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_VIEWS_CONTROLS_MENU_MENU_RUNNER_H_ 6 #define UI_VIEWS_CONTROLS_MENU_MENU_RUNNER_H_ 7 8 #include "base/basictypes.h" 9 #include "base/compiler_specific.h" 10 #include "base/memory/scoped_ptr.h" 11 #include "ui/views/controls/menu/menu_item_view.h" 12 13 namespace ui { 14 class MenuModel; 15 } 16 17 namespace views { 18 19 class MenuButton; 20 class MenuModelAdapter; 21 class Widget; 22 23 namespace internal { 24 class DisplayChangeListener; 25 class MenuRunnerImpl; 26 } 27 28 // MenuRunner is responsible for showing (running) the menu and additionally 29 // owning the MenuItemView. RunMenuAt() runs a nested message loop. It is safe 30 // to delete MenuRunner at any point, but MenuRunner internally only deletes the 31 // MenuItemView *after* the nested message loop completes. If MenuRunner is 32 // deleted while the menu is showing the delegate of the menu is reset. This is 33 // done to ensure delegates aren't notified after they may have been deleted. 34 // 35 // NOTE: while you can delete a MenuRunner at any point, the nested message loop 36 // won't return immediately. This means if you delete the object that owns 37 // the MenuRunner while the menu is running, your object is effectively still 38 // on the stack. A return value of MENU_DELETED indicated this. In most cases 39 // if RunMenuAt() returns MENU_DELETED, you should return immediately. 40 // 41 // Similarly you should avoid creating MenuRunner on the stack. Doing so means 42 // MenuRunner may not be immediately destroyed if your object is destroyed, 43 // resulting in possible callbacks to your now deleted object. Instead you 44 // should define MenuRunner as a scoped_ptr in your class so that when your 45 // object is destroyed MenuRunner initiates the proper cleanup and ensures your 46 // object isn't accessed again. 47 class VIEWS_EXPORT MenuRunner { 48 public: 49 enum RunTypes { 50 // The menu has mnemonics. 51 HAS_MNEMONICS = 1 << 0, 52 53 // The menu is a nested context menu. For example, click a folder on the 54 // bookmark bar, then right click an entry to get its context menu. 55 IS_NESTED = 1 << 1, 56 57 // Used for showing a menu during a drop operation. This does NOT block the 58 // caller, instead the delegate is notified when the menu closes via the 59 // DropMenuClosed method. 60 FOR_DROP = 1 << 2, 61 62 // The menu is a context menu (not necessarily nested), for example right 63 // click on a link on a website in the browser. 64 CONTEXT_MENU = 1 << 3, 65 }; 66 67 enum RunResult { 68 // Indicates RunMenuAt is returning because the MenuRunner was deleted. 69 MENU_DELETED, 70 71 // Indicates RunMenuAt returned and MenuRunner was not deleted. 72 NORMAL_EXIT 73 }; 74 75 // Creates a new MenuRunner. 76 explicit MenuRunner(ui::MenuModel* menu_model); 77 explicit MenuRunner(MenuItemView* menu); 78 ~MenuRunner(); 79 80 // Returns the menu. 81 MenuItemView* GetMenu(); 82 83 // Takes ownership of |menu|, deleting it when MenuRunner is deleted. You 84 // only need call this if you create additional menus from 85 // MenuDelegate::GetSiblingMenu. 86 void OwnMenu(MenuItemView* menu); 87 88 // Runs the menu. |types| is a bitmask of RunTypes. If this returns 89 // MENU_DELETED the method is returning because the MenuRunner was deleted. 90 // Typically callers should NOT do any processing if this returns 91 // MENU_DELETED. 92 // If |anchor| uses a |BUBBLE_..| type, the bounds will get determined by 93 // using |bounds| as the thing to point at in screen coordinates. 94 RunResult RunMenuAt(Widget* parent, 95 MenuButton* button, 96 const gfx::Rect& bounds, 97 MenuItemView::AnchorPosition anchor, 98 ui::MenuSourceType source_type, 99 int32 types) WARN_UNUSED_RESULT; 100 101 // Returns true if we're in a nested message loop running the menu. 102 bool IsRunning() const; 103 104 // Hides and cancels the menu. This does nothing if the menu is not open. 105 void Cancel(); 106 107 // Returns the time from the event which closed the menu - or 0. 108 base::TimeDelta closing_event_time() const; 109 110 private: 111 scoped_ptr<MenuModelAdapter> menu_model_adapter_; 112 113 internal::MenuRunnerImpl* holder_; 114 115 scoped_ptr<internal::DisplayChangeListener> display_change_listener_; 116 117 DISALLOW_COPY_AND_ASSIGN(MenuRunner); 118 }; 119 120 namespace internal { 121 122 // DisplayChangeListener is intended to listen for changes in the display size 123 // and cancel the menu. DisplayChangeListener is created when the menu is 124 // shown. 125 class DisplayChangeListener { 126 public: 127 virtual ~DisplayChangeListener() {} 128 129 // Creates the platform specified DisplayChangeListener, or NULL if there 130 // isn't one. Caller owns the returned value. 131 static DisplayChangeListener* Create(Widget* parent, 132 MenuRunner* runner); 133 134 protected: 135 DisplayChangeListener() {} 136 }; 137 138 } 139 140 } // namespace views 141 142 #endif // UI_VIEWS_CONTROLS_MENU_MENU_RUNNER_H_ 143
