Touch emulator: allow multiple touch streams.

content/browser/renderer_host/input/touch_emulator.cc

 // Copyright 2014 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.
 
 #include "content/browser/renderer_host/input/touch_emulator.h"
 
 #include "content/browser/renderer_host/input/motion_event_web.h"
 #include "content/browser/renderer_host/input/web_input_event_util.h"
 #include "content/common/input/web_touch_event_traits.h"
 #include "content/public/common/content_client.h"
@@ skipping 29 matching lines @@
 // Time between two consecutive mouse moves, during which second mouse move
 // is not converted to touch.
 const double kMouseMoveDropIntervalSeconds = 5.f / 1000;
 
 } // namespace
 
 TouchEmulator::TouchEmulator(TouchEmulatorClient* client)
     : client_(client),
       gesture_provider_(GetGestureProviderConfig(), this),
       enabled_(false),
-      allow_pinch_(false) {
+      allow_pinch_(false),
+      emulated_stream_active_sequence_count_(0),

[jdduke (slow), 2014/07/18 15:01:05]

Good catch.

+      native_stream_active_sequence_count_(0) {
   DCHECK(client_);
   ResetState();
 
   bool use_2x = gfx::Screen::GetNativeScreen()->
       GetPrimaryDisplay().device_scale_factor() > 1.5f;
   float cursor_scale_factor = use_2x ? 2.f : 1.f;
   cursor_size_ = InitCursorFromResource(&touch_cursor_,
       cursor_scale_factor,
       use_2x ? IDR_DEVTOOLS_TOUCH_CURSOR_ICON_2X :
           IDR_DEVTOOLS_TOUCH_CURSOR_ICON);
@@ skipping 17 matching lines @@
   // We cannot cleanup properly in destructor, as we need roundtrip to the
   // renderer for ack. Instead, the owner should call Disable, and only
   // destroy this object when renderer is dead.
 }
 
 void TouchEmulator::ResetState() {
   last_mouse_event_was_move_ = false;
   last_mouse_move_timestamp_ = 0;
   mouse_pressed_ = false;
   shift_pressed_ = false;
-  touch_active_ = false;
   suppress_next_fling_cancel_ = false;
   pinch_scale_ = 1.f;
   pinch_gesture_active_ = false;
 }
 
 void TouchEmulator::Enable(bool allow_pinch) {
   if (!enabled_) {
     enabled_ = true;
     ResetState();
   }
@@ skipping 49 matching lines @@
 
   if (mouse_event.type == WebInputEvent::MouseDown)
     mouse_pressed_ = true;
   else if (mouse_event.type == WebInputEvent::MouseUp)
     mouse_pressed_ = false;
 
   UpdateShiftPressed((mouse_event.modifiers & WebInputEvent::ShiftKey) != 0);
 
   if (FillTouchEventAndPoint(mouse_event) &&
       gesture_provider_.OnTouchEvent(MotionEventWeb(touch_event_))) {
-    client_->ForwardTouchEvent(touch_event_);
+    ForwardTouchEventToClient();
   }
 
   // Do not pass mouse events to the renderer.
   return true;
 }
 
 bool TouchEmulator::HandleMouseWheelEvent(const WebMouseWheelEvent& event) {
   if (!enabled_)
     return false;
 
   // Send mouse wheel for easy scrolling when there is no active touch.
-  return touch_active_;
+  return emulated_stream_active_sequence_count_ > 0;
 }
 
 bool TouchEmulator::HandleKeyboardEvent(const WebKeyboardEvent& event) {
   if (!enabled_)
     return false;
 
   if (!UpdateShiftPressed((event.modifiers & WebInputEvent::ShiftKey) != 0))
     return false;
 
   if (!mouse_pressed_)
     return false;
 
   // Note: The necessary pinch events will be lazily inserted by
   // |OnGestureEvent| depending on the state of |shift_pressed_|, using the
   // scroll stream as the event driver.
   if (shift_pressed_) {
     // TODO(dgozman): Add secondary touch point and set anchor.
   } else {
     // TODO(dgozman): Remove secondary touch point and anchor.
   }
 
   // Never block keyboard events.
   return false;
 }
 
-bool TouchEmulator::HandleTouchEventAck(InputEventAckState ack_result) {
-  const bool event_consumed = ack_result == INPUT_EVENT_ACK_STATE_CONSUMED;
-  gesture_provider_.OnTouchEventAck(event_consumed);
-  // TODO(dgozman): Disable emulation when real touch events are available.
-  return true;
+bool TouchEmulator::HandleTouchEvent(const blink::WebTouchEvent& event) {
+  // Block native event when emulated touch stream is active.
+  if (emulated_stream_active_sequence_count_)
+    return true;
+
+  bool is_sequence_start = WebTouchEventTraits::IsTouchSequenceStart(event);
+  // Do not allow middle-sequence event to pass through, if start was blocked.
+  if (!native_stream_active_sequence_count_ && !is_sequence_start)
+    return true;
+
+  if (is_sequence_start)
+    native_stream_active_sequence_count_++;
+  return false;
+}
+
+void TouchEmulator::ForwardTouchEventToClient() {
+  const bool event_consumed = true;
+  // Block emulated event when emulated native stream is active.
+  if (native_stream_active_sequence_count_) {
+    gesture_provider_.OnTouchEventAck(event_consumed);
+    return;
+  }
+
+  bool is_sequence_start =
+      WebTouchEventTraits::IsTouchSequenceStart(touch_event_);
+  // Do not allow middle-sequence event to pass through, if start was blocked.
+  if (!emulated_stream_active_sequence_count_ && !is_sequence_start) {
+    gesture_provider_.OnTouchEventAck(event_consumed);
+    return;
+  }
+
+  if (is_sequence_start)
+    emulated_stream_active_sequence_count_++;
+  client_->ForwardEmulatedTouchEvent(touch_event_);
+}
+
+bool TouchEmulator::HandleTouchEventAck(
+    const blink::WebTouchEvent& event, InputEventAckState ack_result) {
+  bool is_sequence_end = WebTouchEventTraits::IsTouchSequenceEnd(event);
+  if (emulated_stream_active_sequence_count_) {
+    if (is_sequence_end)
+      emulated_stream_active_sequence_count_--;
+
+    const bool event_consumed = ack_result == INPUT_EVENT_ACK_STATE_CONSUMED;
+    gesture_provider_.OnTouchEventAck(event_consumed);
+    return true;
+  }
+
+  // We may have not seen native touch sequence start (when created in the
+  // middle of a sequence), so don't decrement sequence count below zero.
+  if (is_sequence_end && native_stream_active_sequence_count_)
+    native_stream_active_sequence_count_--;
+  return false;
 }
 
 void TouchEmulator::OnGestureEvent(const ui::GestureEventData& gesture) {
   WebGestureEvent gesture_event =
       CreateWebGestureEventFromGestureEventData(gesture);
 
   switch (gesture_event.type) {
     case WebInputEvent::Undefined:
       NOTREACHED() << "Undefined WebInputEvent type";
       // Bail without sending the junk event to the client.
@@ skipping 49 matching lines @@
       suppress_next_fling_cancel_ = false;
       break;
 
     default:
       // Everything else goes through.
       client_->ForwardGestureEvent(gesture_event);
   }
 }
 
 void TouchEmulator::CancelTouch() {
-  if (!touch_active_)
+  if (!emulated_stream_active_sequence_count_)
     return;
 
   WebTouchEventTraits::ResetTypeAndTouchStates(
       WebInputEvent::TouchCancel,
       (base::TimeTicks::Now() - base::TimeTicks()).InSecondsF(),
       &touch_event_);
-  touch_active_ = false;
   if (gesture_provider_.OnTouchEvent(MotionEventWeb(touch_event_)))
-    client_->ForwardTouchEvent(touch_event_);
+    ForwardTouchEventToClient();
 }
 
 void TouchEmulator::UpdateCursor() {
   if (!enabled_)
     client_->SetCursor(pointer_cursor_);
   else
     client_->SetCursor(InPinchGestureMode() ? pinch_cursor_ : touch_cursor_);
 }
 
 bool TouchEmulator::UpdateShiftPressed(bool shift_pressed) {
@@ skipping 55 matching lines @@
   if (mouse_event.type != WebInputEvent::MouseDown &&
       mouse_event.type != WebInputEvent::MouseMove &&
       mouse_event.type != WebInputEvent::MouseUp) {
     return false;
   }
 
   WebInputEvent::Type eventType;
   switch (mouse_event.type) {
     case WebInputEvent::MouseDown:
       eventType = WebInputEvent::TouchStart;
-      touch_active_ = true;
       break;
     case WebInputEvent::MouseMove:
       eventType = WebInputEvent::TouchMove;
       break;
     case WebInputEvent::MouseUp:
       eventType = WebInputEvent::TouchEnd;
-      touch_active_ = false;
       break;
     default:
       eventType = WebInputEvent::Undefined;
       NOTREACHED();
   }
   touch_event_.touchesLength = 1;
   touch_event_.modifiers = mouse_event.modifiers;
   WebTouchEventTraits::ResetTypeAndTouchStates(
       eventType, mouse_event.timeStampSeconds, &touch_event_);
 
   WebTouchPoint& point = touch_event_.touches[0];
   point.id = 0;
   point.radiusX = 0.5f * cursor_size_.width();
   point.radiusY = 0.5f * cursor_size_.height();
   point.force = 1.f;
   point.rotationAngle = 0.f;
   point.position.x = mouse_event.x;
   point.screenPosition.x = mouse_event.globalX;
   point.position.y = mouse_event.y;
   point.screenPosition.y = mouse_event.globalY;
 
   return true;
 }
 
 bool TouchEmulator::InPinchGestureMode() const {
   return shift_pressed_ && allow_pinch_;
 }
 
 }  // namespace content