source: Dev/trunk/src/client/dojox/app/controllers/History.js

define(["dojo/_base/lang", "dojo/_base/declare", "dojo/on", "../Controller", "../utils/hash", "dojo/topic"],
function(lang, declare, on, Controller, hash, topic){
        // module:
        //              dojox/app/controllers/History
        // summary:
        //              Bind "app-domNode" event on dojox/app application instance.
        //              Bind "startTransition" event on dojox/app application domNode.
        //              Bind "popstate" event on window object.
        //              Maintain history by HTML5 "pushState" method and "popstate" event.

        return declare("dojox.app.controllers.History", Controller, {
                // _currentPosition:     Integer
                //              Persistent variable which indicates the current position/index in the history
                //              (so as to be able to figure out whether the popState event was triggerd by
                //              a backward or forward action).
                _currentPosition: 0,

                // currentState: Object
                //              Current state
                currentState: {},

                constructor: function(){
                        // summary:
                        //              Bind "app-domNode" event on dojox/app application instance.
                        //              Bind "startTransition" event on dojox/app application domNode.
                        //              Bind "popstate" event on window object.
                        //

                        this.events = {
                                "app-domNode": this.onDomNodeChange
                        };
                        if(this.app.domNode){
                                this.onDomNodeChange({oldNode: null, newNode: this.app.domNode});
                        }
                        this.bind(window, "popstate", lang.hitch(this, this.onPopState));
                },

                onDomNodeChange: function(evt){
                        if(evt.oldNode != null){
                                this.unbind(evt.oldNode, "startTransition");
                        }
                        this.bind(evt.newNode, "startTransition", lang.hitch(this, this.onStartTransition));
                },

                onStartTransition: function(evt){
                        // summary:
                        //              Response to dojox/app "startTransition" event.
                        //
                        // example:
                        //              Use "dojox/mobile/TransitionEvent" to trigger "startTransition" event, and this function will response the event. For example:
                        //              |       var transOpts = {
                        //              |               title:"List",
                        //              |               target:"items,list",
                        //              |               url: "#items,list",
                        //              |               params: {"param1":"p1value"}
                        //              |       };
                        //              |       new TransitionEvent(domNode, transOpts, e).dispatch();
                        //
                        // evt: Object
                        //              Transition options parameter
                        var currentHash = window.location.hash;
                        var currentView = hash.getTarget(currentHash, this.app.defaultView);
                        var currentParams =  hash.getParams(currentHash);
                        var _detail = lang.clone(evt.detail);
                        _detail.target = _detail.title = currentView;
                        _detail.url = currentHash;
                        _detail.params = currentParams;
                        _detail.id = this._currentPosition;

                        // Create initial state if necessary
                        if(history.length == 1){
                                history.pushState(_detail, _detail.href, currentHash);
                        }

                        // Update the current state
                        _detail.bwdTransition = _detail.transition;
                        lang.mixin(this.currentState, _detail);
                        history.replaceState(this.currentState, this.currentState.href, currentHash);

                        // Create a new "current state" history entry
                        this._currentPosition += 1;
                        evt.detail.id = this._currentPosition;

                        var newHash = evt.detail.url || "#" + evt.detail.target;

                        if(evt.detail.params){
                                newHash = hash.buildWithParams(newHash, evt.detail.params);
                        }

                        evt.detail.fwdTransition = evt.detail.transition;
                        history.pushState(evt.detail, evt.detail.href, newHash);
                        this.currentState = lang.clone(evt.detail);

                        // Finally: Publish pushState topic
                        topic.publish("/app/history/pushState", evt.detail.target);
                },

                onPopState: function(evt){
                        // summary:
                        //              Response to dojox/app "popstate" event.
                        //
                        // evt: Object
                        //              Transition options parameter

                        // Clean browser's cache and refresh the current page will trigger popState event,
                        // but in this situation the application has not started and throws an error.
                        // So we need to check application status, if application not STARTED, do nothing.
                        if((this.app.getStatus() !== this.app.lifecycle.STARTED) || !evt.state ){
                                return;
                        }

                        // Get direction of navigation and update _currentPosition accordingly
                        var backward = evt.state.id < this._currentPosition;
                        backward ? this._currentPosition -= 1 : this._currentPosition += 1;

                        // Publish popState topic and transition to the target view. Important: Use correct transition.
                        // Reverse transitionDir only if the user navigates backwards.
                        var opts = lang.mixin({reverse: backward ? true : false}, evt.state);
                        opts.transition = backward ? opts.bwdTransition : opts.fwdTransition;
                        this.app.emit("app-transition", {
                                viewId: evt.state.target,
                                opts: opts
                        });
                        topic.publish("/app/history/popState", evt.state.target);
                }
        });
});