PromiseMonitor.js

/** @license MIT License (c) copyright 2010-2014 original author or authors */
/** @author Brian Cavalier */
/** @author John Hann */

(function(define) { 'use strict';
define(function(require) {

	var defaultStackJumpSeparator = 'from execution context:';
	var defaultStackFilter = /(node|module|timers)\.js:|when([\/\\]{1,2}(lib|monitor|es6-shim)[\/\\]{1,2}|\.js)|(new\sPromise)\b|(\b(PromiseMonitor|ConsoleReporter|Scheduler|RunHandlerTask|ProgressTask|Promise|.*Handler)\.[\w_]\w\w+\b)|\b(tryCatch\w+|getHandler\w*)\b/i;

	var setTimer = require('../lib/timer').set;
	var error = require('./error');

	function PromiseMonitor(reporter) {
		this._traces = {};
		this.traceTask = 0;
		this.logDelay = 100;
		this.stackFilter = defaultStackFilter;
		this.stackJumpSeparator = defaultStackJumpSeparator;
		this.filterDuplicateFrames = true;

		this._reporter = reporter;

		if(typeof reporter.configurePromiseMonitor === 'function') {
			reporter.configurePromiseMonitor(this);
		}

		var self = this;
		this._doLogTraces = function() {
			self._logTraces();
		};
	}

	PromiseMonitor.prototype.captureStack = function(host, at) {
		return error.captureStack(host, at);
	};

	PromiseMonitor.prototype.addTrace = function(handler, extraContext) {
		this._traces[handler.id] = {
			error: handler.value,
			context: handler.context,
			extraContext: extraContext
		};
		this.logTraces();
	};

	PromiseMonitor.prototype.removeTrace = function(handler) {
		if(handler.id in this._traces) {
			delete this._traces[handler.id];
			this.logTraces();
		}
	};

	PromiseMonitor.prototype.fatal = function(handler) {
		var err = new Error();
		err.stack = this._createLongTrace(handler.value, handler.context).join('\n');
		setTimer(function() {
			throw err;
		}, 0);
	};

	PromiseMonitor.prototype.logTraces = function() {
		if(!this.traceTask) {
			this.traceTask = setTimer(this._doLogTraces, this.logDelay);
		}
	};

	PromiseMonitor.prototype._logTraces = function() {
		this.traceTask = void 0;
		this._reporter.log(this.formatTraces(this._traces));
	};


	PromiseMonitor.prototype.formatTraces = function(traces) {
		var keys = Object.keys(traces);
		var formatted = [];
		var longTrace, t, i;

		for(i=0; i<keys.length; ++i) {
			t = traces[keys[i]];
			longTrace = this._createLongTrace(t.error, t.context, t.extraContext);
			formatted.push(longTrace);
		}

		return formatted;
	};

	PromiseMonitor.prototype._createLongTrace = function(e, context, extraContext) {
		var trace = error.parse(e) || [];
		trace = filterFrames(this.stackFilter, trace, 0);
		this._appendContext(trace, context);
		this._appendContext(trace, extraContext);
		return this.filterDuplicateFrames ? this._removeDuplicates(trace) : trace;
	};

	PromiseMonitor.prototype._removeDuplicates = function(trace) {
		var seen = {};
		var sep = this.stackJumpSeparator;
		var count = 0;
		return trace.reduceRight(function(deduped, line, i) {
			if(i === 0) {
				deduped.unshift(line);
			} else if(line === sep) {
				if(count > 0) {
					deduped.unshift(line);
					count = 0;
				}
			} else if(!seen[line]) {
				seen[line] = true;
				deduped.unshift(line);
				++count;
			}
			return deduped;
		}, []);
	};

	PromiseMonitor.prototype._appendContext = function(trace, context) {
		trace.push.apply(trace, this._createTrace(context));
	};

	PromiseMonitor.prototype._createTrace = function(traceChain) {
		var trace = [];
		var stack;

		while(traceChain) {
			stack = error.parse(traceChain);

			if (stack) {
				stack = filterFrames(this.stackFilter, stack);
				appendStack(trace, stack, this.stackJumpSeparator);
			}

			traceChain = traceChain.parent;
		}

		return trace;
	};

	function appendStack(trace, stack, separator) {
		if (stack.length > 1) {
			stack[0] = separator;
			trace.push.apply(trace, stack);
		}
	}

	function filterFrames(stackFilter, stack) {
		return stack.filter(function(frame) {
			return !stackFilter.test(frame);
		});
	}

	return PromiseMonitor;
});
}(typeof define === 'function' && define.amd ? define : function(factory) { module.exports = factory(require); }));