Files
scylladb/sstables/m_format_write_helpers.hh
Tomasz Grabiec fad4fba4bc sstables: Templetize write() functions on the writer
Will allow writing to both a file_writer, or an in-memory writer like
a bytes_ostream.
2018-12-10 20:08:16 +01:00

108 lines
3.9 KiB
C++

/*
* Copyright (C) 2018 ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <type_traits>
#include <seastar/util/bool_class.hh>
#include "bytes.hh"
#include "types.hh"
#include "timestamp.hh"
class schema;
class row;
class clustering_key_prefix;
class encoding_stats;
namespace sstables {
using indexed_columns = std::vector<std::reference_wrapper<const column_definition>>;
// Utilities for writing integral values in variable-length format
// See vint-serialization.hh for more details
template <typename W>
GCC6_CONCEPT(requires Writer<W>())
void write_unsigned_vint(W& out, uint64_t value);
template <typename W>
GCC6_CONCEPT(requires Writer<W>())
void write_signed_vint(W& out, int64_t value);
template <typename T, typename W>
GCC6_CONCEPT(requires Writer<W>())
typename std::enable_if_t<!std::is_integral_v<T>>
write_vint(W& out, T t) = delete;
template <typename T, typename W>
GCC6_CONCEPT(requires Writer<W>())
inline void write_vint(W& out, T value) {
static_assert(std::is_integral_v<T>, "Non-integral values can't be written using write_vint");
return std::is_unsigned_v<T> ? write_unsigned_vint(out, value) : write_signed_vint(out, value);
}
// There is a special case when we need to treat a non-full clustering key prefix as a full one
// for serialization purposes. This is the case that may occur with a compact table.
// For historical reasons a compact table may have rows with missing trailing clustering columns in their clustering keys.
// Consider:
// cqlsh:test> CREATE TABLE cf (pk int, ck1 int, ck2 int, rc int, primary key (pk, ck1, ck2)) WITH COMPACT STORAGE;
// cqlsh:test> INSERT INTO cf (pk, ck1, rc) VALUES (1, 1, 1);
// cqlsh:test> SELECT * FROM cf;
//
// pk | ck1 | ck2 | rc
// ----+-----+------+----
// 1 | 1 | null | 1
//
// (1 rows)
// In this case, the clustering key of the row will have length 1, but for serialization purposes we want to treat
// it as a full prefix of length 2.
// So we use ephemerally_full_prefix to distinguish this kind of clustering keys
using ephemerally_full_prefix = seastar::bool_class<struct ephemerally_full_prefix_tag>;
// Writes clustering prefix, full or not, encoded in SSTables 3.0 format
template <typename W>
GCC6_CONCEPT(requires Writer<W>())
void write_clustering_prefix(W& out, const schema& s,
const clustering_key_prefix& prefix, ephemerally_full_prefix is_ephemerally_full);
// Writes encoded information about missing columns in the given row
template <typename W>
GCC6_CONCEPT(requires Writer<W>())
void write_missing_columns(W& out, const indexed_columns& columns, const row& row);
// Helper functions for writing delta-encoded time-related values
template <typename W>
GCC6_CONCEPT(requires Writer<W>())
void write_delta_timestamp(W& out, api::timestamp_type timestamp, const encoding_stats& enc_stats);
template <typename W>
GCC6_CONCEPT(requires Writer<W>())
void write_delta_ttl(W& out, uint32_t ttl, const encoding_stats& enc_stats);
template <typename W>
GCC6_CONCEPT(requires Writer<W>())
void write_delta_local_deletion_time(W& out, uint32_t local_deletion_time, const encoding_stats& enc_stats);
template <typename W>
GCC6_CONCEPT(requires Writer<W>())
void write_delta_deletion_time(W& out, deletion_time dt, const encoding_stats& enc_stats);
}; // namespace sstables