Merge pull request #899 from abarth/pointer_router

Add PointerRouter

packages/flutter/lib/base/pointer_router.dart

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:sky' as sky;
+
+import 'package:sky/base/hit_test.dart';
+
+typedef void _Route(sky.PointerEvent event);
+
+class PointerRouter extends HitTestTarget {
+  final Map<int, List<_Route>> _routeMap = new Map<int, List<_Route>>();
+
+  void addRoute(int pointer, _Route route) {
+    List<_Route> routes = _routeMap.putIfAbsent(pointer, () => new List<_Route>());
+    assert(!routes.contains(route));
+    routes.add(route);
+  }
+
+  void removeRoute(int pointer, _Route route) {
+    assert(_routeMap.containsKey(pointer));
+    List<_Route> routes = _routeMap[pointer];
+    assert(routes.contains(route));
+    routes.remove(route);
+    if (routes.isEmpty)
+      _routeMap.remove(pointer);
+  }
+
+  EventDisposition handleEvent(sky.Event e, HitTestEntry entry) {
+    if (e is! sky.PointerEvent)
+      return EventDisposition.ignored;
+    sky.PointerEvent event = e;
+    List<_Route> routes = _routeMap[event.pointer];
+    if (routes == null)
+      return EventDisposition.ignored;
+    for (_Route route in new List<_Route>.from(routes))
+      route(event);
+    return EventDisposition.processed;
+  }
+}

packages/flutter/lib/rendering/sky_binding.dart

@@ -4,6 +4,7 @@
 
 import 'dart:sky' as sky;
 
+import 'package:sky/base/pointer_router.dart';
 import 'package:sky/base/hit_test.dart';
 import 'package:sky/base/scheduler.dart' as scheduler;
 import 'package:sky/rendering/box.dart';
@@ -92,6 +93,8 @@ class SkyBinding {
     }
   }
 
+  final PointerRouter pointerRouter = new PointerRouter();
+
   Map<int, PointerState> _stateForPointer = new Map<int, PointerState>();
 
   PointerState _createStateForPointer(sky.PointerEvent event, Point position) {
@@ -127,6 +130,7 @@ class SkyBinding {
 
   HitTestResult hitTest(Point position) {
     HitTestResult result = new HitTestResult();
+    result.add(new HitTestEntry(pointerRouter));
     _renderView.hitTest(result, position: position);
     return result;
   }

packages/flutter/lib/widgets/drag_target.dart

@@ -5,6 +5,7 @@
 import 'dart:collection';
 
 import 'package:sky/base/hit_test.dart';
+import 'package:sky/rendering/object.dart';
 import 'package:sky/rendering/sky_binding.dart';
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/widgets/framework.dart';
@@ -80,6 +81,8 @@ class DragController {
 
   DragTarget _getDragTarget(List<HitTestEntry> path) {
     for (HitTestEntry entry in path.reversed) {
+      if (entry.target is! RenderObject)
+        continue;
       for (Widget widget in RenderObjectWrapper.getWidgetsForRenderObject(entry.target)) {
         if (widget is DragTarget)
           return widget;

packages/flutter/lib/widgets/framework.dart

@@ -1282,6 +1282,8 @@ class WidgetSkyBinding extends SkyBinding {
     if (disposition == EventDisposition.consumed)
       return EventDisposition.consumed;
     for (HitTestEntry entry in result.path.reversed) {
+      if (entry.target is! RenderObject)
+        continue;
       for (Widget target in RenderObjectWrapper.getWidgetsForRenderObject(entry.target)) {
         if (target is Listener) {
           EventDisposition targetDisposition = target._handleEvent(event);