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toolkit/components/telemetry/TelemetryStopwatch.jsm@925c144e1f1f (annotated)

toolkit/components/telemetry/TelemetryStopwatch.jsm

Fri, 16 Jan 2015 18:13:44 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Fri, 16 Jan 2015 18:13:44 +0100

branch

TOR_BUG_9701

changeset 14

925c144e1f1f

permissions

-rw-r--r--

Integrate suggestion from review to improve consistency with existing code.

michael@0	1	/* This Source Code Form is subject to the terms of the Mozilla Public
michael@0	2	* License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0	3	* You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0	4
michael@0	5	const Cc = Components.classes;
michael@0	6	const Ci = Components.interfaces;
michael@0	7	const Cu = Components.utils;
michael@0	8
michael@0	9	this.EXPORTED_SYMBOLS = ["TelemetryStopwatch"];
michael@0	10
michael@0	11	let Telemetry = Cc["@mozilla.org/base/telemetry;1"]
michael@0	12	.getService(Ci.nsITelemetry);
michael@0	13
michael@0	14	// simpleTimers are directly associated with a histogram
michael@0	15	// name. objectTimers are associated with an object _and_
michael@0	16	// a histogram name.
michael@0	17	let simpleTimers = {};
michael@0	18	let objectTimers = new WeakMap();
michael@0	19
michael@0	20	this.TelemetryStopwatch = {
michael@0	21	/**
michael@0	22	* Starts a timer associated with a telemetry histogram. The timer can be
michael@0	23	* directly associated with a histogram, or with a pair of a histogram and
michael@0	24	* an object.
michael@0	25	*
michael@0	26	* @param aHistogram a string which must be a valid histogram name
michael@0	27	* from TelemetryHistograms.h
michael@0	28	*
michael@0	29	* @param aObj Optional parameter. If specified, the timer is associated
michael@0	30	* with this object, meaning that multiple timers for a same
michael@0	31	* histogram may be run concurrently, as long as they are
michael@0	32	* associated with different objects.
michael@0	33	*
michael@0	34	* @return true if the timer was successfully started, false otherwise. If a
michael@0	35	* timer already exists, it can't be started again, and the existing
michael@0	36	* one will be cleared in order to avoid measurements errors.
michael@0	37	*/
michael@0	38	start: function(aHistogram, aObj) {
michael@0	39	if (!validTypes(aHistogram, aObj))
michael@0	40	return false;
michael@0	41
michael@0	42	let timers;
michael@0	43	if (aObj) {
michael@0	44	timers = objectTimers.get(aObj, {});
michael@0	45	objectTimers.set(aObj, timers);
michael@0	46	} else {
michael@0	47	timers = simpleTimers;
michael@0	48	}
michael@0	49
michael@0	50	if (timers.hasOwnProperty(aHistogram)) {
michael@0	51	delete timers[aHistogram];
michael@0	52	Cu.reportError("TelemetryStopwatch: key \"" +
michael@0	53	aHistogram + "\" was already initialized");
michael@0	54	return false;
michael@0	55	}
michael@0	56
michael@0	57	timers[aHistogram] = Date.now();
michael@0	58	return true;
michael@0	59	},
michael@0	60
michael@0	61	/**
michael@0	62	* Deletes the timer associated with a telemetry histogram. The timer can be
michael@0	63	* directly associated with a histogram, or with a pair of a histogram and
michael@0	64	* an object. Important: Only use this method when a legitimate cancellation
michael@0	65	* should be done.
michael@0	66	*
michael@0	67	* @param aHistogram a string which must be a valid histogram name
michael@0	68	* from TelemetryHistograms.json
michael@0	69	*
michael@0	70	* @param aObj Optional parameter. If specified, the timer is associated
michael@0	71	* with this object, meaning that multiple timers for a same
michael@0	72	* histogram may be run concurrently, as long as they are
michael@0	73	* associated with different objects.
michael@0	74	*
michael@0	75	* @return true if the timer exist and it was cleared, false otherwise.
michael@0	76	*/
michael@0	77	cancel: function ts_cancel(aHistogram, aObj) {
michael@0	78	if (!validTypes(aHistogram, aObj))
michael@0	79	return false;
michael@0	80
michael@0	81	let timers = aObj
michael@0	82	? objectTimers.get(aObj, {})
michael@0	83	: simpleTimers;
michael@0	84
michael@0	85	if (timers.hasOwnProperty(aHistogram)) {
michael@0	86	delete timers[aHistogram];
michael@0	87	return true;
michael@0	88	}
michael@0	89
michael@0	90	return false;
michael@0	91	},
michael@0	92
michael@0	93	/**
michael@0	94	* Stops the timer associated with the given histogram (and object),
michael@0	95	* calculates the time delta between start and finish, and adds the value
michael@0	96	* to the histogram.
michael@0	97	*
michael@0	98	* @param aHistogram a string which must be a valid histogram name
michael@0	99	* from TelemetryHistograms.h. If an invalid name
michael@0	100	* is given, the function will throw.
michael@0	101	*
michael@0	102	* @param aObj Optional parameter which associates the histogram timer with
michael@0	103	* the given object.
michael@0	104	*
michael@0	105	* @return true if the timer was succesfully stopped and the data was
michael@0	106	* added to the histogram, false otherwise.
michael@0	107	*/
michael@0	108	finish: function(aHistogram, aObj) {
michael@0	109	if (!validTypes(aHistogram, aObj))
michael@0	110	return false;
michael@0	111
michael@0	112	let timers = aObj
michael@0	113	? objectTimers.get(aObj, {})
michael@0	114	: simpleTimers;
michael@0	115
michael@0	116	let start = timers[aHistogram];
michael@0	117	delete timers[aHistogram];
michael@0	118
michael@0	119	if (start) {
michael@0	120	let delta = Date.now() - start;
michael@0	121	let histogram = Telemetry.getHistogramById(aHistogram);
michael@0	122	histogram.add(delta);
michael@0	123	return true;
michael@0	124	}
michael@0	125
michael@0	126	return false;
michael@0	127	}
michael@0	128	}
michael@0	129
michael@0	130	function validTypes(aKey, aObj) {
michael@0	131	return (typeof aKey == "string") &&
michael@0	132	(aObj === undefined || typeof aObj == "object");
michael@0	133	}