engine.js

DWR is the way for AJAX implementation

    batch.postHooks = null;
  }
};

/** @private A call has finished by whatever means and we need to shut it all down. */
dwr.engine._clearUp = function(batch) {
  if (!batch) { dwr.engine._debug("Warning: null batch in dwr.engine._clearUp()", true); return; }
  if (batch.completed) { dwr.engine._debug("Warning: Double complete", true); return; }

  // IFrame tidyup
  if (batch.div) batch.div.parentNode.removeChild(batch.div);
  if (batch.iframe) {
    // If this is a poll frame then stop comet polling
    for (var i = 0; i < dwr.engine._outstandingIFrames.length; i++) {
      if (dwr.engine._outstandingIFrames[i] == batch.iframe) {
        dwr.engine._outstandingIFrames.splice(i, 1);
      }
    }
    batch.iframe.parentNode.removeChild(batch.iframe);
  }
  if (batch.form) batch.form.parentNode.removeChild(batch.form);

  // XHR tidyup: avoid IE handles increase
  if (batch.req) {
    // If this is a poll frame then stop comet polling
    if (batch.req == dwr.engine._pollReq) dwr.engine._pollReq = null;
    delete batch.req;
  }

  // Timeout tidyup
  if (batch.timeoutId) {
    clearTimeout(batch.timeoutId);
    delete batch.timeoutId;
  }

  if (batch.map && (batch.map.batchId || batch.map.batchId == 0)) {
    delete dwr.engine._batches[batch.map.batchId];
    dwr.engine._batchesLength--;
  }

  batch.completed = true;

  // If there is anything on the queue waiting to go out, then send it.
  // We don't need to check for ordered mode, here because when ordered mode
  // gets turned off, we still process *waiting* batches in an ordered way.
  if (dwr.engine._batchQueue.length != 0) {
    var sendbatch = dwr.engine._batchQueue.shift();
    dwr.engine._sendData(sendbatch);
  }
};

/** @private Abort any XHRs in progress at page unload (solves zombie socket problems in IE). */
dwr.engine._unloader = function() {
  dwr.engine._unloading = true;

  // Empty queue of waiting ordered requests
  dwr.engine._batchQueue.length = 0;

  // Abort any ongoing XHRs and clear their batches
  for (var batchId in dwr.engine._batches) {
    var batch = dwr.engine._batches[batchId];
    // Only process objects that look like batches (avoid prototype additions!)
    if (batch && batch.map) {
      if (batch.req) {
        batch.req.abort();
      }
      dwr.engine._clearUp(batch);
    }
  }
};
// Now register the unload handler
if (window.addEventListener) window.addEventListener('unload', dwr.engine._unloader, false);
else if (window.attachEvent) window.attachEvent('onunload', dwr.engine._unloader);

/** @private Generic error handling routing to save having null checks everywhere */
dwr.engine._handleError = function(batch, ex) {
  if (typeof ex == "string") ex = { name:"unknown", message:ex };
  if (ex.message == null) ex.message = "";
  if (ex.name == null) ex.name = "unknown";
  if (batch && typeof batch.errorHandler == "function") batch.errorHandler(ex.message, ex);
  else if (dwr.engine._errorHandler) dwr.engine._errorHandler(ex.message, ex);
  if (batch) dwr.engine._clearUp(batch);
};

/** @private Generic error handling routing to save having null checks everywhere */
dwr.engine._handleWarning = function(batch, ex) {
  if (typeof ex == "string") ex = { name:"unknown", message:ex };
  if (ex.message == null) ex.message = "";
  if (ex.name == null) ex.name = "unknown";
  if (batch && typeof batch.warningHandler == "function") batch.warningHandler(ex.message, ex);
  else if (dwr.engine._warningHandler) dwr.engine._warningHandler(ex.message, ex);
  if (batch) dwr.engine._clearUp(batch);
};

/**
 * @private Marshall a data item
 * @param batch A map of variables to how they have been marshalled
 * @param referto An array of already marshalled variables to prevent recurrsion
 * @param data The data to be marshalled
 * @param name The name of the data being marshalled
 */
dwr.engine._serializeAll = function(batch, referto, data, name) {
  if (data == null) {
    batch.map[name] = "null:null";
    return;
  }

  switch (typeof data) {
  case "boolean":
    batch.map[name] = "boolean:" + data;
    break;
  case "number":
    batch.map[name] = "number:" + data;
    break;
  case "string":
    batch.map[name] = "string:" + encodeURIComponent(data);
    break;
  case "object":
    if (data instanceof String) batch.map[name] = "String:" + encodeURIComponent(data);
    else if (data instanceof Boolean) batch.map[name] = "Boolean:" + data;
    else if (data instanceof Number) batch.map[name] = "Number:" + data;
    else if (data instanceof Date) batch.map[name] = "Date:" + data.getTime();
    else if (data && data.join) batch.map[name] = dwr.engine._serializeArray(batch, referto, data, name);
    else batch.map[name] = dwr.engine._serializeObject(batch, referto, data, name);
    break;
  case "function":
    // We just ignore functions.
    break;
  default:
    dwr.engine._handleWarning(null, { name:"dwr.engine.unexpectedType", message:"Unexpected type: " + typeof data + ", attempting default converter." });
    batch.map[name] = "default:" + data;
    break;
  }
};

/** @private Have we already converted this object? */
dwr.engine._lookup = function(referto, data, name) {
  var lookup;
  // Can't use a map: getahead.org/ajax/javascript-gotchas
  for (var i = 0; i < referto.length; i++) {
    if (referto[i].data == data) {
      lookup = referto[i];
      break;
    }
  }
  if (lookup) return "reference:" + lookup.name;
  referto.push({ data:data, name:name });
  return null;
};

/** @private Marshall an object */
dwr.engine._serializeObject = function(batch, referto, data, name) {
  var ref = dwr.engine._lookup(referto, data, name);
  if (ref) return ref;

  // This check for an HTML is not complete, but is there a better way?
  // Maybe we should add: data.hasChildNodes typeof "function" == true
  if (data.nodeName && data.nodeType) {
    return dwr.engine._serializeXml(batch, referto, data, name);
  }

  // treat objects as an associative arrays
  var reply = "Object_" + dwr.engine._getObjectClassName(data) + ":{";
  var element;
  for (element in data) {
    if (typeof data[element] != "function") {
      batch.paramCount++;
      var childName = "c" + dwr.engine._batch.map.callCount + "-e" + batch.paramCount;
      dwr.engine._serializeAll(batch, referto, data[element], childName);

      reply += encodeURIComponent(element) + ":reference:" + childName + ", ";
    }
  }

  if (reply.substring(reply.length - 2) == ", ") {
    reply = reply.substring(0, reply.length - 2);
  }
  reply += "}";

  return reply;
};

/** @private Returns the classname of supplied argument obj */
dwr.engine._errorClasses = { "Error":Error, "EvalError":EvalError, "RangeError":RangeError, "ReferenceError":ReferenceError, "SyntaxError":SyntaxError, "TypeError":TypeError, "URIError":URIError };
dwr.engine._getObjectClassName = function(obj) {
  // Try to find the classname by stringifying the object's constructor
  // and extract <class> from "function <class>".
  if (obj && obj.constructor && obj.constructor.toString)
  {
    var str = obj.constructor.toString();
    var regexpmatch = str.match(/function\s+(\w+)/);
    if (regexpmatch && regexpmatch.length == 2) {
      return regexpmatch[1];
    }
  }

  // Now manually test against the core Error classes, as these in some 
  // browsers successfully match to the wrong class in the 
  // Object.toString() test we will do later
  if (obj && obj.constructor) {
	for (var errorname in dwr.engine._errorClasses) {
      if (obj.constructor == dwr.engine._errorClasses[errorname]) return errorname;
    }
  }

  // Try to find the classname by calling Object.toString() on the object
  // and extracting <class> from "[object <class>]"
  if (obj) {
    var str = Object.prototype.toString.call(obj);
    var regexpmatch = str.match(/\[object\s+(\w+)/);
    if (regexpmatch && regexpmatch.length==2) {
      return regexpmatch[1];
    }
  }

  // Supplied argument was probably not an object, but what is better?
  return "Object";
};

/** @private Marshall an object */
dwr.engine._serializeXml = function(batch, referto, data, name) {
  var ref = dwr.engine._lookup(referto, data, name);
  if (ref) return ref;

  var output;
  if (window.XMLSerializer) output = new XMLSerializer().serializeToString(data);
  else if (data.toXml) output = data.toXml;
  else output = data.innerHTML;

  return "XML:" + encodeURIComponent(output);
};

/** @private Marshall an array */
dwr.engine._serializeArray = function(batch, referto, data, name) {
  var ref = dwr.engine._lookup(referto, data, name);
  if (ref) return ref;

  if (document.all && !window.opera) {
    // Use array joining on IE (fastest)
    var buf = ["Array:["];
    for (var i = 0; i < data.length; i++) {
      if (i != 0) buf.push(",");
      batch.paramCount++;
      var childName = "c" + dwr.engine._batch.map.callCount + "-e" + batch.paramCount;
      dwr.engine._serializeAll(batch, referto, data[i], childName);
      buf.push("reference:");
      buf.push(childName);
    }
    buf.push("]");
    reply = buf.join("");
  }
  else {
    // Use string concat on other browsers (fastest)
    var reply = "Array:[";
    for (var i = 0; i < data.length; i++) {
      if (i != 0) reply += ",";
      batch.paramCount++;
      var childName = "c" + dwr.engine._batch.map.callCount + "-e" + batch.paramCount;
      dwr.engine._serializeAll(batch, referto, data[i], childName);
      reply += "reference:";
      reply += childName;
    }
    reply += "]";
  }

  return reply;
};

/** @private Convert an XML string into a DOM object. */
dwr.engine._unserializeDocument = function(xml) {
  var dom;
  if (window.DOMParser) {
    var parser = new DOMParser();
    dom = parser.parseFromString(xml, "text/xml");
    if (!dom.documentElement || dom.documentElement.tagName == "parsererror") {
      var message = dom.documentElement.firstChild.data;
      message += "\n" + dom.documentElement.firstChild.nextSibling.firstChild.data;
      throw message;
    }
    return dom;
  }
  else if (window.ActiveXObject) {
    dom = dwr.engine._newActiveXObject(dwr.engine._DOMDocument);
    dom.loadXML(xml); // What happens on parse fail with IE?
    return dom;
  }
  else {
    var div = document.createElement("div");
    div.innerHTML = xml;
    return div;
  }
};

/** @param axarray An array of strings to attempt to create ActiveX objects from */
dwr.engine._newActiveXObject = function(axarray) {
  var returnValue;  
  for (var i = 0; i < axarray.length; i++) {
    try {
      returnValue = new ActiveXObject(axarray[i]);
      break;
    }
    catch (ex) { /* ignore */ }
  }
  return returnValue;
};

/** @private Used internally when some message needs to get to the programmer */
dwr.engine._debug = function(message, stacktrace) {
  var written = false;
  try {
    if (window.console) {
      if (stacktrace && window.console.trace) window.console.trace();
      window.console.log(message);
      written = true;
    }
    else if (window.opera && window.opera.postError) {
      window.opera.postError(message);
      written = true;
    }
  }
  catch (ex) { /* ignore */ }

  if (!written) {
    var debug = document.getElementById("dwr-debug");
    if (debug) {
      var contents = message + "<br/>" + debug.innerHTML;
      if (contents.length > 2048) contents = contents.substring(0, 2048);
      debug.innerHTML = contents;
    }
  }
};