IPC::ParamTraits for ui::Event (towards ui::Events over mojo IPC)

ui/events/event.h

 // Copyright (c) 2012 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.
 
 #ifndef UI_EVENTS_EVENT_H_
 #define UI_EVENTS_EVENT_H_
 
 #include <stdint.h>
-
 #include "base/compiler_specific.h"
 #include "base/event_types.h"
 #include "base/gtest_prod_util.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
+#include "ipc/ipc_message_utils.h"
 #include "ui/events/event_constants.h"
 #include "ui/events/gesture_event_details.h"
 #include "ui/events/gestures/gesture_types.h"
 #include "ui/events/keycodes/dom/dom_key.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 #include "ui/events/latency_info.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/point_conversions.h"
 
 namespace gfx {
 class Transform;
 }
 
 namespace ui {
 class EventTarget;
 enum class DomCode;
+class Event;
+
+typedef scoped_ptr<Event> ScopedEvent;
 

[Tom Sepez, 2016/02/18 18:46:10]

nit: using ScopedEvent = scoped_ptr<Event>;

[Mark Dittmer, 2016/02/18 19:12:56]

Done.

 class EVENTS_EXPORT Event {
  public:
   static scoped_ptr<Event> Clone(const Event& event);
 
   virtual ~Event();
 
   class DispatcherApi {
    public:
     explicit DispatcherApi(Event* event) : event_(event) {}
 
@@ skipping 189 matching lines @@
 
   void set_time_stamp(const base::TimeDelta& time_stamp) {
     time_stamp_ = time_stamp;
   }
 
   void set_name(const std::string& name) { name_ = name; }
 
  private:
   friend class EventTestApi;
 
+  // For (de)serialization.
+  friend struct IPC::ParamTraits<ui::ScopedEvent>;

[Tom Sepez, 2016/02/18 18:46:10]

jam@ and I have argued about this in the past -- it's a layering violation for
this code to know about IPC traits.  I'll add him to see if he still feels the
same way.

[Mark Dittmer, 2016/02/18 19:12:56]

What is the proposed implementation alternative? Require getters + setters for
all serializable data?

[jam, 2016/02/18 21:01:26]

I care less about this now. 

My main question is who will use these traits? If it's just mus, why aren't the
ipc related code in mus' directory?

+
   EventType type_;
   std::string name_;
   base::TimeDelta time_stamp_;
   LatencyInfo latency_;
   int flags_;
   base::NativeEvent native_event_;
   bool delete_native_event_;
   bool cancelable_;
   EventTarget* target_;
   EventPhase phase_;
   EventResult result_;
 
   // The device id the event came from, or ED_UNKNOWN_DEVICE if the information
   // is not available.
   int source_device_id_;
 };
 
 class EVENTS_EXPORT CancelModeEvent : public Event {
  public:
   CancelModeEvent();
   ~CancelModeEvent() override;
+
+ private:
+  // For (de)serialization.
+  explicit CancelModeEvent(EventType type,

[Tom Sepez, 2016/02/18 18:46:10]

Nit: no |explicit| as it's not a single-arg ctor.

[Mark Dittmer, 2016/02/18 19:12:56]

Done.

+                           base::TimeDelta time_stamp,
+                           int flags)
+      : Event(type, time_stamp, flags) {}
+  friend struct IPC::ParamTraits<ui::ScopedEvent>;
+  friend struct IPC::ParamTraits<ui::CancelModeEvent>;
 };
 
+class MouseWheelEvent;

[Tom Sepez, 2016/02/18 18:46:10]

nit: move to top

[Mark Dittmer, 2016/02/18 19:12:56]

Done.

+
 class EVENTS_EXPORT LocatedEvent : public Event {
  public:
   ~LocatedEvent() override;
 
   float x() const { return location_.x(); }
   float y() const { return location_.y(); }
   void set_location(const gfx::Point& location) {
     location_ = gfx::PointF(location);
   }
   void set_location_f(const gfx::PointF& location) { location_ = location; }
@@ skipping 21 matching lines @@
     if (!target || target == source)
       return;
     gfx::Point offset = gfx::ToFlooredPoint(location_);
     T::ConvertPointToTarget(source, target, &offset);
     gfx::Vector2d diff = gfx::ToFlooredPoint(location_) - offset;
     location_= location_ - diff;
   }
 
  protected:
   friend class LocatedEventTestApi;
+
+  // For (de)serialization.
+  explicit LocatedEvent(EventType type, base::TimeDelta time_stamp, int flags)
+      : Event(type, time_stamp, flags) {}
+  friend struct IPC::ParamTraits<ui::ScopedEvent>;
+  friend struct IPC::ParamTraits<ui::LocatedEvent>;
+
   explicit LocatedEvent(const base::NativeEvent& native_event);
 
   // Create a new LocatedEvent which is identical to the provided model.
   // If source / target windows are provided, the model location will be
   // converted from |source| coordinate system to |target| coordinate system.
   template <class T>
   LocatedEvent(const LocatedEvent& model, T* source, T* target)
       : Event(model),
         location_(model.location_),
         root_location_(model.root_location_) {
@@ skipping 40 matching lines @@
   bool operator==(const PointerDetails& other) const {
     return pointer_type == other.pointer_type &&
            radius_x == other.radius_x &&
            radius_y == other.radius_y &&
            (force == other.force ||
             (std::isnan(force) && std::isnan(other.force))) &&
            tilt_x == other.tilt_x &&
            tilt_y == other.tilt_y;
   }
 
+  // For serialization.
+  friend struct IPC::ParamTraits<ui::PointerDetails>;
+
   // The type of pointer device.
   EventPointerType pointer_type = EventPointerType::POINTER_TYPE_UNKNOWN;
 
   // Radius of the X (major) axis of the touch ellipse. 0.0 if unknown.
   float radius_x = 0.0;
 
   // Radius of the Y (minor) axis of the touch ellipse. 0.0 if unknown.
   float radius_y = 0.0;
 
   // Force (pressure) of the touch. Normalized to be [0, 1] except NaN means
@@ skipping 99 matching lines @@
 
   // Updates the button that changed.
   void set_changed_button_flags(int flags) { changed_button_flags_ = flags; }
 
   // Event details common to MouseEvent and TouchEvent.
   const PointerDetails& pointer_details() const { return pointer_details_; }
   void set_pointer_details(const PointerDetails& details) {
     pointer_details_ = details;
   }
 
+ protected:
+  // For (de)serialization.
+  explicit MouseEvent(EventType type, base::TimeDelta time_stamp, int flags)
+      : LocatedEvent(type, time_stamp, flags) {}
+  friend struct IPC::ParamTraits<ui::ScopedEvent>;
+  friend struct IPC::ParamTraits<ui::MouseEvent>;
+
  private:
   FRIEND_TEST_ALL_PREFIXES(EventTest, DoubleClickRequiresRelease);
   FRIEND_TEST_ALL_PREFIXES(EventTest, SingleClickRightLeft);
 
   // Returns the repeat count based on the previous mouse click, if it is
   // recent enough and within a small enough distance.
   static int GetRepeatCount(const MouseEvent& click_event);
 
   // Resets the last_click_event_ for unit tests.
   static void ResetLastClickForTest();
@@ skipping 40 matching lines @@
                   int flags,
                   int changed_button_flags);
 
   // The amount to scroll. This is in multiples of kWheelDelta.
   // Note: x_offset() > 0/y_offset() > 0 means scroll left/up.
   int x_offset() const { return offset_.x(); }
   int y_offset() const { return offset_.y(); }
   const gfx::Vector2d& offset() const { return offset_; }
 
  private:
+  // For (de)serialization.
+  explicit MouseWheelEvent(EventType type,
+                           base::TimeDelta time_stamp,
+                           int flags)
+      : MouseEvent(type, time_stamp, flags) {}
+  friend struct IPC::ParamTraits<ui::ScopedEvent>;
+  friend struct IPC::ParamTraits<ui::MouseWheelEvent>;
+
   gfx::Vector2d offset_;
 };
 
 class EVENTS_EXPORT TouchEvent : public LocatedEvent {
  public:
   explicit TouchEvent(const base::NativeEvent& native_event);
 
   // Create a new TouchEvent which is identical to the provided model.
   // If source / target windows are provided, the model location will be
   // converted from |source| coordinate system to |target| coordinate system.
@@ skipping 52 matching lines @@
     return !!(result() & ER_DISABLE_SYNC_HANDLING);
   }
 
   // Event details common to MouseEvent and TouchEvent.
   const PointerDetails& pointer_details() const { return pointer_details_; }
   void set_pointer_details(const PointerDetails& pointer_details) {
     pointer_details_ = pointer_details;
   }
 
  private:
+  // For (de)serialization.
+  explicit TouchEvent(EventType type, base::TimeDelta time_stamp, int flags)
+      : LocatedEvent(type, time_stamp, flags),
+        should_remove_native_touch_id_mapping_(false) {}
+  friend struct IPC::ParamTraits<ui::ScopedEvent>;
+  friend struct IPC::ParamTraits<ui::TouchEvent>;
+
   // Adjusts rotation_angle_ to within the acceptable range.
   void FixRotationAngle();
 
   // The identity (typically finger) of the touch starting at 0 and incrementing
   // for each separable additional touch that the hardware can detect.
-  const int touch_id_;
+  int touch_id_;
 
   // A unique identifier for the touch event.
-  const uint32_t unique_event_id_;
+  uint32_t unique_event_id_;
 
   // Clockwise angle (in degrees) of the major axis from the X axis. Must be
   // less than 180 and non-negative.
   float rotation_angle_;
 
   // Whether the (unhandled) touch event will produce a scroll event (e.g., a
   // touchmove that exceeds the platform slop region, or a touchend that
   // causes a fling). Defaults to false.
   bool may_cause_scrolling_;
 
@@ skipping 180 matching lines @@
   // (Native X11 event flags describe the state before the event.)
   void NormalizeFlags();
 
  protected:
   friend class KeyEventTestApi;
 
   // This allows a subclass TranslatedKeyEvent to be a non character event.
   void set_is_char(bool is_char) { is_char_ = is_char; }
 
  private:
+  // For (de)serialization.
+  explicit KeyEvent(EventType type, base::TimeDelta time_stamp, int flags);
+  friend struct IPC::ParamTraits<ui::ScopedEvent>;
+  friend struct IPC::ParamTraits<ui::KeyEvent>;
+
   // Determine key_ on a keystroke event from code_ and flags().
   void ApplyLayout() const;
 
   KeyboardCode key_code_;
 
   // DOM KeyboardEvent |code| (e.g. DomCode::US_A, DomCode::SPACE).
   // http://www.w3.org/TR/DOM-Level-3-Events-code/
   //
   // This value represents the physical position in the keyboard and can be
   // converted from / to keyboard scan code like XKB.
@@ skipping 58 matching lines @@
   // to provide a consistent user experience.
   void Scale(const float factor);
 
   float x_offset() const { return x_offset_; }
   float y_offset() const { return y_offset_; }
   float x_offset_ordinal() const { return x_offset_ordinal_; }
   float y_offset_ordinal() const { return y_offset_ordinal_; }
   int finger_count() const { return finger_count_; }
 
  private:
+  // For (de)serialization.
+  explicit ScrollEvent(EventType type, base::TimeDelta time_stamp, int flags)
+      : MouseEvent(type, time_stamp, flags) {}
+  friend struct IPC::ParamTraits<ui::ScopedEvent>;
+  friend struct IPC::ParamTraits<ui::ScrollEvent>;
+
   // Potential accelerated offsets.
   float x_offset_;
   float y_offset_;
   // Unaccelerated offsets.
   float x_offset_ordinal_;
   float y_offset_ordinal_;
   // Number of fingers on the pad.
   int finger_count_;
 };
 
@@ skipping 12 matching lines @@
   GestureEvent(const GestureEvent& model, T* source, T* target)
       : LocatedEvent(model, source, target),
         details_(model.details_) {
   }
 
   ~GestureEvent() override;
 
   const GestureEventDetails& details() const { return details_; }
 
  private:
+  // For (de)serialization.
+  explicit GestureEvent(EventType type, base::TimeDelta time_stamp, int flags)
+      : LocatedEvent(type, time_stamp, flags) {}
+  friend struct IPC::ParamTraits<ui::ScopedEvent>;
+  friend struct IPC::ParamTraits<ui::GestureEvent>;
+
   GestureEventDetails details_;
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_EVENT_H_