Shim that converts Chrome's SetVersion to the standard IndexedDB onupgradeneeded events

IndexedDB.setVersionShim.js

////////////////////////////////////////////////////////////////////////////////////////////////////
			
			var openReqShim = function(dbName, version){
				var me = this;
				var IDBRequest = function(){
					this.onsuccess = this.onerror = this.onblocked = this.onupgradeneeded = null;
				};
				
				function copyReq(req){
					req = req || dbOpenReq;
					for (var key in req) {
						if (typeof result[key] === "undefined") {
							result[key] = req[key];
						}
					}
				}
				
				function callback(fn, context, argArray, func){
					//window.setTimeout(function(){
					(typeof context[fn] === "function") && context[fn].apply(context, argArray);
					(typeof func === "function") && func();
					//}, 1);
				}
				
				var indexedDB = window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB;
				var dbOpenReq = version ? indexedDB.open(dbName, version) : indexedDB.open(dbName);
				var result = new IDBRequest();
				dbOpenReq.onsuccess = function(e){
					copyReq();
					var db = dbOpenReq.result;
					if (typeof db.setVersion === "function") {
						var oldVersion = parseInt(db.version || 1, 10);
						var newVersion = typeof version === "undefined" ? oldVersion : parseInt(version, 10);
						if (oldVersion < newVersion) {
							var versionReq = db.setVersion(version);
							versionReq.onsuccess = function(upgradeEvent){
								result.transaction = versionReq.result;
								var event = new Event("upgradeneeded");
								event.oldVersion = oldVersion;
								event.newVersion = newVersion;
								for (key in upgradeEvent) {
									if (key !== "type") {
										event[key] = upgradeEvent[key];
									}
								}
								callback("onupgradeneeded", result, [event]);
								// Version transaction is now complete, to open ordinary transaction
								versionReq.result.db.close();
								//console.log("Database closed, and will try to open again, with same version");
								var newDbOpenReq = indexedDB.open(dbName);
								delete result.transaction;
								delete result.result;
								
								newDbOpenReq.onsuccess = function(e){
									//console.log("DB Opened without version change", newDbOpenReq.result);
									copyReq(newDbOpenReq);
									callback("onsuccess", result, [e], function(){
										newDbOpenReq.result.close();
									});
									newDbOpenReq.result.close();
								};
								newDbOpenReq.onerror = function(e){
									copyReq(newDbOpenReq);
									callback("onerror", result, [e], function(){
										//console.log("Closed database in newRequest on error", newDbOpenReq);
										newDbOpenReq.result.close();
									});
								};
								newDbOpenReq.onblocked = function(e){
									//console.log("DB Blocked without version change", newDbOpenReq.result);
									copyReq(newDbOpenReq);
									callback("onblocked", result, [e], function(){
										//console.log("Closed database in newRequest on blocked", newDbOpenReq);
										newDbOpenReq.result.close();
									});
								};
							};
							versionReq.onerror = function(){
								callback("onerror", result, [e]);
								versionReq.result.close();
							};
							versionReq.onblocked = function(e){
								// This always gets called, resulting the blocking the DB upgrade
								//console.log("Version transaction blocked, so calling the on blocked method");
								callback("onblocked", result, [e]);
							};
						} else if (oldVersion === newVersion) {
							callback("onsuccess", result, [e]);
							db.close();
						} else {
							callback("onerror", result, [e]);
							db.close();
						}
					} else {
						callback("onsuccess", result, [e]);
					}
				};
				dbOpenReq.onerror = function(e){
					copyReq();
					//console.log("Error", dbOpenReq);
					callback("onerror", result, [e]);
				};
				dbOpenReq.onblocked = function(e){
					copyReq();
					callback("onblocked", result, [e]);
				};
				dbOpenReq.onupgradeneeded = function(e){
					copyReq();
					if (typeof result["onupgradeneeded"] === "function") {
						result["onupgradeneeded"](e);
					}
				};
				
				return result;
			}