ui/wm/core/transient_window_manager.h

   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 #ifndef UI_WM_CORE_TRANSIENT_WINDOW_MANAGER_H_
   6 #define UI_WM_CORE_TRANSIENT_WINDOW_MANAGER_H_
   7
   8 #include <vector>
   9
  10 #include "base/observer_list.h"
  11 #include "ui/aura/window_observer.h"
  12 #include "ui/wm/wm_export.h"
  13
  14 namespace wm {
  15
  16 class TransientWindowObserver;
  17
  18 // TransientWindowManager manages the set of transient children for a window
  19 // along with the transient parent. Transient children get the following
  20 // behavior:
  21 // . The transient parent destroys any transient children when it is
  22 //   destroyed. This means a transient child is destroyed if either its parent
  23 //   or transient parent is destroyed.
  24 // . If a transient child and its transient parent share the same parent, then
  25 //   transient children are always ordered above the transient parent.
  26 // Transient windows are typically used for popups and menus.
  27 // TODO(sky): when we nuke TransientWindowClient rename this to
  28 // TransientWindowController.
  29 class WM_EXPORT TransientWindowManager : public aura::WindowObserver {
  30  public:
  31   typedef std::vector<aura::Window*> Windows;
  32
  33   virtual ~TransientWindowManager();
  34
  35   // Returns the TransientWindowManager for |window|. This never returns NULL.
  36   static TransientWindowManager* Get(aura::Window* window);
  37
  38   // Returns the TransientWindowManager for |window| only if it already exists.
  39   // WARNING: this may return NULL.
  40   static const TransientWindowManager* Get(const aura::Window* window);
  41
  42   void AddObserver(TransientWindowObserver* observer);
  43   void RemoveObserver(TransientWindowObserver* observer);
  44
  45   // Adds or removes a transient child.
  46   void AddTransientChild(aura::Window* child);
  47   void RemoveTransientChild(aura::Window* child);
  48
  49   const Windows& transient_children() const { return transient_children_; }
  50
  51   aura::Window* transient_parent() { return transient_parent_; }
  52   const aura::Window* transient_parent() const { return transient_parent_; }
  53
  54   // Returns true if in the process of stacking |window_| on top of |target|.
  55   // That is, when the stacking order of a window changes
  56   // (OnWindowStackingChanged()) the transients may get restacked as well. This
  57   // function can be used to detect if TransientWindowManager is in the process
  58   // of stacking a transient as the result of window stacking changing.
  59   bool IsStackingTransient(const aura::Window* target) const;
  60
  61  private:
  62   explicit TransientWindowManager(aura::Window* window);
  63
  64   // Stacks transient descendants of this window that are its siblings just
  65   // above it.
  66   void RestackTransientDescendants();
  67
  68   // WindowObserver:
  69   virtual void OnWindowParentChanged(aura::Window* window,
  70                                      aura::Window* parent) OVERRIDE;
  71   virtual void OnWindowVisibilityChanging(aura::Window* window,
  72                                           bool visible) OVERRIDE;
  73   virtual void OnWindowStackingChanged(aura::Window* window) OVERRIDE;
  74   virtual void OnWindowDestroying(aura::Window* window) OVERRIDE;
  75
  76   aura::Window* window_;
  77   aura::Window* transient_parent_;
  78   Windows transient_children_;
  79
  80   // If non-null we're actively restacking transient as the result of a
  81   // transient ancestor changing.
  82   aura::Window* stacking_target_;
  83
  84   ObserverList<TransientWindowObserver> observers_;
  85
  86   DISALLOW_COPY_AND_ASSIGN(TransientWindowManager);
  87 };
  88
  89 }  // namespace wm
  90
  91 #endif  // UI_WM_CORE_TRANSIENT_WINDOW_MANAGER_H_