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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 #include "ui/base/win/window_impl.h"
      6 
      7 #include <list>
      8 
      9 #include "base/debug/alias.h"
     10 #include "base/memory/singleton.h"
     11 #include "base/strings/string_number_conversions.h"
     12 #include "base/synchronization/lock.h"
     13 #include "base/win/wrapped_window_proc.h"
     14 #include "ui/base/win/hwnd_util.h"
     15 
     16 namespace ui {
     17 
     18 static const DWORD kWindowDefaultChildStyle =
     19     WS_CHILD | WS_VISIBLE | WS_CLIPCHILDREN | WS_CLIPSIBLINGS;
     20 static const DWORD kWindowDefaultStyle = WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN;
     21 static const DWORD kWindowDefaultExStyle = 0;
     22 
     23 ///////////////////////////////////////////////////////////////////////////////
     24 // WindowImpl class tracking.
     25 
     26 // Several external scripts rely explicitly on this base class name for
     27 // acquiring the window handle and will break if this is modified!
     28 // static
     29 const wchar_t* const WindowImpl::kBaseClassName = L"Chrome_WidgetWin_";
     30 
     31 // WindowImpl class information used for registering unique windows.
     32 struct ClassInfo {
     33   UINT style;
     34   HICON icon;
     35 
     36   ClassInfo(int style, HICON icon)
     37       : style(style),
     38         icon(icon) {}
     39 
     40   // Compares two ClassInfos. Returns true if all members match.
     41   bool Equals(const ClassInfo& other) const {
     42     return (other.style == style && other.icon == icon);
     43   }
     44 };
     45 
     46 // WARNING: this class may be used on multiple threads.
     47 class ClassRegistrar {
     48  public:
     49   ~ClassRegistrar();
     50 
     51   static ClassRegistrar* GetInstance();
     52 
     53   // Returns the atom identifying the class matching |class_info|,
     54   // creating and registering a new class if the class is not yet known.
     55   ATOM RetrieveClassAtom(const ClassInfo& class_info);
     56 
     57  private:
     58   // Represents a registered window class.
     59   struct RegisteredClass {
     60     RegisteredClass(const ClassInfo& info, ATOM atom);
     61 
     62     // Info used to create the class.
     63     ClassInfo info;
     64 
     65     // The atom identifying the window class.
     66     ATOM atom;
     67   };
     68 
     69   ClassRegistrar();
     70   friend struct DefaultSingletonTraits<ClassRegistrar>;
     71 
     72   typedef std::list<RegisteredClass> RegisteredClasses;
     73   RegisteredClasses registered_classes_;
     74 
     75   // Counter of how many classes have been registered so far.
     76   int registered_count_;
     77 
     78   base::Lock lock_;
     79 
     80   DISALLOW_COPY_AND_ASSIGN(ClassRegistrar);
     81 };
     82 
     83 ClassRegistrar::~ClassRegistrar() {}
     84 
     85 // static
     86 ClassRegistrar* ClassRegistrar::GetInstance() {
     87   return Singleton<ClassRegistrar,
     88                    LeakySingletonTraits<ClassRegistrar> >::get();
     89 }
     90 
     91 ATOM ClassRegistrar::RetrieveClassAtom(const ClassInfo& class_info) {
     92   base::AutoLock auto_lock(lock_);
     93   for (RegisteredClasses::const_iterator i = registered_classes_.begin();
     94        i != registered_classes_.end(); ++i) {
     95     if (class_info.Equals(i->info))
     96       return i->atom;
     97   }
     98 
     99   // No class found, need to register one.
    100   string16 name = string16(WindowImpl::kBaseClassName) +
    101       base::IntToString16(registered_count_++);
    102 
    103   HBRUSH background = NULL;
    104   WNDCLASSEX window_class;
    105   base::win::InitializeWindowClass(
    106       name.c_str(),
    107       &base::win::WrappedWindowProc<WindowImpl::WndProc>,
    108       class_info.style,
    109       0,
    110       0,
    111       NULL,
    112       reinterpret_cast<HBRUSH>(background + 1),
    113       NULL,
    114       class_info.icon,
    115       class_info.icon,
    116       &window_class);
    117   HMODULE instance = window_class.hInstance;
    118   ATOM atom = RegisterClassEx(&window_class);
    119   CHECK(atom) << GetLastError();
    120 
    121   registered_classes_.push_back(RegisteredClass(class_info, atom));
    122 
    123   return atom;
    124 }
    125 
    126 ClassRegistrar::RegisteredClass::RegisteredClass(const ClassInfo& info,
    127                                                  ATOM atom)
    128     : info(info),
    129       atom(atom) {}
    130 
    131 ClassRegistrar::ClassRegistrar() : registered_count_(0) {}
    132 
    133 
    134 ///////////////////////////////////////////////////////////////////////////////
    135 // WindowImpl, public
    136 
    137 WindowImpl::WindowImpl()
    138     : window_style_(0),
    139       window_ex_style_(kWindowDefaultExStyle),
    140       class_style_(CS_DBLCLKS),
    141       hwnd_(NULL),
    142       got_create_(false),
    143       got_valid_hwnd_(false),
    144       destroyed_(NULL) {
    145 }
    146 
    147 WindowImpl::~WindowImpl() {
    148   if (destroyed_)
    149     *destroyed_ = true;
    150   ClearUserData();
    151 }
    152 
    153 void WindowImpl::Init(HWND parent, const gfx::Rect& bounds) {
    154   if (window_style_ == 0)
    155     window_style_ = parent ? kWindowDefaultChildStyle : kWindowDefaultStyle;
    156 
    157   if (parent == HWND_DESKTOP) {
    158     // Only non-child windows can have HWND_DESKTOP (0) as their parent.
    159     CHECK((window_style_ & WS_CHILD) == 0);
    160     parent = GetWindowToParentTo(false);
    161   } else if (parent == ::GetDesktopWindow()) {
    162     // Any type of window can have the "Desktop Window" as their parent.
    163     parent = GetWindowToParentTo(true);
    164   } else if (parent != HWND_MESSAGE) {
    165     CHECK(::IsWindow(parent));
    166   }
    167 
    168   int x, y, width, height;
    169   if (bounds.IsEmpty()) {
    170     x = y = width = height = CW_USEDEFAULT;
    171   } else {
    172     x = bounds.x();
    173     y = bounds.y();
    174     width = bounds.width();
    175     height = bounds.height();
    176   }
    177 
    178   ATOM atom = GetWindowClassAtom();
    179   bool destroyed = false;
    180   destroyed_ = &destroyed;
    181   HWND hwnd = CreateWindowEx(window_ex_style_,
    182                              reinterpret_cast<wchar_t*>(atom), NULL,
    183                              window_style_, x, y, width, height,
    184                              parent, NULL, NULL, this);
    185 
    186   // First nccalcszie (during CreateWindow) for captioned windows is
    187   // deliberately ignored so force a second one here to get the right
    188   // non-client set up.
    189   if (hwnd && (window_style_ & WS_CAPTION)) {
    190     SetWindowPos(hwnd, NULL, 0, 0, 0, 0,
    191                  SWP_FRAMECHANGED | SWP_NOMOVE | SWP_NOSIZE |
    192                  SWP_NOZORDER | SWP_NOACTIVATE | SWP_NOREDRAW);
    193   }
    194 
    195   if (!hwnd_ && GetLastError() == 0) {
    196     base::debug::Alias(&destroyed);
    197     base::debug::Alias(&hwnd);
    198     bool got_create = got_create_;
    199     base::debug::Alias(&got_create);
    200     bool got_valid_hwnd = got_valid_hwnd_;
    201     base::debug::Alias(&got_valid_hwnd);
    202     WNDCLASSEX class_info;
    203     memset(&class_info, 0, sizeof(WNDCLASSEX));
    204     class_info.cbSize = sizeof(WNDCLASSEX);
    205     BOOL got_class = GetClassInfoEx(GetModuleHandle(NULL),
    206                                     reinterpret_cast<wchar_t*>(atom),
    207                                     &class_info);
    208     base::debug::Alias(&got_class);
    209     bool procs_match = got_class && class_info.lpfnWndProc ==
    210         base::win::WrappedWindowProc<&WindowImpl::WndProc>;
    211     base::debug::Alias(&procs_match);
    212     CHECK(false);
    213   }
    214   if (!destroyed)
    215     destroyed_ = NULL;
    216 
    217   CheckWindowCreated(hwnd_);
    218 
    219   // The window procedure should have set the data for us.
    220   CHECK_EQ(this, ui::GetWindowUserData(hwnd));
    221 }
    222 
    223 HICON WindowImpl::GetDefaultWindowIcon() const {
    224   return NULL;
    225 }
    226 
    227 LRESULT WindowImpl::OnWndProc(UINT message, WPARAM w_param, LPARAM l_param) {
    228   LRESULT result = 0;
    229 
    230   // Handle the message if it's in our message map; otherwise, let the system
    231   // handle it.
    232   if (!ProcessWindowMessage(hwnd_, message, w_param, l_param, result))
    233     result = DefWindowProc(hwnd_, message, w_param, l_param);
    234 
    235   return result;
    236 }
    237 
    238 void WindowImpl::ClearUserData() {
    239   if (::IsWindow(hwnd_))
    240     ui::SetWindowUserData(hwnd_, NULL);
    241 }
    242 
    243 // static
    244 LRESULT CALLBACK WindowImpl::WndProc(HWND hwnd,
    245                                      UINT message,
    246                                      WPARAM w_param,
    247                                      LPARAM l_param) {
    248   if (message == WM_NCCREATE) {
    249     CREATESTRUCT* cs = reinterpret_cast<CREATESTRUCT*>(l_param);
    250     WindowImpl* window = reinterpret_cast<WindowImpl*>(cs->lpCreateParams);
    251     DCHECK(window);
    252     ui::SetWindowUserData(hwnd, window);
    253     window->hwnd_ = hwnd;
    254     window->got_create_ = true;
    255     if (hwnd)
    256       window->got_valid_hwnd_ = true;
    257     return TRUE;
    258   }
    259 
    260   WindowImpl* window = reinterpret_cast<WindowImpl*>(
    261       ui::GetWindowUserData(hwnd));
    262   if (!window)
    263     return 0;
    264 
    265   return window->OnWndProc(message, w_param, l_param);
    266 }
    267 
    268 ATOM WindowImpl::GetWindowClassAtom() {
    269   HICON icon = GetDefaultWindowIcon();
    270   ClassInfo class_info(initial_class_style(), icon);
    271   return ClassRegistrar::GetInstance()->RetrieveClassAtom(class_info);
    272 }
    273 
    274 }  // namespace ui
    275