mirror of
https://github.com/matrix-construct/construct
synced 2024-11-30 02:32:43 +01:00
132 lines
4 KiB
C++
132 lines
4 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_DB_ROW_H
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namespace ircd::db
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{
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struct row;
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// [SET] Delete row from DB (convenience to an op::DELETE delta)
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void del(row &, const sopts & = {});
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}
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/// A `row` is a collection of cells from different columns which all share the same
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/// key. This is an interface for dealing with those cells in the aggregate.
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///
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/// Note that in a `row` each `cell` comes from a different `column`, but `cell::key()`
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/// will all return the same index value across the whole `row`. To get the names
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/// of the columns themselves to build ex. the key name of a JSON key-value pair,
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/// use `cell::col()`, which will be different for each `cell` across the `row`.
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///
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/// The db::row::iterator iterates over the cells in a row; to iterate over
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/// multiple rows use the db::cursor
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struct ircd::db::row
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:vector_view<cell>
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{
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struct delta;
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public:
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bool valid() const; // true on any cell valid; false on empty
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bool valid(const string_view &) const; // true on any cell valid equal; false on empty
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// [GET] Find cell by name
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const_iterator find(const string_view &column) const;
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iterator find(const string_view &column);
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// [GET] Get cell (or throw)
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const cell &operator[](const size_t &column) const;
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const cell &operator[](const string_view &column) const;
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cell &operator[](const size_t &column);
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cell &operator[](const string_view &column);
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// [SET] Perform operation
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void operator()(const op &, const string_view &col, const string_view &val = {}, const sopts & = {});
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using vector_view<cell>::vector_view;
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row(database &,
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const string_view &key = {},
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const vector_view<string_view> &columns = {},
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const vector_view<cell> &buf = {},
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gopts opts = {});
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template<class... T>
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row(database &,
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const string_view &key = {},
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const json::tuple<T...> & = {},
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const vector_view<cell> &buf = {},
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gopts opts = {});
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template<class pos> friend size_t seek(row &, const pos &);
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};
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namespace ircd::db
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{
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// [SET] Perform operations in a sequence as a single transaction. No template
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// iterators supported yet, just a ptr range good for contiguous sequences.
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void write(const row::delta *const &begin, const row::delta *const &end, const sopts & = {});
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void write(const std::initializer_list<row::delta> &, const sopts & = {});
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void write(const sopts &, const std::initializer_list<row::delta> &);
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void write(const row::delta &, const sopts & = {});
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}
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//
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// A delta is an element of a database transaction. You can use this to make
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// an all-succeed-or-all-fail commitment to multiple rows at once. It is also
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// useful to make a commitment on a single row as a convenient way to compose
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// all of a row's cells together.
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//
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struct ircd::db::row::delta
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:std::tuple<op, row *>
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{
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enum
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{
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OP, ROW
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};
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delta(row &r, const enum op &op = op::SET)
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:std::tuple<enum op, row *>{op, &r}
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{}
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delta(const enum op &op, row &r)
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:std::tuple<enum op, row *>{op, &r}
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{}
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};
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template<class... T>
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ircd::db::row::row(database &d,
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const string_view &key,
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const json::tuple<T...> &t,
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const vector_view<cell> &buf,
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gopts opts)
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:row{[&d, &key, &t, &buf, &opts]
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() -> row
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{
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std::array<string_view, t.size()> cols;
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json::_key_transform(t, std::begin(cols), std::end(cols));
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return { d, key, cols, buf, opts };
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}()}
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{
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}
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inline ircd::db::cell &
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ircd::db::row::operator[](const size_t &i)
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{
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return vector_view<cell>::at(i);
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}
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inline const ircd::db::cell &
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ircd::db::row::operator[](const size_t &i)
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const
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{
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return vector_view<cell>::at(i);
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}
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