[ReactNative][Navigation]: Add method `preventDefault()` to `NavigationEvent`

Libraries/CustomComponents/Navigator/Navigation/NavigationEvent.js

@@ -1,20 +1,119 @@
 /**
- * Copyright 2004-present Facebook. All Rights Reserved.
+ * Copyright (c) 2015, Facebook, Inc.  All rights reserved.
+ *
+ * Facebook, Inc. (“Facebook”) owns all right, title and interest, including
+ * all intellectual property and other proprietary rights, in and to the React
+ * Native CustomComponents software (the “Software”).  Subject to your
+ * compliance with these terms, you are hereby granted a non-exclusive,
+ * worldwide, royalty-free copyright license to (1) use and copy the Software;
+ * and (2) reproduce and distribute the Software as part of your own software
+ * (“Your Software”).  Facebook reserves all rights not expressly granted to
+ * you in this license agreement.
+ *
+ * THE SOFTWARE AND DOCUMENTATION, IF ANY, ARE PROVIDED "AS IS" AND ANY EXPRESS
+ * OR IMPLIED WARRANTIES (INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE) ARE DISCLAIMED.
+ * IN NO EVENT SHALL FACEBOOK OR ITS AFFILIATES, OFFICERS, DIRECTORS OR
+ * EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THE SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * @providesModule NavigationEvent
  * @flow
  */
 'use strict';
 
+var invariant = require('invariant');
+
+class NavigationEventPool {
+  _list: Array<any>;
+
+  constructor() {
+    this._list = [];
+  }
+
+  get(type: String, target: Object, data: any): NavigationEvent {
+    var event;
+    if (this._list.length > 0) {
+      event = this._list.pop();
+      event.constructor.call(event, type, target, data);
+    } else {
+      event = new NavigationEvent(type, target, data);
+    }
+    return event;
+  }
+
+  put(event: NavigationEvent) {
+    this._list.push(event);
+  }
+}
+
+var _navigationEventPool = new NavigationEventPool();
+
 class NavigationEvent {
-  type: String;
-  target: Object;
-  data: any;
+  _data: any;
+  _defaultPrevented: boolean;
+  _disposed: boolean;
+  _target: ?Object;
+  _type: ?String;
+
+  static pool(type: String, target: Object, data: any): NavigationEvent {
+    return _navigationEventPool.get(type, target, data);
+  }
 
   constructor(type: String, target: Object, data: any) {
-    this.type = type;
-    this.target = target;
-    this.data = data;
+    this._type = type;
+    this._target = target;
+    this._data = data;
+    this._defaultPrevented = false;
+    this._disposed = false;
+  }
+
+  /* $FlowFixMe - get/set properties not yet supported */
+  get type(): string {
+    return this._type;
+  }
+
+  /* $FlowFixMe - get/set properties not yet supported */
+  get target(): Object {
+    return this._target;
+  }
+
+  /* $FlowFixMe - get/set properties not yet supported */
+  get data(): any {
+    return this._data;
+  }
+
+  /* $FlowFixMe - get/set properties not yet supported */
+  get defaultPrevented(): boolean {
+    return this._defaultPrevented;
+  }
+
+  preventDefault(): void {
+    this._defaultPrevented = true;
+  }
+
+  /**
+   * Dispose the event.
+   * NavigationEvent shall be disposed after being emitted by
+   * `NavigationEventEmitter`.
+   */
+  dispose(): void {
+    invariant(!this._disposed, 'NavigationEvent is already disposed');
+    this._disposed = true;
+
+    // Clean up.
+    this._type = null;
+    this._target = null;
+    this._data = null;
+    this._defaultPrevented = false;
+
+    // Put this back to the pool to reuse the instance.
+    _navigationEventPool.put(this);
   }
 }
 

Libraries/CustomComponents/Navigator/Navigation/__tests__/NavigationEvent-test.js

@@ -0,0 +1,71 @@
+
+/**
+ * Copyright (c) 2015, Facebook, Inc.  All rights reserved.
+ *
+ * Facebook, Inc. (“Facebook”) owns all right, title and interest, including
+ * all intellectual property and other proprietary rights, in and to the React
+ * Native CustomComponents software (the “Software”).  Subject to your
+ * compliance with these terms, you are hereby granted a non-exclusive,
+ * worldwide, royalty-free copyright license to (1) use and copy the Software;
+ * and (2) reproduce and distribute the Software as part of your own software
+ * (“Your Software”).  Facebook reserves all rights not expressly granted to
+ * you in this license agreement.
+ *
+ * THE SOFTWARE AND DOCUMENTATION, IF ANY, ARE PROVIDED "AS IS" AND ANY EXPRESS
+ * OR IMPLIED WARRANTIES (INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE) ARE DISCLAIMED.
+ * IN NO EVENT SHALL FACEBOOK OR ITS AFFILIATES, OFFICERS, DIRECTORS OR
+ * EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THE SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+'use strict';
+
+jest
+  .dontMock('NavigationEvent')
+  .dontMock('invariant');
+
+var NavigationEvent = require('NavigationEvent');
+
+describe('NavigationEvent', () => {
+  it('constructs', () => {
+    var target = {};
+    var event = new NavigationEvent('foo', target, 123);
+    expect(event.type).toBe('foo');
+    expect(event.target).toBe(target);
+    expect(event.data).toBe(123);
+  });
+
+  it('constructs from pool', () => {
+    var target = {};
+    var event = NavigationEvent.pool('foo', target, 123);
+    expect(event.type).toBe('foo');
+    expect(event.target).toBe(target);
+    expect(event.data).toBe(123);
+  });
+
+  it('prevents default', () => {
+    var event = new NavigationEvent('foo', {}, 123);
+    expect(event.defaultPrevented).toBe(false);
+    event.preventDefault();
+    expect(event.defaultPrevented).toBe(true);
+  });
+
+  it('recycles', () => {
+    var event1 = NavigationEvent.pool('foo', {}, 123);
+    event1.dispose();
+    expect(event1.type).toBe(null);
+    expect(event1.data).toBe(null);
+    expect(event1.target).toBe(null);
+
+    var event2 = NavigationEvent.pool('bar', {}, 456);
+    expect(event2.type).toBe('bar');
+    expect(event2).toBe(event1);
+  });
+});
+
+