Initial commit

cron.js

@@ -0,0 +1,174 @@
+/**
+ * cron.js
+ * ---
+ * VERSION 0.1
+ * ---
+ * DON'T USE THIS -- IT'S NOT QUITE THERE YET!
+ * ---
+ * @author James Padolsey
+ * ---
+ * Dual licensed under the MIT and GPL licenses.
+ *    - http://www.opensource.org/licenses/mit-license.php
+ *    - http://www.gnu.org/copyleft/gpl.html
+ */
+
+var CronJob = (function(){
+
+    var undefined;
+
+    function CronTime(time) {
+
+        this.source = time;
+
+        this.map = ['second', 'minute', 'hour', 'dayOfMonth', 'month', 'dayOfWeek'];
+        this.constraints = [[0,59],[0,59],[0,23],[1,31],[0,11],[1,7]];
+        this.aliases = {
+            jan:1,feb:2,mar:3,apr:4,may:5,jun:6,jul:7,aug:8,sep:9,oct:10,nov:11,dec:12,
+            sun:0,mon:1,tue:2,wed:3,thu:4,fri:5,sat:6
+        };
+
+        this.second = {};
+        this.minute = {};
+        this.hour = {};
+        this.dayOfMonth = {};
+        this.month = {};
+        this.dayOfWeek = {};
+
+        this._parse();
+
+    };
+
+    CronTime.prototype = {
+        _parse: function() {
+
+            var aliases = this.aliases,
+                source = this.source.replace(/[a-z]/i, function(alias){
+
+                    alias = alias.toLowerCase();
+
+                    if (alias in aliases) {
+                        return aliases[alias];
+                    }
+
+                    throw new Error('Unknown alias: ' + alias);
+
+                }),
+                split = this.source.replace(/^\s\s*|\s\s*$/g, '').split(/\s+/),
+                cur, len = 6;
+
+            while (len--) {
+                cur = split[len] || '*';
+                this._parseField(cur, this.map[len], this.constraints[len]);
+            }
+
+        },
+        _parseField: function(field, type, constraints) {
+
+            var rangePattern = /(\d+?)(?:-(\d+?))?(?:\/(\d+?))?(?:,|$)/g,
+                typeObj = this[type],
+                diff,
+                low = constraints[0],
+                high = constraints[1];
+
+            // * is a shortcut to [lower-upper] range
+            field = field.replace(/\*/g,  low + '-' + high);
+
+            if (field.match(rangePattern)) {
+
+                field.replace(rangePattern, function($0, lower, upper, step) {
+
+                    step = step || 1;
+
+                    // Positive integer higher than constraints[0]
+                    lower = Math.max(low, ~~Math.abs(lower));
+
+                    // Positive integer lower than constraints[1]
+                    upper = upper ? Math.min(high, ~~Math.abs(upper)) : lower;
+
+                    diff = step + upper - lower;
+
+                    while ((diff-=step) > -1) {
+                        typeObj[diff + lower] = true;
+                    }
+
+                });
+
+            } else {
+
+                throw new Error('Field (' + field + ') cannot be parsed');
+
+            }
+
+        }
+    };
+
+    function CronJob(cronTime, event) {
+
+        if (!(this instanceof CronJob)) {
+            return new CronJob(cronTime, event);
+        }
+
+        this.events = [event];
+        this.cronTime = new CronTime(cronTime);
+        this.now = {};
+        this.initiated = false;
+
+        this.clock();
+
+    }
+
+    CronJob.prototype = {
+
+        addEvent: function(event) {
+            this.events.push(event);
+        },
+
+        runEvents: function() {
+            for (var i = -1, l = this.events.length; ++i < l; ) {
+                if (typeof this.events[i] === 'function') {
+                    this.events[i]();
+                }
+            }
+        },
+
+        clock: function() {
+
+            var date = new Date,
+                now = this.now,
+                self = this,
+                cronTime = this.cronTime,
+                i;
+
+            if (!this.initiated) {
+                // Make sure we start the clock precisely ON the 0th millisecond
+                setTimeout(function(){
+                    self.initiated = true;
+                    self.clock();
+                }, Math.ceil(+date / 1000) * 1000 - +date);
+                return;
+            }
+
+            this.timer = this.timer || setInterval(function(){self.clock();}, 1000);
+
+            now.second = date.getSeconds();
+            now.minute = date.getMinutes();
+            now.hour = date.getHours();
+            now.dayOfMonth = date.getDate();
+            now.month = date.getMonth() + 1;
+            now.dayOfWeek = date.getDay();
+
+            for (i in now) {
+                if (!(now[i] in cronTime[i])) {
+                    return;
+                }
+            }
+
+            this.runEvents();
+
+        }
+
+    };
+
+    return CronJob;
+
+})();