source: Dev/trunk/src/client/dojox/xmpp/bosh.js

dojo.provide("dojox.xmpp.bosh");

dojo.require("dojo.io.script");
dojo.require("dojo.io.iframe");
dojo.require("dojox.xml.parser");

/*=====
dojo.declare("dojox.xmpp.bosh.__initArgs", null, {
        constructor: function(){
                // summary:
                //              The arguments passed to dojox.xmpp.bosh.initialize
                // iframes:
                //              The number of iframes to use for transmission
                // load:
                //              The function called when the first iframe is
                //              loaded.  Generally used to signal when to send
                //              login information
                this.iframes = iframes;
                this.load = load;
        }
});
dojo.declare("dojox.xmpp.bosh.__ioArgs", dojo.__IoArgs, {
        constructor: function(){
                // summary:
                //              All the properties described in the dojo.__ioArgs type, apply to this
                //              type as well, EXCEPT "handleAs". It is not applicable to
                //              dojox.xmpp.bosh.get() calls, since it is implied that the
                //              return will be a string of XML.
                // rid:
                //              The rid of the message being sent.
                this.rid = rid;
        }
});
=====*/

dojox.xmpp.bosh = {
        transportIframes: [],
        initialize: function(/*dojox.xmpp.bosh.__initArgs*/ args){
                this.transportIframes = [];

                var scopedObj = dojox._scopeName + '.xmpp.bosh';

                var c = dojo.connect(dojo.getObject(scopedObj), '_iframeOnload', this, function(index){
                        if(index==0){
                                args.load();
                                dojo.disconnect(c);
                        }
                });

                for(var i = 0; i < args.iframes; i++){
                        var fname = 'xmpp-transport-'+i;
                        var iframe = dojo.byId('xmpp-transport-'+i);
                        if(iframe){
                                // we have to clean up the dojo.io.iframe references
                                if(window[fname]){ window[fname] = null; }
                                if(window.frames[fname]){ window.frames[fname] = null; }
                                dojo.destroy(iframe);
                        }
                        iframe = dojo.io.iframe.create("xmpp-transport-" + i, scopedObj + "._iframeOnload("+i+");" );
                        this.transportIframes.push(iframe);
                }
        },

        _iframeOnload: function(index){
                var doc = dojo.io.iframe.doc(dojo.byId("xmpp-transport-" + index));
                doc.write("<script>var isLoaded=true; var rid=0; var transmiting=false; function _BOSH_(msg) { transmiting=false; parent.dojox.xmpp.bosh.handle(msg, rid); } </script>");
        },

        findOpenIframe: function() {
                for(var i = 0; i < this.transportIframes.length; i++) {
                        var iframe = this.transportIframes[i];
                        var win = iframe.contentWindow;
                        //console.log("Open transport?", win, win.isLoaded, win.transmiting);
                        
                        if(win.isLoaded && !win.transmiting) {
                                return iframe;
                        }
                }
                return false;
        },

        handle: function(msg, rid){
                var dfd = this['rid'+rid];

                var xmlMsg = dojox.xml.parser.parse(msg, 'text/xml');

                if(xmlMsg){
                        dfd.ioArgs.xmppMessage = xmlMsg;
                }else{
                        dfd.errback(new Error("Recieved bad document from server: " + msg));
                }
        },

        get: function(/*dojox.xmpp.bosh.__ioArgs*/args){
                // summary:
                //              sends a get request using a dynamically created script tag.
                var iframe = this.findOpenIframe();
                var iframeDoc = dojo.io.iframe.doc(iframe);

                args.frameDoc = iframeDoc;

                var dfd = this._makeScriptDeferred(args);
                var ioArgs = dfd.ioArgs;

                iframe.contentWindow.rid=ioArgs.rid;
                iframe.contentWindow.transmiting=true;

                dojo._ioAddQueryToUrl(ioArgs);
                dojo._ioNotifyStart(dfd);

                dojo.io.script.attach(ioArgs.id, ioArgs.url, iframeDoc);

                dojo._ioWatch(dfd, this._validCheck, this._ioCheck, this._resHandle);
                return dfd;
        },

        remove: function(/*String*/id, /*Document?*/frameDocument){
                // summary:
                //              removes the script element with the given id, from the given frameDocument.
                //              If no frameDocument is passed, the current document is used.
                dojo.destroy(dojo.byId(id, frameDocument));

                //Remove the BOSH callback on dojox.xmpp.bosh, if it exists.
                if(this[id]){
                        delete this[id];
                }
        },

        _makeScriptDeferred: function(/*Object*/args){
                // summary:
                //              sets up a Deferred object for an IO request.
                var dfd = dojo._ioSetArgs(args, this._deferredCancel, this._deferredOk, this._deferredError);

                var ioArgs = dfd.ioArgs;

                ioArgs.id = 'rid' + args.rid;
                ioArgs.rid = args.rid;
                ioArgs.canDelete = true;
                ioArgs.frameDoc = args.frameDoc;

                this[ioArgs.id] = dfd;

                return dfd; // dojo.Deferred
        },

        _deferredCancel: function(/*Deferred*/dfd){
                // summary:
                //              canceller function for dojo._ioSetArgs call.

                //DO NOT use "this" and expect it to be dojox.xmpp.bosh.
                dfd.canceled = true;
                if(dfd.ioArgs.canDelete){
                        dojox.xmpp.bosh._addDeadScript(dfd.ioArgs);
                }
        },

        _deferredOk: function(/*Deferred*/dfd){
                // summary:
                //              okHandler function for dojo._ioSetArgs call.

                //DO NOT use "this" and expect it to be dojo.xmpp.bosh.
                var ioArgs = dfd.ioArgs;

                //Add script to list of things that can be removed.
                if(ioArgs.canDelete){
                        dojox.xmpp.bosh._addDeadScript(ioArgs);
                }

                //Favor JSONP responses, script load events then lastly ioArgs.
                //The ioArgs are goofy, but cannot return the dfd since that stops
                //the callback chain in Deferred. The return value is not that important
                //in that case, probably a checkString case.
                return ioArgs.xmppMessage || ioArgs;
        },

        _deferredError: function(/*Error*/error, /*Deferred*/dfd){
                // summary:
                //              errHandler function for dojo._ioSetArgs call.

                if(dfd.ioArgs.canDelete){
                        //DO NOT use "this" and expect it to be dojox.xmpp.bosh
                        if(error.dojoType == "timeout"){
                                //For timeouts, remove the script element immediately to
                                //avoid a response from it coming back later and causing trouble.
                                dojox.xmpp.bosh.remove(dfd.ioArgs.id, dfd.ioArgs.frameDoc);
                        }else{
                                dojox.xmpp.bosh._addDeadScript(dfd.ioArgs);
                        }
                }
                return error;
        },

        _deadScripts: [],
        _addDeadScript: function(/*Object*/ioArgs){
                // summary:
                //              sets up an entry in the deadScripts array.
                dojox.xmpp.bosh._deadScripts.push({id: ioArgs.id, frameDoc: ioArgs.frameDoc});
                //Being extra paranoid about leaks:
                ioArgs.frameDoc = null;
        },

        _validCheck: function(/*Deferred*/dfd){
                // summary:
                //              inflight check function to see if dfd is still valid.

                //Do script cleanup here. We wait for one inflight pass
                //to make sure we don't get any weird things by trying to remove a script
                //tag that is part of the call chain (IE 6 has been known to
                //crash in that case).
                var _self = dojox.xmpp.bosh;
                var deadScripts = _self._deadScripts;
                if(deadScripts && deadScripts.length > 0){
                        for(var i = 0; i < deadScripts.length; i++){
                                //Remove the script tag
                                _self.remove(deadScripts[i].id, deadScripts[i].frameDoc);
                                deadScripts[i].frameDoc = null;
                        }
                        dojox.xmpp.bosh._deadScripts = [];
                }

                return true;
        },

        _ioCheck: function(/*Deferred*/dfd){
                // summary:
                //              inflight check function to see if IO finished.
                var ioArgs = dfd.ioArgs;
                //Check for returned message
                if(ioArgs.xmppMessage){
                        return true;
                }
                return false;
        },

        _resHandle: function(/*Deferred*/dfd){
                // summary:
                //              inflight function to handle a completed response.
                if(dojox.xmpp.bosh._ioCheck(dfd)){
                        dfd.callback(dfd);
                }else{
                        //This path should never happen since the only way we can get
                        //to _resHandle is if _ioCheck is true.
                        dfd.errback(new Error("inconceivable dojox.xmpp.bosh._resHandle error"));
                }
        }
};