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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 CEF_LIBCEF_BROWSER_NATIVE_NATIVE_MENU_WIN_H_
6 #define CEF_LIBCEF_BROWSER_NATIVE_NATIVE_MENU_WIN_H_
7 
8 #include <memory>
9 #include <vector>
10 
11 #include "libcef/browser/native/menu_wrapper.h"
12 
13 #include "base/compiler_specific.h"
14 #include "base/macros.h"
15 #include "base/memory/weak_ptr.h"
16 #include "base/observer_list.h"
17 
18 namespace ui {
19 class MenuModel;
20 }
21 
22 namespace views {
23 
24 // A Windows implementation of MenuWrapper.
25 // TODO(beng): rename to MenuWin once the old class is dead.
26 class CefNativeMenuWin : public MenuWrapper {
27  public:
28   // Construct a CefNativeMenuWin, with a model and delegate. If
29   // |system_menu_for| is non-NULL, the CefNativeMenuWin wraps the system menu
30   // for that window.
31   // The caller owns the model and the delegate.
32   CefNativeMenuWin(ui::MenuModel* model, HWND system_menu_for);
33   ~CefNativeMenuWin() override;
34 
35   // Overridden from MenuWrapper:
36   void RunMenuAt(const gfx::Point& point, int alignment) override;
37   void CancelMenu() override;
38   void Rebuild(MenuInsertionDelegateWin* delegate) override;
39   void UpdateStates() override;
40   HMENU GetNativeMenu() const override;
41   MenuAction GetMenuAction() const override;
42   void SetMinimumWidth(int width) override;
43 
44  private:
45   // IMPORTANT: Note about indices.
46   //            Functions in this class deal in two index spaces:
47   //            1. menu_index - the index of an item within the actual Windows
48   //               native menu.
49   //            2. model_index - the index of the item within our model.
50   //            These two are most often but not always the same value! The
51   //            notable exception is when this object is used to wrap the
52   //            Windows System Menu. In this instance, the model indices start
53   //            at 0, but the insertion index into the existing menu is not.
54   //            It is important to take this into consideration when editing the
55   //            code in the functions in this class.
56 
57   struct HighlightedMenuItemInfo;
58 
59   // Returns true if the item at the specified index is a separator.
60   bool IsSeparatorItemAt(int menu_index) const;
61 
62   // Add items. See note above about indices.
63   void AddMenuItemAt(int menu_index, int model_index);
64   void AddSeparatorItemAt(int menu_index, int model_index);
65 
66   // Sets the state of the item at the specified index.
67   void SetMenuItemState(int menu_index,
68                         bool enabled,
69                         bool checked,
70                         bool is_default);
71 
72   // Sets the label of the item at the specified index.
73   void SetMenuItemLabel(int menu_index,
74                         int model_index,
75                         const std::wstring& label);
76 
77   // Updates the local data structure with the correctly formatted version of
78   // |label| at the specified model_index, and adds string data to |mii| if
79   // the menu is not owner-draw. That's a mouthful. This function exists because
80   // of the peculiarities of the Windows menu API.
81   void UpdateMenuItemInfoForString(MENUITEMINFO* mii,
82                                    int model_index,
83                                    const std::wstring& label);
84 
85   // Returns the alignment flags to be passed to TrackPopupMenuEx, based on the
86   // supplied alignment and the UI text direction.
87   UINT GetAlignmentFlags(int alignment) const;
88 
89   // Resets the native menu stored in |menu_| by destroying any old menu then
90   // creating a new empty one.
91   void ResetNativeMenu();
92 
93   // Creates the host window that receives notifications from the menu.
94   void CreateHostWindow();
95 
96   // Callback from task to notify menu it was selected.
97   void DelayedSelect();
98 
99   // Given a menu that's currently popped-up, find the currently highlighted
100   // item. Returns true if a highlighted item was found.
101   static bool GetHighlightedMenuItemInfo(HMENU menu,
102                                          HighlightedMenuItemInfo* info);
103 
104   // Hook to receive keyboard events while the menu is open.
105   static LRESULT CALLBACK MenuMessageHook(int n_code,
106                                           WPARAM w_param,
107                                           LPARAM l_param);
108 
109   // Our attached model and delegate.
110   ui::MenuModel* model_;
111 
112   HMENU menu_;
113 
114   // True if the contents of menu items in this menu are drawn by the menu host
115   // window, rather than Windows.
116   bool owner_draw_;
117 
118   // An object that collects all of the data associated with an individual menu
119   // item.
120   struct ItemData;
121   typedef std::vector<std::unique_ptr<ItemData>> ItemDataList;
122   ItemDataList items_;
123 
124   // The window that receives notifications from the menu.
125   class MenuHostWindow;
126   friend MenuHostWindow;
127   std::unique_ptr<MenuHostWindow> host_window_;
128 
129   // The HWND this menu is the system menu for, or NULL if the menu is not a
130   // system menu.
131   HWND system_menu_for_;
132 
133   // The index of the first item in the model in the menu.
134   int first_item_index_;
135 
136   // The action that took place during the call to RunMenuAt.
137   MenuAction menu_action_;
138 
139   // See comment in MenuMessageHook for details on these.
140   CefNativeMenuWin* menu_to_select_;
141   int position_to_select_;
142 
143   // If we're a submenu, this is our parent.
144   CefNativeMenuWin* parent_;
145 
146   // If non-null the destructor sets this to true. This is set to non-null while
147   // the menu is showing. It is used to detect if the menu was deleted while
148   // running.
149   bool* destroyed_flag_;
150 
151   base::WeakPtrFactory<CefNativeMenuWin> menu_to_select_factory_;
152 
153   // Ugly: a static pointer to the instance of this class that currently
154   // has a menu open, because our hook function that receives keyboard
155   // events doesn't have a mechanism to get a user data pointer.
156   static CefNativeMenuWin* open_native_menu_win_;
157 
158   DISALLOW_COPY_AND_ASSIGN(CefNativeMenuWin);
159 };
160 
161 }  // namespace views
162 
163 #endif  // CEF_LIBCEF_BROWSER_NATIVE_NATIVE_MENU_WIN_H_
164