ash/accelerators/key_hold_detector.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 "ash/accelerators/key_hold_detector.h"
   6
   7 #include "ash/shell.h"
   8 #include "base/message_loop/message_loop.h"
   9 #include "ui/aura/window_tracker.h"
  10 #include "ui/aura/window_tree_host.h"
  11 #include "ui/events/event_dispatcher.h"
  12 #include "ui/events/event_processor.h"
  13
  14 namespace ash {
  15 namespace {
  16
  17 void DispatchPressedEvent(const ui::KeyEvent& key_event,
  18                           scoped_ptr<aura::WindowTracker> tracker) {
  19   // The target window may be gone.
  20   if (tracker->windows().empty())
  21     return;
  22   ui::KeyEvent event(key_event);
  23   aura::Window* target = *(tracker->windows().begin());
  24   ignore_result(
  25       target->GetHost()->event_processor()->OnEventFromSource(&event));
  26 }
  27
  28 void PostPressedEvent(ui::KeyEvent* event) {
  29   // Modify RELEASED event to PRESSED event.
  30   const ui::KeyEvent pressed_event(
  31       ui::ET_KEY_PRESSED,
  32       event->key_code(),
  33       event->code(),
  34       event->flags() | ui::EF_SHIFT_DOWN | ui::EF_IS_SYNTHESIZED);
  35   scoped_ptr<aura::WindowTracker> tracker(new aura::WindowTracker);
  36   tracker->Add(static_cast<aura::Window*>(event->target()));
  37
  38   base::MessageLoopForUI::current()->PostTask(
  39       FROM_HERE,
  40       base::Bind(&DispatchPressedEvent, pressed_event, base::Passed(&tracker)));
  41 }
  42
  43 }  // namespace
  44
  45 KeyHoldDetector::KeyHoldDetector(scoped_ptr<Delegate> delegate)
  46     : state_(INITIAL),
  47       delegate_(delegate.Pass()) {}
  48
  49 KeyHoldDetector::~KeyHoldDetector() {}
  50
  51 void KeyHoldDetector::OnKeyEvent(ui::KeyEvent* event) {
  52   if (!delegate_->ShouldProcessEvent(event))
  53     return;
  54
  55   if (delegate_->IsStartEvent(event)) {
  56     switch (state_) {
  57       case INITIAL:
  58         // Pass through posted event.
  59         if (event->flags() & ui::EF_IS_SYNTHESIZED) {
  60           event->set_flags(event->flags() & ~ui::EF_IS_SYNTHESIZED);
  61           return;
  62         }
  63         state_ = PRESSED;
  64         // Don't process ET_KEY_PRESSED event yet. The ET_KEY_PRESSED
  65         // event will be generated upon ET_KEY_RELEASEED event below.
  66         event->StopPropagation();
  67         break;
  68       case PRESSED:
  69         state_ = HOLD;
  70         // pass through
  71       case HOLD:
  72         delegate_->OnKeyHold(event);
  73         event->StopPropagation();
  74         break;
  75       }
  76   } else if (event->type() == ui::ET_KEY_RELEASED) {
  77     switch (state_) {
  78       case INITIAL:
  79         break;
  80       case PRESSED: {
  81         PostPressedEvent(event);
  82         event->StopPropagation();
  83         break;
  84       }
  85       case HOLD: {
  86         delegate_->OnKeyUnhold(event);
  87         event->StopPropagation();
  88         break;
  89       }
  90     }
  91     state_ = INITIAL;
  92   }
  93 }
  94
  95 }  // namespace ash