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construct/include/ircd/m/room/events.h

96 lines
3.5 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2019 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. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_M_ROOM_EVENTS_H
/// Interface to room events
///
/// This interface has the form of an STL-style iterator over room events
/// which are state and non-state events from all integrated timelines.
/// Moving the iterator is cheap, but the dereference operators fetch a
/// full event. One can iterate just event_idx's by using event_idx() instead
/// of the dereference operators.
///
struct ircd::m::room::events
{
struct sounding;
struct missing;
struct horizon;
static conf::item<ssize_t> viewport_size;
m::room room;
db::domain::const_iterator it;
event::fetch _event;
public:
explicit operator bool() const { return bool(it); }
bool operator!() const { return !it; }
// Observers from the current valid iterator
uint64_t depth() const;
event::idx event_idx() const;
explicit operator event::idx() const;
// Perform a new lookup / iterator
bool seek_idx(const event::idx &, const bool &lower_bound = false);
bool seek(const uint64_t &depth = -1);
bool seek(const event::id &);
// Prefetch a new iterator lookup (async)
bool preseek(const uint64_t &depth = -1);
// Move the iterator
auto &operator++() { return --it; }
auto &operator--() { return ++it; }
// Fetch the actual event data at the iterator's position
const m::event &fetch(std::nothrow_t, bool *valid = nullptr);
const m::event &fetch();
const m::event &operator*() { return fetch(std::nothrow); }
const m::event *operator->() { return &operator*(); }
// Prefetch the actual event data at the iterator's position (async)
bool prefetch(const string_view &event_prop);
bool prefetch(); // uses supplied fetch::opts.
// Seeks to closest event in the room by depth; room.event_id ignored.
events(const m::room &,
const uint64_t &depth,
const event::fetch::opts *const & = nullptr);
// Seeks to event_id; null iteration when not found; seekless when empty.
events(const m::room &,
const event::id &,
const event::fetch::opts *const & = nullptr);
// Seeks to latest event in the room unless room.event_id given. Null
// iteration when given and not found.
events(const m::room &,
const event::fetch::opts *const & = nullptr);
events() = default;
events(const events &) = delete;
events &operator=(const events &) = delete;
// Prefetch a new iterator (without any construction)
static bool preseek(const m::room &, const uint64_t &depth = -1);
// Prefetch the actual room event data for a range; or most recent.
using depth_range = std::pair<uint64_t, uint64_t>;
static size_t prefetch(const m::room &, const depth_range &);
static size_t prefetch_viewport(const m::room &);
// Note the range here is unusual: The start index is exclusive, the ending
// index is inclusive. The start index must be valid and in the room.
static size_t count(const m::room &, const event::idx_range &);
static size_t count(const event::idx_range &);
};