From a33fe94dace7863131a3fa8d87a8ad75bfeaff02 Mon Sep 17 00:00:00 2001
From: Hedger Wang <hedger@fb.com>
Date: Fri, 30 Oct 2015 11:06:35 -0700
Subject: [PATCH] build nested navigation context based on the hierarchy of
 navigators.

Reviewed By: zjj010104

Differential Revision: D2598388

fb-gh-sync-id: 9655bcc86021678984e2a29df20ad2496a1762d1
---
 .../Navigator/Navigation/NavigationContext.js | 123 ++++++++++++------
 1 file changed, 80 insertions(+), 43 deletions(-)

diff --git a/Libraries/CustomComponents/Navigator/Navigation/NavigationContext.js b/Libraries/CustomComponents/Navigator/Navigation/NavigationContext.js
index dfce209bf..f1280295b 100644
--- a/Libraries/CustomComponents/Navigator/Navigation/NavigationContext.js
+++ b/Libraries/CustomComponents/Navigator/Navigation/NavigationContext.js
@@ -30,6 +30,8 @@ var NavigationEvent = require('NavigationEvent');
 var NavigationEventEmitter = require('NavigationEventEmitter');
 var NavigationTreeNode = require('NavigationTreeNode');
 
+var Set = require('Set');
+
 var emptyFunction = require('emptyFunction');
 var invariant = require('invariant');
 
@@ -41,6 +43,13 @@ var {
   CAPTURING_PHASE,
 } = NavigationEvent;
 
+// Event types that do not support event bubbling, capturing and
+// reconciliation API (e.g event.preventDefault(), event.stopPropagation()).
+var LegacyEventTypes = new Set([
+  'willfocus',
+  'didfocus',
+]);
+
 /**
  * Class that contains the info and methods for app navigation.
  */
@@ -88,9 +97,14 @@ class NavigationContext {
     context: ?Object,
     useCapture: ?boolean
   ): EventSubscription {
+    if (LegacyEventTypes.has(eventType)) {
+      useCapture = false;
+    }
+
     var emitter = useCapture ?
       this._captureEventEmitter :
       this._bubbleEventEmitter;
+
     if (emitter) {
       return emitter.addListener(eventType, listener, context);
     } else {
@@ -109,50 +123,65 @@ class NavigationContext {
 
     this._emitCounter++;
 
-    var targets = [this];
-    var parentTarget = this.parent;
-    while (parentTarget) {
-      targets.unshift(parentTarget);
-      parentTarget = parentTarget.parent;
+    if (LegacyEventTypes.has(eventType)) {
+      // Legacy events does not support event bubbling and reconciliation.
+      this.__emit(
+        eventType,
+        data,
+        null,
+        {
+          defaultPrevented: false,
+          eventPhase: AT_TARGET,
+          propagationStopped: true,
+          target: this,
+        }
+      );
+    } else {
+      var targets = [this];
+      var parentTarget = this.parent;
+      while (parentTarget) {
+        targets.unshift(parentTarget);
+        parentTarget = parentTarget.parent;
+      }
+
+      var propagationStopped = false;
+      var defaultPrevented = false;
+      var callback = (event) => {
+        propagationStopped = propagationStopped || event.isPropagationStopped();
+        defaultPrevented = defaultPrevented || event.defaultPrevented;
+      };
+
+      // Capture phase
+      targets.some((currentTarget) => {
+        if (propagationStopped) {
+          return true;
+        }
+
+        var extraInfo = {
+          defaultPrevented,
+          eventPhase: CAPTURING_PHASE,
+          propagationStopped,
+          target: this,
+        };
+
+        currentTarget.__emit(eventType, data, callback, extraInfo);
+      }, this);
+
+      // bubble phase
+      targets.reverse().some((currentTarget) => {
+        if (propagationStopped) {
+          return true;
+        }
+        var extraInfo = {
+          defaultPrevented,
+          eventPhase: BUBBLING_PHASE,
+          propagationStopped,
+          target: this,
+        };
+        currentTarget.__emit(eventType, data, callback, extraInfo);
+      }, this);
     }
 
-    var propagationStopped = false;
-    var defaultPrevented = false;
-    var callback = (event) => {
-      propagationStopped = propagationStopped || event.isPropagationStopped();
-      defaultPrevented = defaultPrevented || event.defaultPrevented;
-    };
-
-    // capture phase
-    targets.some((currentTarget) => {
-      if (propagationStopped) {
-        return true;
-      }
-
-      var extraInfo = {
-        defaultPrevented,
-        eventPhase: CAPTURING_PHASE,
-        propagationStopped,
-        target: this,
-      };
-
-      currentTarget.__emit(eventType, data, callback, extraInfo);
-    }, this);
-
-    // bubble phase
-    targets.reverse().some((currentTarget) => {
-      if (propagationStopped) {
-        return true;
-      }
-      var extraInfo = {
-        defaultPrevented,
-        eventPhase: BUBBLING_PHASE,
-        propagationStopped,
-        target: this,
-      };
-      currentTarget.__emit(eventType, data, callback, extraInfo);
-    }, this);
-
     if (didEmitCallback) {
       var event = NavigationEvent.pool(eventType, this, data);
       propagationStopped && event.stopPropagation();
@@ -189,9 +218,15 @@ class NavigationContext {
       case CAPTURING_PHASE: // phase = 1
         emitter = this._captureEventEmitter;
         break;
+
+      case AT_TARGET: // phase = 2
+        emitter = this._bubbleEventEmitter;
+        break;
+
       case BUBBLING_PHASE: // phase = 3
         emitter = this._bubbleEventEmitter;
         break;
+
       default:
         invariant(false, 'invalid event phase %s', extraInfo.eventPhase);
     }
@@ -214,8 +249,10 @@ class NavigationContext {
   _onFocus(event: NavigationEvent): void {
     invariant(
       event.data && event.data.hasOwnProperty('route'),
-      'didfocus event should provide route'
+      'event type "%s" should provide route',
+      event.type
     );
+
     this._currentRoute = event.data.route;
   }
 }