66 lines
2.5 KiB
C++
66 lines
2.5 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) 2016-2023 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_M_ROOM_SOUNDING_H
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// The "viewport" is comprised of events starting from the tophead (most recent
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// in room timeline) and covering about ~20 events leading up to that. Note
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// that this is a completely ad hoc and configurable server value. Events in
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// the viewport must be eval'ed and synced to clients in the order they will
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// be displayed. Events not in the viewport are not /synced to clients and any
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// client request provides event ordering: thus older events (backfills, etc)
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// can be eval'ed without this constraint.
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//
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// The "sounding" is the depth of the first gap. In any attempt to trace
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// the room timeline from the tophead to the m.room.create event: the sounding
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// is the [highest number] depth preventing that.
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//
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// The "twain" marks the depth at the end of the first gap; the server is in
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// possession of one or more events again at the twain.
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//
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// The "hazard" is the depth of the first gap starting from the m.room.create
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// event toward the tophead. In any attempt to trace the room timeline with
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// an increasing depth, the hazard is the next gap to frontfill.
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namespace ircd::m
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{
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std::pair<int64_t, event::idx> viewport(const room &);
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std::pair<int64_t, event::idx> sounding(const room &); // Last missing (one)
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std::pair<int64_t, event::idx> twain(const room &);
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std::pair<int64_t, event::idx> hazard(const room &); // First missing (one)
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}
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/// Find gaps in the room's events. A gap is where this server has no events
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/// at a certain depth. This is a path-finding diagnostic interface, useful to
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/// understand what areas of the timeline have not been acquired by the server
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/// to calculate backfill requests, etc. This interface is depth-first oriented,
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/// rather than the breadth-first room::missing interface.
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///
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struct ircd::m::room::sounding
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{
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using range = std::pair<int64_t, int64_t>;
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using closure = util::function_bool
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<
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const range &, const event::idx &
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>;
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m::room room;
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public:
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bool for_each(const closure &) const;
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bool rfor_each(const closure &) const;
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sounding() = default;
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sounding(const m::room &room)
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:room{room}
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{}
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};
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