1 files changed, 335 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/desktop_capture/cropping_window_capturer_win.cc b/third_party/libwebrtc/modules/desktop_capture/cropping_window_capturer_win.cc
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+++ b/third_party/libwebrtc/modules/desktop_capture/cropping_window_capturer_win.cc
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+/*
+ *  Copyright (c) 2014 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 "modules/desktop_capture/cropping_window_capturer.h"
+#include "modules/desktop_capture/desktop_capturer_differ_wrapper.h"
+#include "modules/desktop_capture/win/screen_capture_utils.h"
+#include "modules/desktop_capture/win/selected_window_context.h"
+#include "modules/desktop_capture/win/window_capture_utils.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/trace_event.h"
+#include "rtc_base/win/windows_version.h"
+
+namespace webrtc {
+
+namespace {
+
+// Used to pass input data for verifying the selected window is on top.
+struct TopWindowVerifierContext : public SelectedWindowContext {
+  TopWindowVerifierContext(HWND selected_window,
+                           HWND excluded_window,
+                           DesktopRect selected_window_rect,
+                           WindowCaptureHelperWin* window_capture_helper)
+      : SelectedWindowContext(selected_window,
+                              selected_window_rect,
+                              window_capture_helper),
+        excluded_window(excluded_window) {
+    RTC_DCHECK_NE(selected_window, excluded_window);
+  }
+
+  // Determines whether the selected window is on top (not occluded by any
+  // windows except for those it owns or any excluded window).
+  bool IsTopWindow() {
+    if (!IsSelectedWindowValid()) {
+      return false;
+    }
+
+    // Enumerate all top-level windows above the selected window in Z-order,
+    // checking whether any overlaps it. This uses FindWindowEx rather than
+    // EnumWindows because the latter excludes certain system windows (e.g. the
+    // Start menu & other taskbar menus) that should be detected here to avoid
+    // inadvertent capture.
+    int num_retries = 0;
+    while (true) {
+      HWND hwnd = nullptr;
+      while ((hwnd = FindWindowEx(nullptr, hwnd, nullptr, nullptr))) {
+        if (hwnd == selected_window()) {
+          // Windows are enumerated in top-down Z-order, so we can stop
+          // enumerating upon reaching the selected window & report it's on top.
+          return true;
+        }
+
+        // Ignore the excluded window.
+        if (hwnd == excluded_window) {
+          continue;
+        }
+
+        // Ignore windows that aren't visible on the current desktop.
+        if (!window_capture_helper()->IsWindowVisibleOnCurrentDesktop(hwnd)) {
+          continue;
+        }
+
+        // Ignore Chrome notification windows, especially the notification for
+        // the ongoing window sharing. Notes:
+        // - This only works with notifications from Chrome, not other Apps.
+        // - All notifications from Chrome will be ignored.
+        // - This may cause part or whole of notification window being cropped
+        // into the capturing of the target window if there is overlapping.
+        if (window_capture_helper()->IsWindowChromeNotification(hwnd)) {
+          continue;
+        }
+
+        // Ignore windows owned by the selected window since we want to capture
+        // them.
+        if (IsWindowOwnedBySelectedWindow(hwnd)) {
+          continue;
+        }
+
+        // Check whether this window intersects with the selected window.
+        if (IsWindowOverlappingSelectedWindow(hwnd)) {
+          // If intersection is not empty, the selected window is not on top.
+          return false;
+        }
+      }
+
+      DWORD lastError = GetLastError();
+      if (lastError == ERROR_SUCCESS) {
+        // The enumeration completed successfully without finding the selected
+        // window (which may have been closed).
+        RTC_LOG(LS_WARNING) << "Failed to find selected window (only expected "
+                               "if it was closed)";
+        RTC_DCHECK(!IsWindow(selected_window()));
+        return false;
+      } else if (lastError == ERROR_INVALID_WINDOW_HANDLE) {
+        // This error may occur if a window is closed around the time it's
+        // enumerated; retry the enumeration in this case up to 10 times
+        // (this should be a rare race & unlikely to recur).
+        if (++num_retries <= 10) {
+          RTC_LOG(LS_WARNING) << "Enumeration failed due to race with a window "
+                                 "closing; retrying - retry #"
+                              << num_retries;
+          continue;
+        } else {
+          RTC_LOG(LS_ERROR)
+              << "Exhausted retry allowance around window enumeration failures "
+                 "due to races with windows closing";
+        }
+      }
+
+      // The enumeration failed with an unexpected error (or more repeats of
+      // an infrequently-expected error than anticipated). After logging this &
+      // firing an assert when enabled, report that the selected window isn't
+      // topmost to avoid inadvertent capture of other windows.
+      RTC_LOG(LS_ERROR) << "Failed to enumerate windows: " << lastError;
+      RTC_DCHECK_NOTREACHED();
+      return false;
+    }
+  }
+
+  const HWND excluded_window;
+};
+
+class CroppingWindowCapturerWin : public CroppingWindowCapturer {
+ public:
+  explicit CroppingWindowCapturerWin(const DesktopCaptureOptions& options)
+      : CroppingWindowCapturer(options),
+        enumerate_current_process_windows_(
+            options.enumerate_current_process_windows()),
+        full_screen_window_detector_(options.full_screen_window_detector()) {}
+
+  void CaptureFrame() override;
+
+ private:
+  bool ShouldUseScreenCapturer() override;
+  DesktopRect GetWindowRectInVirtualScreen() override;
+
+  // Returns either selected by user sourceId or sourceId provided by
+  // FullScreenWindowDetector
+  WindowId GetWindowToCapture() const;
+
+  // The region from GetWindowRgn in the desktop coordinate if the region is
+  // rectangular, or the rect from GetWindowRect if the region is not set.
+  DesktopRect window_region_rect_;
+
+  WindowCaptureHelperWin window_capture_helper_;
+
+  bool enumerate_current_process_windows_;
+
+  rtc::scoped_refptr<FullScreenWindowDetector> full_screen_window_detector_;
+
+  // Used to make sure that we only log the usage of fullscreen detection once.
+  mutable bool fullscreen_usage_logged_ = false;
+};
+
+void CroppingWindowCapturerWin::CaptureFrame() {
+  DesktopCapturer* win_capturer = window_capturer();
+  if (win_capturer) {
+    // Feed the actual list of windows into full screen window detector.
+    if (full_screen_window_detector_) {
+      full_screen_window_detector_->UpdateWindowListIfNeeded(
+          selected_window(), [this](DesktopCapturer::SourceList* sources) {
+            // Get the list of top level windows, including ones with empty
+            // title. win_capturer_->GetSourceList can't be used here
+            // cause it filters out the windows with empty titles and
+            // it uses responsiveness check which could lead to performance
+            // issues.
+            SourceList result;
+            int window_list_flags =
+                enumerate_current_process_windows_
+                    ? GetWindowListFlags::kNone
+                    : GetWindowListFlags::kIgnoreCurrentProcessWindows;
+
+            if (!webrtc::GetWindowList(window_list_flags, &result))
+              return false;
+
+            // Filter out windows not visible on current desktop
+            auto it = std::remove_if(
+                result.begin(), result.end(), [this](const auto& source) {
+                  HWND hwnd = reinterpret_cast<HWND>(source.id);
+                  return !window_capture_helper_
+                              .IsWindowVisibleOnCurrentDesktop(hwnd);
+                });
+            result.erase(it, result.end());
+
+            sources->swap(result);
+            return true;
+          });
+    }
+    win_capturer->SelectSource(GetWindowToCapture());
+  }
+
+  CroppingWindowCapturer::CaptureFrame();
+}
+
+bool CroppingWindowCapturerWin::ShouldUseScreenCapturer() {
+  if (rtc::rtc_win::GetVersion() < rtc::rtc_win::Version::VERSION_WIN8 &&
+      window_capture_helper_.IsAeroEnabled()) {
+    return false;
+  }
+
+  const HWND selected = reinterpret_cast<HWND>(GetWindowToCapture());
+  // Check if the window is visible on current desktop.
+  if (!window_capture_helper_.IsWindowVisibleOnCurrentDesktop(selected)) {
+    return false;
+  }
+
+  // Check if the window is a translucent layered window.
+  const LONG window_ex_style = GetWindowLong(selected, GWL_EXSTYLE);
+  if (window_ex_style & WS_EX_LAYERED) {
+    COLORREF color_ref_key = 0;
+    BYTE alpha = 0;
+    DWORD flags = 0;
+
+    // GetLayeredWindowAttributes fails if the window was setup with
+    // UpdateLayeredWindow. We have no way to know the opacity of the window in
+    // that case. This happens for Stiky Note (crbug/412726).
+    if (!GetLayeredWindowAttributes(selected, &color_ref_key, &alpha, &flags))
+      return false;
+
+    // UpdateLayeredWindow is the only way to set per-pixel alpha and will cause
+    // the previous GetLayeredWindowAttributes to fail. So we only need to check
+    // the window wide color key or alpha.
+    if ((flags & LWA_COLORKEY) || ((flags & LWA_ALPHA) && (alpha < 255))) {
+      return false;
+    }
+  }
+
+  if (!GetWindowRect(selected, &window_region_rect_)) {
+    return false;
+  }
+
+  DesktopRect content_rect;
+  if (!GetWindowContentRect(selected, &content_rect)) {
+    return false;
+  }
+
+  DesktopRect region_rect;
+  // Get the window region and check if it is rectangular.
+  const int region_type =
+      GetWindowRegionTypeWithBoundary(selected, &region_rect);
+
+  // Do not use the screen capturer if the region is empty or not rectangular.
+  if (region_type == COMPLEXREGION || region_type == NULLREGION) {
+    return false;
+  }
+
+  if (region_type == SIMPLEREGION) {
+    // The `region_rect` returned from GetRgnBox() is always in window
+    // coordinate.
+    region_rect.Translate(window_region_rect_.left(),
+                          window_region_rect_.top());
+    // MSDN: The window region determines the area *within* the window where the
+    // system permits drawing.
+    // https://msdn.microsoft.com/en-us/library/windows/desktop/dd144950(v=vs.85).aspx.
+    //
+    // `region_rect` should always be inside of `window_region_rect_`. So after
+    // the intersection, `window_region_rect_` == `region_rect`. If so, what's
+    // the point of the intersecting operations? Why cannot we directly retrieve
+    // `window_region_rect_` from GetWindowRegionTypeWithBoundary() function?
+    // TODO(zijiehe): Figure out the purpose of these intersections.
+    window_region_rect_.IntersectWith(region_rect);
+    content_rect.IntersectWith(region_rect);
+  }
+
+  // Check if the client area is out of the screen area. When the window is
+  // maximized, only its client area is visible in the screen, the border will
+  // be hidden. So we are using `content_rect` here.
+  if (!GetFullscreenRect().ContainsRect(content_rect)) {
+    return false;
+  }
+
+  // Check if the window is occluded by any other window, excluding the child
+  // windows, context menus, and `excluded_window_`.
+  // `content_rect` is preferred, see the comments on
+  // IsWindowIntersectWithSelectedWindow().
+  TopWindowVerifierContext context(selected,
+                                   reinterpret_cast<HWND>(excluded_window()),
+                                   content_rect, &window_capture_helper_);
+  return context.IsTopWindow();
+}
+
+DesktopRect CroppingWindowCapturerWin::GetWindowRectInVirtualScreen() {
+  TRACE_EVENT0("webrtc",
+               "CroppingWindowCapturerWin::GetWindowRectInVirtualScreen");
+  DesktopRect window_rect;
+  HWND hwnd = reinterpret_cast<HWND>(GetWindowToCapture());
+  if (!GetCroppedWindowRect(hwnd, /*avoid_cropping_border*/ false, &window_rect,
+                            /*original_rect*/ nullptr)) {
+    RTC_LOG(LS_WARNING) << "Failed to get window info: " << GetLastError();
+    return window_rect;
+  }
+  window_rect.IntersectWith(window_region_rect_);
+
+  // Convert `window_rect` to be relative to the top-left of the virtual screen.
+  DesktopRect screen_rect(GetFullscreenRect());
+  window_rect.IntersectWith(screen_rect);
+  window_rect.Translate(-screen_rect.left(), -screen_rect.top());
+  return window_rect;
+}
+
+WindowId CroppingWindowCapturerWin::GetWindowToCapture() const {
+  const auto selected_source = selected_window();
+  const auto full_screen_source =
+      full_screen_window_detector_
+          ? full_screen_window_detector_->FindFullScreenWindow(selected_source)
+          : 0;
+  if (full_screen_source && full_screen_source != selected_source &&
+      !fullscreen_usage_logged_) {
+    fullscreen_usage_logged_ = true;
+    LogDesktopCapturerFullscreenDetectorUsage();
+  }
+  return full_screen_source ? full_screen_source : selected_source;
+}
+
+}  // namespace
+
+// static
+std::unique_ptr<DesktopCapturer> CroppingWindowCapturer::CreateCapturer(
+    const DesktopCaptureOptions& options) {
+  std::unique_ptr<DesktopCapturer> capturer(
+      new CroppingWindowCapturerWin(options));
+  if (capturer && options.detect_updated_region()) {
+    capturer.reset(new DesktopCapturerDifferWrapper(std::move(capturer)));
+  }
+
+  return capturer;
+}
+
+}  // namespace webrtc