Replace WindowUnderPoint free function with WindowFinder interface

WindowUnderPoint have different signatures on different platforms, which should
be abstract as an interface.
So this change adds a WindowFinder interface to replace WindowUnderPoint free
function. Meanwhile, this change also includes the implementation of
WindowFinderX11 for X11.

Bug: webrtc:7950
Change-Id: I897a50d4033e713b339b6b6f48b5dbbe601e8db0
Reviewed-on: https://chromium-review.googlesource.com/611745
Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
Commit-Queue: Zijie He <zijiehe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#19375}

webrtc/modules/desktop_capture/BUILD.gn

@@ -251,10 +251,11 @@ rtc_static_library("desktop_capture") {
     "win/window_capture_utils.h",
     "window_capturer_mac.mm",
     "window_capturer_win.cc",
-    "window_under_point.h",
+    "window_finder.h",
-    "window_under_point_linux.cc",
+    "window_finder_mac.h",
-    "window_under_point_mac.mm",
+    "window_finder_mac.mm",
-    "window_under_point_win.cc",
+    "window_finder_win.cc",
+    "window_finder_win.h",
   ]
 
   if (use_x11) {
@@ -262,6 +263,8 @@ rtc_static_library("desktop_capture") {
       "mouse_cursor_monitor_x11.cc",
       "screen_capturer_x11.cc",
       "window_capturer_x11.cc",
+      "window_finder_x11.cc",
+      "window_finder_x11.h",
       "x11/shared_x_display.cc",
       "x11/shared_x_display.h",
       "x11/window_list_utils.cc",

webrtc/modules/desktop_capture/window_capturer_x11.cc

@@ -219,14 +219,17 @@ void WindowCapturerLinux::CaptureFrame() {
 bool WindowCapturerLinux::HandleXEvent(const XEvent& event) {
   if (event.type == ConfigureNotify) {
     XConfigureEvent xce = event.xconfigure;
-    if (!DesktopSize(xce.width, xce.height).equals(
+    if (xce.window == selected_window_) {
-            x_server_pixel_buffer_.window_size())) {
+      if (!DesktopRectFromXAttributes(xce).equals(
-      if (!x_server_pixel_buffer_.Init(display(), selected_window_)) {
+            x_server_pixel_buffer_.window_rect())) {
-        LOG(LS_ERROR) << "Failed to initialize pixel buffer after resizing.";
+        if (!x_server_pixel_buffer_.Init(display(), selected_window_)) {
+          LOG(LS_ERROR) << "Failed to initialize pixel buffer after resizing.";
+        }
       }
-      return true;
     }
   }
+
+  // Always returns false, so other observers can still receive the events.
   return false;
 }
 

webrtc/modules/desktop_capture/window_finder.h

@@ -0,0 +1,33 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_H_
+#define WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_H_
+
+#include "webrtc/modules/desktop_capture/desktop_capture_types.h"
+#include "webrtc/modules/desktop_capture/desktop_geometry.h"
+
+namespace webrtc {
+
+// An interface to return the id of the visible window under a certain point.
+class WindowFinder {
+ public:
+  WindowFinder() = default;
+  virtual ~WindowFinder() = default;
+
+  // Returns the id of the visible window under |point|. This function returns
+  // kNullWindowId if no window is under |point| and the platform does not have
+  // "root window" concept, i.e. the visible area under |point| is the desktop.
+  virtual WindowId GetWindowUnderPoint(DesktopVector point) = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_H_

webrtc/modules/desktop_capture/window_finder_mac.h

@@ -0,0 +1,30 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_MAC_H_
+#define WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_MAC_H_
+
+#include "webrtc/modules/desktop_capture/window_finder.h"
+
+namespace webrtc {
+
+// The implementation of WindowFinder for Windows.
+class WindowFinderMac final : public WindowFinder {
+ public:
+  WindowFinderMac();
+  ~WindowFinderMac() override;
+
+  // WindowFinder implementation.
+  WindowId GetWindowUnderPoint(DesktopVector point) override;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_MAC_H_

webrtc/modules/desktop_capture/window_finder_mac.mm

@@ -0,0 +1,36 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/desktop_capture/window_finder_mac.h"
+
+#include <CoreFoundation/CoreFoundation.h>
+
+#include "webrtc/modules/desktop_capture/mac/window_list_utils.h"
+
+namespace webrtc {
+
+WindowFinderMac::WindowFinderMac() = default;
+WindowFinderMac::~WindowFinderMac() = default;
+
+WindowId WindowFinderMac::GetWindowUnderPoint(DesktopVector point) {
+  WindowId id = kNullWindowId;
+  GetWindowList([&id, point](CFDictionaryRef window) {
+                  DesktopRect bounds = GetWindowBounds(window);
+                  if (bounds.Contains(point)) {
+                    id = GetWindowId(window);
+                    return false;
+                  }
+                  return true;
+                },
+                true);
+  return id;
+}
+
+}  // namespace webrtc

webrtc/modules/desktop_capture/window_finder_win.cc

@@ -8,13 +8,16 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include "webrtc/modules/desktop_capture/window_under_point.h"
+#include "webrtc/modules/desktop_capture/window_finder_win.h"
 
 #include <windows.h>
 
 namespace webrtc {
 
-WindowId GetWindowUnderPoint(DesktopVector point) {
+WindowFinderWin::WindowFinderWin() = default;
+WindowFinderWin::~WindowFinderWin() = default;
+
+WindowId WindowFinderWin::GetWindowUnderPoint(DesktopVector point) {
   HWND window = WindowFromPoint(POINT { point.x(), point.y() });
   if (!window) {
     return kNullWindowId;

webrtc/modules/desktop_capture/window_finder_win.h

@@ -0,0 +1,30 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_WIN_H_
+#define WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_WIN_H_
+
+#include "webrtc/modules/desktop_capture/window_finder.h"
+
+namespace webrtc {
+
+// The implementation of WindowFinder for Windows.
+class WindowFinderWin final : public WindowFinder {
+ public:
+  WindowFinderWin();
+  ~WindowFinderWin() override;
+
+  // WindowFinder implementation.
+  WindowId GetWindowUnderPoint(DesktopVector point) override;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_WIN_H_

webrtc/modules/desktop_capture/window_finder_x11.cc

@@ -0,0 +1,40 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/desktop_capture/window_finder_x11.h"
+
+#include "webrtc/modules/desktop_capture/x11/window_list_utils.h"
+#include "webrtc/rtc_base/checks.h"
+
+namespace webrtc {
+
+WindowFinderX11::WindowFinderX11(XAtomCache* cache)
+    : cache_(cache) {
+  RTC_DCHECK(cache_);
+}
+
+WindowFinderX11::~WindowFinderX11() = default;
+
+WindowId WindowFinderX11::GetWindowUnderPoint(DesktopVector point) {
+  WindowId id = kNullWindowId;
+  GetWindowList(cache_,
+                [&id, this, point](::Window window) {
+                  DesktopRect rect;
+                  if (GetWindowRect(this->cache_->display(), window, &rect) &&
+                      rect.Contains(point)) {
+                    id = window;
+                    return false;
+                  }
+                  return true;
+                });
+  return id;
+}
+
+}  // namespace webrtc

webrtc/modules/desktop_capture/window_finder_x11.h

@@ -0,0 +1,35 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_X11_H_
+#define WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_X11_H_
+
+#include "webrtc/modules/desktop_capture/window_finder.h"
+
+namespace webrtc {
+
+class XAtomCache;
+
+// The implementation of WindowFinder for Windows.
+class WindowFinderX11 final : public WindowFinder {
+ public:
+  explicit WindowFinderX11(XAtomCache* cache);
+  ~WindowFinderX11() override;
+
+  // WindowFinder implementation.
+  WindowId GetWindowUnderPoint(DesktopVector point) override;
+
+ private:
+  XAtomCache* const cache_;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_X11_H_

webrtc/modules/desktop_capture/window_under_point.h

@@ -1,26 +0,0 @@
-/*
- *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_UNDER_POINT_H_
-#define WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_UNDER_POINT_H_
-
-#include "webrtc/modules/desktop_capture/desktop_capture_types.h"
-#include "webrtc/modules/desktop_capture/desktop_geometry.h"
-
-namespace webrtc {
-
-// Returns the id of the visible window under |point|. This function returns
-// kNullWindowId if no window is under |point| and the platform does not have
-// "root window" concept, i.e. the visible area under |point| is the desktop.
-WindowId GetWindowUnderPoint(DesktopVector point);
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WINDOW_UNDER_POINT_H_

webrtc/modules/desktop_capture/window_under_point_linux.cc

@@ -1,20 +0,0 @@
-/*
- *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#include "webrtc/modules/desktop_capture/window_under_point.h"
-
-namespace webrtc {
-
-WindowId GetWindowUnderPoint(DesktopVector point) {
-  // TODO(zijiehe): Implementation required.
-  return kNullWindowId;
-}
-
-}  // namespace webrtc

webrtc/modules/desktop_capture/window_under_point_mac.mm

@@ -1,34 +0,0 @@
-/*
- *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#include <CoreFoundation/CoreFoundation.h>
-
-#include "webrtc/modules/desktop_capture/mac/window_list_utils.h"
-#include "webrtc/modules/desktop_capture/window_under_point.h"
-
-namespace webrtc {
-
-WindowId GetWindowUnderPoint(DesktopVector point) {
-  WindowId id;
-  if (!GetWindowList([&id, point](CFDictionaryRef window) {
-                       DesktopRect bounds = GetWindowBounds(window);
-                       if (bounds.Contains(point)) {
-                         id = GetWindowId(window);
-                         return false;
-                       }
-                       return true;
-                     },
-                     true)) {
-    return kNullWindowId;
-  }
-  return id;
-}
-
-}  // namespace webrtc

webrtc/modules/desktop_capture/x11/window_list_utils.cc

@@ -216,4 +216,25 @@ bool GetWindowList(XAtomCache* cache,
   return failed_screens < num_screens;
 }
 
+bool GetWindowRect(::Display* display,
+                   ::Window window,
+                   DesktopRect* rect,
+                   XWindowAttributes* attributes /* = nullptr */) {
+  XWindowAttributes local_attributes;
+  if (attributes == nullptr) {
+    attributes = &local_attributes;
+  }
+
+  {
+    XErrorTrap error_trap(display);
+    if (!XGetWindowAttributes(display, window, attributes) ||
+        error_trap.GetLastErrorAndDisable() != 0) {
+      return false;
+    }
+  }
+
+  *rect = DesktopRectFromXAttributes(*attributes);
+  return true;
+}
+
 }  // namespace webrtc

webrtc/modules/desktop_capture/x11/window_list_utils.h

@@ -13,6 +13,7 @@
 
 #include <X11/Xlib.h>
 
+#include "webrtc/modules/desktop_capture/desktop_geometry.h"
 #include "webrtc/modules/desktop_capture/x11/x_atom_cache.h"
 #include "webrtc/rtc_base/function_view.h"
 
@@ -32,6 +33,23 @@ bool GetWindowList(XAtomCache* cache,
 // WithdrawnState if the |window| is missing.
 int32_t GetWindowState(XAtomCache* cache, ::Window window);
 
+// Returns the rectangle of the |window| in the coordinates of |display|. This
+// function returns false if native APIs failed. If |attributes| is provided, it
+// will be filled with the attributes of |window|.
+bool GetWindowRect(::Display* display,
+                   ::Window window,
+                   DesktopRect* rect,
+                   XWindowAttributes* attributes = nullptr);
+
+// Creates a DesktopRect from |attributes|.
+template <typename T>
+DesktopRect DesktopRectFromXAttributes(const T& attributes) {
+  return DesktopRect::MakeXYWH(attributes.x,
+                               attributes.y,
+                               attributes.width,
+                               attributes.height);
+}
+
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_X11_WINDOW_LIST_UTILS_H_

webrtc/modules/desktop_capture/x11/x_server_pixel_buffer.cc

@@ -10,12 +10,13 @@
 
 #include "webrtc/modules/desktop_capture/x11/x_server_pixel_buffer.h"
 
-#include <assert.h>
 #include <string.h>
 #include <sys/shm.h>
 
 #include "webrtc/modules/desktop_capture/desktop_frame.h"
+#include "webrtc/modules/desktop_capture/x11/window_list_utils.h"
 #include "webrtc/modules/desktop_capture/x11/x_error_trap.h"
+#include "webrtc/rtc_base/checks.h"
 #include "webrtc/rtc_base/logging.h"
 
 namespace webrtc {
@@ -175,15 +176,10 @@ bool XServerPixelBuffer::Init(Display* display, Window window) {
   display_ = display;
 
   XWindowAttributes attributes;
-  {
+  if (!GetWindowRect(display_, window, &window_rect_, &attributes)) {
-    XErrorTrap error_trap(display_);
+    return false;
-    if (!XGetWindowAttributes(display_, window, &attributes) ||
-        error_trap.GetLastErrorAndDisable() != 0) {
-      return false;
-    }
   }
 
-  window_size_ = DesktopSize(attributes.width, attributes.height);
   window_ = window;
   InitShm(attributes);
 
@@ -208,7 +204,7 @@ void XServerPixelBuffer::InitShm(const XWindowAttributes& attributes) {
   shm_segment_info_->readOnly = False;
   x_shm_image_ = XShmCreateImage(display_, default_visual, default_depth,
                                  ZPixmap, 0, shm_segment_info_,
-                                 window_size_.width(), window_size_.height());
+                                 window_rect_.width(), window_rect_.height());
   if (x_shm_image_) {
     shm_segment_info_->shmid =
         shmget(IPC_PRIVATE, x_shm_image_->bytes_per_line * x_shm_image_->height,
@@ -261,8 +257,8 @@ bool XServerPixelBuffer::InitPixmaps(int depth) {
     shm_pixmap_ = XShmCreatePixmap(display_, window_,
                                    shm_segment_info_->shmaddr,
                                    shm_segment_info_,
-                                   window_size_.width(),
+                                   window_rect_.width(),
-                                   window_size_.height(), depth);
+                                   window_rect_.height(), depth);
     XSync(display_, False);
     if (error_trap.GetLastErrorAndDisable() != 0) {
       // |shm_pixmap_| is not not valid because the request was not processed
@@ -316,8 +312,8 @@ void XServerPixelBuffer::Synchronize() {
 
 bool XServerPixelBuffer::CaptureRect(const DesktopRect& rect,
                                      DesktopFrame* frame) {
-  assert(rect.right() <= window_size_.width());
+  RTC_DCHECK_LE(rect.right(), window_rect_.width());
-  assert(rect.bottom() <= window_size_.height());
+  RTC_DCHECK_LE(rect.bottom(), window_rect_.height());
 
   XImage* image;
   uint8_t* data;

webrtc/modules/desktop_capture/x11/x_server_pixel_buffer.h

@@ -39,7 +39,10 @@ class XServerPixelBuffer {
   bool is_initialized() { return window_ != 0; }
 
   // Returns the size of the window the buffer was initialized for.
-  const DesktopSize& window_size() { return window_size_; }
+  DesktopSize window_size() { return window_rect_.size(); }
+
+  // Returns the rectangle of the window the buffer was initialized for.
+  const DesktopRect& window_rect() { return window_rect_; }
 
   // Returns true if the window can be found.
   bool IsWindowValid() const;
@@ -65,7 +68,7 @@ class XServerPixelBuffer {
 
   Display* display_ = nullptr;
   Window window_ = 0;
-  DesktopSize window_size_;
+  DesktopRect window_rect_;
   XImage* x_image_ = nullptr;
   XShmSegmentInfo* shm_segment_info_ = nullptr;
   XImage* x_shm_image_ = nullptr;