js-multithreading.js

!function () {

  var URL = window.URL || window.webkitURL;
  if (!URL) {
    throw new Error('This browser does not support Blob URLs');
  }

  if (!window.Worker) {
    throw new Error('This browser does not support Web Workers');
  }

  function RedyCRM_Multithread(threads) {
    this.threads = Math.max(2, threads | 0);
    this._queue = [];
    this._queueSize = 0;
    this._activeThreads = 0;
    this._debug = {
      start: 0,
      end: 0,
      time: 0
    };
  }

  RedyCRM_Multithread.prototype._worker = {
    JSON: function () {
      var /**/name/**/ = (/**/func/**/);
      self.addEventListener('message', function (e) {
        var data = e.data;
        var view = new DataView(data);
        var len = data.byteLength;
        var str = Array(len);
        for (var i = 0; i < len; i++) {
          str[i] = String.fromCharCode(view.getUint8(i));
        }
        var args = JSON.parse(str.join(''));
        var value = (/**/name/**/).apply(/**/name/**/, args);
        try {
          data = JSON.stringify(value);
        } catch (e) {
          throw new Error('Parallel function must return JSON serializable response');
        }
        len = typeof (data) === 'undefined' ? 0 : data.length;
        var buffer = new ArrayBuffer(len);
        view = new DataView(buffer);
        for (i = 0; i < len; i++) {
          view.setUint8(i, data.charCodeAt(i) & 255);
        }
        self.postMessage(buffer, [buffer]);
        self.close();
      })
    },
    Int32: function () {
      var /**/name/**/ = (/**/func/**/);
      self.addEventListener('message', function (e) {
        var data = e.data;
        var view = new DataView(data);
        var len = data.byteLength / 4;
        var arr = Array(len);
        for (var i = 0; i < len; i++) {
          arr[i] = view.getInt32(i * 4);
        }
        var value = (/**/name/**/).apply(/**/name/**/, arr);
        if (!(value instanceof Array)) {
          value = [value];
        }
        len = value.length;
        var buffer = new ArrayBuffer(len * 4);
        view = new DataView(buffer);
        for (i = 0; i < len; i++) {
          view.setInt32(i * 4, value[i]);
        }
        self.postMessage(buffer, [buffer]);
        self.close();
      })
    },
    Float64: function () {
      var /**/name/**/ = (/**/func/**/);
      self.addEventListener('message', function (e) {
        var data = e.data;
        var view = new DataView(data);
        var len = data.byteLength / 8;
        var arr = Array(len);
        for (var i = 0; i < len; i++) {
          arr[i] = view.getFloat64(i * 8);
        }
        var value = (/**/name/**/).apply(/**/name/**/, arr);
        if (!(value instanceof Array)) {
          value = [value];
        }
        len = value.length;
        var buffer = new ArrayBuffer(len * 8);
        view = new DataView(buffer);
        for (i = 0; i < len; i++) {
          view.setFloat64(i * 8, value[i]);
        }
        self.postMessage(buffer, [buffer]);
        self.close();
      })
    }
  };

  RedyCRM_Multithread.prototype._encode = {
    JSON: function (args) {
      try {
        var data = JSON.stringify(args);
      } catch (e) {
        throw new Error('Arguments provided to parallel function must be JSON serializable');
      }
      len = data.length;
      var buffer = new ArrayBuffer(len);
      var view = new DataView(buffer);
      for (var i = 0; i < len; i++) {
        view.setUint8(i, data.charCodeAt(i) & 255);
      }
      return buffer;
    },
    Int32: function (args) {
      len = args.length;
      var buffer = new ArrayBuffer(len * 4);
      var view = new DataView(buffer);
      for (var i = 0; i < len; i++) {
        view.setInt32(i * 4, args[i]);
      }
      return buffer;
    },
    Float64: function (args) {
      len = args.length;
      var buffer = new ArrayBuffer(len * 8);
      var view = new DataView(buffer);
      for (var i = 0; i < len; i++) {
        view.setFloat64(i * 8, args[i]);
      }
      return buffer;
    }
  };

  RedyCRM_Multithread.prototype._decode = {
    JSON: function (data) {
      var view = new DataView(data);
      var len = data.byteLength;
      var str = Array(len);
      for (var i = 0; i < len; i++) {
        str[i] = String.fromCharCode(view.getUint8(i));
      }
      if (!str.length) {
        return;
      } else {
        return JSON.parse(str.join(''));
      }
    },
    Int32: function (data) {
      var view = new DataView(data);
      var len = data.byteLength / 4;
      var arr = Array(len);
      for (var i = 0; i < len; i++) {
        arr[i] = view.getInt32(i * 4);
      }
      return arr;
    },
    Float64: function (data) {
      var view = new DataView(data);
      var len = data.byteLength / 8;
      var arr = Array(len);
      for (var i = 0; i < len; i++) {
        arr[i] = view.getFloat64(i * 8);
      }
      return arr;
    },
  };

  RedyCRM_Multithread.prototype._execute = function (resource, args, type, callback) {
    if (!this._activeThreads) {
      this._debug.start = (new Date).valueOf();
    }
    if (this._activeThreads < this.threads) {
      this._activeThreads++;
      var t = (new Date()).valueOf();
      var worker = new Worker(resource);
      var buffer = this._encode[type](args);
      var decode = this._decode[type];
      var self = this;
      if (type === 'JSON') {
        var listener = function (e) {
          callback.call(self, decode(e.data));
          self.ready();
        };
      } else {
        var listener = function (e) {
          callback.apply(self, decode(e.data));
          self.ready();
        };
      }
      worker.addEventListener('message', listener);
      worker.postMessage(buffer, [buffer]);
    } else {
      this._queueSize++;
      this._queue.push([resource, args, type, callback]);
    }
  };

  RedyCRM_Multithread.prototype.ready = function () {
    this._activeThreads--;
    if (this._queueSize) {
      this._execute.apply(this, this._queue.shift());
      this._queueSize--;
    } else if (!this._activeThreads) {
      this._debug.end = (new Date).valueOf();
      this._debug.time = this._debug.end - this._debug.start;
    }
  };

  RedyCRM_Multithread.prototype._prepare = function (fn, type) {

    fn = fn;

    var name = fn.name;
    var fnStr = fn.toString();
    if (!name) {
      name = '$' + ((Math.random() * 10) | 0);
      while (fnStr.indexOf(name) !== -1) {
        name += ((Math.random() * 10) | 0);
      }
    }

    var script = this._worker[type]
      .toString()
      .replace(/^.*?[\n\r]+/gi, '')
      .replace(/\}[\s]*$/, '')
      .replace(/\/\*\*\/name\/\*\*\//gi, name)
      .replace(/\/\*\*\/func\/\*\*\//gi, fnStr);

    var resource = URL.createObjectURL(new Blob([script], {type: 'text/javascript'}));

    return resource;

  };

  RedyCRM_Multithread.prototype.process = function (fn, callback) {

    var resource = this._prepare(fn, 'JSON');
    var self = this;

    return function () {
      self._execute(resource, [].slice.call(arguments), 'JSON', callback)
    };

  };

  RedyCRM_Multithread.prototype.processInt32 = function (fn, callback) {

    var resource = this._prepare(fn, 'Int32');
    var self = this;

    return function () {
      self._execute(resource, [].slice.call(arguments), 'Int32', callback)
    };

  };

  RedyCRM_Multithread.prototype.processFloat64 = function (fn, callback) {

    var resource = this._prepare(fn, 'Float64');
    var self = this;

    return function () {
      self._execute(resource, [].slice.call(arguments), 'Float64', callback)
    };

  };

  window['RedyCRM_Multithread'] = RedyCRM_Multithread;

}();