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construct/share/webapp/js/room/timeline.js
2018-09-13 21:17:08 -07:00

427 lines
9.9 KiB
JavaScript

/*
// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 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.
*/
'use strict';
/******************************************************************************
* Timeline
*
* The primary collection of events in a room. The view is watching it directly.
* All known events for a room are stored in order here. This means state events
* accumulate at the front of this array. The index at which this accumulation
* ends is called the horizon. At and after the horizon index, state and non-state
* events are mixed.
*
* Adding events to the timeline must be done through the room.events.insert() iface.
* Insertion is unary function there are no options. The intent of a user to scroll
* backward or forward is deduced by which half of the timeline the insertions are
* occurring so the other side can be trimmed.
*
* The user `class state` is kept in sync with the timeline automatically by making
* queries into it and caching some results as needed for Angular.
*/
room.timeline = class extends Array
{
constructor(...events)
{
super(...events);
this.opts = Object.copy(room.timeline.opts);
this.id = null;
}
static get [Symbol.species]()
{
return Array;
}
get horizon()
{
return room.timeline.horizon.call(this);
}
};
/**
* Default options for events system. The `room.opts` may contain an `events`
* structure which will override these defaults.
*/
room.timeline.opts =
{
// The number of non-state events in the timeline is trimmed to this value
// on the antipode to the last insertion. Increasing this value can make
// scrolling smoother. Decreasing this value can save memory.
limit: mc.opts.timeline_limit,
// Keeps the timeline filled to the limit
autofill: true,
};
/** Last modification timestamp.
*
* Updated to reflect the last modification to the timeline. This can be
* used for cache coherence purposes etc.
*/
room.timeline.prototype.modified = 0;
/**
* @returns an array of indexes to the timeline ordered from youngest
* to oldest which have passed the filter condition. Optionally limited
* by lim.
*/
room.timeline.prototype.query = function(filter = () => true, lim = this.length)
{
let ret = [];
for(let i = this.length - 1; i >= 0 && lim > 0; i--)
{
let event = (this)[i];
if(!filter(event, i))
continue;
ret.push(i);
lim--;
}
return ret;
};
/**
* @returns the most recent event index for the query
*/
room.timeline.prototype.current = function(filter = () => true)
{
return this.query(filter, 1)[0];
};
/**
* @returns the most recent event value for the query
*/
room.timeline.prototype.current_event = function(filter = () => true)
{
return (this)[this.current(filter)];
};
/** Linear search for event in timeline
*/
room.timeline.prototype.get = function(event_id)
{
return (this)[this.pos(event_id)];
};
/** Linear search for event in timeline
*/
room.timeline.prototype.pos = function(event_id)
{
return this.findIndex((event) => event.event_id == event_id);
};
/** Linear search for event in timeline
*/
room.timeline.prototype.has = function(event_id)
{
return this.some((event) => event.event_id == event_id);
};
/**
* Timeline must be sorted so events with the same ID are next to
* each other. This removes duplicate events which are expected
* to have identical content.
*/
room.timeline.prototype.unique = function()
{
let i = 0;
while(i < this.length - 1)
{
let self = (this)[i];
let next = (this)[i+1];
if(self.event_id == next.event_id)
this.splice(i+1, 1);
else
i++;
}
};
/** Alias for forEach()
*/
room.timeline.prototype.each = function(closure)
{
return this.forEach(closure);
};
/** Reduces the iteration seen by the closure based on the condition.
*/
room.timeline.prototype.only = function(condition, closure)
{
return this.filter(condition).forEach(closure);
};
/** Tally events that pass the condition test
*/
room.timeline.prototype.count = function(condition)
{
let mapper = (event) =>
condition(event)? true : false;
let reducer = (acc, val) =>
acc + val;
return this.map(mapper).reduce(reducer, 0);
}
room.timeline.prototype.horizon_event = function()
{
return (this)[this.horizon];
};
/** The length of the timeline after the horizon. This includes
* both state and non-state events.
*/
room.timeline.prototype.window = function()
{
return this.length - this.horizon;
};
/** Extracts a specific value from each event and returns
* an array of only that data.
*/
room.timeline.prototype.child_values = function(key)
{
let mapper = (event) =>
event[key];
let reducer = (acc, val) =>
{
acc.push(val);
return acc;
}
return this.map(mapper).reduce(reducer, []);
}
/** A list of all event types known by the timeline
*/
room.timeline.prototype.types = function()
{
let ret = [];
this.child_values("type").forEach((type) =>
{
if(!ret.includes(type))
ret.push(type);
});
return ret;
}
room.timeline.prototype.servers = function()
{
let ret = [];
this.child_values("sender").forEach((sender) =>
{
let domain = mc.m.domid(sender);
if(!ret.includes(domain))
ret.push(domain);
});
return ret;
}
room.timeline.prototype.filter_by_sender = function(mxid)
{
return this.filtered((event) => event.sender == mxid);
};
room.timeline.prototype.filter_by_server = function(hostname)
{
return this.filtered((event) => mc.m.domid(event.sender) == hostname);
};
room.timeline.prototype.stats = function()
{
return {
total: this.length,
types: this.types().length,
state: this.count(mc.event.is_state),
servers: this.servers().length,
horizon: this.horizon,
};
};
room.timeline.prototype.pending = {};
/**
* The legitimate way to create a new event
*/
room.timeline.prototype.issue = function(event, opts = {})
{
this.pending[event.type] = event;
mc.m.rooms.state.put(this.id, event.type, event.state_key, event.content, opts, (error, data) =>
{
if(error)
{
delete this.pending[event.type];
throw new mc.error(error);
}
this.pending[event.type].event_id = data.event_id;
this.pending[event.type].sender = mc.session.user_id;
this.insert(this.pending[event.type]);
delete this.pending[event.type];
});
};
/**
* The legitimate way for the room to process an event
*/
room.timeline.prototype.insert = function(event)
{
if(typeof(event) != "object")
return false;
if(Array.isArray(event))
return this.insert.array.call(this, event);
else
return this.insert.array.call(this, [event]);
};
room.timeline.prototype.insert.array = function(events)
{
if(empty(events))
return;
events = events.map((event) =>
{
if(!(event instanceof mc.event))
return new mc.event(event);
else
return event;
});
events.forEach(this.fix.bind(this));
events.sort(mc.event.cmp);
this.push(...events);
this.sort(mc.event.cmp);
this.unique();
let last_a = events.back().event_id;
let last_b = this.back().event_id;
let dir = last_a != last_b? 'b' : 'f';
this.trim(dir);
this.modified = mc.now();
};
/**
* Maintains the size of the timeline relative to the closest side
* of the last insertion index.
*/
room.timeline.prototype.trim = function(dir = 'f')
{
let window = this.window();
if(window < this.opts.limit)
return;
if(dir == 'b')
this.trim.newest.call(this);
else
this.trim.oldest.call(this);
};
/**
* Maintains the size of the timeline by removing the latest events.
* This is intended for going back in time, i.e scrolling up.
*
* We treat with both state and non-state events the same for this end
* by simply slicing them all off (the future is opaque).
*/
room.timeline.prototype.trim.newest = function()
{
if(!this.opts.limit)
return false;
let length = this.count(mc.event.is_not_state);
let start = this.opts.limit - length;
if(start >= 0)
return false;
this.splice(start);
return true;
};
/**
* Maintains the size of the timeline by removing the oldest events
* This is intended for going forward in time, i.e scrolling down.
*
* We have to deal with state and non-state events differently here.
* Non-state events can fall off the front below the horizon, but state
* events have to accumulate at the horizon. When a state event hits the
* horizon, some older state event it replaces is also dropped.
*/
room.timeline.prototype.trim.oldest = function()
{
let window = () => this.count(mc.event.is_not_state);
while(window() > this.opts.limit)
{
let horizon = this.horizon;
let event = (this)[horizon];
if(mc.event.is_not_state(event))
{
// Trivial removal of oldest non-state event
this.splice(horizon, 1);
continue;
}
// Accumulate state events at the front of the timeline. Attempt
// to remove the event which is outdated by this event.
for(let i = 0; i < horizon; i++)
{
let other = (this)[i];
if(other.type != event.type)
continue;
if(other.state_key != event.state_key)
continue;
this.splice(i, 1);
break;
}
}
};
room.timeline.prototype.fix = function(event)
{
if(event.room_id === undefined)
event.room_id = this.id;
if(!event.origin_server_ts)
event.origin_server_ts = mc.now();
};
/** The index of the horizon. Before this index, all events are state
* events. For this index and after, state and non-state events are mixed.
*
* this = timeline
*/
room.timeline.horizon = function()
{
if(this._horizon_cache_ts < this.modified)
{
this._horizon_cache = this.findIndex(mc.event.is_not_state);
this._horizon_cache_ts = this.modified;
}
return this._horizon_cache;
};
/** Instance variable for horizon caching. When this doesn't match
* the timeline.modified then the horizon has to be recalculated
*/
room.timeline.prototype._horizon_cache_ts = -1;
room.timeline.prototype._horizon_cache = 0;