ash : Decouple power button controller and session state controller.

ash/wm/session_state_controller.h

Index: ash/wm/session_state_controller.h
diff --git a/ash/wm/session_state_controller.h b/ash/wm/session_state_controller.h
new file mode 100644
index 0000000000000000000000000000000000000000..28ef08aaf05ab4bc03d450913ff0479ee91b3a45
--- /dev/null
+++ b/ash/wm/session_state_controller.h
@@ -0,0 +1,277 @@
+// Copyright (c) 2012 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.
+
+#ifndef ASH_WM_SESSION_STATE_CONTROLLER_H_
+#define ASH_WM_SESSION_STATE_CONTROLLER_H_
+
+#include "ash/ash_export.h"
+#include "ash/shell_observer.h"
+#include "ash/wm/session_state_animator.h"
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/time.h"
+#include "base/timer.h"
+#include "ui/aura/root_window_observer.h"
+
+namespace gfx {
+class Rect;
+class Size;
+}
+
+namespace ui {
+class Layer;
+}
+
+namespace ash {
+
+namespace test {
+class PowerButtonControllerTest;
+}
+
+// Performs system-related functions on behalf of SessionStateController.
+class ASH_EXPORT SessionStateControllerDelegate {
+ public:
+  SessionStateControllerDelegate() {}
+  virtual ~SessionStateControllerDelegate() {}
+
+  virtual void RequestLockScreen() = 0;
+  virtual void RequestShutdown() = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SessionStateControllerDelegate);
+};
+
+// Displays onscreen animations and locks or suspends the system in response to
+// the power button being pressed or released.
+class ASH_EXPORT SessionStateController : public aura::RootWindowObserver,
+                                          public ShellObserver {
+ public:
+  // Amount of time that the power button needs to be held before we lock the
+  // screen.
+  static const int kLockTimeoutMs;
+
+  // Amount of time that the power button needs to be held before we shut down.
+  static const int kShutdownTimeoutMs;
+
+  // Amount of time to wait for our lock requests to be honored before giving
+  // up.
+  static const int kLockFailTimeoutMs;
+
+  // When the button has been held continuously from the unlocked state, amount
+  // of time that we wait after the screen locker window is shown before
+  // starting the pre-shutdown animation.
+  static const int kLockToShutdownTimeoutMs;
+
+  // Amount of time taken to scale the snapshot of the screen down to a
+  // slightly-smaller size once the user starts holding the power button.  Used
+  // for both the pre-lock and pre-shutdown animations.
+  static const int kSlowCloseAnimMs;
+
+  // Amount of time taken to scale the snapshot of the screen back to its
+  // original size when the button is released.
+  static const int kUndoSlowCloseAnimMs;
+
+  // Amount of time taken to scale the snapshot down to a point in the center of
+  // the screen once the screen has been locked or we've been notified that the
+  // system is shutting down.
+  static const int kFastCloseAnimMs;
+
+  // Additional time (beyond kFastCloseAnimMs) to wait after starting the
+  // fast-close shutdown animation before actually requesting shutdown, to give
+  // the animation time to finish.
+  static const int kShutdownRequestDelayMs;
+
+  // Helper class used by tests to access internal state.
+  class ASH_EXPORT TestApi {
+   public:
+    explicit TestApi(SessionStateController* controller);
+
+    virtual ~TestApi();
+
+    bool lock_timer_is_running() const {
+      return controller_->lock_timer_.IsRunning();
+    }
+    bool lock_fail_timer_is_running() const {
+      return controller_->lock_fail_timer_.IsRunning();
+    }
+    bool lock_to_shutdown_timer_is_running() const {
+      return controller_->lock_to_shutdown_timer_.IsRunning();
+    }
+    bool shutdown_timer_is_running() const {
+      return controller_->pre_shutdown_timer_.IsRunning();
+    }
+    bool real_shutdown_timer_is_running() const {
+      return controller_->real_shutdown_timer_.IsRunning();
+    }
+
+    void trigger_lock_timeout() {
+      controller_->OnLockTimeout();
+      controller_->lock_timer_.Stop();
+    }
+    void trigger_lock_fail_timeout() {
+      controller_->OnLockFailTimeout();
+      controller_->lock_fail_timer_.Stop();
+    }
+    void trigger_lock_to_shutdown_timeout() {
+      controller_->OnLockToShutdownTimeout();
+      controller_->lock_to_shutdown_timer_.Stop();
+    }
+    void trigger_shutdown_timeout() {
+      controller_->OnPreShutdownAnimationTimeout();
+      controller_->pre_shutdown_timer_.Stop();
+    }
+    void trigger_real_shutdown_timeout() {
+      controller_->OnRealShutdownTimeout();
+      controller_->real_shutdown_timer_.Stop();
+    }
+   private:
+    SessionStateController* controller_;  // not owned
+
+    DISALLOW_COPY_AND_ASSIGN(TestApi);
+  };
+
+  SessionStateController();
+  virtual ~SessionStateController();
+
+  void set_delegate(SessionStateControllerDelegate* delegate) {
+    delegate_.reset(delegate);

[Nikita (slow), 2012/10/16 12:43:45]

That's not a trivial setter as

  void reset(C* p = NULL) {
    if (p != ptr_) {
      enum { type_must_be_complete = sizeof(C) };
      delete ptr_;
      ptr_ = p;
    }
  }

Please move implementation to .cc and rename to SetDelegate

[Denis Kuznetsov (DE-MUC), 2012/10/16 14:24:53]

Done.

+  }
+
+  // Returns true iff when we're in state when user session can be locked.
+  virtual bool IsEligibleForLock();
+
+  // Returns true if system is locked.
+  virtual bool IsLocked();
+
+  // Starts locking (with slow animation) that can be cancelled.
+  // After locking and |kLockToShutdownTimeoutMs| StartShutdownAnimation()
+  // will be called unless CancelShutdown() is called.

[Daniel Erat, 2012/10/15 13:24:47]

nit: this is a TODO at best rather than something that should happen in this
change, but i wonder if it'd be cleaner if this method didn't automatically
start the shutdown animation, and the caller had to call StartShutdownAnimation
explicitly instead.  opinions?

[Denis Kuznetsov (DE-MUC), 2012/10/16 14:24:53]

I'd like to have PowerButtonController as stateless as possible - it's just a
source of events for SessionStateController.
If StartShutdownAnimation should be called from outside, then 
PowerButtonController should keep it's own timer, that have to be matched with
animation (lock animation time + a bit of extra delay time). If by some reason
we would have two different lock animation times for two implementaions, code
would become much more coupled (e.g. there might appear something like
GetLockAnimationDuration() method).

+  virtual void StartLockAnimation();
+
+  // Starts shutting down (with slow animation) that can be cancelled.
+  virtual void StartShutdownAnimation();
+
+  // Starts usual lock animation, but lock immediately.

[Daniel Erat, 2012/10/15 13:24:47]

nit: s/lock/locks/

also describe whether StartLockAnimation will be called automatically as in
StartLockAnimation or not

[Denis Kuznetsov (DE-MUC), 2012/10/16 14:24:53]

Done.

[Denis Kuznetsov (DE-MUC), 2012/10/16 14:24:53]

Done.

+  virtual void StartLockAnimationAndLockImmediately();
+
+  // Returns true if we have requested system to lock, but haven't recieved

[Daniel Erat, 2012/10/15 13:24:47]

nit: s/recieved/received/

[Denis Kuznetsov (DE-MUC), 2012/10/16 14:24:53]

Done.

+  // confirmation yet.
+  virtual bool LockRequested();
+
+  // Returns true if we are shutting down.
+  virtual bool ShutdownRequested();
+
+  // Returns true if we are within cancellable lock timeframe.
+  virtual bool CanCancelLockAnimation();
+
+  // Cancels locking and reverts lock animation.
+  virtual void CancelLockAnimation();
+
+  // Cancels locking and reverts lock animation with slightly different
+  // parameters. Seems to be some bug, but refactoring should keep all bugs.
+  // TODO(antrim): remove this, animations should actually be the same.
+  virtual void CancelLockWithOtherAnimation();
+
+  // Returns true if we are within cancellable shutdown timeframe.
+  virtual bool CanCancelShutdownAnimation();
+
+  // Cancels shutting down and reverts shutdown animation.
+  virtual void CancelShutdownAnimation();
+
+  // Called when Chrome gets a request to display the lock screen.
+  virtual void OnStartingLock();
+
+  // Displays the shutdown animation and requests shutdown when it's done.
+  virtual void RequestShutdown();
+
+  // RootWindowObserver override:
+  virtual void OnRootWindowHostCloseRequested(

[Nikita (slow), 2012/10/16 12:43:45]

Place these overrides first. Then other public methods.
Or as an alternative you should place these into protected: section.

[Daniel Erat, 2012/10/16 14:04:16]

I think that overrides usually come after non-overridden method in each section,
not before.  I can't find this in the style guide, though.  Please check
surrounding code, but I'm pretty sure that what's currently here in this change
is preferred.

[Denis Kuznetsov (DE-MUC), 2012/10/16 14:24:53]

Done.

+     const aura::RootWindow* root) OVERRIDE;
+
+  // ShellObserver overrides:
+  virtual void OnLoginStateChanged(user::LoginStatus status) OVERRIDE;

[Nikita (slow), 2012/10/16 12:43:45]

Same with these.

[Denis Kuznetsov (DE-MUC), 2012/10/16 14:24:53]

Done.

+  virtual void OnAppTerminating() OVERRIDE;
+  virtual void OnLockStateChanged(bool locked) OVERRIDE;
+
+ protected:
+  friend class test::PowerButtonControllerTest;
+
+  bool LoggedInAsNonGuest() const;

[Nikita (slow), 2012/10/16 12:43:45]

nit: IsLoggedInAsNonGuest()

[Denis Kuznetsov (DE-MUC), 2012/10/16 14:24:53]

Done.

+
+ private:
+  void RequestShutdownImpl();
+
+  // Starts lock timer.
+  void StartLockTimer();

[Nikita (slow), 2012/10/16 12:43:45]

Just for the record (I'm not asking to fix this in this class though as you have
another CL depending on it): when creating new class,  it is nice to order all
methods alphabetically in each section (public/protected/private).

[Daniel Erat, 2012/10/16 14:04:16]

I need to disagree with this one too -- I find logical grouping (e.g. lock
methods, then shutdown methods, etc.) more intuitive.  I haven't noticed
alphabetical method ordering anywhere else in Chrome.

+
+  // Requests that the screen be locked and starts |lock_fail_timer_|.
+  void OnLockTimeout();
+
+  // Reverts the pre-lock animation, reports the error.
+  void OnLockFailTimeout();
+
+  // Starts timer for gap between lock and shutdown.
+  void StartLockToShutdownTimer();
+
+  // Calls StartShutdownAnimation().
+  void OnLockToShutdownTimeout();
+
+  // Starts timer for undoable shutdown animation.
+  void StartPreShutdownAnimationTimer();
+
+  // Calls RequestShutdownImpl();
+  void OnPreShutdownAnimationTimeout();
+
+  // Starts timer for final shutdown animation.
+  void StartRealShutdownTimer();
+
+  // Requests that the machine be shut down.
+  void OnRealShutdownTimeout();
+
+  // The current login status.
+  user::LoginStatus login_status_;
+
+  // Original login status during locked.  LOGGED_IN_NONE if it's not locked.

[Daniel Erat, 2012/10/15 13:24:47]

nit: s/during locked/from before we locked/

[Denis Kuznetsov (DE-MUC), 2012/10/16 14:24:53]

Done.

+  user::LoginStatus unlocked_login_status_;

[Nikita (slow), 2012/10/16 12:43:45]

I find having these two login_status_ /  unlocked_login_status_  quite
confusing.

I think you should simplify that by having just login_status_ to track logged in
/ not logged in / as guest / etc. and you need just boolean variable locked_.

I know this has been part of existing code but since you're doing a refactoring
now's the right time to simplify this.

[Denis Kuznetsov (DE-MUC), 2012/10/16 14:24:53]

Will think about fixing it in next CL.

+
+  // Are we in the process of shutting the machine down?
+  bool shutting_down_;
+
+  // Indicates whether controller should proceed to (cancellable) shutdown after
+  // locking.
+  bool shutdown_after_lock_;
+
+  // Started when the user first presses the power button while in a
+  // logged-in-as-a-non-guest-user, unlocked state.  When it fires, we lock the
+  // screen.
+  base::OneShotTimer<SessionStateController> lock_timer_;
+
+  // Started when we request that the screen be locked.  When it fires, we
+  // assume that our request got dropped.
+  base::OneShotTimer<SessionStateController> lock_fail_timer_;
+
+  // Started when the screen is locked while the power button is held.  Adds a
+  // delay between the appearance of the lock screen and the beginning of the
+  // pre-shutdown animation.
+  base::OneShotTimer<SessionStateController> lock_to_shutdown_timer_;
+
+  // Started when we begin displaying the pre-shutdown animation.  When it
+  // fires, we start the shutdown animation and get ready to request shutdown.
+  base::OneShotTimer<SessionStateController> pre_shutdown_timer_;
+
+  // Started when we display the shutdown animation.  When it fires, we actually
+  // request shutdown.  Gives the animation time to complete before Chrome, X,
+  // etc. are shut down.
+  base::OneShotTimer<SessionStateController> real_shutdown_timer_;
+
+  scoped_ptr<internal::SessionStateAnimator> animator_;
+
+  scoped_ptr<SessionStateControllerDelegate> delegate_;
+
+  DISALLOW_COPY_AND_ASSIGN(SessionStateController);
+};
+
+}  // namespace ash
+
+#endif  // ASH_WM_SESSION_STATE_CONTROLLER_H_