ash/system/power/power_button_display_controller.cc

// Copyright 2017 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 "ash/system/power/power_button_display_controller.h"

#include "ash/accessibility/accessibility_controller.h"
#include "ash/media/media_controller.h"
#include "ash/shell.h"
#include "ash/system/power/scoped_backlights_forced_off.h"
#include "ash/wm/tablet_mode/tablet_mode_controller.h"
#include "base/time/tick_clock.h"
#include "chromeos/dbus/dbus_thread_manager.h"
#include "ui/events/devices/input_device_manager.h"
#include "ui/events/devices/stylus_state.h"
#include "ui/events/event.h"

namespace ash {

namespace {

// Returns true if device is currently in tablet/tablet mode, otherwise false.
bool IsTabletModeActive() {
  TabletModeController* tablet_mode_controller =
      Shell::Get()->tablet_mode_controller();
  return tablet_mode_controller &&
         tablet_mode_controller->IsTabletModeWindowManagerEnabled();
}

}  // namespace

PowerButtonDisplayController::PowerButtonDisplayController(
    BacklightsForcedOffSetter* backlights_forced_off_setter,
    const base::TickClock* tick_clock)
    : backlights_forced_off_setter_(backlights_forced_off_setter),
      backlights_forced_off_observer_(this),
      tick_clock_(tick_clock),
      weak_ptr_factory_(this) {
  chromeos::PowerManagerClient::Get()->AddObserver(this);
  ui::InputDeviceManager::GetInstance()->AddObserver(this);
  Shell::Get()->AddPreTargetHandler(this, ui::EventTarget::Priority::kSystem);

  backlights_forced_off_observer_.Add(backlights_forced_off_setter_);
}

PowerButtonDisplayController::~PowerButtonDisplayController() {
  Shell::Get()->RemovePreTargetHandler(this);
  ui::InputDeviceManager::GetInstance()->RemoveObserver(this);
  chromeos::PowerManagerClient::Get()->RemoveObserver(this);
}

bool PowerButtonDisplayController::IsScreenOn() const {
  return backlights_forced_off_setter_->screen_state() ==
         BacklightsForcedOffSetter::ScreenState::ON;
}

void PowerButtonDisplayController::SetBacklightsForcedOff(bool forced_off) {
  if ((backlights_forced_off_ != nullptr) == forced_off)
    return;

  send_accessibility_alert_on_backlights_forced_off_change_ = true;

  if (forced_off) {
    backlights_forced_off_ =
        backlights_forced_off_setter_->ForceBacklightsOff();
  } else {
    backlights_forced_off_.reset();
  }

  if (forced_off)
    Shell::Get()->media_controller()->SuspendMediaSessions();
}

void PowerButtonDisplayController::OnBacklightsForcedOffChanged(
    bool forced_off) {
  if (send_accessibility_alert_on_backlights_forced_off_change_) {
    Shell::Get()->accessibility_controller()->TriggerAccessibilityAlert(
        forced_off ? mojom::AccessibilityAlert::SCREEN_OFF
                   : mojom::AccessibilityAlert::SCREEN_ON);
  }
  send_accessibility_alert_on_backlights_forced_off_change_ = false;
}

void PowerButtonDisplayController::OnScreenStateChanged(
    BacklightsForcedOffSetter::ScreenState screen_state) {
  screen_state_last_changed_ = tick_clock_->NowTicks();
}

void PowerButtonDisplayController::SuspendDone(
    const base::TimeDelta& sleep_duration) {
  // Stop forcing backlights off on resume to handle situations where the power
  // button resumed but we didn't receive the event (crbug.com/735291).
  SetBacklightsForcedOff(false);
}

void PowerButtonDisplayController::LidEventReceived(
    chromeos::PowerManagerClient::LidState state,
    const base::TimeTicks& timestamp) {
  SetBacklightsForcedOff(false);
}

void PowerButtonDisplayController::TabletModeEventReceived(
    chromeos::PowerManagerClient::TabletMode mode,
    const base::TimeTicks& timestamp) {
  SetBacklightsForcedOff(false);
}

void PowerButtonDisplayController::OnKeyEvent(ui::KeyEvent* event) {
  // Ignore key events generated by the power button since power button activity
  // is already handled elsewhere.
  if (event->key_code() == ui::VKEY_POWER)
    return;

  if (!IsTabletModeActive())
    SetBacklightsForcedOff(false);
}

void PowerButtonDisplayController::OnMouseEvent(ui::MouseEvent* event) {
  if (event->flags() & ui::EF_IS_SYNTHESIZED)
    return;

  if (!IsTabletModeActive())
    SetBacklightsForcedOff(false);
}

void PowerButtonDisplayController::OnStylusStateChanged(ui::StylusState state) {
  if (state == ui::StylusState::REMOVED)
    SetBacklightsForcedOff(false);
}

}  // namespace ash