@qooxdoo/framework
Version:
The JS Framework for Coders
183 lines (156 loc) • 4.25 kB
JavaScript
/* ************************************************************************
qooxdoo - the new era of web development
http://qooxdoo.org
Copyright:
2004-2011 1&1 Internet AG, Germany, http://www.1und1.de
License:
MIT: https://opensource.org/licenses/MIT
See the LICENSE file in the project's top-level directory for details.
Authors:
* Tino Butz (tbtz)
* Adrian Olaru (adrianolaru)
************************************************************************ */
/**
*
* Web Workers allows us to run JavaScript in parallel on a web page,
* without blocking the user interface. A 'worker' is just another script
* file that will be loaded and executed in the background.
*
* NOTE: Instances of this class must be disposed of after use
*
* For more information see:
* http://www.w3.org/TR/workers/
*/
qx.Class.define("qx.bom.WebWorker", {
extend: qx.core.Object,
implement: [qx.core.IDisposable],
/**
* Create a new instance.
*
* @param src {String} The path to worker as an URL
*/
construct(src) {
super();
this.__isNative = qx.core.Environment.get("html.webworker");
this.__isNative ? this.__initNative(src) : this.__initFake(src);
},
events: {
/** Fired when worker sends a message */
message: "qx.event.type.Data",
/** Fired when an error occurs */
error: "qx.event.type.Data"
},
members: {
_worker: null,
_handleErrorBound: null,
_handleMessageBound: null,
__isNative: true,
__fake: null,
/**
* Initialize the native worker
* @param src {String} The path to worker as an URL
*/
__initNative(src) {
this._worker = new window.Worker(src);
this._handleMessageBound = qx.lang.Function.bind(
this._handleMessage,
this
);
this._handleErrorBound = qx.lang.Function.bind(this._handleError, this);
qx.bom.Event.addNativeListener(
this._worker,
"message",
this._handleMessageBound
);
qx.bom.Event.addNativeListener(
this._worker,
"error",
this._handleErrorBound
);
},
/**
* Initialize the fake worker
* @param src {String} The path to worker as an URL
* @lint ignoreDeprecated(eval)
*/
__initFake(src) {
var that = this;
var req = new qx.bom.request.Xhr();
req.onload = function () {
that.__fake = (function () {
var postMessage = function (e) {
that.fireDataEvent("message", e);
};
//set up context vars before evaluating the code
eval(
"var onmessage = null, postMessage = " +
postMessage +
";" +
req.responseText
);
//pick the right onmessage because of the uglyfier
return {
onmessage: eval("onmessage"),
postMessage: postMessage
};
})();
};
req.open("GET", src, false);
req.send();
},
/**
* Send a message to the worker.
* @param msg {String} the message
*/
postMessage(msg) {
var that = this;
if (this.__isNative) {
this._worker.postMessage(msg);
} else {
setTimeout(function () {
try {
that.__fake.onmessage && that.__fake.onmessage({ data: msg });
} catch (ex) {
that.fireDataEvent("error", ex);
}
}, 0);
}
},
/**
* Message handler
* @param e {Event} message event
*/
_handleMessage(e) {
this.fireDataEvent("message", e.data);
},
/**
* Error handler
* @param e {Event} error event
*/
_handleError(e) {
this.fireDataEvent("error", e.message);
}
},
destruct() {
if (this.__isNative) {
qx.bom.Event.removeNativeListener(
this._worker,
"message",
this._handleMessageBound
);
qx.bom.Event.removeNativeListener(
this._worker,
"error",
this._handleErrorBound
);
if (this._worker) {
this._worker.terminate();
this._worker = null;
}
} else {
if (this.__fake) {
this.__fake = null;
}
}
}
});