ui/aura/window_event_dispatcher.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/aura/window_event_dispatcher.h"
   6
   7 #include "base/bind.h"
   8 #include "base/debug/trace_event.h"
   9 #include "base/logging.h"
  10 #include "base/message_loop/message_loop.h"
  11 #include "ui/aura/client/capture_client.h"
  12 #include "ui/aura/client/cursor_client.h"
  13 #include "ui/aura/client/event_client.h"
  14 #include "ui/aura/client/focus_client.h"
  15 #include "ui/aura/client/screen_position_client.h"
  16 #include "ui/aura/env.h"
  17 #include "ui/aura/window.h"
  18 #include "ui/aura/window_delegate.h"
  19 #include "ui/aura/window_targeter.h"
  20 #include "ui/aura/window_tracker.h"
  21 #include "ui/aura/window_tree_host.h"
  22 #include "ui/base/hit_test.h"
  23 #include "ui/compositor/dip_util.h"
  24 #include "ui/events/event.h"
  25 #include "ui/events/gestures/gesture_recognizer.h"
  26 #include "ui/events/gestures/gesture_types.h"
  27
  28 typedef ui::EventDispatchDetails DispatchDetails;
  29
  30 namespace aura {
  31
  32 namespace {
  33
  34 // Returns true if |target| has a non-client (frame) component at |location|,
  35 // in window coordinates.
  36 bool IsNonClientLocation(Window* target, const gfx::Point& location) {
  37   if (!target->delegate())
  38     return false;
  39   int hit_test_code = target->delegate()->GetNonClientComponent(location);
  40   return hit_test_code != HTCLIENT && hit_test_code != HTNOWHERE;
  41 }
  42
  43 Window* ConsumerToWindow(ui::GestureConsumer* consumer) {
  44   return consumer ? static_cast<Window*>(consumer) : NULL;
  45 }
  46
  47 void SetLastMouseLocation(const Window* root_window,
  48                           const gfx::Point& location_in_root) {
  49   client::ScreenPositionClient* client =
  50       client::GetScreenPositionClient(root_window);
  51   if (client) {
  52     gfx::Point location_in_screen = location_in_root;
  53     client->ConvertPointToScreen(root_window, &location_in_screen);
  54     Env::GetInstance()->set_last_mouse_location(location_in_screen);
  55   } else {
  56     Env::GetInstance()->set_last_mouse_location(location_in_root);
  57   }
  58 }
  59
  60 bool IsEventCandidateForHold(const ui::Event& event) {
  61   if (event.type() == ui::ET_TOUCH_MOVED)
  62     return true;
  63   if (event.type() == ui::ET_MOUSE_DRAGGED)
  64     return true;
  65   if (event.IsMouseEvent() && (event.flags() & ui::EF_IS_SYNTHESIZED))
  66     return true;
  67   return false;
  68 }
  69
  70 }  // namespace
  71
  72 ////////////////////////////////////////////////////////////////////////////////
  73 // WindowEventDispatcher, public:
  74
  75 WindowEventDispatcher::WindowEventDispatcher(WindowTreeHost* host)
  76     : host_(host),
  77       touch_ids_down_(0),
  78       mouse_pressed_handler_(NULL),
  79       mouse_moved_handler_(NULL),
  80       event_dispatch_target_(NULL),
  81       old_dispatch_target_(NULL),
  82       synthesize_mouse_move_(false),
  83       move_hold_count_(0),
  84       dispatching_held_event_(false),
  85       observer_manager_(this),
  86       repost_event_factory_(this),
  87       held_event_factory_(this) {
  88   ui::GestureRecognizer::Get()->AddGestureEventHelper(this);
  89   Env::GetInstance()->AddObserver(this);
  90 }
  91
  92 WindowEventDispatcher::~WindowEventDispatcher() {
  93   TRACE_EVENT0("shutdown", "WindowEventDispatcher::Destructor");
  94   Env::GetInstance()->RemoveObserver(this);
  95   ui::GestureRecognizer::Get()->RemoveGestureEventHelper(this);
  96 }
  97
  98 void WindowEventDispatcher::RepostEvent(const ui::LocatedEvent& event) {
  99   DCHECK(event.type() == ui::ET_MOUSE_PRESSED ||
 100          event.type() == ui::ET_GESTURE_TAP_DOWN);
 101   // We allow for only one outstanding repostable event. This is used
 102   // in exiting context menus.  A dropped repost request is allowed.
 103   if (event.type() == ui::ET_MOUSE_PRESSED) {
 104     held_repostable_event_.reset(
 105         new ui::MouseEvent(
 106             static_cast<const ui::MouseEvent&>(event),
 107             static_cast<aura::Window*>(event.target()),
 108             window()));
 109     base::MessageLoop::current()->PostNonNestableTask(
 110         FROM_HERE, base::Bind(
 111             base::IgnoreResult(&WindowEventDispatcher::DispatchHeldEvents),
 112             repost_event_factory_.GetWeakPtr()));
 113   } else {
 114     DCHECK(event.type() == ui::ET_GESTURE_TAP_DOWN);
 115     held_repostable_event_.reset();
 116     // TODO(rbyers): Reposing of gestures is tricky to get
 117     // right, so it's not yet supported.  crbug.com/170987.
 118   }
 119 }
 120
 121 void WindowEventDispatcher::OnMouseEventsEnableStateChanged(bool enabled) {
 122   // Send entered / exited so that visual state can be updated to match
 123   // mouse events state.
 124   PostSynthesizeMouseMove();
 125   // TODO(mazda): Add code to disable mouse events when |enabled| == false.
 126 }
 127
 128 void WindowEventDispatcher::DispatchCancelModeEvent() {
 129   ui::CancelModeEvent event;
 130   Window* focused_window = client::GetFocusClient(window())->GetFocusedWindow();
 131   if (focused_window && !window()->Contains(focused_window))
 132     focused_window = NULL;
 133   DispatchDetails details =
 134       DispatchEvent(focused_window ? focused_window : window(), &event);
 135   if (details.dispatcher_destroyed)
 136     return;
 137 }
 138
 139 void WindowEventDispatcher::DispatchGestureEvent(ui::GestureEvent* event) {
 140   DispatchDetails details = DispatchHeldEvents();
 141   if (details.dispatcher_destroyed)
 142     return;
 143
 144   Window* target = GetGestureTarget(event);
 145   if (target) {
 146     event->ConvertLocationToTarget(window(), target);
 147     DispatchDetails details = DispatchEvent(target, event);
 148     if (details.dispatcher_destroyed)
 149       return;
 150   }
 151 }
 152
 153 DispatchDetails WindowEventDispatcher::DispatchMouseExitAtPoint(
 154     const gfx::Point& point) {
 155   ui::MouseEvent event(ui::ET_MOUSE_EXITED, point, point, ui::EF_NONE,
 156                        ui::EF_NONE);
 157   return DispatchMouseEnterOrExit(event, ui::ET_MOUSE_EXITED);
 158 }
 159
 160 void WindowEventDispatcher::ProcessedTouchEvent(ui::TouchEvent* event,
 161                                                 Window* window,
 162                                                 ui::EventResult result) {
 163   ui::TouchEvent orig_event(*event, window, this->window());
 164   // Once we've fully migrated to the eager gesture detector, we won't need to
 165   // pass an event here.
 166   scoped_ptr<ui::GestureRecognizer::Gestures> gestures(
 167       ui::GestureRecognizer::Get()->ProcessTouchEventOnAsyncAck(
 168           orig_event, result, window));
 169   DispatchDetails details = ProcessGestures(gestures.get());
 170   if (details.dispatcher_destroyed)
 171     return;
 172 }
 173
 174 void WindowEventDispatcher::HoldPointerMoves() {
 175   if (!move_hold_count_)
 176     held_event_factory_.InvalidateWeakPtrs();
 177   ++move_hold_count_;
 178   TRACE_EVENT_ASYNC_BEGIN0("ui", "WindowEventDispatcher::HoldPointerMoves",
 179                            this);
 180 }
 181
 182 void WindowEventDispatcher::ReleasePointerMoves() {
 183   --move_hold_count_;
 184   DCHECK_GE(move_hold_count_, 0);
 185   if (!move_hold_count_ && held_move_event_) {
 186     // We don't want to call DispatchHeldEvents directly, because this might be
 187     // called from a deep stack while another event, in which case dispatching
 188     // another one may not be safe/expected.  Instead we post a task, that we
 189     // may cancel if HoldPointerMoves is called again before it executes.
 190     base::MessageLoop::current()->PostNonNestableTask(
 191         FROM_HERE, base::Bind(
 192           base::IgnoreResult(&WindowEventDispatcher::DispatchHeldEvents),
 193           held_event_factory_.GetWeakPtr()));
 194   }
 195   TRACE_EVENT_ASYNC_END0("ui", "WindowEventDispatcher::HoldPointerMoves", this);
 196 }
 197
 198 gfx::Point WindowEventDispatcher::GetLastMouseLocationInRoot() const {
 199   gfx::Point location = Env::GetInstance()->last_mouse_location();
 200   client::ScreenPositionClient* client =
 201       client::GetScreenPositionClient(window());
 202   if (client)
 203     client->ConvertPointFromScreen(window(), &location);
 204   return location;
 205 }
 206
 207 void WindowEventDispatcher::OnHostLostMouseGrab() {
 208   mouse_pressed_handler_ = NULL;
 209   mouse_moved_handler_ = NULL;
 210 }
 211
 212 void WindowEventDispatcher::OnCursorMovedToRootLocation(
 213     const gfx::Point& root_location) {
 214   SetLastMouseLocation(window(), root_location);
 215   synthesize_mouse_move_ = false;
 216 }
 217
 218 void WindowEventDispatcher::OnPostNotifiedWindowDestroying(Window* window) {
 219   OnWindowHidden(window, WINDOW_DESTROYED);
 220 }
 221
 222 ////////////////////////////////////////////////////////////////////////////////
 223 // WindowEventDispatcher, private:
 224
 225 Window* WindowEventDispatcher::window() {
 226   return host_->window();
 227 }
 228
 229 const Window* WindowEventDispatcher::window() const {
 230   return host_->window();
 231 }
 232
 233 void WindowEventDispatcher::TransformEventForDeviceScaleFactor(
 234     ui::LocatedEvent* event) {
 235   event->UpdateForRootTransform(host_->GetInverseRootTransform());
 236 }
 237
 238 void WindowEventDispatcher::DispatchMouseExitToHidingWindow(Window* window) {
 239   // The mouse capture is intentionally ignored. Think that a mouse enters
 240   // to a window, the window sets the capture, the mouse exits the window,
 241   // and then it releases the capture. In that case OnMouseExited won't
 242   // be called. So it is natural not to emit OnMouseExited even though
 243   // |window| is the capture window.
 244   gfx::Point last_mouse_location = GetLastMouseLocationInRoot();
 245   if (window->Contains(mouse_moved_handler_) &&
 246       window->ContainsPointInRoot(last_mouse_location)) {
 247     DispatchDetails details = DispatchMouseExitAtPoint(last_mouse_location);
 248     if (details.dispatcher_destroyed)
 249       return;
 250   }
 251 }
 252
 253 ui::EventDispatchDetails WindowEventDispatcher::DispatchMouseEnterOrExit(
 254     const ui::MouseEvent& event,
 255     ui::EventType type) {
 256   if (event.type() != ui::ET_MOUSE_CAPTURE_CHANGED &&
 257       !(event.flags() & ui::EF_IS_SYNTHESIZED)) {
 258     SetLastMouseLocation(window(), event.root_location());
 259   }
 260
 261   if (!mouse_moved_handler_ || !mouse_moved_handler_->delegate() ||
 262       !window()->Contains(mouse_moved_handler_))
 263     return DispatchDetails();
 264
 265   // |event| may be an event in the process of being dispatched to a target (in
 266   // which case its locations will be in the event's target's coordinate
 267   // system), or a synthetic event created in root-window (in which case, the
 268   // event's target will be NULL, and the event will be in the root-window's
 269   // coordinate system.
 270   aura::Window* target = static_cast<Window*>(event.target());
 271   if (!target)
 272     target = window();
 273   ui::MouseEvent translated_event(event,
 274                                   target,
 275                                   mouse_moved_handler_,
 276                                   type,
 277                                   event.flags() | ui::EF_IS_SYNTHESIZED);
 278   return DispatchEvent(mouse_moved_handler_, &translated_event);
 279 }
 280
 281 ui::EventDispatchDetails WindowEventDispatcher::ProcessGestures(
 282     ui::GestureRecognizer::Gestures* gestures) {
 283   DispatchDetails details;
 284   if (!gestures || gestures->empty())
 285     return details;
 286
 287   Window* target = GetGestureTarget(gestures->get().at(0));
 288   if (!target)
 289     return details;
 290
 291   for (size_t i = 0; i < gestures->size(); ++i) {
 292     ui::GestureEvent* event = gestures->get().at(i);
 293     event->ConvertLocationToTarget(window(), target);
 294     details = DispatchEvent(target, event);
 295     if (details.dispatcher_destroyed || details.target_destroyed)
 296       break;
 297   }
 298   return details;
 299 }
 300
 301 void WindowEventDispatcher::OnWindowHidden(Window* invisible,
 302                                            WindowHiddenReason reason) {
 303   // If the window the mouse was pressed in becomes invisible, it should no
 304   // longer receive mouse events.
 305   if (invisible->Contains(mouse_pressed_handler_))
 306     mouse_pressed_handler_ = NULL;
 307   if (invisible->Contains(mouse_moved_handler_))
 308     mouse_moved_handler_ = NULL;
 309
 310   // If events are being dispatched from a nested message-loop, and the target
 311   // of the outer loop is hidden or moved to another dispatcher during
 312   // dispatching events in the inner loop, then reset the target for the outer
 313   // loop.
 314   if (invisible->Contains(old_dispatch_target_))
 315     old_dispatch_target_ = NULL;
 316
 317   invisible->CleanupGestureState();
 318
 319   // Do not clear the capture, and the |event_dispatch_target_| if the
 320   // window is moving across hosts, because the target itself is actually still
 321   // visible and clearing them stops further event processing, which can cause
 322   // unexpected behaviors. See crbug.com/157583
 323   if (reason != WINDOW_MOVING) {
 324     // We don't ask |invisible| here, because invisible may have been removed
 325     // from the window hierarchy already by the time this function is called
 326     // (OnWindowDestroyed).
 327     client::CaptureClient* capture_client =
 328         client::GetCaptureClient(host_->window());
 329     Window* capture_window =
 330         capture_client ? capture_client->GetCaptureWindow() : NULL;
 331
 332     if (invisible->Contains(event_dispatch_target_))
 333       event_dispatch_target_ = NULL;
 334
 335     // If the ancestor of the capture window is hidden, release the capture.
 336     // Note that this may delete the window so do not use capture_window
 337     // after this.
 338     if (invisible->Contains(capture_window) && invisible != window())
 339       capture_window->ReleaseCapture();
 340   }
 341 }
 342
 343 Window* WindowEventDispatcher::GetGestureTarget(ui::GestureEvent* event) {
 344   Window* target = NULL;
 345   if (!event->IsEndingEvent()) {
 346     // The window that received the start event (e.g. scroll begin) needs to
 347     // receive the end event (e.g. scroll end).
 348     target = client::GetCaptureWindow(window());
 349   }
 350   if (!target) {
 351     target = ConsumerToWindow(
 352         ui::GestureRecognizer::Get()->GetTargetForGestureEvent(*event));
 353   }
 354
 355   return target;
 356 }
 357
 358 ////////////////////////////////////////////////////////////////////////////////
 359 // WindowEventDispatcher, aura::client::CaptureDelegate implementation:
 360
 361 void WindowEventDispatcher::UpdateCapture(Window* old_capture,
 362                                           Window* new_capture) {
 363   // |mouse_moved_handler_| may have been set to a Window in a different root
 364   // (see below). Clear it here to ensure we don't end up referencing a stale
 365   // Window.
 366   if (mouse_moved_handler_ && !window()->Contains(mouse_moved_handler_))
 367     mouse_moved_handler_ = NULL;
 368
 369   if (old_capture && old_capture->GetRootWindow() == window() &&
 370       old_capture->delegate()) {
 371     // Send a capture changed event with bogus location data.
 372     ui::MouseEvent event(ui::ET_MOUSE_CAPTURE_CHANGED, gfx::Point(),
 373                          gfx::Point(), 0, 0);
 374
 375     DispatchDetails details = DispatchEvent(old_capture, &event);
 376     if (details.dispatcher_destroyed)
 377       return;
 378
 379     old_capture->delegate()->OnCaptureLost();
 380   }
 381
 382   if (new_capture) {
 383     // Make all subsequent mouse events go to the capture window. We shouldn't
 384     // need to send an event here as OnCaptureLost() should take care of that.
 385     if (mouse_moved_handler_ || Env::GetInstance()->IsMouseButtonDown())
 386       mouse_moved_handler_ = new_capture;
 387   } else {
 388     // Make sure mouse_moved_handler gets updated.
 389     DispatchDetails details = SynthesizeMouseMoveEvent();
 390     if (details.dispatcher_destroyed)
 391       return;
 392   }
 393   mouse_pressed_handler_ = NULL;
 394 }
 395
 396 void WindowEventDispatcher::OnOtherRootGotCapture() {
 397   // Windows provides the TrackMouseEvents API which allows us to rely on the
 398   // OS to send us the mouse exit events (WM_MOUSELEAVE). Additionally on
 399   // desktop Windows, every top level window could potentially have its own
 400   // root window, in which case this function will get called whenever those
 401   // windows grab mouse capture. Sending mouse exit messages in these cases
 402   // causes subtle bugs like (crbug.com/394672).
 403 #if !defined(OS_WIN)
 404   if (mouse_moved_handler_) {
 405     // Dispatch a mouse exit to reset any state associated with hover. This is
 406     // important when going from no window having capture to a window having
 407     // capture because we do not dispatch ET_MOUSE_CAPTURE_CHANGED in this case.
 408     DispatchDetails details = DispatchMouseExitAtPoint(
 409         GetLastMouseLocationInRoot());
 410     if (details.dispatcher_destroyed)
 411       return;
 412   }
 413 #endif
 414
 415   mouse_moved_handler_ = NULL;
 416   mouse_pressed_handler_ = NULL;
 417 }
 418
 419 void WindowEventDispatcher::SetNativeCapture() {
 420   host_->SetCapture();
 421 }
 422
 423 void WindowEventDispatcher::ReleaseNativeCapture() {
 424   host_->ReleaseCapture();
 425 }
 426
 427 ////////////////////////////////////////////////////////////////////////////////
 428 // WindowEventDispatcher, ui::EventProcessor implementation:
 429 ui::EventTarget* WindowEventDispatcher::GetRootTarget() {
 430   return window();
 431 }
 432
 433 void WindowEventDispatcher::PrepareEventForDispatch(ui::Event* event) {
 434   if (dispatching_held_event_) {
 435     // The held events are already in |window()|'s coordinate system. So it is
 436     // not necessary to apply the transform to convert from the host's
 437     // coordinate system to |window()|'s coordinate system.
 438     return;
 439   }
 440   if (event->IsMouseEvent() ||
 441       event->IsScrollEvent() ||
 442       event->IsTouchEvent() ||
 443       event->IsGestureEvent()) {
 444     TransformEventForDeviceScaleFactor(static_cast<ui::LocatedEvent*>(event));
 445   }
 446 }
 447
 448 ////////////////////////////////////////////////////////////////////////////////
 449 // WindowEventDispatcher, ui::EventDispatcherDelegate implementation:
 450
 451 bool WindowEventDispatcher::CanDispatchToTarget(ui::EventTarget* target) {
 452   return event_dispatch_target_ == target;
 453 }
 454
 455 ui::EventDispatchDetails WindowEventDispatcher::PreDispatchEvent(
 456     ui::EventTarget* target,
 457     ui::Event* event) {
 458   Window* target_window = static_cast<Window*>(target);
 459   CHECK(window()->Contains(target_window));
 460
 461   if (!dispatching_held_event_) {
 462     bool can_be_held = IsEventCandidateForHold(*event);
 463     if (!move_hold_count_ || !can_be_held) {
 464       if (can_be_held)
 465         held_move_event_.reset();
 466       DispatchDetails details = DispatchHeldEvents();
 467       if (details.dispatcher_destroyed || details.target_destroyed)
 468         return details;
 469     }
 470   }
 471
 472   if (event->IsMouseEvent()) {
 473     PreDispatchMouseEvent(target_window, static_cast<ui::MouseEvent*>(event));
 474   } else if (event->IsScrollEvent()) {
 475     PreDispatchLocatedEvent(target_window,
 476                             static_cast<ui::ScrollEvent*>(event));
 477   } else if (event->IsTouchEvent()) {
 478     PreDispatchTouchEvent(target_window, static_cast<ui::TouchEvent*>(event));
 479   }
 480   old_dispatch_target_ = event_dispatch_target_;
 481   event_dispatch_target_ = static_cast<Window*>(target);
 482   return DispatchDetails();
 483 }
 484
 485 ui::EventDispatchDetails WindowEventDispatcher::PostDispatchEvent(
 486     ui::EventTarget* target,
 487     const ui::Event& event) {
 488   DispatchDetails details;
 489   if (!target || target != event_dispatch_target_)
 490     details.target_destroyed = true;
 491   event_dispatch_target_ = old_dispatch_target_;
 492   old_dispatch_target_ = NULL;
 493 #ifndef NDEBUG
 494   DCHECK(!event_dispatch_target_ || window()->Contains(event_dispatch_target_));
 495 #endif
 496
 497   if (event.IsTouchEvent() && !details.target_destroyed) {
 498     // Do not let 'held' touch events contribute to any gestures unless it is
 499     // being dispatched.
 500     if (dispatching_held_event_ || !held_move_event_ ||
 501         !held_move_event_->IsTouchEvent()) {
 502       // If the event is being handled asynchronously, ignore it.
 503       if(event.result() & ui::ER_CONSUMED)
 504         return details;
 505       scoped_ptr<ui::GestureRecognizer::Gestures> gestures;
 506
 507       // Once we've fully migrated to the eager gesture detector, we won't
 508       // need to pass an event here.
 509       ui::TouchEvent orig_event(static_cast<const ui::TouchEvent&>(event),
 510                                 static_cast<Window*>(event.target()),
 511                                 window());
 512       gestures.reset(
 513           ui::GestureRecognizer::Get()->ProcessTouchEventPostDispatch(
 514               orig_event, event.result(), static_cast<Window*>(target)));
 515
 516       return ProcessGestures(gestures.get());
 517     }
 518   }
 519
 520   return details;
 521 }
 522
 523 ////////////////////////////////////////////////////////////////////////////////
 524 // WindowEventDispatcher, ui::GestureEventHelper implementation:
 525
 526 bool WindowEventDispatcher::CanDispatchToConsumer(
 527     ui::GestureConsumer* consumer) {
 528   Window* consumer_window = ConsumerToWindow(consumer);
 529   return (consumer_window && consumer_window->GetRootWindow() == window());
 530 }
 531
 532 void WindowEventDispatcher::DispatchCancelTouchEvent(ui::TouchEvent* event) {
 533   DispatchDetails details = OnEventFromSource(event);
 534   if (details.dispatcher_destroyed)
 535     return;
 536 }
 537
 538 ////////////////////////////////////////////////////////////////////////////////
 539 // WindowEventDispatcher, WindowObserver implementation:
 540
 541 void WindowEventDispatcher::OnWindowDestroying(Window* window) {
 542   if (!host_->window()->Contains(window))
 543     return;
 544
 545   DispatchMouseExitToHidingWindow(window);
 546   SynthesizeMouseMoveAfterChangeToWindow(window);
 547 }
 548
 549 void WindowEventDispatcher::OnWindowDestroyed(Window* window) {
 550   // We observe all windows regardless of what root Window (if any) they're
 551   // attached to.
 552   observer_manager_.Remove(window);
 553 }
 554
 555 void WindowEventDispatcher::OnWindowAddedToRootWindow(Window* attached) {
 556   if (!observer_manager_.IsObserving(attached))
 557     observer_manager_.Add(attached);
 558
 559   if (!host_->window()->Contains(attached))
 560     return;
 561
 562   SynthesizeMouseMoveAfterChangeToWindow(attached);
 563 }
 564
 565 void WindowEventDispatcher::OnWindowRemovingFromRootWindow(Window* detached,
 566                                                            Window* new_root) {
 567   if (!host_->window()->Contains(detached))
 568     return;
 569
 570   DCHECK(client::GetCaptureWindow(window()) != window());
 571
 572   DispatchMouseExitToHidingWindow(detached);
 573   SynthesizeMouseMoveAfterChangeToWindow(detached);
 574
 575   // Hiding the window releases capture which can implicitly destroy the window
 576   // so the window may no longer be valid after this call.
 577   OnWindowHidden(detached, new_root ? WINDOW_MOVING : WINDOW_HIDDEN);
 578 }
 579
 580 void WindowEventDispatcher::OnWindowVisibilityChanging(Window* window,
 581                                                        bool visible) {
 582   if (!host_->window()->Contains(window))
 583     return;
 584
 585   DispatchMouseExitToHidingWindow(window);
 586 }
 587
 588 void WindowEventDispatcher::OnWindowVisibilityChanged(Window* window,
 589                                                       bool visible) {
 590   if (!host_->window()->Contains(window))
 591     return;
 592
 593   if (window->ContainsPointInRoot(GetLastMouseLocationInRoot()))
 594     PostSynthesizeMouseMove();
 595
 596   // Hiding the window releases capture which can implicitly destroy the window
 597   // so the window may no longer be valid after this call.
 598   if (!visible)
 599     OnWindowHidden(window, WINDOW_HIDDEN);
 600 }
 601
 602 void WindowEventDispatcher::OnWindowBoundsChanged(Window* window,
 603                                                   const gfx::Rect& old_bounds,
 604                                                   const gfx::Rect& new_bounds) {
 605   if (!host_->window()->Contains(window))
 606     return;
 607
 608   if (window == host_->window()) {
 609     TRACE_EVENT1("ui", "WindowEventDispatcher::OnWindowBoundsChanged(root)",
 610                  "size", new_bounds.size().ToString());
 611
 612     DispatchDetails details = DispatchHeldEvents();
 613     if (details.dispatcher_destroyed)
 614       return;
 615
 616     synthesize_mouse_move_ = false;
 617   }
 618
 619   if (window->IsVisible() && !window->ignore_events()) {
 620     gfx::Rect old_bounds_in_root = old_bounds, new_bounds_in_root = new_bounds;
 621     Window::ConvertRectToTarget(window->parent(), host_->window(),
 622                                 &old_bounds_in_root);
 623     Window::ConvertRectToTarget(window->parent(), host_->window(),
 624                                 &new_bounds_in_root);
 625     gfx::Point last_mouse_location = GetLastMouseLocationInRoot();
 626     if (old_bounds_in_root.Contains(last_mouse_location) !=
 627         new_bounds_in_root.Contains(last_mouse_location)) {
 628       PostSynthesizeMouseMove();
 629     }
 630   }
 631 }
 632
 633 void WindowEventDispatcher::OnWindowTransforming(Window* window) {
 634   if (!host_->window()->Contains(window))
 635     return;
 636
 637   SynthesizeMouseMoveAfterChangeToWindow(window);
 638 }
 639
 640 void WindowEventDispatcher::OnWindowTransformed(Window* window) {
 641   if (!host_->window()->Contains(window))
 642     return;
 643
 644   SynthesizeMouseMoveAfterChangeToWindow(window);
 645 }
 646
 647 ///////////////////////////////////////////////////////////////////////////////
 648 // WindowEventDispatcher, EnvObserver implementation:
 649
 650 void WindowEventDispatcher::OnWindowInitialized(Window* window) {
 651   observer_manager_.Add(window);
 652 }
 653
 654 ////////////////////////////////////////////////////////////////////////////////
 655 // WindowEventDispatcher, private:
 656
 657 ui::EventDispatchDetails WindowEventDispatcher::DispatchHeldEvents() {
 658   if (!held_repostable_event_ && !held_move_event_)
 659     return DispatchDetails();
 660
 661   CHECK(!dispatching_held_event_);
 662   dispatching_held_event_ = true;
 663
 664   DispatchDetails dispatch_details;
 665   if (held_repostable_event_) {
 666     if (held_repostable_event_->type() == ui::ET_MOUSE_PRESSED) {
 667       scoped_ptr<ui::MouseEvent> mouse_event(
 668           static_cast<ui::MouseEvent*>(held_repostable_event_.release()));
 669       dispatch_details = OnEventFromSource(mouse_event.get());
 670     } else {
 671       // TODO(rbyers): GESTURE_TAP_DOWN not yet supported: crbug.com/170987.
 672       NOTREACHED();
 673     }
 674     if (dispatch_details.dispatcher_destroyed)
 675       return dispatch_details;
 676   }
 677
 678   if (held_move_event_) {
 679     // If a mouse move has been synthesized, the target location is suspect,
 680     // so drop the held mouse event.
 681     if (held_move_event_->IsTouchEvent() ||
 682         (held_move_event_->IsMouseEvent() && !synthesize_mouse_move_)) {
 683       dispatch_details = OnEventFromSource(held_move_event_.get());
 684     }
 685     if (!dispatch_details.dispatcher_destroyed)
 686       held_move_event_.reset();
 687   }
 688
 689   if (!dispatch_details.dispatcher_destroyed)
 690     dispatching_held_event_ = false;
 691   return dispatch_details;
 692 }
 693
 694 void WindowEventDispatcher::PostSynthesizeMouseMove() {
 695   if (synthesize_mouse_move_)
 696     return;
 697   synthesize_mouse_move_ = true;
 698   base::MessageLoop::current()->PostNonNestableTask(
 699       FROM_HERE,
 700       base::Bind(base::IgnoreResult(
 701           &WindowEventDispatcher::SynthesizeMouseMoveEvent),
 702           held_event_factory_.GetWeakPtr()));
 703 }
 704
 705 void WindowEventDispatcher::SynthesizeMouseMoveAfterChangeToWindow(
 706     Window* window) {
 707   if (window->IsVisible() &&
 708       window->ContainsPointInRoot(GetLastMouseLocationInRoot())) {
 709     PostSynthesizeMouseMove();
 710   }
 711 }
 712
 713 ui::EventDispatchDetails WindowEventDispatcher::SynthesizeMouseMoveEvent() {
 714   DispatchDetails details;
 715   if (!synthesize_mouse_move_)
 716     return details;
 717   synthesize_mouse_move_ = false;
 718
 719   // If one of the mouse buttons is currently down, then do not synthesize a
 720   // mouse-move event. In such cases, aura could synthesize a DRAGGED event
 721   // instead of a MOVED event, but in multi-display/multi-host scenarios, the
 722   // DRAGGED event can be synthesized in the incorrect host. So avoid
 723   // synthesizing any events at all.
 724   if (Env::GetInstance()->mouse_button_flags())
 725     return details;
 726
 727   gfx::Point root_mouse_location = GetLastMouseLocationInRoot();
 728   if (!window()->bounds().Contains(root_mouse_location))
 729     return details;
 730   gfx::Point host_mouse_location = root_mouse_location;
 731   host_->ConvertPointToHost(&host_mouse_location);
 732   ui::MouseEvent event(ui::ET_MOUSE_MOVED,
 733                        host_mouse_location,
 734                        host_mouse_location,
 735                        ui::EF_IS_SYNTHESIZED,
 736                        0);
 737   return OnEventFromSource(&event);
 738 }
 739
 740 void WindowEventDispatcher::PreDispatchLocatedEvent(Window* target,
 741                                                     ui::LocatedEvent* event) {
 742   int flags = event->flags();
 743   if (IsNonClientLocation(target, event->location()))
 744     flags |= ui::EF_IS_NON_CLIENT;
 745   event->set_flags(flags);
 746
 747   if (!dispatching_held_event_ &&
 748       (event->IsMouseEvent() || event->IsScrollEvent()) &&
 749       !(event->flags() & ui::EF_IS_SYNTHESIZED)) {
 750     if (event->type() != ui::ET_MOUSE_CAPTURE_CHANGED)
 751       SetLastMouseLocation(window(), event->root_location());
 752     synthesize_mouse_move_ = false;
 753   }
 754 }
 755
 756 void WindowEventDispatcher::PreDispatchMouseEvent(Window* target,
 757                                                   ui::MouseEvent* event) {
 758   client::CursorClient* cursor_client = client::GetCursorClient(window());
 759   // We allow synthesized mouse exit events through even if mouse events are
 760   // disabled. This ensures that hover state, etc on controls like buttons is
 761   // cleared.
 762   if (cursor_client &&
 763       !cursor_client->IsMouseEventsEnabled() &&
 764       (event->flags() & ui::EF_IS_SYNTHESIZED) &&
 765       (event->type() != ui::ET_MOUSE_EXITED)) {
 766     event->SetHandled();
 767     return;
 768   }
 769
 770   if (IsEventCandidateForHold(*event) && !dispatching_held_event_) {
 771     if (move_hold_count_) {
 772       if (!(event->flags() & ui::EF_IS_SYNTHESIZED) &&
 773           event->type() != ui::ET_MOUSE_CAPTURE_CHANGED) {
 774         SetLastMouseLocation(window(), event->root_location());
 775       }
 776       held_move_event_.reset(new ui::MouseEvent(*event, target, window()));
 777       event->SetHandled();
 778       return;
 779     } else {
 780       // We may have a held event for a period between the time move_hold_count_
 781       // fell to 0 and the DispatchHeldEvents executes. Since we're going to
 782       // dispatch the new event directly below, we can reset the old one.
 783       held_move_event_.reset();
 784     }
 785   }
 786
 787   const int kMouseButtonFlagMask = ui::EF_LEFT_MOUSE_BUTTON |
 788                                    ui::EF_MIDDLE_MOUSE_BUTTON |
 789                                    ui::EF_RIGHT_MOUSE_BUTTON;
 790   switch (event->type()) {
 791     case ui::ET_MOUSE_EXITED:
 792       if (!target || target == window()) {
 793         DispatchDetails details =
 794             DispatchMouseEnterOrExit(*event, ui::ET_MOUSE_EXITED);
 795         if (details.dispatcher_destroyed) {
 796           event->SetHandled();
 797           return;
 798         }
 799         mouse_moved_handler_ = NULL;
 800       }
 801       break;
 802     case ui::ET_MOUSE_MOVED:
 803       // Send an exit to the current |mouse_moved_handler_| and an enter to
 804       // |target|. Take care that both us and |target| aren't destroyed during
 805       // dispatch.
 806       if (target != mouse_moved_handler_) {
 807         aura::Window* old_mouse_moved_handler = mouse_moved_handler_;
 808         WindowTracker live_window;
 809         live_window.Add(target);
 810         DispatchDetails details =
 811             DispatchMouseEnterOrExit(*event, ui::ET_MOUSE_EXITED);
 812         if (details.dispatcher_destroyed) {
 813           event->SetHandled();
 814           return;
 815         }
 816         // If the |mouse_moved_handler_| changes out from under us, assume a
 817         // nested message loop ran and we don't need to do anything.
 818         if (mouse_moved_handler_ != old_mouse_moved_handler) {
 819           event->SetHandled();
 820           return;
 821         }
 822         if (!live_window.Contains(target) || details.target_destroyed) {
 823           mouse_moved_handler_ = NULL;
 824           event->SetHandled();
 825           return;
 826         }
 827         live_window.Remove(target);
 828
 829         mouse_moved_handler_ = target;
 830         details = DispatchMouseEnterOrExit(*event, ui::ET_MOUSE_ENTERED);
 831         if (details.dispatcher_destroyed || details.target_destroyed) {
 832           event->SetHandled();
 833           return;
 834         }
 835       }
 836       break;
 837     case ui::ET_MOUSE_PRESSED:
 838       // Don't set the mouse pressed handler for non client mouse down events.
 839       // These are only sent by Windows and are not always followed with non
 840       // client mouse up events which causes subsequent mouse events to be
 841       // sent to the wrong target.
 842       if (!(event->flags() & ui::EF_IS_NON_CLIENT) && !mouse_pressed_handler_)
 843         mouse_pressed_handler_ = target;
 844       Env::GetInstance()->set_mouse_button_flags(
 845           event->flags() & kMouseButtonFlagMask);
 846       break;
 847     case ui::ET_MOUSE_RELEASED:
 848       mouse_pressed_handler_ = NULL;
 849       Env::GetInstance()->set_mouse_button_flags(event->flags() &
 850           kMouseButtonFlagMask & ~event->changed_button_flags());
 851       break;
 852     default:
 853       break;
 854   }
 855
 856   PreDispatchLocatedEvent(target, event);
 857 }
 858
 859 void WindowEventDispatcher::PreDispatchTouchEvent(Window* target,
 860                                                   ui::TouchEvent* event) {
 861   switch (event->type()) {
 862     case ui::ET_TOUCH_PRESSED:
 863       touch_ids_down_ |= (1 << event->touch_id());
 864       Env::GetInstance()->set_touch_down(touch_ids_down_ != 0);
 865       break;
 866
 867       // Handle ET_TOUCH_CANCELLED only if it has a native event.
 868     case ui::ET_TOUCH_CANCELLED:
 869       if (!event->HasNativeEvent())
 870         break;
 871       // fallthrough
 872     case ui::ET_TOUCH_RELEASED:
 873       touch_ids_down_ = (touch_ids_down_ | (1 << event->touch_id())) ^
 874             (1 << event->touch_id());
 875       Env::GetInstance()->set_touch_down(touch_ids_down_ != 0);
 876       break;
 877
 878     case ui::ET_TOUCH_MOVED:
 879       if (move_hold_count_ && !dispatching_held_event_) {
 880         held_move_event_.reset(new ui::TouchEvent(*event, target, window()));
 881         event->SetHandled();
 882         return;
 883       }
 884       break;
 885
 886     default:
 887       NOTREACHED();
 888       break;
 889   }
 890
 891   if (dispatching_held_event_ || !held_move_event_ ||
 892       !held_move_event_->IsTouchEvent()) {
 893     ui::TouchEvent orig_event(*event, target, window());
 894
 895     // If the touch event is invalid in some way, the gesture recognizer will
 896     // reject it. This must call |StopPropagation()|, in order to prevent the
 897     // touch from being acked in |PostDispatchEvent|.
 898     if (!ui::GestureRecognizer::Get()->ProcessTouchEventPreDispatch(orig_event,
 899                                                                     target)) {
 900       event->StopPropagation();
 901     }
 902   }
 903
 904   PreDispatchLocatedEvent(target, event);
 905 }
 906
 907 }  // namespace aura