chrome/browser/ui/views/tabs/window_finder_win.cc

   1 // Copyright 2014 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 "chrome/browser/ui/views/tabs/window_finder.h"
   6
   7 #include "base/win/scoped_gdi_object.h"
   8 #include "base/win/windows_version.h"
   9 #include "ui/aura/window.h"
  10 #include "ui/gfx/screen.h"
  11 #include "ui/gfx/win/dpi.h"
  12 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_win.h"
  13 #include "ui/views/win/hwnd_util.h"
  14
  15 #if defined(USE_ASH)
  16 gfx::NativeWindow GetLocalProcessWindowAtPointAsh(
  17     const gfx::Point& screen_point,
  18     const std::set<gfx::NativeWindow>& ignore);
  19 #endif
  20
  21 namespace {
  22
  23 // BaseWindowFinder -----------------------------------------------------------
  24
  25 // Base class used to locate a window. This is intended to be used with the
  26 // various win32 functions that iterate over windows.
  27 //
  28 // A subclass need only override ShouldStopIterating to determine when
  29 // iteration should stop.
  30 class BaseWindowFinder {
  31  public:
  32   // Creates a BaseWindowFinder with the specified set of HWNDs to ignore.
  33   explicit BaseWindowFinder(const std::set<HWND>& ignore) : ignore_(ignore) {}
  34   virtual ~BaseWindowFinder() {}
  35
  36  protected:
  37   static BOOL CALLBACK WindowCallbackProc(HWND hwnd, LPARAM lParam) {
  38     // Cast must match that in as_lparam().
  39     BaseWindowFinder* finder = reinterpret_cast<BaseWindowFinder*>(lParam);
  40     if (finder->ignore_.find(hwnd) != finder->ignore_.end())
  41       return TRUE;
  42
  43     return finder->ShouldStopIterating(hwnd) ? FALSE : TRUE;
  44   }
  45
  46   LPARAM as_lparam() {
  47     // Cast must match that in WindowCallbackProc().
  48     return reinterpret_cast<LPARAM>(static_cast<BaseWindowFinder*>(this));
  49   }
  50
  51   // Returns true if iteration should stop, false if iteration should continue.
  52   virtual bool ShouldStopIterating(HWND window) = 0;
  53
  54  private:
  55   const std::set<HWND>& ignore_;
  56
  57   DISALLOW_COPY_AND_ASSIGN(BaseWindowFinder);
  58 };
  59
  60 // TopMostFinder --------------------------------------------------------------
  61
  62 // Helper class to determine if a particular point of a window is not obscured
  63 // by another window.
  64 class TopMostFinder : public BaseWindowFinder {
  65  public:
  66   // Returns true if |window| is the topmost window at the location
  67   // |screen_loc|, not including the windows in |ignore|.
  68   static bool IsTopMostWindowAtPoint(HWND window,
  69                                      const gfx::Point& screen_loc,
  70                                      const std::set<HWND>& ignore) {
  71     TopMostFinder finder(window, screen_loc, ignore);
  72     return finder.is_top_most_;
  73   }
  74
  75   virtual bool ShouldStopIterating(HWND hwnd) {
  76     if (hwnd == target_) {
  77       // Window is topmost, stop iterating.
  78       is_top_most_ = true;
  79       return true;
  80     }
  81
  82     if (!IsWindowVisible(hwnd)) {
  83       // The window isn't visible, keep iterating.
  84       return false;
  85     }
  86
  87     RECT r;
  88     if (!GetWindowRect(hwnd, &r) || !PtInRect(&r, screen_loc_.ToPOINT())) {
  89       // The window doesn't contain the point, keep iterating.
  90       return false;
  91     }
  92
  93     LONG ex_styles = GetWindowLong(hwnd, GWL_EXSTYLE);
  94     if (ex_styles & WS_EX_TRANSPARENT || ex_styles & WS_EX_LAYERED) {
  95       // Mouse events fall through WS_EX_TRANSPARENT windows, so we ignore them.
  96       //
  97       // WS_EX_LAYERED is trickier. Apps like Switcher create a totally
  98       // transparent WS_EX_LAYERED window that is always on top. If we don't
  99       // ignore WS_EX_LAYERED windows and there are totally transparent
 100       // WS_EX_LAYERED windows then there are effectively holes on the screen
 101       // that the user can't reattach tabs to. So we ignore them. This is a bit
 102       // problematic in so far as WS_EX_LAYERED windows need not be totally
 103       // transparent in which case we treat chrome windows as not being obscured
 104       // when they really are, but this is better than not being able to
 105       // reattach tabs.
 106       return false;
 107     }
 108
 109     // hwnd is at the point. Make sure the point is within the windows region.
 110     if (GetWindowRgn(hwnd, tmp_region_.Get()) == ERROR) {
 111       // There's no region on the window and the window contains the point. Stop
 112       // iterating.
 113       return true;
 114     }
 115
 116     // The region is relative to the window's rect.
 117     BOOL is_point_in_region = PtInRegion(tmp_region_.Get(),
 118         screen_loc_.x() - r.left, screen_loc_.y() - r.top);
 119     tmp_region_ = CreateRectRgn(0, 0, 0, 0);
 120     // Stop iterating if the region contains the point.
 121     return !!is_point_in_region;
 122   }
 123
 124  private:
 125   TopMostFinder(HWND window,
 126                 const gfx::Point& screen_loc,
 127                 const std::set<HWND>& ignore)
 128       : BaseWindowFinder(ignore),
 129         target_(window),
 130         is_top_most_(false),
 131         tmp_region_(CreateRectRgn(0, 0, 0, 0)) {
 132     screen_loc_ = gfx::win::DIPToScreenPoint(screen_loc);
 133     EnumWindows(WindowCallbackProc, as_lparam());
 134   }
 135
 136   // The window we're looking for.
 137   HWND target_;
 138
 139   // Location of window to find in pixel coordinates.
 140   gfx::Point screen_loc_;
 141
 142   // Is target_ the top most window? This is initially false but set to true
 143   // in ShouldStopIterating if target_ is passed in.
 144   bool is_top_most_;
 145
 146   base::win::ScopedRegion tmp_region_;
 147
 148   DISALLOW_COPY_AND_ASSIGN(TopMostFinder);
 149 };
 150
 151 // WindowFinder ---------------------------------------------------------------
 152
 153 // Helper class to determine if a particular point contains a window from our
 154 // process.
 155 class LocalProcessWindowFinder : public BaseWindowFinder {
 156  public:
 157   // Returns the hwnd from our process at screen_loc that is not obscured by
 158   // another window. Returns NULL otherwise.
 159   static gfx::NativeWindow GetProcessWindowAtPoint(
 160       const gfx::Point& screen_loc,
 161       const std::set<HWND>& ignore) {
 162     LocalProcessWindowFinder finder(screen_loc, ignore);
 163     // Windows 8 has a window that appears first in the list of iterated
 164     // windows, yet is not visually on top of everything.
 165     // TODO(sky): figure out a better way to ignore this window.
 166     if (finder.result_ &&
 167         ((base::win::OSInfo::GetInstance()->version() >=
 168           base::win::VERSION_WIN8) ||
 169          TopMostFinder::IsTopMostWindowAtPoint(finder.result_,
 170                                                screen_loc,
 171                                                ignore))) {
 172       return views::DesktopWindowTreeHostWin::GetContentWindowForHWND(
 173           finder.result_);
 174     }
 175     return NULL;
 176   }
 177
 178  protected:
 179   virtual bool ShouldStopIterating(HWND hwnd) {
 180     RECT r;
 181     if (IsWindowVisible(hwnd) && GetWindowRect(hwnd, &r) &&
 182         PtInRect(&r, screen_loc_.ToPOINT())) {
 183       result_ = hwnd;
 184       return true;
 185     }
 186     return false;
 187   }
 188
 189  private:
 190   LocalProcessWindowFinder(const gfx::Point& screen_loc,
 191                            const std::set<HWND>& ignore)
 192       : BaseWindowFinder(ignore),
 193         result_(NULL) {
 194     screen_loc_ = gfx::win::DIPToScreenPoint(screen_loc);
 195     EnumThreadWindows(GetCurrentThreadId(), WindowCallbackProc, as_lparam());
 196   }
 197
 198   // Position of the mouse in pixel coordinates.
 199   gfx::Point screen_loc_;
 200
 201   // The resulting window. This is initially null but set to true in
 202   // ShouldStopIterating if an appropriate window is found.
 203   HWND result_;
 204
 205   DISALLOW_COPY_AND_ASSIGN(LocalProcessWindowFinder);
 206 };
 207
 208 std::set<HWND> RemapIgnoreSet(const std::set<gfx::NativeView>& ignore) {
 209   std::set<HWND> hwnd_set;
 210   std::set<gfx::NativeView>::const_iterator it = ignore.begin();
 211   for (; it != ignore.end(); ++it) {
 212     HWND w = (*it)->GetHost()->GetAcceleratedWidget();
 213     if (w)
 214       hwnd_set.insert(w);
 215   }
 216   return hwnd_set;
 217 }
 218
 219 }  // namespace
 220
 221 gfx::NativeWindow GetLocalProcessWindowAtPoint(
 222     chrome::HostDesktopType host_desktop_type,
 223     const gfx::Point& screen_point,
 224     const std::set<gfx::NativeWindow>& ignore) {
 225 #if defined(USE_ASH)
 226   if (host_desktop_type == chrome::HOST_DESKTOP_TYPE_ASH)
 227     return GetLocalProcessWindowAtPointAsh(screen_point, ignore);
 228 #endif
 229   return LocalProcessWindowFinder::GetProcessWindowAtPoint(
 230           screen_point, RemapIgnoreSet(ignore));
 231 }