1 // Copyright (c) 2012 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_FOCUS_RULES_H_ 6 #define UI_WM_CORE_FOCUS_RULES_H_ 7 8 #include "ui/wm/wm_export.h" 9 10 namespace aura { 11 class Window; 12 } 13 14 namespace wm { 15 16 // Implemented by an object that establishes the rules about what can be 17 // focused or activated. 18 class WM_EXPORT FocusRules { 19 public: 20 virtual ~FocusRules() {} 21 22 // Returns true if |window| is a toplevel window. Whether or not a window 23 // is considered toplevel is determined by a similar set of rules that 24 // govern activation and focus. Not all toplevel windows are activatable, 25 // call CanActivateWindow() to determine if a window can be activated. 26 virtual bool IsToplevelWindow(aura::Window* window) const = 0; 27 // Returns true if |window| can be activated or focused. 28 virtual bool CanActivateWindow(aura::Window* window) const = 0; 29 // For CanFocusWindow(), NULL is supported, because NULL is a valid focusable 30 // window (in the case of clearing focus). 31 virtual bool CanFocusWindow(aura::Window* window) const = 0; 32 33 // Returns the toplevel window containing |window|. Not all toplevel windows 34 // are activatable, call GetActivatableWindow() instead to return the 35 // activatable window, which might be in a different hierarchy. 36 // Will return NULL if |window| is not contained by a window considered to be 37 // a toplevel window. 38 virtual aura::Window* GetToplevelWindow(aura::Window* window) const = 0; 39 // Returns the activatable or focusable window given an attempt to activate or 40 // focus |window|. Some possible scenarios (not intended to be exhaustive): 41 // - |window| is a child of a non-focusable window and so focus must be set 42 // according to rules defined by the delegate, e.g. to a parent. 43 // - |window| is an activatable window that is the transient parent of a modal 44 // window, so attempts to activate |window| should result in the modal 45 // transient being activated instead. 46 // These methods may return NULL if they are unable to find an activatable 47 // or focusable window given |window|. 48 virtual aura::Window* GetActivatableWindow(aura::Window* window) const = 0; 49 virtual aura::Window* GetFocusableWindow(aura::Window* window) const = 0; 50 51 // Returns the next window to activate in the event that |ignore| is no longer 52 // activatable. This function is called when something is happening to 53 // |ignore| that means it can no longer have focus or activation, including 54 // but not limited to: 55 // - it or its parent hierarchy is being hidden, or removed from the 56 // RootWindow. 57 // - it is being destroyed. 58 // - it is being explicitly deactivated. 59 // |ignore| cannot be NULL. 60 virtual aura::Window* GetNextActivatableWindow( 61 aura::Window* ignore) const = 0; 62 }; 63 64 } // namespace wm 65 66 #endif // UI_WM_CORE_FOCUS_RULES_H_ 67
