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https://github.com/matrix-construct/construct
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ircd::db: Add preliminary cursor and where clause query.
This commit is contained in:
Jason Volk
parent
80f1d30505
commit
a89a8dfa5f
4 changed files with 372 additions and 0 deletions
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@ -120,6 +120,8 @@ enum class ircd::db::pos
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#include "db/index.h"
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#include "db/value.h"
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#include "db/tuple.h"
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#include "db/where.h"
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#include "db/cursor.h"
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namespace ircd::db
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{
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235
include/ircd/db/cursor.h
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235
include/ircd/db/cursor.h
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@ -0,0 +1,235 @@
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/*
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* Copyright (C) 2016 Charybdis Development Team
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* Copyright (C) 2016 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.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#pragma once
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#define HAVE_IRCD_DB_CURSOR_H
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namespace ircd::db
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{
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template<database *const &d, class tuple> struct cursor;
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}
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template<ircd::db::database *const &d,
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class tuple>
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struct ircd::db::cursor
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{
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struct const_iterator;
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using where_type = db::where<tuple>;
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using iterator_type = const_iterator;
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using const_iterator_type = const_iterator;
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using index_iterator = ircd::db::index::const_iterator;
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struct index index;
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const where_type *where;
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const_iterator end();
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const_iterator begin();
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const_iterator find(const string_view &key);
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cursor(const string_view &index)
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:index{*d, index}
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,where{nullptr}
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{}
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};
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template<ircd::db::database *const &d,
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class tuple>
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struct ircd::db::cursor<d, tuple>::const_iterator
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{
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using value_type = const tuple;
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using pointer = value_type *;
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using reference = value_type &;
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using difference_type = size_t;
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using iterator_category = std::bidirectional_iterator_tag;
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using index_iterator = ircd::db::index::const_iterator;
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using where_type = cursor::where_type;
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const where_type *where{nullptr};
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index_iterator idx;
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db::row row;
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mutable tuple v;
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mutable bool stale{true};
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bool invalid{false};
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bool operator!() const { return invalid || !row.valid(); }
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operator bool() const { return !operator!(); }
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bool operator==(const const_iterator &o) const;
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bool operator!=(const const_iterator &o) const;
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value_type &operator*() const;
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value_type *operator->() const;
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private:
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bool seek(const pos &p);
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public:
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const_iterator &operator++();
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const_iterator &operator--();
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const_iterator();
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const_iterator(const cursor &, index_iterator, const gopts & = {});
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};
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//
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// cursor
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//
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template<ircd::db::database *const &d,
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class tuple>
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typename ircd::db::cursor<d, tuple>::const_iterator
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ircd::db::cursor<d, tuple>::find(const string_view &key)
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{
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return const_iterator { *this, index.find(key), {} };
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}
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template<ircd::db::database *const &d,
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class tuple>
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typename ircd::db::cursor<d, tuple>::const_iterator
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ircd::db::cursor<d, tuple>::begin()
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{
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return const_iterator { *this, index.begin(), {} };
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}
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template<ircd::db::database *const &d,
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class tuple>
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typename ircd::db::cursor<d, tuple>::const_iterator
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ircd::db::cursor<d, tuple>::end()
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{
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return {};
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}
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//
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// const iterator
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//
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template<ircd::db::database *const &d,
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class tuple>
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ircd::db::cursor<d, tuple>::const_iterator::const_iterator()
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:invalid{true}
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{
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}
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template<ircd::db::database *const &d,
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class tuple>
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ircd::db::cursor<d, tuple>::const_iterator::const_iterator(const cursor &c,
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index_iterator idx,
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const gopts &opts)
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:where{c.where}
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,idx{std::move(idx)}
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,row
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{
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*d, bool(this->idx)? this->idx->first : string_view{}, tuple{}, opts
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}
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,invalid
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{
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!this->idx || !row.valid()
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}
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{
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if(!invalid && this->where && !(*this->where)(this->operator*()))
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seek(pos::NEXT);
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}
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template<ircd::db::database *const &d,
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class tuple>
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typename ircd::db::cursor<d, tuple>::const_iterator &
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ircd::db::cursor<d, tuple>::const_iterator::operator++()
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{
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seek(pos::NEXT);
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return *this;
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}
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template<ircd::db::database *const &d,
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class tuple>
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typename ircd::db::cursor<d, tuple>::const_iterator &
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ircd::db::cursor<d, tuple>::const_iterator::operator--()
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{
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seek(pos::PREV);
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return *this;
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}
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template<ircd::db::database *const &d,
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class tuple>
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bool
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ircd::db::cursor<d, tuple>::const_iterator::seek(const pos &p)
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{
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while(!(invalid = !db::seek(idx, p)))
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{
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if(db::seek(row, idx->first))
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{
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stale = true;
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if(!this->where || (*this->where)(this->operator*()))
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return true;
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}
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}
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return false;
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}
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template<ircd::db::database *const &d,
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class tuple>
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const typename ircd::db::cursor<d, tuple>::const_iterator::value_type *
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ircd::db::cursor<d, tuple>::const_iterator::operator->()
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const
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{
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return &operator*();
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}
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template<ircd::db::database *const &d,
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class tuple>
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const typename ircd::db::cursor<d, tuple>::const_iterator::value_type &
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ircd::db::cursor<d, tuple>::const_iterator::operator*()
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const
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{
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if(stale)
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{
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set(v, row);
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stale = false;
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}
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return v;
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}
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template<ircd::db::database *const &d,
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class tuple>
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bool
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ircd::db::cursor<d, tuple>::const_iterator::operator!=(const const_iterator &o)
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const
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{
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return !(*this == o);
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}
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template<ircd::db::database *const &d,
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class tuple>
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bool
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ircd::db::cursor<d, tuple>::const_iterator::operator==(const const_iterator &o)
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const
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{
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if(!row.valid() && !o.row.valid())
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return true;
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if(!row.valid() || !o.row.valid())
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return false;
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return row.its.at(0).key() == o.row.its.at(0).key();
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}
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130
include/ircd/db/where.h
Normal file
130
include/ircd/db/where.h
Normal file
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@ -0,0 +1,130 @@
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/*
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* Copyright (C) 2016 Charybdis Development Team
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* Copyright (C) 2016 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.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#pragma once
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#define HAVE_IRCD_DB_WHERE_H
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namespace ircd::db
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{
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template<class tuple> struct where;
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}
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template<class tuple>
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struct ircd::db::where
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{
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struct noop;
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struct equal;
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struct not_equal;
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virtual bool operator()(const tuple &) const = 0;
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virtual ~where() noexcept = default;
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};
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template<class tuple>
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struct ircd::db::where<tuple>::noop
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:ircd::db::where<tuple>
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{
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bool operator()(const tuple &) const override
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{
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return true;
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}
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};
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template<class tuple>
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struct ircd::db::where<tuple>::equal
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:ircd::db::where<tuple>
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{
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tuple value;
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bool operator()(const tuple &) const override;
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equal(const tuple &value)
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:value{value}
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{}
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equal(std::initializer_list<json::index::member> members)
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:value{std::move(members)}
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{}
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};
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template<class tuple>
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bool
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ircd::db::where<tuple>::equal::operator()(const tuple &t)
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const
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{
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return json::until(this->value, [&t]
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(const auto &key, auto&& where_value)
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{
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if(!where_value)
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return true;
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bool equal(true);
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at(t, key, [&where_value, &equal]
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(auto&& value)
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{
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//equal = value == where_value;
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equal = (byte_view<>(value) == byte_view<>(where_value));
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});
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return equal;
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});
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}
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template<class tuple>
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struct ircd::db::where<tuple>::not_equal
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:ircd::db::where<tuple>
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{
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tuple value;
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bool operator()(const tuple &) const override;
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not_equal(const tuple &value)
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:value{value}
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{}
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not_equal(std::initializer_list<json::index::member> members)
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:value{std::move(members)}
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{}
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};
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template<class tuple>
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bool
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ircd::db::where<tuple>::not_equal::operator()(const tuple &t)
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const
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{
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return json::until(this->value, [&t]
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(const auto &key, auto&& where_value)
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{
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if(!where_value)
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return true;
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bool not_equal(true);
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at(t, key, [&where_value, ¬_equal]
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(auto&& value)
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{
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//equal = value == where_value;
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not_equal = (byte_view<>(value) != byte_view<>(where_value));
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});
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return not_equal;
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});
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}
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@ -1291,6 +1291,11 @@ const
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return &this->operator*();
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}
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///////////////////////////////////////////////////////////////////////////////
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//
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// db/cursor.h
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//
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///////////////////////////////////////////////////////////////////////////////
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//
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// db/cell.h
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