JavaScript中的Webworker多线程API研究

var worker = new Worker("my.js");
var bundle = {message:'Hello world', id:1};
worker.postMessage(bundle); //postMessage可以传一个可序列化的对象过去
worker.Onmessage= function(evt){
    console.log(evt.data);    //比较worker中传回来的对象和主线程中的对象
    console.log(bundle);  //{message:'Hello world', id:1}
}

//in my.js
Onmessage= function(evt){
    var data = evt.data;
    data.id++;
    postMessage(data); //{message:'Hello world', id:2}
}

var worker = new ThreadWorker(bundle /*shared obj*/);

worker.run(function(bundle){
    //do sth in worker thread...
    this.runOnUiThread(function(bundle /*shared obj*/){
        //do sth in main ui thread...
    });
    //...
});

function WorkerThread(sharedObj){
    this._worker = new Worker("thread.js");
    this._completes = {};
    this._task_id = 0;
    this.sharedObj = sharedObj;

    var self = this;
    this._worker.Onmessage= function(evt){
        var ret = evt.data;
        if(ret.__UI_TASK__){
            //run on ui task
            var fn = (new Function("return "+ret.__UI_TASK__))();
            fn(ret.sharedObj);
        }else{
            self.sharedObj = ret.sharedObj;
            self._completes[ret.taskId](ret);
        }
    }
}

WorkerThread.prototype.run = function(task, complete){
    var _task = {__THREAD_TASK__:task.toString(), sharedObj: this.sharedObj, taskId: this._task_id};
    this._completes[this._task_id++] = complete;
    this._worker.postMessage(_task);
}

Onmessage= function(evt){
    var data = evt.data;

    if(data && data.__THREAD_TASK__){
        var task = data.__THREAD_TASK__;
        try{
            var fn = (new Function("return "+task))();

            var ctx = {
                threadSignal: true,
                sleep: function(interval){
                    ctx.threadSignal = false;
                    setTimeout(_run, interval);
                },
                runOnUiThread: function(task){
                    postMessage({__UI_TASK__:task.toString(), sharedObj:data.sharedObj});
                }
            }

            function _run(){
                ctx.threadSignal = true;
                var ret = fn.call(ctx, data.sharedObj);
                postMessage({error:null, returnValue:ret, __THREAD_TASK__:task, sharedObj:data.sharedObj, taskId: data.taskId});
            }

            _run(0);

        }catch(ex){
            postMessage({error:ex.toString() , returnValue:null, sharedObj: data.sharedObj});
        }
    }
}

var t1 = new WorkerThread({i: 100} /*shared obj*/);

        setInterval(function(){
            t1.run(function(sharedObj){
                    return sharedObj.i++;
                },
                function(r){
                    console.log("t1>" + r.returnValue + ":" + r.error);
                }
            );
        }, 500);
var t2 = new WorkerThread({i: 50});

        t2.run(function(sharedObj){  
            while(this.threadSignal){
                sharedObj.i++;

                this.runOnUiThread(function(sharedObj){
                    W("body ul").appendChild("

"+sharedObj.i+"

");
                });

                this.sleep(500);
            }
            return sharedObj.i;
        }, function(r){
            console.log("t2>" + r.returnValue + ":" + r.error);
        });