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construct/modules/static/js/task.js
2018-02-05 21:24:34 -08:00

109 lines
2.1 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';
/**************************************
*
*/
mc.task = class
{
constructor(generator, opts = {})
{
Object.defaults(opts,
{
interval: 0, // The attempt cadence.
skips: false, // skips cycles when there is no idle time
fills: true, // invokes generator until idle slice has diminished.
});
this.opts = opts;
this.generator = generator;
this.rid = null; // request id
this.cycle = 0; // number of task handler invocations
this.skips = 0; // number of skipped cycles due to no idle time
this.generation = 0; // number of generator next invocations
// Note the initial execution of the generator
// does NOT take place on an idle slice.
this.generated = generator();
this.generation++;
// Init task cycle
this.request();
}
request()
{
if(this.requested())
this.cancel();
let handler = (deadline) =>
{
this.rid = null;
this.handler(deadline);
this.cycle++;
};
let opts =
{
timeout: this.opts.interval,
};
this.rid = window.requestIdleCallback(handler, opts);
}
handler(deadline)
{
let remain = () => deadline.timeRemaining();
let timeout = deadline.didTimeout;
if(timeout && this.opts.skips)
{
this.skips++;
this.request();
return;
}
if(this.generate(remain))
this.request();
}
generate(remain)
{
let result; do
{
result = this.generated.next();
this.generation++;
}
while(!result.done && remain() > 0)
return result.done;
}
cancel()
{
if(!this.requested())
return false;
window.cancelIdleCallback(this.rid);
this.rid = null;
return true;
}
requested()
{
return this.rid !== undefined && this.rid !== null;
}
};