feat(directionality): a provider to get the overall directionality

- Looks at the `html` and `body` elements for `dir` attribute and sets the Directionality service value to it
- Whenever someone would try to inject Directionality - if there's a Dir directive up the dom tree it would be provided

fixes angular#3600

src/lib/autocomplete/autocomplete-trigger.ts

@@ -20,7 +20,7 @@ import {ConnectedPositionStrategy} from '../core/overlay/position/connected-posi
 import {Observable} from 'rxjs/Observable';
 import {MdOptionSelectionChange, MdOption} from '../core/option/option';
 import {ENTER, UP_ARROW, DOWN_ARROW, ESCAPE} from '../core/keyboard/keycodes';
-import {Dir} from '../core/rtl/dir';
+import {Directionality} from '../core/bidi/index';
 import {MdInputContainer} from '../input/input-container';
 import {ScrollDispatcher} from '../core/overlay/scroll/scroll-dispatcher';
 import {Subscription} from 'rxjs/Subscription';
@@ -103,9 +103,10 @@ export class MdAutocompleteTrigger implements ControlValueAccessor, OnDestroy {
 
   constructor(private _element: ElementRef, private _overlay: Overlay,
               private _viewContainerRef: ViewContainerRef,
+              private _zone: NgZone,
               private _changeDetectorRef: ChangeDetectorRef,
               private _scrollDispatcher: ScrollDispatcher,
-              @Optional() private _dir: Dir, private _zone: NgZone,
+              @Optional() private _dir: Directionality,
               @Optional() @Host() private _inputContainer: MdInputContainer,
               @Optional() @Inject(DOCUMENT) private _document: any) {}
 

src/lib/autocomplete/autocomplete.spec.ts

@@ -13,7 +13,7 @@ import {NoopAnimationsModule} from '@angular/platform-browser/animations';
 import {MdAutocompleteModule, MdAutocompleteTrigger} from './index';
 import {OverlayContainer} from '../core/overlay/overlay-container';
 import {MdInputModule} from '../input/index';
-import {Dir, LayoutDirection} from '../core/rtl/dir';
+import {Directionality, Direction} from '../core/bidi/index';
 import {FormControl, FormsModule, ReactiveFormsModule} from '@angular/forms';
 import {Subscription} from 'rxjs/Subscription';
 import {ENTER, DOWN_ARROW, SPACE, UP_ARROW, ESCAPE} from '../core/keyboard/keycodes';
@@ -31,7 +31,7 @@ import 'rxjs/add/operator/map';
 
 describe('MdAutocomplete', () => {
   let overlayContainerElement: HTMLElement;
-  let dir: LayoutDirection;
+  let dir: Direction;
   let scrolledSubject = new Subject();
 
   beforeEach(async(() => {
@@ -65,7 +65,7 @@ describe('MdAutocomplete', () => {
 
           return {getContainerElement: () => overlayContainerElement};
         }},
-        {provide: Dir, useFactory: () => ({value: dir})},
+        {provide: Directionality, useFactory: () => ({value: dir})},
         {provide: ScrollDispatcher, useFactory: () => {
           return {scrolled: (delay: number, callback: () => any) => {
             return scrolledSubject.asObservable().subscribe(callback);

src/lib/core/bidi/dir.ts

@@ -0,0 +1,58 @@
+import {
+  Directive,
+  HostBinding,
+  Output,
+  Input,
+  EventEmitter
+} from '@angular/core';
+
+import {Direction, Directionality} from './directionality';
+
+/**
+ * Directive to listen for changes of direction of part of the DOM.
+ *
+ * Would provide itself in case a component looks for the Directionality service
+ */
+@Directive({
+  selector: '[dir]',
+  // TODO(hansl): maybe `$implicit` isn't the best option here, but for now that's the best we got.
+  exportAs: '$implicit',
+  providers: [
+    {provide: Directionality, useExisting: Dir}
+  ]
+})
+export class Dir implements Directionality {
+  /** Layout direction of the element. */
+  _dir: Direction = 'ltr';
+
+  /** Whether the `value` has been set to its initial value. */
+  private _isInitialized: boolean = false;
+
+  /** Event emitted when the direction changes. */
+  @Output('dirChange') change = new EventEmitter<void>();
+
+  /** @docs-private */
+  @HostBinding('attr.dir')
+  @Input('dir')
+  get dir(): Direction {
+    return this._dir;
+  }
+
+  set dir(v: Direction) {
+    let old = this._dir;
+    this._dir = v;
+    if (old !== this._dir && this._isInitialized) {
+      this.change.emit();
+    }
+  }
+
+  /** Current layout direction of the element. */
+  get value(): Direction { return this.dir; }
+  set value(v: Direction) { this.dir = v; }
+
+  /** Initialize once default value has been set. */
+  ngAfterContentInit() {
+    this._isInitialized = true;
+  }
+}
+

src/lib/core/bidi/directionality.spec.ts

@@ -0,0 +1,121 @@
+import {async, fakeAsync, TestBed} from '@angular/core/testing';
+import {Component, getDebugNode} from '@angular/core';
+import {Dir, Directionality} from './index';
+import {tick} from "@angular/core/testing";
+
+function initDir () {
+  document.documentElement.dir = '';
+  document.body.dir = '';
+}
+
+fdescribe('Directionality', () => {
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      providers: [Directionality],
+      declarations: [TestAppWithoutDir]
+    });
+
+    TestBed.compileComponents();
+
+    initDir();
+  }));
+
+  it('should read dir from the html element if not specified on the body', () => {
+    document.documentElement.dir = 'rtl';
+
+    let fixture = TestBed.createComponent(TestAppWithoutDir);
+    let testComponent = fixture.debugElement.componentInstance;
+
+    expect(testComponent.dir.value).toBe('rtl');
+  });
+
+  it('should read dir from the body even it is also specified on the html element', () => {
+    document.documentElement.dir = 'ltr';
+    document.body.dir = 'rtl';
+
+    let fixture = TestBed.createComponent(TestAppWithoutDir);
+    let testComponent = fixture.debugElement.componentInstance;
+
+    expect(testComponent.dir.value).toBe('rtl');
+  });
+
+  it('should default to ltr if nothing is specified on either body or the html element', () => {
+    let fixture = TestBed.createComponent(TestAppWithoutDir);
+    let testComponent = fixture.debugElement.componentInstance;
+
+    expect(testComponent.dir.value).toBe('ltr');
+  });
+});
+
+fdescribe('Dir directive', () => {
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      declarations: [Dir, TestAppWithDir, DirTest]
+    });
+
+    TestBed.compileComponents();
+
+    initDir();
+  }));
+
+  it('should provide itself as Directionality', () => {
+    let fixture = TestBed.createComponent(TestAppWithDir);
+    let testComponent =
+      getDebugNode(fixture.nativeElement.querySelector('dir-test')).componentInstance;
+
+    fixture.detectChanges();
+
+    expect(testComponent.dir.value).toBe('rtl');
+  });
+
+  it('should emit a change event when the value changes', fakeAsync(() => {
+    let fixture = TestBed.createComponent(TestAppWithDir);
+    let testComponent =
+      getDebugNode(fixture.nativeElement.querySelector('dir-test')).componentInstance;
+
+    fixture.detectChanges();
+
+    expect(testComponent.dir.value).toBe('rtl');
+    expect(fixture.componentInstance.changeCount).toBe(0);
+
+    fixture.componentInstance.direction = 'ltr';
+
+    fixture.detectChanges();
+    tick();
+
+    expect(testComponent.dir.value).toBe('ltr');
+    expect(fixture.componentInstance.changeCount).toBe(1);
+  }));
+});
+
+/** Test component without Dir. */
+@Component({
+  selector: 'test-app-without-dir',
+  template: `<div></div>`
+})
+class TestAppWithoutDir {
+  constructor(public dir: Directionality) {}
+}
+
+/** Test component without Dir. */
+@Component({
+  selector: 'test-app-with-dir',
+  template: `
+    <div [dir]="direction" (dirChange)="changeCount= changeCount + 1">
+      <dir-test></dir-test>
+    </div>
+  `
+})
+class TestAppWithDir {
+  direction = 'rtl';
+  changeCount = 0;
+}
+
+/** Test component with Dir directive. */
+@Component({
+  selector: 'dir-test',
+  template: `<div></div>`
+})
+class DirTest {
+  constructor(public dir: Directionality) {}
+}

src/lib/core/bidi/directionality.ts

@@ -0,0 +1,40 @@
+import {
+  EventEmitter,
+  Injectable,
+  Optional,
+  SkipSelf
+} from '@angular/core';
+
+export type Direction = 'ltr' | 'rtl';
+
+/**
+ * The directionality (LTR / RTL) context for the application (or a subtree of it).
+ * Exposes the current direction and a stream of direction changes.
+ */
+@Injectable()
+export class Directionality {
+  value: Direction = 'ltr';
+  public change = new EventEmitter<void>();
+
+  constructor() {
+    if (typeof document) {
+      // TODO: handle 'auto' value -
+      // We still need to account for dir="auto".
+      // It looks like HTMLElemenet.dir is also "auto" when that's set to the attribute,
+      // but getComputedStyle return either "ltr" or "rtl". avoiding getComputedStyle for now
+      // though, we're already calling it for the theming check.
+      this.value = (document.body.dir || document.documentElement.dir || 'ltr') as Direction;
+    }
+  }
+}
+
+export function DIRECTIONALITY_PROVIDER_FACTORY(parentDirectionality) {
+  return parentDirectionality || new Directionality();
+}
+
+export const DIRECTIONALITY_PROVIDER = {
+  // If there is already a Directionality available, use that. Otherwise, provide a new one.
+  provide: Directionality,
+  deps: [[new Optional(), new SkipSelf(), Directionality]],
+  useFactory: DIRECTIONALITY_PROVIDER_FACTORY
+};

src/lib/core/bidi/index.ts

@@ -0,0 +1,25 @@
+import {ModuleWithProviders, NgModule} from '@angular/core';
+import {Dir} from './dir';
+import {Directionality, DIRECTIONALITY_PROVIDER} from './directionality';
+
+export {
+  Directionality,
+  DIRECTIONALITY_PROVIDER,
+  Direction
+} from './directionality';
+export {Dir} from './dir';
+
+@NgModule({
+  exports: [Dir],
+  declarations: [Dir],
+  providers: [Directionality]
+})
+export class BidiModule {
+  /** @deprecated */
+  static forRoot(): ModuleWithProviders {
+    return {
+      ngModule: BidiModule,
+      providers: [DIRECTIONALITY_PROVIDER]
+    };
+  }
+}

src/lib/core/core.ts

@@ -1,6 +1,6 @@
 import {NgModule} from '@angular/core';
 import {MdLineModule} from './line/line';
-import {RtlModule} from './rtl/dir';
+import {BidiModule} from './bidi/index';
 import {ObserveContentModule} from './observe-content/observe-content';
 import {MdOptionModule} from './option/option';
 import {PortalModule} from './portal/portal-directives';
@@ -11,7 +11,7 @@ import {MdRippleModule} from './ripple/index';
 
 
 // RTL
-export {Dir, LayoutDirection, RtlModule} from './rtl/dir';
+export {Dir, Direction, Directionality, BidiModule} from './bidi/index';
 
 // Mutation Observer
 export {ObserveContentModule, ObserveContent} from './observe-content/observe-content';
@@ -106,7 +106,7 @@ export * from './datetime/index';
 @NgModule({
   imports: [
     MdLineModule,
-    RtlModule,
+    BidiModule,
     MdRippleModule,
     ObserveContentModule,
     PortalModule,
@@ -117,7 +117,7 @@ export * from './datetime/index';
   ],
   exports: [
     MdLineModule,
-    RtlModule,
+    BidiModule,
     MdRippleModule,
     ObserveContentModule,
     PortalModule,

src/lib/core/overlay/overlay-directives.spec.ts

@@ -5,7 +5,7 @@ import {ConnectedOverlayDirective, OverlayModule, OverlayOrigin} from './overlay
 import {OverlayContainer} from './overlay-container';
 import {ConnectedPositionStrategy} from './position/connected-position-strategy';
 import {ConnectedOverlayPositionChange} from './position/connected-position';
-import {Dir} from '../rtl/dir';
+import {Directionality} from '../bidi/index';
 import {dispatchKeyboardEvent} from '../testing/dispatch-events';
 import {ESCAPE} from '../keyboard/keycodes';
 
@@ -24,7 +24,7 @@ describe('Overlay directives', () => {
           overlayContainerElement = document.createElement('div');
           return {getContainerElement: () => overlayContainerElement};
         }},
-        {provide: Dir, useFactory: () => {
+        {provide: Directionality, useFactory: () => {
           return dir = { value: 'ltr' };
         }}
       ],

src/lib/core/overlay/overlay-directives.ts

@@ -23,7 +23,7 @@ import {
 } from './position/connected-position';
 import {PortalModule} from '../portal/portal-directives';
 import {ConnectedPositionStrategy} from './position/connected-position-strategy';
-import {Dir, LayoutDirection} from '../rtl/dir';
+import {Directionality, Direction} from '../bidi/index';
 import {Scrollable} from './scroll/scrollable';
 import {RepositionScrollStrategy} from './scroll/reposition-scroll-strategy';
 import {ScrollStrategy} from './scroll/scroll-strategy';
@@ -160,7 +160,7 @@ export class ConnectedOverlayDirective implements OnDestroy, OnChanges {
       private _scrollDispatcher: ScrollDispatcher,
       templateRef: TemplateRef<any>,
       viewContainerRef: ViewContainerRef,
-      @Optional() private _dir: Dir) {
+      @Optional() private _dir: Directionality) {
     this._templatePortal = new TemplatePortal(templateRef, viewContainerRef);
   }
 
@@ -170,7 +170,7 @@ export class ConnectedOverlayDirective implements OnDestroy, OnChanges {
   }
 
   /** The element's layout direction. */
-  get dir(): LayoutDirection {
+  get dir(): Direction {
     return this._dir ? this._dir.value : 'ltr';
   }
 

src/lib/core/overlay/overlay-state.ts

@@ -1,5 +1,5 @@
 import {PositionStrategy} from './position/position-strategy';
-import {LayoutDirection} from '../rtl/dir';
+import {Direction} from '../bidi/index';
 import {ScrollStrategy} from './scroll/scroll-strategy';
 import {NoopScrollStrategy} from './scroll/noop-scroll-strategy';
 
@@ -37,7 +37,7 @@ export class OverlayState {
   minHeight: number | string;
 
   /** The direction of the text in the overlay panel. */
-  direction: LayoutDirection = 'ltr';
+  direction: Direction = 'ltr';
 
   // TODO(jelbourn): configuration still to add
   // - focus trap