, or "NS", "BS"
// and returns set's type and a pointer to that set. If the object does not encode a set,
// returned value is {"", nullptr}
const std::pair<std::string, const rjson::value*> unwrap_set(const rjson::value& v);
// Check if a given JSON object encodes a list (i.e., it is a {"L": [...]}
// and returns a pointer to that list.
const rjson::value* unwrap_list(const rjson::value& v);
// Take two JSON-encoded numeric values ({"N": "thenumber"}) and return the
// sum, again as a JSON-encoded number.
rjson::value number_add(const rjson::value& v1, const rjson::value& v2);
rjson::value number_subtract(const rjson::value& v1, const rjson::value& v2);
// Take two JSON-encoded set values (e.g. {"SS": [...the actual set]}) and
// return the sum of both sets, again as a set value.
rjson::value set_sum(const rjson::value& v1, const rjson::value& v2);
// Take two JSON-encoded set values (e.g. {"SS": [...the actual list]}) and
// return the difference of s1 - s2, again as a set value.
// DynamoDB does not allow empty sets, so if resulting set is empty, return
// an unset optional instead.
std::optional<rjson::value> set_diff(const rjson::value& v1, const rjson::value& v2);
// Take two JSON-encoded list values (remember that a list value is
// {"L": [...the actual list]}) and return the concatenation, again as
// a list value.
// Returns a null value if one of the arguments is not actually a list.
rjson::value list_concatenate(const rjson::value& v1, const rjson::value& v2);
}