ui/views/controls/menu/native_menu_win.cc

   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 #include "ui/views/controls/menu/native_menu_win.h"
   6
   7 #include <Windowsx.h>
   8
   9 #include "base/bind.h"
  10 #include "base/logging.h"
  11 #include "base/message_loop/message_loop.h"
  12 #include "base/profiler/scoped_tracker.h"
  13 #include "base/stl_util.h"
  14 #include "base/strings/string_util.h"
  15 #include "base/win/wrapped_window_proc.h"
  16 #include "ui/base/accelerators/accelerator.h"
  17 #include "ui/base/l10n/l10n_util.h"
  18 #include "ui/base/l10n/l10n_util_win.h"
  19 #include "ui/base/models/menu_model.h"
  20 #include "ui/events/keycodes/keyboard_codes.h"
  21 #include "ui/gfx/canvas.h"
  22 #include "ui/gfx/font_list.h"
  23 #include "ui/gfx/geometry/rect.h"
  24 #include "ui/gfx/image/image.h"
  25 #include "ui/gfx/image/image_skia.h"
  26 #include "ui/gfx/text_utils.h"
  27 #include "ui/gfx/win/hwnd_util.h"
  28 #include "ui/native_theme/native_theme.h"
  29 #include "ui/native_theme/native_theme_win.h"
  30 #include "ui/views/controls/menu/menu_2.h"
  31 #include "ui/views/controls/menu/menu_config.h"
  32 #include "ui/views/controls/menu/menu_insertion_delegate_win.h"
  33 #include "ui/views/controls/menu/menu_listener.h"
  34 #include "ui/views/layout/layout_constants.h"
  35
  36 using ui::NativeTheme;
  37
  38 namespace views {
  39
  40 // The width of an icon, including the pixels between the icon and
  41 // the item label.
  42 static const int kIconWidth = 23;
  43 // Margins between the top of the item and the label.
  44 static const int kItemTopMargin = 3;
  45 // Margins between the bottom of the item and the label.
  46 static const int kItemBottomMargin = 4;
  47 // Margins between the left of the item and the icon.
  48 static const int kItemLeftMargin = 4;
  49 // The width for displaying the sub-menu arrow.
  50 static const int kArrowWidth = 10;
  51
  52 struct NativeMenuWin::ItemData {
  53   // The Windows API requires that whoever creates the menus must own the
  54   // strings used for labels, and keep them around for the lifetime of the
  55   // created menu. So be it.
  56   base::string16 label;
  57
  58   // Someone needs to own submenus, it may as well be us.
  59   scoped_ptr<Menu2> submenu;
  60
  61   // We need a pointer back to the containing menu in various circumstances.
  62   NativeMenuWin* native_menu_win;
  63
  64   // The index of the item within the menu's model.
  65   int model_index;
  66 };
  67
  68 // Returns the NativeMenuWin for a particular HMENU.
  69 static NativeMenuWin* GetNativeMenuWinFromHMENU(HMENU hmenu) {
  70   MENUINFO mi = {0};
  71   mi.cbSize = sizeof(mi);
  72   mi.fMask = MIM_MENUDATA | MIM_STYLE;
  73   GetMenuInfo(hmenu, &mi);
  74   return reinterpret_cast<NativeMenuWin*>(mi.dwMenuData);
  75 }
  76
  77 // A window that receives messages from Windows relevant to the native menu
  78 // structure we have constructed in NativeMenuWin.
  79 class NativeMenuWin::MenuHostWindow {
  80  public:
  81   explicit MenuHostWindow(NativeMenuWin* parent) : parent_(parent) {
  82     RegisterClass();
  83     hwnd_ = CreateWindowEx(l10n_util::GetExtendedStyles(), kWindowClassName,
  84                            L"", 0, 0, 0, 0, 0, HWND_MESSAGE, NULL, NULL, NULL);
  85     gfx::CheckWindowCreated(hwnd_);
  86     gfx::SetWindowUserData(hwnd_, this);
  87   }
  88
  89   ~MenuHostWindow() {
  90     DestroyWindow(hwnd_);
  91   }
  92
  93   HWND hwnd() const { return hwnd_; }
  94
  95  private:
  96   static const wchar_t* kWindowClassName;
  97
  98   void RegisterClass() {
  99     static bool registered = false;
 100     if (registered)
 101       return;
 102
 103     WNDCLASSEX window_class;
 104     base::win::InitializeWindowClass(
 105         kWindowClassName,
 106         &base::win::WrappedWindowProc<MenuHostWindowProc>,
 107         CS_DBLCLKS,
 108         0,
 109         0,
 110         NULL,
 111         reinterpret_cast<HBRUSH>(COLOR_WINDOW+1),
 112         NULL,
 113         NULL,
 114         NULL,
 115         &window_class);
 116     ATOM clazz = RegisterClassEx(&window_class);
 117     CHECK(clazz);
 118     registered = true;
 119   }
 120
 121   // Converts the WPARAM value passed to WM_MENUSELECT into an index
 122   // corresponding to the menu item that was selected.
 123   int GetMenuItemIndexFromWPARAM(HMENU menu, WPARAM w_param) const {
 124     int count = GetMenuItemCount(menu);
 125     // For normal command menu items, Windows passes a command id as the LOWORD
 126     // of WPARAM for WM_MENUSELECT. We need to walk forward through the menu
 127     // items to find an item with a matching ID. Ugh!
 128     for (int i = 0; i < count; ++i) {
 129       MENUITEMINFO mii = {0};
 130       mii.cbSize = sizeof(mii);
 131       mii.fMask = MIIM_ID;
 132       GetMenuItemInfo(menu, i, MF_BYPOSITION, &mii);
 133       if (mii.wID == w_param)
 134         return i;
 135     }
 136     // If we didn't find a matching command ID, this means a submenu has been
 137     // selected instead, and rather than passing a command ID in
 138     // LOWORD(w_param), Windows has actually passed us a position, so we just
 139     // return it.
 140     return w_param;
 141   }
 142
 143   NativeMenuWin::ItemData* GetItemData(ULONG_PTR item_data) {
 144     return reinterpret_cast<NativeMenuWin::ItemData*>(item_data);
 145   }
 146
 147   // Called when the user selects a specific item.
 148   void OnMenuCommand(int position, HMENU menu) {
 149     NativeMenuWin* menu_win = GetNativeMenuWinFromHMENU(menu);
 150     ui::MenuModel* model = menu_win->model_;
 151     NativeMenuWin* root_menu = menu_win;
 152     while (root_menu->parent_)
 153       root_menu = root_menu->parent_;
 154
 155     // Only notify the model if it didn't already send out notification.
 156     // See comment in MenuMessageHook for details.
 157     if (root_menu->menu_action_ == MenuWrapper::MENU_ACTION_NONE)
 158       model->ActivatedAt(position);
 159   }
 160
 161   // Called as the user moves their mouse or arrows through the contents of the
 162   // menu.
 163   void OnMenuSelect(WPARAM w_param, HMENU menu) {
 164     if (!menu)
 165       return;  // menu is null when closing on XP.
 166
 167     int position = GetMenuItemIndexFromWPARAM(menu, w_param);
 168     if (position >= 0)
 169       GetNativeMenuWinFromHMENU(menu)->model_->HighlightChangedTo(position);
 170   }
 171
 172   // Called by Windows to measure the size of an owner-drawn menu item.
 173   void OnMeasureItem(WPARAM w_param, MEASUREITEMSTRUCT* measure_item_struct) {
 174     NativeMenuWin::ItemData* data = GetItemData(measure_item_struct->itemData);
 175     if (data) {
 176       gfx::FontList font_list;
 177       measure_item_struct->itemWidth =
 178           gfx::GetStringWidth(data->label, font_list) +
 179           kIconWidth + kItemLeftMargin + views::kItemLabelSpacing -
 180           GetSystemMetrics(SM_CXMENUCHECK);
 181       if (data->submenu.get())
 182         measure_item_struct->itemWidth += kArrowWidth;
 183       // If the label contains an accelerator, make room for tab.
 184       if (data->label.find(L'\t') != base::string16::npos)
 185         measure_item_struct->itemWidth += gfx::GetStringWidth(L" ", font_list);
 186       measure_item_struct->itemHeight =
 187           font_list.GetHeight() + kItemBottomMargin + kItemTopMargin;
 188     } else {
 189       // Measure separator size.
 190       measure_item_struct->itemHeight = GetSystemMetrics(SM_CYMENU) / 2;
 191       measure_item_struct->itemWidth = 0;
 192     }
 193   }
 194
 195   // Called by Windows to paint an owner-drawn menu item.
 196   void OnDrawItem(UINT w_param, DRAWITEMSTRUCT* draw_item_struct) {
 197     HDC dc = draw_item_struct->hDC;
 198     COLORREF prev_bg_color, prev_text_color;
 199
 200     // Set background color and text color
 201     if (draw_item_struct->itemState & ODS_SELECTED) {
 202       prev_bg_color = SetBkColor(dc, GetSysColor(COLOR_HIGHLIGHT));
 203       prev_text_color = SetTextColor(dc, GetSysColor(COLOR_HIGHLIGHTTEXT));
 204     } else {
 205       prev_bg_color = SetBkColor(dc, GetSysColor(COLOR_MENU));
 206       if (draw_item_struct->itemState & ODS_DISABLED)
 207         prev_text_color = SetTextColor(dc, GetSysColor(COLOR_GRAYTEXT));
 208       else
 209         prev_text_color = SetTextColor(dc, GetSysColor(COLOR_MENUTEXT));
 210     }
 211
 212     if (draw_item_struct->itemData) {
 213       NativeMenuWin::ItemData* data = GetItemData(draw_item_struct->itemData);
 214       // Draw the background.
 215       HBRUSH hbr = CreateSolidBrush(GetBkColor(dc));
 216       FillRect(dc, &draw_item_struct->rcItem, hbr);
 217       DeleteObject(hbr);
 218
 219       // Draw the label.
 220       RECT rect = draw_item_struct->rcItem;
 221       rect.top += kItemTopMargin;
 222       // Should we add kIconWidth only when icon.width() != 0 ?
 223       rect.left += kItemLeftMargin + kIconWidth;
 224       rect.right -= views::kItemLabelSpacing;
 225       UINT format = DT_TOP | DT_SINGLELINE;
 226       // Check whether the mnemonics should be underlined.
 227       BOOL underline_mnemonics;
 228       SystemParametersInfo(SPI_GETKEYBOARDCUES, 0, &underline_mnemonics, 0);
 229       if (!underline_mnemonics)
 230         format |= DT_HIDEPREFIX;
 231       gfx::FontList font_list;
 232       HGDIOBJ old_font = static_cast<HFONT>(
 233           SelectObject(dc, font_list.GetPrimaryFont().GetNativeFont()));
 234
 235       // If an accelerator is specified (with a tab delimiting the rest of the
 236       // label from the accelerator), we have to justify the fist part on the
 237       // left and the accelerator on the right.
 238       // TODO(jungshik): This will break in RTL UI. Currently, he/ar use the
 239       //                 window system UI font and will not hit here.
 240       base::string16 label = data->label;
 241       base::string16 accel;
 242       base::string16::size_type tab_pos = label.find(L'\t');
 243       if (tab_pos != base::string16::npos) {
 244         accel = label.substr(tab_pos);
 245         label = label.substr(0, tab_pos);
 246       }
 247       DrawTextEx(dc, const_cast<wchar_t*>(label.data()),
 248                  static_cast<int>(label.size()), &rect, format | DT_LEFT, NULL);
 249       if (!accel.empty())
 250         DrawTextEx(dc, const_cast<wchar_t*>(accel.data()),
 251                    static_cast<int>(accel.size()), &rect,
 252                    format | DT_RIGHT, NULL);
 253       SelectObject(dc, old_font);
 254
 255       ui::MenuModel::ItemType type =
 256           data->native_menu_win->model_->GetTypeAt(data->model_index);
 257
 258       // Draw the icon after the label, otherwise it would be covered
 259       // by the label.
 260       gfx::Image icon;
 261       if (data->native_menu_win->model_->GetIconAt(data->model_index, &icon)) {
 262         // We currently don't support items with both icons and checkboxes.
 263         const gfx::ImageSkia* skia_icon = icon.ToImageSkia();
 264         DCHECK(type != ui::MenuModel::TYPE_CHECK);
 265         gfx::Canvas canvas(
 266             skia_icon->GetRepresentation(1.0f),
 267             false);
 268         skia::DrawToNativeContext(
 269             canvas.sk_canvas(), dc,
 270             draw_item_struct->rcItem.left + kItemLeftMargin,
 271             draw_item_struct->rcItem.top + (draw_item_struct->rcItem.bottom -
 272                 draw_item_struct->rcItem.top - skia_icon->height()) / 2, NULL);
 273       } else if (type == ui::MenuModel::TYPE_CHECK &&
 274                  data->native_menu_win->model_->IsItemCheckedAt(
 275                      data->model_index)) {
 276         // Manually render a checkbox.
 277         ui::NativeThemeWin* native_theme = ui::NativeThemeWin::instance();
 278         const MenuConfig& config = MenuConfig::instance(native_theme);
 279         NativeTheme::State state;
 280         if (draw_item_struct->itemState & ODS_DISABLED) {
 281           state = NativeTheme::kDisabled;
 282         } else {
 283           state = draw_item_struct->itemState & ODS_SELECTED ?
 284               NativeTheme::kHovered : NativeTheme::kNormal;
 285         }
 286         gfx::Canvas canvas(gfx::Size(config.check_width, config.check_height),
 287                            1.0f,
 288                            false);
 289         NativeTheme::ExtraParams extra;
 290         extra.menu_check.is_radio = false;
 291         gfx::Rect bounds(0, 0, config.check_width, config.check_height);
 292
 293         // Draw the background and the check.
 294         native_theme->Paint(
 295             canvas.sk_canvas(), NativeTheme::kMenuCheckBackground,
 296             state, bounds, extra);
 297         native_theme->Paint(
 298             canvas.sk_canvas(), NativeTheme::kMenuCheck, state, bounds, extra);
 299
 300         // Draw checkbox to menu.
 301         skia::DrawToNativeContext(canvas.sk_canvas(), dc,
 302             draw_item_struct->rcItem.left + kItemLeftMargin,
 303             draw_item_struct->rcItem.top + (draw_item_struct->rcItem.bottom -
 304                 draw_item_struct->rcItem.top - config.check_height) / 2, NULL);
 305       }
 306
 307     } else {
 308       // Draw the separator
 309       draw_item_struct->rcItem.top +=
 310           (draw_item_struct->rcItem.bottom - draw_item_struct->rcItem.top) / 3;
 311       DrawEdge(dc, &draw_item_struct->rcItem, EDGE_ETCHED, BF_TOP);
 312     }
 313
 314     SetBkColor(dc, prev_bg_color);
 315     SetTextColor(dc, prev_text_color);
 316   }
 317
 318   bool ProcessWindowMessage(HWND window,
 319                             UINT message,
 320                             WPARAM w_param,
 321                             LPARAM l_param,
 322                             LRESULT* l_result) {
 323     switch (message) {
 324       case WM_MENUCOMMAND:
 325         OnMenuCommand(w_param, reinterpret_cast<HMENU>(l_param));
 326         *l_result = 0;
 327         return true;
 328       case WM_MENUSELECT:
 329         OnMenuSelect(LOWORD(w_param), reinterpret_cast<HMENU>(l_param));
 330         *l_result = 0;
 331         return true;
 332       case WM_MEASUREITEM:
 333         OnMeasureItem(w_param, reinterpret_cast<MEASUREITEMSTRUCT*>(l_param));
 334         *l_result = 0;
 335         return true;
 336       case WM_DRAWITEM:
 337         OnDrawItem(w_param, reinterpret_cast<DRAWITEMSTRUCT*>(l_param));
 338         *l_result = 0;
 339         return true;
 340       // TODO(beng): bring over owner draw from old menu system.
 341     }
 342     return false;
 343   }
 344
 345   static LRESULT CALLBACK MenuHostWindowProc(HWND window,
 346                                              UINT message,
 347                                              WPARAM w_param,
 348                                              LPARAM l_param) {
 349     MenuHostWindow* host =
 350         reinterpret_cast<MenuHostWindow*>(gfx::GetWindowUserData(window));
 351     // host is null during initial construction.
 352     LRESULT l_result = 0;
 353     if (!host || !host->ProcessWindowMessage(window, message, w_param, l_param,
 354                                              &l_result)) {
 355       return DefWindowProc(window, message, w_param, l_param);
 356     }
 357     return l_result;
 358   }
 359
 360   HWND hwnd_;
 361   NativeMenuWin* parent_;
 362
 363   DISALLOW_COPY_AND_ASSIGN(MenuHostWindow);
 364 };
 365
 366 struct NativeMenuWin::HighlightedMenuItemInfo {
 367   HighlightedMenuItemInfo()
 368       : has_parent(false),
 369         has_submenu(false),
 370         menu(NULL),
 371         position(-1) {
 372   }
 373
 374   bool has_parent;
 375   bool has_submenu;
 376
 377   // The menu and position. These are only set for non-disabled menu items.
 378   NativeMenuWin* menu;
 379   int position;
 380 };
 381
 382 // static
 383 const wchar_t* NativeMenuWin::MenuHostWindow::kWindowClassName =
 384     L"ViewsMenuHostWindow";
 385
 386 ////////////////////////////////////////////////////////////////////////////////
 387 // NativeMenuWin, public:
 388
 389 NativeMenuWin::NativeMenuWin(ui::MenuModel* model, HWND system_menu_for)
 390     : model_(model),
 391       menu_(NULL),
 392       owner_draw_(l10n_util::NeedOverrideDefaultUIFont(NULL, NULL) &&
 393                   !system_menu_for),
 394       system_menu_for_(system_menu_for),
 395       first_item_index_(0),
 396       menu_action_(MENU_ACTION_NONE),
 397       menu_to_select_(NULL),
 398       position_to_select_(-1),
 399       parent_(NULL),
 400       destroyed_flag_(NULL),
 401       menu_to_select_factory_(this) {
 402 }
 403
 404 NativeMenuWin::~NativeMenuWin() {
 405   if (destroyed_flag_)
 406     *destroyed_flag_ = true;
 407   STLDeleteContainerPointers(items_.begin(), items_.end());
 408   DestroyMenu(menu_);
 409 }
 410
 411 ////////////////////////////////////////////////////////////////////////////////
 412 // NativeMenuWin, MenuWrapper implementation:
 413
 414 void NativeMenuWin::RunMenuAt(const gfx::Point& point, int alignment) {
 415   CreateHostWindow();
 416   UpdateStates();
 417   UINT flags = TPM_LEFTBUTTON | TPM_RIGHTBUTTON | TPM_RECURSE;
 418   flags |= GetAlignmentFlags(alignment);
 419   menu_action_ = MENU_ACTION_NONE;
 420
 421   // Set a hook function so we can listen for keyboard events while the
 422   // menu is open, and store a pointer to this object in a static
 423   // variable so the hook has access to it (ugly, but it's the
 424   // only way).
 425   open_native_menu_win_ = this;
 426   HHOOK hhook = SetWindowsHookEx(WH_MSGFILTER, MenuMessageHook,
 427                                  GetModuleHandle(NULL), ::GetCurrentThreadId());
 428
 429   // Mark that any registered listeners have not been called for this particular
 430   // opening of the menu.
 431   listeners_called_ = false;
 432
 433   // Command dispatch is done through WM_MENUCOMMAND, handled by the host
 434   // window.
 435   menu_to_select_ = NULL;
 436   position_to_select_ = -1;
 437   menu_to_select_factory_.InvalidateWeakPtrs();
 438   bool destroyed = false;
 439   destroyed_flag_ = &destroyed;
 440   model_->MenuWillShow();
 441   TrackPopupMenu(menu_, flags, point.x(), point.y(), 0, host_window_->hwnd(),
 442                  NULL);
 443   UnhookWindowsHookEx(hhook);
 444   open_native_menu_win_ = NULL;
 445   if (destroyed)
 446     return;
 447   destroyed_flag_ = NULL;
 448   if (menu_to_select_) {
 449     // Folks aren't too happy if we notify immediately. In particular, notifying
 450     // the delegate can cause destruction leaving the stack in a weird
 451     // state. Instead post a task, then notify. This mirrors what WM_MENUCOMMAND
 452     // does.
 453     menu_to_select_factory_.InvalidateWeakPtrs();
 454     base::MessageLoop::current()->PostTask(
 455         FROM_HERE,
 456         base::Bind(&NativeMenuWin::DelayedSelect,
 457                    menu_to_select_factory_.GetWeakPtr()));
 458     menu_action_ = MENU_ACTION_SELECTED;
 459   }
 460   // Send MenuClosed after we schedule the select, otherwise MenuClosed is
 461   // processed after the select (MenuClosed posts a delayed task too).
 462   model_->MenuClosed();
 463 }
 464
 465 void NativeMenuWin::CancelMenu() {
 466   EndMenu();
 467 }
 468
 469 void NativeMenuWin::Rebuild(MenuInsertionDelegateWin* delegate) {
 470   ResetNativeMenu();
 471   items_.clear();
 472
 473   owner_draw_ = model_->HasIcons() || owner_draw_;
 474   first_item_index_ = delegate ? delegate->GetInsertionIndex(menu_) : 0;
 475   for (int menu_index = first_item_index_;
 476         menu_index < first_item_index_ + model_->GetItemCount(); ++menu_index) {
 477     int model_index = menu_index - first_item_index_;
 478     if (model_->GetTypeAt(model_index) == ui::MenuModel::TYPE_SEPARATOR)
 479       AddSeparatorItemAt(menu_index, model_index);
 480     else
 481       AddMenuItemAt(menu_index, model_index);
 482   }
 483 }
 484
 485 void NativeMenuWin::UpdateStates() {
 486   // A depth-first walk of the menu items, updating states.
 487   int model_index = 0;
 488   std::vector<ItemData*>::const_iterator it;
 489   for (it = items_.begin(); it != items_.end(); ++it, ++model_index) {
 490     int menu_index = model_index + first_item_index_;
 491     SetMenuItemState(menu_index, model_->IsEnabledAt(model_index),
 492                      model_->IsItemCheckedAt(model_index), false);
 493     if (model_->IsItemDynamicAt(model_index)) {
 494       // TODO(atwilson): Update the icon as well (http://crbug.com/66508).
 495       SetMenuItemLabel(menu_index, model_index,
 496                        model_->GetLabelAt(model_index));
 497     }
 498     Menu2* submenu = (*it)->submenu.get();
 499     if (submenu)
 500       submenu->UpdateStates();
 501   }
 502 }
 503
 504 HMENU NativeMenuWin::GetNativeMenu() const {
 505   return menu_;
 506 }
 507
 508 NativeMenuWin::MenuAction NativeMenuWin::GetMenuAction() const {
 509   return menu_action_;
 510 }
 511
 512 void NativeMenuWin::AddMenuListener(MenuListener* listener) {
 513   listeners_.AddObserver(listener);
 514 }
 515
 516 void NativeMenuWin::RemoveMenuListener(MenuListener* listener) {
 517   listeners_.RemoveObserver(listener);
 518 }
 519
 520 void NativeMenuWin::SetMinimumWidth(int width) {
 521   NOTIMPLEMENTED();
 522 }
 523
 524 ////////////////////////////////////////////////////////////////////////////////
 525 // NativeMenuWin, private:
 526
 527 // static
 528 NativeMenuWin* NativeMenuWin::open_native_menu_win_ = NULL;
 529
 530 void NativeMenuWin::DelayedSelect() {
 531   if (menu_to_select_)
 532     menu_to_select_->model_->ActivatedAt(position_to_select_);
 533 }
 534
 535 // static
 536 bool NativeMenuWin::GetHighlightedMenuItemInfo(
 537     HMENU menu,
 538     HighlightedMenuItemInfo* info) {
 539   for (int i = 0; i < ::GetMenuItemCount(menu); i++) {
 540     UINT state = ::GetMenuState(menu, i, MF_BYPOSITION);
 541     if (state & MF_HILITE) {
 542       if (state & MF_POPUP) {
 543         HMENU submenu = GetSubMenu(menu, i);
 544         if (GetHighlightedMenuItemInfo(submenu, info))
 545           info->has_parent = true;
 546         else
 547           info->has_submenu = true;
 548       } else if (!(state & MF_SEPARATOR) && !(state & MF_DISABLED)) {
 549         info->menu = GetNativeMenuWinFromHMENU(menu);
 550         info->position = i;
 551       }
 552       return true;
 553     }
 554   }
 555   return false;
 556 }
 557
 558 // static
 559 LRESULT CALLBACK NativeMenuWin::MenuMessageHook(
 560     int n_code, WPARAM w_param, LPARAM l_param) {
 561   LRESULT result = CallNextHookEx(NULL, n_code, w_param, l_param);
 562
 563   NativeMenuWin* this_ptr = open_native_menu_win_;
 564   if (!this_ptr)
 565     return result;
 566
 567   // The first time this hook is called, that means the menu has successfully
 568   // opened, so call the callback function on all of our listeners.
 569   if (!this_ptr->listeners_called_) {
 570     FOR_EACH_OBSERVER(MenuListener, this_ptr->listeners_, OnMenuOpened());
 571     this_ptr->listeners_called_ = true;
 572   }
 573
 574   MSG* msg = reinterpret_cast<MSG*>(l_param);
 575   if (msg->message == WM_LBUTTONUP || msg->message == WM_RBUTTONUP) {
 576     HighlightedMenuItemInfo info;
 577     if (GetHighlightedMenuItemInfo(this_ptr->menu_, &info) && info.menu) {
 578       // It appears that when running a menu by way of TrackPopupMenu(Ex) win32
 579       // gets confused if the underlying window paints itself. As its very easy
 580       // for the underlying window to repaint itself (especially since some menu
 581       // items trigger painting of the tabstrip on mouse over) we have this
 582       // workaround. When the mouse is released on a menu item we remember the
 583       // menu item and end the menu. When the nested message loop returns we
 584       // schedule a task to notify the model. It's still possible to get a
 585       // WM_MENUCOMMAND, so we have to be careful that we don't notify the model
 586       // twice.
 587       this_ptr->menu_to_select_ = info.menu;
 588       this_ptr->position_to_select_ = info.position;
 589       EndMenu();
 590     }
 591   } else if (msg->message == WM_KEYDOWN) {
 592     HighlightedMenuItemInfo info;
 593     if (GetHighlightedMenuItemInfo(this_ptr->menu_, &info)) {
 594       if (msg->wParam == VK_LEFT && !info.has_parent) {
 595         this_ptr->menu_action_ = MENU_ACTION_PREVIOUS;
 596         ::EndMenu();
 597       } else if (msg->wParam == VK_RIGHT && !info.has_parent &&
 598                  !info.has_submenu) {
 599         this_ptr->menu_action_ = MENU_ACTION_NEXT;
 600         ::EndMenu();
 601       }
 602     }
 603   }
 604
 605   return result;
 606 }
 607
 608 bool NativeMenuWin::IsSeparatorItemAt(int menu_index) const {
 609   MENUITEMINFO mii = {0};
 610   mii.cbSize = sizeof(mii);
 611   mii.fMask = MIIM_FTYPE;
 612   GetMenuItemInfo(menu_, menu_index, MF_BYPOSITION, &mii);
 613   return !!(mii.fType & MF_SEPARATOR);
 614 }
 615
 616 void NativeMenuWin::AddMenuItemAt(int menu_index, int model_index) {
 617   MENUITEMINFO mii = {0};
 618   mii.cbSize = sizeof(mii);
 619   mii.fMask = MIIM_FTYPE | MIIM_ID | MIIM_DATA;
 620   if (!owner_draw_)
 621     mii.fType = MFT_STRING;
 622   else
 623     mii.fType = MFT_OWNERDRAW;
 624
 625   ItemData* item_data = new ItemData;
 626   item_data->label = base::string16();
 627   ui::MenuModel::ItemType type = model_->GetTypeAt(model_index);
 628   if (type == ui::MenuModel::TYPE_SUBMENU) {
 629     item_data->submenu.reset(new Menu2(model_->GetSubmenuModelAt(model_index)));
 630     mii.fMask |= MIIM_SUBMENU;
 631     mii.hSubMenu = item_data->submenu->GetNativeMenu();
 632     GetNativeMenuWinFromHMENU(mii.hSubMenu)->parent_ = this;
 633   } else {
 634     if (type == ui::MenuModel::TYPE_RADIO)
 635       mii.fType |= MFT_RADIOCHECK;
 636     mii.wID = model_->GetCommandIdAt(model_index);
 637   }
 638   item_data->native_menu_win = this;
 639   item_data->model_index = model_index;
 640   items_.insert(items_.begin() + model_index, item_data);
 641   mii.dwItemData = reinterpret_cast<ULONG_PTR>(item_data);
 642   UpdateMenuItemInfoForString(&mii, model_index,
 643                               model_->GetLabelAt(model_index));
 644   InsertMenuItem(menu_, menu_index, TRUE, &mii);
 645 }
 646
 647 void NativeMenuWin::AddSeparatorItemAt(int menu_index, int model_index) {
 648   MENUITEMINFO mii = {0};
 649   mii.cbSize = sizeof(mii);
 650   mii.fMask = MIIM_FTYPE;
 651   mii.fType = MFT_SEPARATOR;
 652   // Insert a dummy entry into our label list so we can index directly into it
 653   // using item indices if need be.
 654   items_.insert(items_.begin() + model_index, new ItemData);
 655   InsertMenuItem(menu_, menu_index, TRUE, &mii);
 656 }
 657
 658 void NativeMenuWin::SetMenuItemState(int menu_index, bool enabled, bool checked,
 659                                      bool is_default) {
 660   if (IsSeparatorItemAt(menu_index))
 661     return;
 662
 663   UINT state = enabled ? MFS_ENABLED : MFS_DISABLED;
 664   if (checked)
 665     state |= MFS_CHECKED;
 666   if (is_default)
 667     state |= MFS_DEFAULT;
 668
 669   MENUITEMINFO mii = {0};
 670   mii.cbSize = sizeof(mii);
 671   mii.fMask = MIIM_STATE;
 672   mii.fState = state;
 673   SetMenuItemInfo(menu_, menu_index, MF_BYPOSITION, &mii);
 674 }
 675
 676 void NativeMenuWin::SetMenuItemLabel(int menu_index,
 677                                      int model_index,
 678                                      const base::string16& label) {
 679   if (IsSeparatorItemAt(menu_index))
 680     return;
 681
 682   MENUITEMINFO mii = {0};
 683   mii.cbSize = sizeof(mii);
 684   UpdateMenuItemInfoForString(&mii, model_index, label);
 685   SetMenuItemInfo(menu_, menu_index, MF_BYPOSITION, &mii);
 686 }
 687
 688 void NativeMenuWin::UpdateMenuItemInfoForString(MENUITEMINFO* mii,
 689                                                 int model_index,
 690                                                 const base::string16& label) {
 691   base::string16 formatted = label;
 692   ui::MenuModel::ItemType type = model_->GetTypeAt(model_index);
 693   // Strip out any tabs, otherwise they get interpreted as accelerators and can
 694   // lead to weird behavior.
 695   base::ReplaceSubstringsAfterOffset(&formatted, 0, L"\t", L" ");
 696   if (type != ui::MenuModel::TYPE_SUBMENU) {
 697     // Add accelerator details to the label if provided.
 698     ui::Accelerator accelerator(ui::VKEY_UNKNOWN, ui::EF_NONE);
 699     if (model_->GetAcceleratorAt(model_index, &accelerator)) {
 700       formatted += L"\t";
 701       formatted += accelerator.GetShortcutText();
 702     }
 703   }
 704
 705   // Update the owned string, since Windows will want us to keep this new
 706   // version around.
 707   items_[model_index]->label = formatted;
 708
 709   // Give Windows a pointer to the label string.
 710   mii->fMask |= MIIM_STRING;
 711   mii->dwTypeData =
 712       const_cast<wchar_t*>(items_[model_index]->label.c_str());
 713 }
 714
 715 UINT NativeMenuWin::GetAlignmentFlags(int alignment) const {
 716   UINT alignment_flags = TPM_TOPALIGN;
 717   if (alignment == Menu2::ALIGN_TOPLEFT)
 718     alignment_flags |= TPM_LEFTALIGN;
 719   else if (alignment == Menu2::ALIGN_TOPRIGHT)
 720     alignment_flags |= TPM_RIGHTALIGN;
 721   return alignment_flags;
 722 }
 723
 724 void NativeMenuWin::ResetNativeMenu() {
 725   if (IsWindow(system_menu_for_)) {
 726     if (menu_)
 727       GetSystemMenu(system_menu_for_, TRUE);
 728     menu_ = GetSystemMenu(system_menu_for_, FALSE);
 729   } else {
 730     if (menu_)
 731       DestroyMenu(menu_);
 732     menu_ = CreatePopupMenu();
 733     // Rather than relying on the return value of TrackPopupMenuEx, which is
 734     // always a command identifier, instead we tell the menu to notify us via
 735     // our host window and the WM_MENUCOMMAND message.
 736     MENUINFO mi = {0};
 737     mi.cbSize = sizeof(mi);
 738     mi.fMask = MIM_STYLE | MIM_MENUDATA;
 739     mi.dwStyle = MNS_NOTIFYBYPOS;
 740     mi.dwMenuData = reinterpret_cast<ULONG_PTR>(this);
 741     SetMenuInfo(menu_, &mi);
 742   }
 743 }
 744
 745 void NativeMenuWin::CreateHostWindow() {
 746   // This only gets called from RunMenuAt, and as such there is only ever one
 747   // host window per menu hierarchy, no matter how many NativeMenuWin objects
 748   // exist wrapping submenus.
 749   if (!host_window_.get())
 750     host_window_.reset(new MenuHostWindow(this));
 751 }
 752
 753 ////////////////////////////////////////////////////////////////////////////////
 754 // MenuWrapper, public:
 755
 756 // static
 757 MenuWrapper* MenuWrapper::CreateWrapper(ui::MenuModel* model) {
 758   return new NativeMenuWin(model, NULL);
 759 }
 760
 761 }  // namespace views