// 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 UI_WM_CORE_FOCUS_RULES_H_ #define UI_WM_CORE_FOCUS_RULES_H_ #include "ui/wm/core/wm_core_export.h" namespace aura { class Window; } namespace wm { // Implemented by an object that establishes the rules about what can be // focused or activated. class WM_CORE_EXPORT FocusRules { public: virtual ~FocusRules() {} // Returns true if |window| is a toplevel window. Whether or not a window // is considered toplevel is determined by a similar set of rules that // govern activation and focus. Not all toplevel windows are activatable, // call CanActivateWindow() to determine if a window can be activated. virtual bool IsToplevelWindow(aura::Window* window) const = 0; // Returns true if |window| can be activated or focused. virtual bool CanActivateWindow(aura::Window* window) const = 0; // For CanFocusWindow(), NULL is supported, because NULL is a valid focusable // window (in the case of clearing focus). virtual bool CanFocusWindow(aura::Window* window) const = 0; // Returns the toplevel window containing |window|. Not all toplevel windows // are activatable, call GetActivatableWindow() instead to return the // activatable window, which might be in a different hierarchy. // Will return NULL if |window| is not contained by a window considered to be // a toplevel window. virtual aura::Window* GetToplevelWindow(aura::Window* window) const = 0; // Returns the activatable or focusable window given an attempt to activate or // focus |window|. Some possible scenarios (not intended to be exhaustive): // - |window| is a child of a non-focusable window and so focus must be set // according to rules defined by the delegate, e.g. to a parent. // - |window| is an activatable window that is the transient parent of a modal // window, so attempts to activate |window| should result in the modal // transient being activated instead. // These methods may return NULL if they are unable to find an activatable // or focusable window given |window|. virtual aura::Window* GetActivatableWindow(aura::Window* window) const = 0; virtual aura::Window* GetFocusableWindow(aura::Window* window) const = 0; // Returns the next window to activate in the event that |ignore| is no longer // activatable. This function is called when something is happening to // |ignore| that means it can no longer have focus or activation, including // but not limited to: // - it or its parent hierarchy is being hidden, or removed from the // RootWindow. // - it is being destroyed. // - it is being explicitly deactivated. // |ignore| cannot be NULL. virtual aura::Window* GetNextActivatableWindow( aura::Window* ignore) const = 0; }; } // namespace wm #endif // UI_WM_CORE_FOCUS_RULES_H_