feat(bootstrap): add platform and app initializers

Often some init logic needs to run when a platform or an application is boostrapped.
For example, boostraping a platform requires initializing the dom adapter.
Now, it can be done as follows:

new Provider(PLATFORM_INITIALIZER, {useValue: initDomAdapter, multi: true}),

All platform initializers will be run after the platform injector has been created.

Similarly, all application initializers will be run after the app injector has been
created.

Closes #5355

modules/angular2/core.dart

@@ -9,6 +9,7 @@ export 'package:angular2/src/common/pipes.dart';
 export 'package:angular2/src/facade/facade.dart';
 export 'package:angular2/src/core/application_ref.dart'
     hide ApplicationRef_, PlatformRef_;
+export 'package:angular2/src/core/application_tokens.dart' show APP_ID, APP_COMPONENT, APP_INITIALIZER, PLATFORM_INITIALIZER;
 export 'package:angular2/src/core/linker.dart';
 export 'package:angular2/src/core/zone.dart';
 export 'package:angular2/src/core/render.dart';

modules/angular2/core.ts

@@ -10,7 +10,12 @@ export * from './src/common/pipes';
 export * from './src/facade/facade';
 export * from './src/core/linker';
 export {platform, createNgZone, PlatformRef, ApplicationRef} from './src/core/application_ref';
-export {APP_ID, APP_COMPONENT} from './src/core/application_tokens';
+export {
+  APP_ID,
+  APP_COMPONENT,
+  APP_INITIALIZER,
+  PLATFORM_INITIALIZER
+} from './src/core/application_tokens';
 export * from './src/core/zone';
 export * from './src/core/render';
 export * from './src/common/directives';

modules/angular2/platform/browser.ts

@@ -13,8 +13,7 @@ import {Type, isPresent, CONST_EXPR} from 'angular2/src/facade/lang';
 import {Promise} from 'angular2/src/facade/promise';
 import {
   BROWSER_PROVIDERS,
-  BROWSER_APP_COMMON_PROVIDERS,
-  initDomAdapter
+  BROWSER_APP_COMMON_PROVIDERS
 } from 'angular2/src/platform/browser_common';
 import {COMPILER_PROVIDERS} from 'angular2/compiler';
 import {ComponentRef, platform, reflector} from 'angular2/core';
@@ -120,8 +119,6 @@ export function bootstrap(
     appComponentType: Type,
     customProviders?: Array<any /*Type | Provider | any[]*/>): Promise<ComponentRef> {
   reflector.reflectionCapabilities = new ReflectionCapabilities();
-  initDomAdapter();
-
   let appProviders =
       isPresent(customProviders) ? [BROWSER_APP_PROVIDERS, customProviders] : BROWSER_APP_PROVIDERS;
   return platform(BROWSER_PROVIDERS).application(appProviders).bootstrap(appComponentType);

modules/angular2/platform/browser_static.ts

@@ -12,8 +12,7 @@ import {Type, isPresent, CONST_EXPR} from 'angular2/src/facade/lang';
 import {Promise} from 'angular2/src/facade/promise';
 import {
   BROWSER_PROVIDERS,
-  BROWSER_APP_COMMON_PROVIDERS,
-  initDomAdapter
+  BROWSER_APP_COMMON_PROVIDERS
 } from 'angular2/src/platform/browser_common';
 import {ComponentRef, platform, reflector} from 'angular2/core';
 
@@ -31,7 +30,6 @@ export const BROWSER_APP_PROVIDERS: Array<any /*Type | Provider | any[]*/> =
 export function bootstrapStatic(appComponentType: Type,
                                 customProviders?: Array<any /*Type | Provider | any[]*/>,
                                 initReflector?: Function): Promise<ComponentRef> {
-  initDomAdapter();
   if (isPresent(initReflector)) {
     initReflector();
   }

modules/angular2/src/core/application_ref.ts

@@ -4,7 +4,9 @@ import {provide, Provider, Injector, OpaqueToken} from 'angular2/src/core/di';
 import {
   APP_COMPONENT_REF_PROMISE,
   APP_COMPONENT,
-  APP_ID_RANDOM_PROVIDER
+  APP_ID_RANDOM_PROVIDER,
+  PLATFORM_INITIALIZER,
+  APP_INITIALIZER
 } from './application_tokens';
 import {
   Promise,
@@ -30,7 +32,6 @@ import {wtfLeave, wtfCreateScope, WtfScopeFn} from './profile/profile';
 import {ChangeDetectorRef} from 'angular2/src/core/change_detection/change_detector_ref';
 import {lockDevMode} from 'angular2/src/facade/lang';
 
-
 /**
  * Construct providers specific to an individual root component.
  */
@@ -103,15 +104,32 @@ export function platform(providers?: Array<Type | Provider | any[]>): PlatformRe
   }
 }
 
+/**
+ * Dispose the existing platform.
+ */
+export function disposePlatform(): void {
+  if (isPresent(_platform)) {
+    _platform.dispose();
+    _platform = null;
+  }
+}
+
 function _createPlatform(providers?: Array<Type | Provider | any[]>): PlatformRef {
   _platformProviders = providers;
-  _platform = new PlatformRef_(Injector.resolveAndCreate(providers), () => {
+  let injector = Injector.resolveAndCreate(providers);
+  _platform = new PlatformRef_(injector, () => {
     _platform = null;
     _platformProviders = null;
   });
+  _runPlatformInitializers(injector);
   return _platform;
 }
 
+function _runPlatformInitializers(injector: Injector): void {
+  let inits: Function[] = injector.getOptional(PLATFORM_INITIALIZER);
+  if (isPresent(inits)) inits.forEach(init => init());
+}
+
 /**
  * The Angular platform is the entry point for Angular on a web page. Each page
  * has exactly one platform, and services (such as reflection) which are common
@@ -236,11 +254,12 @@ export class PlatformRef_ extends PlatformRef {
     });
     app = new ApplicationRef_(this, zone, injector);
     this._applications.push(app);
+    _runAppInitializers(injector);
     return app;
   }
 
   dispose(): void {
-    this._applications.forEach((app) => app.dispose());
+    ListWrapper.clone(this._applications).forEach((app) => app.dispose());
     this._disposeListeners.forEach((dispose) => dispose());
     this._dispose();
   }
@@ -249,6 +268,11 @@ export class PlatformRef_ extends PlatformRef {
   _applicationDisposed(app: ApplicationRef): void { ListWrapper.remove(this._applications, app); }
 }
 
+function _runAppInitializers(injector: Injector): void {
+  let inits: Function[] = injector.getOptional(APP_INITIALIZER);
+  if (isPresent(inits)) inits.forEach(init => init());
+}
+
 /**
  * A reference to an Angular application running on a page.
  *
@@ -439,7 +463,7 @@ export class ApplicationRef_ extends ApplicationRef {
 
   dispose(): void {
     // TODO(alxhub): Dispose of the NgZone.
-    this._rootComponents.forEach((ref) => ref.dispose());
+    ListWrapper.clone(this._rootComponents).forEach((ref) => ref.dispose());
     this._disposeListeners.forEach((dispose) => dispose());
     this._platform._applicationDisposed(this);
   }

modules/angular2/src/core/application_tokens.ts

@@ -48,3 +48,14 @@ export const APP_ID_RANDOM_PROVIDER: Provider =
 function _randomChar(): string {
   return StringWrapper.fromCharCode(97 + Math.floor(Math.random() * 25));
 }
+
+/**
+ * A function that will be executed when a platform is initialized.
+ */
+export const PLATFORM_INITIALIZER: OpaqueToken =
+    CONST_EXPR(new OpaqueToken("Platform Initializer"));
+
+/**
+ * A function that will be executed when an application is initialized.
+ */
+export const APP_INITIALIZER: OpaqueToken = CONST_EXPR(new OpaqueToken("Application Initializer"));

modules/angular2/src/platform/browser_common.ts

@@ -11,13 +11,13 @@ import {
   reflector,
   APPLICATION_COMMON_PROVIDERS,
   PLATFORM_COMMON_PROVIDERS,
-  EVENT_MANAGER_PLUGINS
+  EVENT_MANAGER_PLUGINS,
+  PLATFORM_INITIALIZER
 } from "angular2/core";
 import {COMMON_DIRECTIVES, COMMON_PIPES, FORM_PROVIDERS} from "angular2/common";
 import {Renderer} from 'angular2/render';
 import {Testability} from 'angular2/src/core/testability/testability';
 
-// TODO change these imports once dom_adapter is moved out of core
 import {DOM} from 'angular2/src/core/dom/dom_adapter';
 import {DomEventsPlugin} from 'angular2/src/platform/dom/events/dom_events';
 import {KeyEventsPlugin} from 'angular2/src/platform/dom/events/key_events';
@@ -42,8 +42,10 @@ export {
 export {By} from 'angular2/src/platform/browser/debug/by';
 export {BrowserDomAdapter} from './browser/browser_adapter';
 
-export const BROWSER_PROVIDERS: Array<any /*Type | Provider | any[]*/> =
-    CONST_EXPR([PLATFORM_COMMON_PROVIDERS]);
+export const BROWSER_PROVIDERS: Array<any /*Type | Provider | any[]*/> = CONST_EXPR([
+  PLATFORM_COMMON_PROVIDERS,
+  new Provider(PLATFORM_INITIALIZER, {useValue: initDomAdapter, multi: true}),
+]);
 
 function _exceptionHandler(): ExceptionHandler {
   return new ExceptionHandler(DOM, false);
@@ -73,7 +75,6 @@ export const BROWSER_APP_COMMON_PROVIDERS: Array<any /*Type | Provider | any[]*/
 ]);
 
 export function initDomAdapter() {
-  // TODO: refactor into a generic init function
   BrowserDomAdapter.makeCurrent();
   wtfInit();
   BrowserGetTestability.init();

modules/angular2/test/platform/bootstrap_spec.ts

@@ -1,6 +1,7 @@
 import {
   AsyncTestCompleter,
   beforeEach,
+  afterEach,
   ddescribe,
   describe,
   expect,
@@ -8,6 +9,7 @@ import {
   inject,
   it,
   xdescribe,
+  Log,
   xit
 } from 'angular2/testing_internal';
 import {IS_DART, isPresent, stringify} from 'angular2/src/facade/lang';
@@ -18,7 +20,8 @@ import {BROWSER_PROVIDERS, BROWSER_APP_PROVIDERS} from 'angular2/platform/browse
 import {DOM} from 'angular2/src/core/dom/dom_adapter';
 import {DOCUMENT} from 'angular2/src/platform/dom/dom_tokens';
 import {PromiseWrapper} from 'angular2/src/facade/async';
-import {provide, Inject, Injector} from 'angular2/core';
+import {provide, Inject, Injector, PLATFORM_INITIALIZER, APP_INITIALIZER} from 'angular2/core';
+import {disposePlatform} from 'angular2/src/core/application_ref';
 import {ExceptionHandler} from 'angular2/src/facade/exceptions';
 import {Testability, TestabilityRegistry} from 'angular2/src/core/testability/testability';
 import {ComponentRef_} from "angular2/src/core/linker/dynamic_component_loader";
@@ -101,6 +104,8 @@ export function main() {
       testProviders = [provide(DOCUMENT, {useValue: fakeDoc})];
     });
 
+    afterEach(disposePlatform);
+
     it('should throw if bootstrapped Directive is not a Component',
        inject([AsyncTestCompleter], (async) => {
          var logger = new _ArrayLogger();
@@ -213,6 +218,23 @@ export function main() {
          });
        }));
 
+    it("should run platform initializers", inject([Log], (log: Log) => {
+         let p = platform([
+           BROWSER_PROVIDERS,
+           provide(PLATFORM_INITIALIZER, {useValue: log.fn("platform_init1"), multi: true}),
+           provide(PLATFORM_INITIALIZER, {useValue: log.fn("platform_init2"), multi: true})
+         ]);
+         expect(log.result()).toEqual("platform_init1; platform_init2");
+         log.clear();
+         p.application([
+           BROWSER_APP_PROVIDERS,
+           provide(APP_INITIALIZER, {useValue: log.fn("app_init1"), multi: true}),
+           provide(APP_INITIALIZER, {useValue: log.fn("app_init2"), multi: true})
+         ]);
+
+         expect(log.result()).toEqual("app_init1; app_init2");
+       }));
+
     it('should register each application with the testability registry',
        inject([AsyncTestCompleter], (async) => {
          var refPromise1 = bootstrap(HelloRootCmp, testProviders);

modules/angular2/test/public_api_spec.ts

@@ -27,6 +27,7 @@ import {SymbolsDiff} from './symbol_inspector/symbol_differ';
 
 var NG_ALL = [
   'APP_COMPONENT',
+  'APP_INITIALIZER',
   'APP_ID',
   'AbstractProviderError',
   'AbstractProviderError.addKey()',
@@ -1396,6 +1397,7 @@ var NG_ALL = [
   'resolveForwardRef():js',
   'wtfCreateScope():js',
   'PLATFORM_COMMON_PROVIDERS',
+  'PLATFORM_INITIALIZER',
   'wtfCreateScope:dart',
   'wtfEndTimeRange():js',
   'wtfEndTimeRange:dart',