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// Copyright 2019 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 <memory>
#include <queue>
#include <vector>
#include "ash/ash_export.h"
#include "ash/wm/desks/root_window_desk_switch_animator.h"
#include "base/macros.h"
#include "base/observer_list.h"
namespace aura {
class Window;
} // namespace aura
namespace ash {
class Desk;
// Defines a controller for creating, destroying and managing virtual desks and
// their windows.
class ASH_EXPORT DesksController
: public RootWindowDeskSwitchAnimator::Delegate {
class Observer {
// Called when |desk| has been created and added to
// `DesksController::desks_`.
virtual void OnDeskAdded(const Desk* desk) = 0;
// Called when |desk| has been removed from `DesksController::desks_`.
// However |desk| is kept alive temporarily and will be destroyed after all
// observers have been notified with this.
virtual void OnDeskRemoved(const Desk* desk) = 0;
// Called when the |activated| desk gains activation from the |deactivated|
// desk.
virtual void OnDeskActivationChanged(const Desk* activated,
const Desk* deactivated) = 0;
// Called when the desk switch animations on all root windows finish.
virtual void OnDeskSwitchAnimationFinished() = 0;
virtual ~Observer() = default;
~DesksController() override;
// Convenience method for returning the DesksController instance. The actual
// instance is created and owned by Shell.
static DesksController* Get();
const std::vector<std::unique_ptr<Desk>>& desks() const { return desks_; }
const Desk* active_desk() const { return active_desk_; }
void AddObserver(Observer* observer);
void RemoveObserver(Observer* observer);
// Returns true if desks are being modified due to desk creation, removal, or
// activation. It also returns true while the desk switch animation is in
// progress.
bool AreDesksBeingModified() const;
// Returns true if we haven't reached the maximum allowed number of desks.
bool CanCreateDesks() const;
// Returns true as long as there are two or more desks. It is required that
// there is at least one single desk at any time.
bool CanRemoveDesks() const;
// Creates a new desk. CanCreateDesks() must be checked before calling this.
void NewDesk();
// Removes and deletes the given |desk|. |desk| must already exist, and
// CanRemoveDesks() must be checked before this.
void RemoveDesk(const Desk* desk);
// Performs the desk switch animation on all root windows to activate the
// given |desk| and to deactivate the currently active one. |desk| has to be
// an existing desk. The active window on the currently active desk will be
// deactivated, and the most-recently used window from the newly-activated
// desk will be activated.
void ActivateDesk(const Desk* desk);
// Called explicitly by the RootWindowController when a root window has been
// added or about to be removed in order to update all the available desks.
void OnRootWindowAdded(aura::Window* root_window);
void OnRootWindowClosing(aura::Window* root_window);
// RootWindowDeskSwitchAnimator::Delegate:
void OnStartingDeskScreenshotTaken(const Desk* ending_desk) override;
void OnEndingDeskScreenshotTaken() override;
void OnDeskSwitchAnimationFinished() override;
bool HasDesk(const Desk* desk) const;
int GetDeskIndex(const Desk* desk) const;
// Activates the given |desk| and deactivates the currently active one. |desk|
// has to be an existing desk. If |update_window_activation| is true,
// the active desk on the deactivated desk will be deactivated, and the most-
// recently used window on the newly-activated desk will be deactivated. This
// parameter is almost always true except when the active desk is being
// removed while in overview mode. In that case, windows from the active desk
// will move to another desk and remain in the overview grid, and no
// activation or deactivation should be done in order to keep overview mode
// active.
void ActivateDeskInternal(const Desk* desk, bool update_window_activation);
std::vector<std::unique_ptr<Desk>> desks_;
Desk* active_desk_ = nullptr;
// True when desks addition, removal, or activation change are in progress.
// This can be checked when overview mode is active to avoid exiting overview
// mode as a result of desks modifications.
bool are_desks_being_modified_ = false;
// An animator object per each root. Once all the animations are complete,
// this list is cleared.
// A free list of desk container IDs to be used for newly-created desks. New
// desks pops from this queue and removed desks's associated container IDs are
// re-pushed on this queue.
std::queue<int> available_container_ids_;
base::ObserverList<Observer>::Unchecked observers_;
} // namespace ash