Extract TouchEventEmitter from ViewEventEmitter

Summary: In the future, we may want some components (like Virtual Text) to handle only touch events. Therefore, I've extracted `TouchEventEmitter` from `ViewEventEmitter`.

Reviewed By: shergin

Differential Revision: D9696903

fbshipit-source-id: f6acc90d8ff53b5e6badaa472a5e099fb7cf03ff

ReactCommon/fabric/components/view/TouchEventEmitter.cpp

@@ -0,0 +1,63 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "TouchEventEmitter.h"
+
+namespace facebook {
+namespace react {
+  
+#pragma mark - Touches
+  
+static folly::dynamic touchPayload(const Touch &touch) {
+  folly::dynamic object = folly::dynamic::object();
+  object["locationX"] = touch.offsetPoint.x;
+  object["locationY"] = touch.offsetPoint.x;
+  object["pageX"] = touch.pagePoint.x;
+  object["pageY"] = touch.pagePoint.x;
+  object["screenX"] = touch.screenPoint.x;
+  object["screenY"] = touch.screenPoint.x;
+  object["identifier"] = touch.identifier;
+  object["target"] = touch.target;
+  object["timestamp"] = touch.timestamp * 1000;
+  object["force"] = touch.force;
+  return object;
+}
+
+static folly::dynamic touchesPayload(const Touches &touches) {
+  folly::dynamic array = folly::dynamic::array();
+  for (const auto &touch : touches) {
+    array.push_back(touchPayload(touch));
+  }
+  return array;
+}
+
+static folly::dynamic touchEventPayload(const TouchEvent &event) {
+  folly::dynamic object = folly::dynamic::object();
+  object["touches"] = touchesPayload(event.touches);
+  object["changedTouches"] = touchesPayload(event.changedTouches);
+  object["targetTouches"] = touchesPayload(event.targetTouches);
+  return object;
+}
+
+void TouchEventEmitter::onTouchStart(const TouchEvent &event) const {
+  dispatchEvent("touchStart", touchEventPayload(event), EventPriority::SynchronousUnbatched);
+}
+
+void TouchEventEmitter::onTouchMove(const TouchEvent &event) const {
+  dispatchEvent("touchMove", touchEventPayload(event), EventPriority::SynchronousBatched);
+}
+
+void TouchEventEmitter::onTouchEnd(const TouchEvent &event) const {
+  dispatchEvent("touchEnd", touchEventPayload(event), EventPriority::SynchronousBatched);
+}
+
+void TouchEventEmitter::onTouchCancel(const TouchEvent &event) const {
+  dispatchEvent("touchCancel", touchEventPayload(event), EventPriority::SynchronousBatched);
+}
+  
+} // namespace react
+} // namespace facebook

ReactCommon/fabric/components/view/TouchEventEmitter.h

@@ -0,0 +1,112 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+#pragma once
+
+#include <fabric/core/ReactPrimitives.h>
+#include <fabric/core/LayoutMetrics.h>
+#include <fabric/events/EventEmitter.h>
+
+namespace facebook {
+namespace react {
+
+/*
+ * Describes an individual touch point for a touch event.
+ * See https://www.w3.org/TR/touch-events/ for more details.
+ */
+struct Touch {
+  /*
+   * The coordinate of point relative to the root component in points.
+   */
+  Point pagePoint;
+  
+  /*
+   * The coordinate of point relative to the target component in points.
+   */
+  Point offsetPoint;
+  
+  /*
+   * The coordinate of point relative to the screen component in points.
+   */
+  Point screenPoint;
+  
+  /*
+   * An identification number for each touch point.
+   */
+  int identifier;
+  
+  /*
+   * The tag of a component on which the touch point started when it was first placed on the surface,
+   * even if the touch point has since moved outside the interactive area of that element.
+   */
+  Tag target;
+  
+  /*
+   * The force of the touch.
+   */
+  Float force;
+  
+  /*
+   * The time in seconds when the touch occurred or when it was last mutated.
+   */
+  Float timestamp;
+  
+  /*
+   * The particular implementation of `Hasher` and (especially) `Comparator`
+   * make sense only when `Touch` object is used as a *key* in indexed collections.
+   * Because of that they are expressed as separate classes.
+   */
+  struct Hasher {
+    size_t operator()(const Touch &touch) const {
+      return std::hash<decltype(touch.identifier)>()(touch.identifier);
+    }
+  };
+  
+  struct Comparator {
+    bool operator()(const Touch &lhs, const Touch &rhs) const {
+      return lhs.identifier == rhs.identifier;
+    }
+  };
+};
+
+using Touches = std::unordered_set<Touch, Touch::Hasher, Touch::Comparator>;
+
+/*
+ * Defines the `touchstart`, `touchend`, `touchmove`, and `touchcancel` event types.
+ */
+struct TouchEvent {
+  /*
+   * A list of Touches for every point of contact currently touching the surface.
+   */
+  Touches touches;
+  
+  /*
+   * A list of Touches for every point of contact which contributed to the event.
+   */
+  Touches changedTouches;
+  
+  /*
+   * A list of Touches for every point of contact that is touching the surface
+   * and started on the element that is the target of the current event.
+   */
+  Touches targetTouches;
+};
+
+class TouchEventEmitter;
+using SharedTouchEventEmitter = std::shared_ptr<const TouchEventEmitter>;
+
+class TouchEventEmitter: public EventEmitter {
+public:
+  using EventEmitter::EventEmitter;
+  
+  void onTouchStart(const TouchEvent &event) const;
+  void onTouchMove(const TouchEvent &event) const;
+  void onTouchEnd(const TouchEvent &event) const;
+  void onTouchCancel(const TouchEvent &event) const;
+};
+
+} // namespace react
+} // namespace facebook

ReactCommon/fabric/components/view/ViewEventEmitter.cpp

@@ -38,54 +38,5 @@ void ViewEventEmitter::onLayout(const LayoutMetrics &layoutMetrics) const {
   dispatchEvent("layout", payload);
 }
 
-#pragma mark - Touches
-
-static folly::dynamic touchPayload(const Touch &touch) {
-  folly::dynamic object = folly::dynamic::object();
-  object["locationX"] = touch.offsetPoint.x;
-  object["locationY"] = touch.offsetPoint.x;
-  object["pageX"] = touch.pagePoint.x;
-  object["pageY"] = touch.pagePoint.x;
-  object["screenX"] = touch.screenPoint.x;
-  object["screenY"] = touch.screenPoint.x;
-  object["identifier"] = touch.identifier;
-  object["target"] = touch.target;
-  object["timestamp"] = touch.timestamp * 1000;
-  object["force"] = touch.force;
-  return object;
-}
-
-static folly::dynamic touchesPayload(const Touches &touches) {
-  folly::dynamic array = folly::dynamic::array();
-  for (const auto &touch : touches) {
-    array.push_back(touchPayload(touch));
-  }
-  return array;
-}
-
-static folly::dynamic touchEventPayload(const TouchEvent &event) {
-  folly::dynamic object = folly::dynamic::object();
-  object["touches"] = touchesPayload(event.touches);
-  object["changedTouches"] = touchesPayload(event.changedTouches);
-  object["targetTouches"] = touchesPayload(event.targetTouches);
-  return object;
-}
-
-void ViewEventEmitter::onTouchStart(const TouchEvent &event) const {
-  dispatchEvent("touchStart", touchEventPayload(event), EventPriority::SynchronousUnbatched);
-}
-
-void ViewEventEmitter::onTouchMove(const TouchEvent &event) const {
-  dispatchEvent("touchMove", touchEventPayload(event), EventPriority::SynchronousBatched);
-}
-
-void ViewEventEmitter::onTouchEnd(const TouchEvent &event) const {
-  dispatchEvent("touchEnd", touchEventPayload(event), EventPriority::SynchronousBatched);
-}
-
-void ViewEventEmitter::onTouchCancel(const TouchEvent &event) const {
-  dispatchEvent("touchCancel", touchEventPayload(event), EventPriority::SynchronousBatched);
-}
-
 } // namespace react
 } // namespace facebook

ReactCommon/fabric/components/view/ViewEventEmitter.h

@@ -10,103 +10,19 @@
 
 #include <fabric/core/LayoutMetrics.h>
 #include <fabric/core/ReactPrimitives.h>
-#include <fabric/events/EventEmitter.h>
+#include "TouchEventEmitter.h"
 
 namespace facebook {
 namespace react {
 
-/*
- * Describes an individual touch point for a touch event.
- * See https://www.w3.org/TR/touch-events/ for more details.
- */
-struct Touch {
-  /*
-   * The coordinate of point relative to the root component in points.
-   */
-  Point pagePoint;
-
-  /*
-   * The coordinate of point relative to the target component in points.
-   */
-  Point offsetPoint;
-
-  /*
-   * The coordinate of point relative to the screen component in points.
-   */
-  Point screenPoint;
-
-  /*
-   * An identification number for each touch point.
-   */
-  int identifier;
-
-  /*
-   * The tag of a component on which the touch point started when it was first placed on the surface,
-   * even if the touch point has since moved outside the interactive area of that element.
-   */
-  Tag target;
-
-  /*
-   * The force of the touch.
-   */
-  Float force;
-
-  /*
-   * The time in seconds when the touch occurred or when it was last mutated.
-   */
-  Float timestamp;
-
-  /*
-   * The particular implementation of `Hasher` and (especially) `Comparator`
-   * make sense only when `Touch` object is used as a *key* in indexed collections.
-   * Because of that they are expressed as separate classes.
-   */
-  struct Hasher {
-    size_t operator()(const Touch &touch) const {
-      return std::hash<decltype(touch.identifier)>()(touch.identifier);
-    }
-  };
-
-  struct Comparator {
-    bool operator()(const Touch &lhs, const Touch &rhs) const {
-      return lhs.identifier == rhs.identifier;
-    }
-  };
-};
-
-using Touches = std::unordered_set<Touch, Touch::Hasher, Touch::Comparator>;
-
-/*
- * Defines the `touchstart`, `touchend`, `touchmove`, and `touchcancel` event types.
- */
-struct TouchEvent {
-  /*
-   * A list of Touches for every point of contact currently touching the surface.
-   */
-  Touches touches;
-
-  /*
-   * A list of Touches for every point of contact which contributed to the event.
-   */
-  Touches changedTouches;
-
-  /*
-   * A list of Touches for every point of contact that is touching the surface
-   * and started on the element that is the target of the current event.
-   */
-  Touches targetTouches;
-};
-
 class ViewEventEmitter;
 
 using SharedViewEventEmitter = std::shared_ptr<const ViewEventEmitter>;
 
 class ViewEventEmitter:
-  public EventEmitter {
-
+  public TouchEventEmitter {
 public:
-
-  using EventEmitter::EventEmitter;
+  using TouchEventEmitter::TouchEventEmitter;
 
 #pragma mark - Accessibility
 
@@ -117,13 +33,6 @@ public:
 #pragma mark - Layout
 
   void onLayout(const LayoutMetrics &layoutMetrics) const;
-
-#pragma mark - Touches
-
-  void onTouchStart(const TouchEvent &event) const;
-  void onTouchMove(const TouchEvent &event) const;
-  void onTouchEnd(const TouchEvent &event) const;
-  void onTouchCancel(const TouchEvent &event) const;
 };
 
 } // namespace react