Eager Gesture Recognizer (WIP)

ui/events/gestures/gesture_event_queue.cc

+// Copyright 2013 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 "ui/events/gestures/gesture_event_queue.h"
+#include "ui/events/gestures/gesture_sequence.h"
+
+namespace ui {
+
+GestureEventQueue::GestureWithState::GestureWithState(
+    GestureEvent* event,
+    std::vector<TouchPointState*>& touch_point_states)
+    : event_(event) {
+  touch_point_states_.swap(touch_point_states);
+}
+
+GestureEventQueue::GestureWithState::~GestureWithState() {
+  CHECK(event_->IsGestureEvent());
+}
+
+GestureEventQueue::GestureEventQueue(GestureEventQueueDelegate* geqd)
+    :   gesture_event_queue_delegate_(geqd) {
+  touch_point_states_.resize(GestureSequence::kMaxGesturePoints);
+  acked_touch_point_states_.resize(GestureSequence::kMaxGesturePoints);
+  consumed_touch_point_states_.resize(GestureSequence::kMaxGesturePoints);
+
+  for (int i = 0; i < GestureSequence::kMaxGesturePoints; ++i) {
+    touch_point_states_[i] = new TouchPointState(i);
+    acked_touch_point_states_[i] = new TouchPointState(i);
+    consumed_touch_point_states_[i] = new TouchPointState(i);
+  }
+}
+
+GestureEventQueue::~GestureEventQueue() {
+  while (!sequences_.empty()) {
+    delete sequences_.front();
+    sequences_.pop_front();
+  }
+}
+
+void GestureEventQueue::OnTouchEvent(const TouchEvent& event) {
+  touch_point_states_[event.touch_id()]->Update(event);
+
+  // TODO - remove this
+  if (!sequences_.empty() && !(*sequences_.begin())->empty()) {
+    LOG(ERROR) << "length of first sequence is "
+               << (*sequences_.begin())->size();
+  }
+}
+
+void GestureEventQueue::OnTouchEventAck(
+    const TouchEvent& event,
+    EventResult result) {
+  if (result == ER_CONSUMED)
+    consumed_touch_point_states_[event.touch_id()]->Update(event);
+  else
+    acked_touch_point_states_[event.touch_id()]->Update(event);
+
+  DeleteConsumedEvents();
+  SendAckedEvents();
+
+  if (event.type() == ET_TOUCH_RELEASED ||
+      event.type() == ET_TOUCH_CANCELLED) {
+    touch_point_states_[event.touch_id()]->Reset();
+    consumed_touch_point_states_[event.touch_id()]->Reset();
+    acked_touch_point_states_[event.touch_id()]->Reset();
+  }
+}
+
+void GestureEventQueue::QueueGestureEvent(
+    GestureEvent* event,
+    TouchPointState::RequiresAck requires_ack) {
+  std::vector<TouchPointState*> tps;
+
+  for (ScopedVector<TouchPointState>::iterator it = touch_point_states_.begin();
+       it != touch_point_states_.end();
+       ++it) {
+    if ((*it)->has_press())
+      tps.push_back((*it)->CopyForGestureType(event->type(), requires_ack));
+  }
+  // Takes ownership of entries in tps.
+  QueueGestureEvent(event, tps);
+}
+
+void GestureEventQueue::TimerFired() {
+  for (int i = 0; i < GestureSequence::kMaxGesturePoints; ++i) {
+    if (touch_point_states_[i]->has_press())
+      acked_touch_point_states_[i]->TimerFired();
+  }
+  SendAckedEvents();
+}
+
+void GestureEventQueue::TimerCancelled() {
+  for (int i = 0; i < GestureSequence::kMaxGesturePoints; ++i) {
+    if (touch_point_states_[i]->has_press())
+      consumed_touch_point_states_[i]->TimerFired();
+  }
+  DeleteConsumedEvents();
+  SendAckedEvents();
+}
+
+void GestureEventQueue::QueueGestureEvent(
+    GestureEvent* event,
+    std::vector<TouchPointState*>& touch_point_states) {
+  CHECK(event->IsGestureEvent()) << "Event of type " << event->type();
+  // If this marks the beginning of a new sequence, construct a new
+  // |Sequence|. Deleted in |OnTouchEventAck|, and |~GestureEventQueue|.
+  if (event->type() == ET_GESTURE_BEGIN && event->details().touch_points() == 1)
+    sequences_.push_back(new Sequence());
+
+  DCHECK(!sequences_.empty()) << "Possibly missing a gesture begin";
+
+  if (sequences_.empty())
+    LOG(ERROR) << "Missing a gesture begin?";
+  // TODO - this shouldn't be necessary...
+  if (sequences_.empty())
+    sequences_.push_back(new Sequence());
+
+  Sequence* sequence = sequences_.back();
+
+  // The GestureWithState takes ownership of the elements of touch_point_states.
+  sequence->push_back(new GestureWithState(event, touch_point_states));
+
+  if (sequences_.empty()) {
+    LOG(ERROR) << "No sequence";
+  } else if ((*sequences_.begin())->empty())
+    LOG(ERROR) << "First sequence empty";
+  else {
+    LOG(ERROR) << "length of first sequence is "
+               << (*sequences_.begin())->size();
+    LOG(ERROR) << "First element is "
+               << (*(*sequences_.begin())->begin())->event()->type();
+  }
+
+  DeleteConsumedEvents();
+  SendAckedEvents();
+}
+
+void GestureEventQueue::SendGestureEvent(GestureEvent* event) {
+  gesture_event_queue_delegate_->DispatchGestureEvent(event);
+}
+
+bool GestureEventQueue::CanSend(
+    const std::vector<TouchPointState*>& gesture_touches) const {
+  if (gesture_touches.empty())
+    return true;
+  std::vector<TouchPointState*>::const_iterator it;
+  for (it = gesture_touches.begin();
+       it != gesture_touches.end();
+       ++it) {
+    const TouchPointState& current =
+        *acked_touch_point_states_[(*it)->touch_id()];
+
+    if (!current.Contains(*(*it)))
+      return false;
+  }
+  return true;
+}
+
+bool GestureEventQueue::CanDelete(
+    const std::vector<TouchPointState*>& gesture_touches) const {
+  if (gesture_touches.empty())
+    return false;
+  std::vector<TouchPointState*>::const_iterator it;
+  for (it = gesture_touches.begin();
+       it != gesture_touches.end();
+       ++it) {
+    const TouchPointState& current =
+        *consumed_touch_point_states_[(*it)->touch_id()];
+    if (!current.HasEmptyIntersection(*(*it)))
+      return true;
+  }
+  return false;
+}
+
+void GestureEventQueue::SendAckedEvents() {
+  RemoveEmptyFirstSequence();
+  LOG(ERROR) << "SendAckedEvents";
+  // TODO - should these be DCHECKs?
+  if (sequences_.empty()) {
+    LOG(ERROR) << "sequences_ is empty, bailing";
+    return;
+  }
+  Sequence* sequence = sequences_.front();
+  if (sequence->empty()) {
+    LOG(ERROR) << "sequence is empty, bailing";
+    return;
+  }
+  DCHECK(!sequence->empty());
+  for (Sequence::iterator it = sequence->begin();
+       it != sequence->end();) {
+    GestureEvent* event = (*it)->event();
+    CHECK(event->IsGestureEvent()) << "Event of type " << event->type();
+    if (CanSend((*it)->touch_point_states())) {
+      SendGestureEvent(event);
+      LOG(ERROR) << "SENT! " << event->type();
+      it = sequence->erase(it);
+      LOG(ERROR) << "ERASED!";
+    } else if (event->type() == ET_GESTURE_LONG_PRESS ||
+               event->type() == ET_GESTURE_SHOW_PRESS) {
+      // We don't need to respect the ordering of timed events.
+      ++it;
+    } else {
+      break;
+    }
+  }
+}
+
+void GestureEventQueue::DeleteConsumedEvents() {
+  RemoveEmptyFirstSequence();
+  // TODO - should this be a CHECK?
+  if (sequences_.empty())
+    return;
+  Sequence* sequence = sequences_.front();
+  if (sequence->empty())
+    return;
+  DCHECK(!sequence->empty());
+  for (Sequence::iterator it = sequence->begin();
+       it != sequence->end();) {
+    GestureEvent* event = (*it)->event();
+    CHECK(event->IsGestureEvent()) << "Event of type " << event->type();
+    if (CanDelete((*it)->touch_point_states())) {
+      it = sequence->erase(it);
+    } else
+      ++it;
+  }
+}
+
+void GestureEventQueue::RemoveEmptyFirstSequence() {
+  // If we've sent or deleted everything in the current sequence, and a new
+  // sequence has started, get rid of the current sequence.
+  if (sequences_.size() > 1 && sequences_.front()->empty()) {
+    delete sequences_.front();
+    sequences_.pop_front();
+  }
+}
+
+}  // namespace ui