// © 2010 EPFL/LAMP
// code by Gilles Dubochet
function Scheduler() {
var scheduler = this;
var resolution = 0;
this.timeout = undefined;
this.queues = new Array(0); // an array of work pacakges indexed by index in the labels table.
this.labels = new Array(0); // an indexed array of labels indexed by priority. This should be short.
this.label = function(name, priority) {
this.name = name;
this.priority = priority;
}
this.work = function(fn, self, args) {
this.fn = fn;
this.self = self;
this.args = args;
}
this.addLabel = function(name, priority) {
var idx = 0;
while (idx < scheduler.queues.length && scheduler.labels[idx].priority <= priority) { idx = idx + 1; }
scheduler.labels.splice(idx, 0, new scheduler.label(name, priority));
scheduler.queues.splice(idx, 0, new Array(0));
}
this.clearLabel = function(name) {
var idx = 0;
while (idx < scheduler.queues.length && scheduler.labels[idx].name != name) { idx = idx + 1; }
if (idx < scheduler.queues.length && scheduler.labels[i].name == name) {
scheduler.labels.splice(idx, 1);
scheduler.queues.splice(idx, 1);
}
}
this.nextWork = function() {
var fn = undefined;
var idx = 0;
while (idx < scheduler.queues.length && scheduler.queues[idx].length == 0) { idx = idx + 1; }
if (idx < scheduler.queues.length && scheduler.queues[idx].length > 0) {
var fn = scheduler.queues[idx].shift();
}
return fn;
}
this.add = function(labelName, fn, self, args) {
var doWork = function() {
scheduler.timeout = setTimeout(function() {
var work = scheduler.nextWork();
if (work != undefined) {
if (work.args == undefined) { work.args = new Array(0); }
work.fn.apply(work.self, work.args);
doWork();
}
else {
scheduler.timeout = undefined;
}
}, resolution);
}
var idx = 0;
while (idx < scheduler.labels.length && scheduler.labels[idx].name != labelName) { idx = idx + 1; }
if (idx < scheduler.queues.length && scheduler.labels[idx].name == labelName) {
scheduler.queues[idx].push(new scheduler.work(fn, self, args));
if (scheduler.timeout == undefined) doWork();
}
else throw("queue for add is non existant");
}
this.clear = function(labelName) {
var idx = 0;
while (idx < scheduler.labels.length && scheduler.labels[idx].name != labelName) { idx = idx + 1; }
if (idx < scheduler.queues.length && scheduler.labels[idx].name == labelName) {
scheduler.queues[idx] = new Array();
}
}
};
