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construct/include/ircd/db/cell.h
2017-04-04 16:10:29 -07:00

126 lines
4.4 KiB
C++

/*
* Copyright (C) 2016 Charybdis Development Team
* Copyright (C) 2016 Jason Volk <jason@zemos.net>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice is present in all copies.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
#pragma once
#define HAVE_IRCD_DB_CELL_H
namespace ircd {
namespace db {
struct cell
{
struct delta;
column c;
string_view index;
database::snapshot ss;
std::unique_ptr<rocksdb::Iterator> it;
public:
operator const rocksdb::Iterator &() const { return *it; }
operator const database::snapshot &() const { return ss; }
explicit operator const column &() const { return c; }
operator rocksdb::Iterator &() { return *it; }
operator database::snapshot &() { return ss; }
explicit operator column &() { return c; }
bool valid() const; // cell exists
operator bool() const { return valid(); }
bool operator!() const { return !valid(); }
// [GET] read from cell (zero-copy)
string_view col() const { return name(c); /* always column name */ }
string_view key() const; // key == index or empty on invalid
string_view val() const; // empty on !valid()
string_view key(); // reload then key == index or empty on invalid
string_view val(); // reload then empty on !valid()
// [GET] read from cell (zero-copy)
explicit operator string_view() const; // empty on !valid()
explicit operator string_view(); // reload then empty on !valid()
// [SET] assign cell
cell &operator=(const string_view &);
// [GET] -> [SET] assign cell (atomic)
bool compare_exchange(string_view &expected, const string_view &desired);
string_view exchange(const string_view &desired);
bool load(gopts = {});
cell(column, const string_view &index, std::unique_ptr<rocksdb::Iterator>);
cell(column, const string_view &index, gopts = {});
cell(database &, const string_view &column, const string_view &index, gopts = {});
cell();
cell(cell &&) noexcept;
cell(const cell &) = delete;
cell &operator=(cell &&) noexcept;
cell &operator=(const cell &) = delete;
~cell() noexcept;
friend std::ostream &operator<<(std::ostream &s, const cell &c);
};
struct cell::delta
:std::tuple<op, cell &, string_view>
{
delta(const enum op &op, cell &c, const string_view &val = {})
:std::tuple<enum op, cell &, string_view>{op, c, val}
{}
delta(cell &c, const string_view &val, const enum op &op = op::SET)
:std::tuple<enum op, cell &, string_view>{op, c, val}
{}
};
// [SET] Perform operations in a sequence as a single transaction.
void write(const cell::delta &, const sopts & = {});
void write(const std::initializer_list<cell::delta> &, const sopts & = {});
void write(const sopts &, const std::initializer_list<cell::delta> &);
const std::string &name(const cell &);
uint64_t sequence(const cell &);
} // namespace db
} // namespace ircd
inline
uint64_t
ircd::db::sequence(const cell &c)
{
const database::snapshot &ss(c);
return sequence(ss);
}
inline
const std::string &
ircd::db::name(const cell &c)
{
return name(c.c);
}
inline std::ostream &
ircd::db::operator<<(std::ostream &s, const cell &c)
{
s << string_view{c};
return s;
}