ui/base/win/hwnd_subclass.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/base/win/hwnd_subclass.h"
   6
   7 #include <algorithm>
   8
   9 #include "base/logging.h"
  10 #include "base/memory/scoped_vector.h"
  11 #include "base/memory/singleton.h"
  12 #include "ui/gfx/win/dpi.h"
  13 #include "ui/gfx/win/hwnd_util.h"
  14
  15 namespace {
  16 const char kHWNDSubclassKey[] = "__UI_BASE_WIN_HWND_SUBCLASS_PROC__";
  17
  18 LRESULT CALLBACK WndProc(HWND hwnd,
  19                          UINT message,
  20                          WPARAM w_param,
  21                          LPARAM l_param) {
  22   ui::HWNDSubclass* wrapped_wnd_proc =
  23       reinterpret_cast<ui::HWNDSubclass*>(
  24           ui::ViewProp::GetValue(hwnd, kHWNDSubclassKey));
  25   return wrapped_wnd_proc ? wrapped_wnd_proc->OnWndProc(hwnd,
  26                                                         message,
  27                                                         w_param,
  28                                                         l_param)
  29                           : DefWindowProc(hwnd, message, w_param, l_param);
  30 }
  31
  32 WNDPROC GetCurrentWndProc(HWND target) {
  33   return reinterpret_cast<WNDPROC>(GetWindowLongPtr(target, GWLP_WNDPROC));
  34 }
  35
  36 // Not defined before Win7
  37 BOOL GetTouchInputInfoWrapper(HTOUCHINPUT handle, UINT count,
  38                               PTOUCHINPUT pointer, int size) {
  39   typedef BOOL(WINAPI *GetTouchInputInfoPtr)(HTOUCHINPUT, UINT,
  40                                              PTOUCHINPUT, int);
  41   GetTouchInputInfoPtr get_touch_input_info_func =
  42       reinterpret_cast<GetTouchInputInfoPtr>(
  43           GetProcAddress(GetModuleHandleA("user32.dll"), "GetTouchInputInfo"));
  44   if (get_touch_input_info_func)
  45     return get_touch_input_info_func(handle, count, pointer, size);
  46   return FALSE;
  47 }
  48
  49 }  // namespace
  50
  51 namespace ui {
  52
  53 // Singleton factory that creates and manages the lifetime of all
  54 // ui::HWNDSubclass objects.
  55 class HWNDSubclass::HWNDSubclassFactory {
  56  public:
  57   static HWNDSubclassFactory* GetInstance() {
  58     return Singleton<HWNDSubclassFactory,
  59         LeakySingletonTraits<HWNDSubclassFactory> >::get();
  60   }
  61
  62   // Returns a non-null HWNDSubclass corresponding to the HWND |target|. Creates
  63   // one if none exists. Retains ownership of the returned pointer.
  64   HWNDSubclass* GetHwndSubclassForTarget(HWND target) {
  65     DCHECK(target);
  66     HWNDSubclass* subclass = reinterpret_cast<HWNDSubclass*>(
  67         ui::ViewProp::GetValue(target, kHWNDSubclassKey));
  68     if (!subclass) {
  69       subclass = new ui::HWNDSubclass(target);
  70       hwnd_subclasses_.push_back(subclass);
  71     }
  72     return subclass;
  73   }
  74
  75   const ScopedVector<HWNDSubclass>& hwnd_subclasses() {
  76     return hwnd_subclasses_;
  77   }
  78
  79  private:
  80   friend struct DefaultSingletonTraits<HWNDSubclassFactory>;
  81
  82   HWNDSubclassFactory() {}
  83
  84   ScopedVector<HWNDSubclass> hwnd_subclasses_;
  85
  86   DISALLOW_COPY_AND_ASSIGN(HWNDSubclassFactory);
  87 };
  88
  89 // static
  90 void HWNDSubclass::AddFilterToTarget(HWND target, HWNDMessageFilter* filter) {
  91   HWNDSubclassFactory::GetInstance()->GetHwndSubclassForTarget(
  92       target)->AddFilter(filter);
  93 }
  94
  95 // static
  96 void HWNDSubclass::RemoveFilterFromAllTargets(HWNDMessageFilter* filter) {
  97   HWNDSubclassFactory* factory = HWNDSubclassFactory::GetInstance();
  98   ScopedVector<ui::HWNDSubclass>::const_iterator it;
  99   for (it = factory->hwnd_subclasses().begin();
 100       it != factory->hwnd_subclasses().end(); ++it)
 101     (*it)->RemoveFilter(filter);
 102 }
 103
 104 // static
 105 HWNDSubclass* HWNDSubclass::GetHwndSubclassForTarget(HWND target) {
 106   return HWNDSubclassFactory::GetInstance()->GetHwndSubclassForTarget(target);
 107 }
 108
 109 void HWNDSubclass::AddFilter(HWNDMessageFilter* filter) {
 110   DCHECK(filter);
 111   if (std::find(filters_.begin(), filters_.end(), filter) == filters_.end())
 112     filters_.push_back(filter);
 113 }
 114
 115 void HWNDSubclass::RemoveFilter(HWNDMessageFilter* filter) {
 116   std::vector<HWNDMessageFilter*>::iterator it =
 117       std::find(filters_.begin(), filters_.end(), filter);
 118   if (it != filters_.end())
 119     filters_.erase(it);
 120 }
 121
 122 HWNDSubclass::HWNDSubclass(HWND target)
 123     : target_(target),
 124       original_wnd_proc_(GetCurrentWndProc(target)),
 125       prop_(target, kHWNDSubclassKey, this) {
 126   gfx::SetWindowProc(target_, &WndProc);
 127 }
 128
 129 HWNDSubclass::~HWNDSubclass() {
 130 }
 131
 132 LRESULT HWNDSubclass::OnWndProc(HWND hwnd,
 133                                 UINT message,
 134                                 WPARAM w_param,
 135                                 LPARAM l_param) {
 136
 137   // Touch messages are always passed in screen coordinates. If the OS is
 138   // scaled, but the app is not DPI aware, then then WM_TOUCH might be
 139   // intended for a different window.
 140   if (message == WM_TOUCH) {
 141     TOUCHINPUT point;
 142
 143     if (GetTouchInputInfoWrapper(reinterpret_cast<HTOUCHINPUT>(l_param), 1,
 144                                  &point, sizeof(TOUCHINPUT))) {
 145       POINT touch_location = {
 146           TOUCH_COORD_TO_PIXEL(point.x) /
 147           gfx::win::GetUndocumentedDPITouchScale(),
 148           TOUCH_COORD_TO_PIXEL(point.y) /
 149           gfx::win::GetUndocumentedDPITouchScale()};
 150       HWND actual_target = WindowFromPoint(touch_location);
 151       if (actual_target != hwnd) {
 152         return SendMessage(actual_target, message, w_param, l_param);
 153       }
 154     }
 155   }
 156
 157   for (std::vector<HWNDMessageFilter*>::iterator it = filters_.begin();
 158       it != filters_.end(); ++it) {
 159     LRESULT l_result = 0;
 160     if ((*it)->FilterMessage(hwnd, message, w_param, l_param, &l_result))
 161       return l_result;
 162   }
 163
 164   // In most cases, |original_wnd_proc_| will take care of calling
 165   // DefWindowProc.
 166   return CallWindowProc(original_wnd_proc_, hwnd, message, w_param, l_param);
 167 }
 168
 169 HWNDMessageFilter::~HWNDMessageFilter() {
 170   HWNDSubclass::RemoveFilterFromAllTargets(this);
 171 }
 172
 173 }  // namespace ui