commit 8d757ac0a21567b177df231b802961b0a2981d07
author sergeyu@chromium.org <sergeyu@chromium.org@4adac7df-926f-26a2-2b94-8c16560cd09d> Tue Sep 24 23:13:51 2013
committer sergeyu@chromium.org <sergeyu@chromium.org@4adac7df-926f-26a2-2b94-8c16560cd09d> Tue Sep 24 23:13:51 2013
tree c64c32417b4b008afc29cc872c1d75464ba21ae5
parent 958cdf68f308d5c6e3e10a58cdae40cc0044625b

Fix window capturer not to leak HDC.

Previously Windows window capturer kept DC handles between captures. As
result it was leaking DC handles in SelectWindow(). Fixed it so that it
calls GetWindowDC() for each capture.

R=alexeypa@chromium.org

Review URL: https://webrtc-codereview.appspot.com/2289004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4834 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/desktop_capture/window_capturer_win.cc

diff --git a/webrtc/modules/desktop_capture/window_capturer_win.cc b/webrtc/modules/desktop_capture/window_capturer_win.cc
index cdad18b..0a8211f 100644
--- a/webrtc/modules/desktop_capture/window_capturer_win.cc
+++ b/webrtc/modules/desktop_capture/window_capturer_win.cc
@@ -102,7 +102,6 @@
   // HWND and HDC for the currently selected window or NULL if window is not
   // selected.
   HWND window_;
-  HDC window_dc_;
 
   // dwmapi.dll is used to determine if desktop compositing is enabled.
   HMODULE dwmapi_library_;
@@ -113,8 +112,7 @@
 
 WindowCapturerWin::WindowCapturerWin()
     : callback_(NULL),
-      window_(NULL),
-      window_dc_(NULL) {
+      window_(NULL) {
   // Try to load dwmapi.dll dynamically since it is not available on XP.
   dwmapi_library_ = LoadLibrary(L"dwmapi.dll");
   if (dwmapi_library_) {
@@ -149,17 +147,10 @@
 }
 
 bool WindowCapturerWin::SelectWindow(WindowId id) {
-  if (window_dc_)
-    ReleaseDC(window_, window_dc_);
-
-  window_ = reinterpret_cast<HWND>(id);
-  window_dc_ = GetWindowDC(window_);
-  if (!window_dc_) {
-    LOG(LS_WARNING) << "Failed to select window: " << GetLastError();
-    window_ = NULL;
+  HWND window = reinterpret_cast<HWND>(id);
+  if (!IsWindow(window) || !IsWindowVisible(window) || IsIconic(window))
     return false;
-  }
-
+  window_ = window;
   return true;
 }
 
@@ -171,7 +162,7 @@
 }
 
 void WindowCapturerWin::Capture(const DesktopRegion& region) {
-  if (!window_dc_) {
+  if (!window_) {
     LOG(LS_ERROR) << "Window hasn't been selected: " << GetLastError();
     callback_->OnCaptureCompleted(NULL);
     return;
@@ -183,8 +174,6 @@
     return;
   }
 
-  assert(window_);
-
   RECT rect;
   if (!GetWindowRect(window_, &rect)) {
     LOG(LS_WARNING) << "Failed to get window size: " << GetLastError();
@@ -192,15 +181,23 @@
     return;
   }
 
-  scoped_ptr<DesktopFrameWin> frame(DesktopFrameWin::Create(
-      DesktopSize(rect.right - rect.left, rect.bottom - rect.top),
-      NULL, window_dc_));
-  if (!frame.get()) {
+  HDC window_dc = GetWindowDC(window_);
+  if (!window_dc) {
+    LOG(LS_WARNING) << "Failed to get window DC: " << GetLastError();
     callback_->OnCaptureCompleted(NULL);
     return;
   }
 
-  HDC mem_dc = CreateCompatibleDC(window_dc_);
+  scoped_ptr<DesktopFrameWin> frame(DesktopFrameWin::Create(
+      DesktopSize(rect.right - rect.left, rect.bottom - rect.top),
+      NULL, window_dc));
+  if (!frame.get()) {
+    ReleaseDC(window_, window_dc);
+    callback_->OnCaptureCompleted(NULL);
+    return;
+  }
+
+  HDC mem_dc = CreateCompatibleDC(window_dc);
   SelectObject(mem_dc, frame->bitmap());
   BOOL result = FALSE;
 
@@ -220,16 +217,18 @@
   // Aero is enabled or PrintWindow() failed, use BitBlt.
   if (!result) {
     result = BitBlt(mem_dc, 0, 0, frame->size().width(), frame->size().height(),
-                    window_dc_, 0, 0, SRCCOPY);
+                    window_dc, 0, 0, SRCCOPY);
   }
 
-  DeleteDC(mem_dc);
-
   if (!result) {
     LOG(LS_ERROR) << "Both PrintWindow() and BitBlt() failed.";
     frame.reset();
   }
 
+  SelectObject(mem_dc, NULL);
+  DeleteDC(mem_dc);
+  ReleaseDC(window_, window_dc);
+
   callback_->OnCaptureCompleted(frame.release());
 }