Use std::unique_ptr<> to pass frame ownership in DesktopCapturer impls.

webrtc/modules/desktop_capture/window_capturer_mac.mm

 /*
  *  Copyright (c) 2013 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.
  */
 
@@ skipping 14 matching lines @@
 #include "webrtc/modules/desktop_capture/mac/window_list_utils.h"
 #include "webrtc/system_wrappers/include/logging.h"
 
 namespace webrtc {
 
 namespace {
 
 // Returns true if the window exists.
 bool IsWindowValid(CGWindowID id) {
   CFArrayRef window_id_array =
-      CFArrayCreate(NULL, reinterpret_cast<const void **>(&id), 1, NULL);
+      CFArrayCreate(nullptr, reinterpret_cast<const void **>(&id), 1, nullptr);
   CFArrayRef window_array =
       CGWindowListCreateDescriptionFromArray(window_id_array);
   bool valid = window_array && CFArrayGetCount(window_array);
   CFRelease(window_id_array);
   CFRelease(window_array);
 
   return valid;
 }
 
 class WindowCapturerMac : public WindowCapturer {
  public:
   explicit WindowCapturerMac(rtc::scoped_refptr<FullScreenChromeWindowDetector>
                                  full_screen_chrome_window_detector);
   virtual ~WindowCapturerMac();
 
   // WindowCapturer interface.
   bool GetWindowList(WindowList* windows) override;
   bool SelectWindow(WindowId id) override;
   bool BringSelectedWindowToFront() override;
 
   // DesktopCapturer interface.
   void Start(Callback* callback) override;
   void Capture(const DesktopRegion& region) override;
 
  private:
-  Callback* callback_;
+  Callback* callback_ = nullptr;
 
   // The window being captured.
-  CGWindowID window_id_;
+  CGWindowID window_id_ = 0;
 
   rtc::scoped_refptr<FullScreenChromeWindowDetector>
       full_screen_chrome_window_detector_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(WindowCapturerMac);
 };
 
-WindowCapturerMac::WindowCapturerMac(rtc::scoped_refptr<
-    FullScreenChromeWindowDetector> full_screen_chrome_window_detector)
-    : callback_(NULL),
-      window_id_(0),
-      full_screen_chrome_window_detector_(full_screen_chrome_window_detector) {
-}
+WindowCapturerMac::WindowCapturerMac(
+    rtc::scoped_refptr<FullScreenChromeWindowDetector>
+        full_screen_chrome_window_detector)
+    : full_screen_chrome_window_detector_(full_screen_chrome_window_detector) {}
 
-WindowCapturerMac::~WindowCapturerMac() {
-}
+WindowCapturerMac::~WindowCapturerMac() {}
 
 bool WindowCapturerMac::GetWindowList(WindowList* windows) {
   // Only get on screen, non-desktop windows.
   CFArrayRef window_array = CGWindowListCopyWindowInfo(
       kCGWindowListExcludeDesktopElements,
       kCGNullWindowID);
   if (!window_array)
     return false;
   MacDesktopConfiguration desktop_config = MacDesktopConfiguration::GetCurrent(
       MacDesktopConfiguration::TopLeftOrigin);
@@ skipping 44 matching lines @@
   return true;
 }
 
 bool WindowCapturerMac::BringSelectedWindowToFront() {
   if (!window_id_)
     return false;
 
   CGWindowID ids[1];
   ids[0] = window_id_;
   CFArrayRef window_id_array =
-      CFArrayCreate(NULL, reinterpret_cast<const void **>(&ids), 1, NULL);
+      CFArrayCreate(nullptr, reinterpret_cast<const void **>(&ids), 1, nullptr);
 
   CFArrayRef window_array =
       CGWindowListCreateDescriptionFromArray(window_id_array);
-  if (window_array == NULL || 0 == CFArrayGetCount(window_array)) {
+  if (!window_array || 0 == CFArrayGetCount(window_array)) {
     // Could not find the window. It might have been closed.
     LOG(LS_INFO) << "Window not found";
     CFRelease(window_id_array);
     return false;
   }
 
   CFDictionaryRef window = reinterpret_cast<CFDictionaryRef>(
       CFArrayGetValueAtIndex(window_array, 0));
   CFNumberRef pid_ref = reinterpret_cast<CFNumberRef>(
       CFDictionaryGetValue(window, kCGWindowOwnerPID));
@@ skipping 14 matching lines @@
 
 void WindowCapturerMac::Start(Callback* callback) {
   assert(!callback_);
   assert(callback);
 
   callback_ = callback;
 }
 
 void WindowCapturerMac::Capture(const DesktopRegion& region) {
   if (!IsWindowValid(window_id_)) {
-    callback_->OnCaptureCompleted(NULL);
+    callback_->OnCaptureCompleted(std::unique_ptr<DesktopFrame>());

[Wez, 2016/05/18 01:29:51]

Why not using nullptr here?

[Sergey Ulanov, 2016/05/31 12:02:49]

because OnCaptureCompleted(nullptr) would call wrong constructor.

Anyway I've replaced the OnCaptureCompleted() with a new OnCaptureResult(). This
avoids the problem above and should fix compilation issues on windows bots.

     return;
   }
 
   CGWindowID on_screen_window = window_id_;
   if (full_screen_chrome_window_detector_) {
     CGWindowID full_screen_window =
         full_screen_chrome_window_detector_->FindFullScreenWindow(window_id_);
 
     if (full_screen_window != kCGNullWindowID)
       on_screen_window = full_screen_window;
   }
 
   CGImageRef window_image = CGWindowListCreateImage(
       CGRectNull, kCGWindowListOptionIncludingWindow,
       on_screen_window, kCGWindowImageBoundsIgnoreFraming);
 
   if (!window_image) {
-    callback_->OnCaptureCompleted(NULL);
+    callback_->OnCaptureCompleted(std::unique_ptr<DesktopFrame>());
     return;
   }
 
   int bits_per_pixel = CGImageGetBitsPerPixel(window_image);
   if (bits_per_pixel != 32) {
     LOG(LS_ERROR) << "Unsupported window image depth: " << bits_per_pixel;
     CFRelease(window_image);
-    callback_->OnCaptureCompleted(NULL);
+    callback_->OnCaptureCompleted(std::unique_ptr<DesktopFrame>());
     return;
   }
 
   int width = CGImageGetWidth(window_image);
   int height = CGImageGetHeight(window_image);
   CGDataProviderRef provider = CGImageGetDataProvider(window_image);
   CFDataRef cf_data = CGDataProviderCopyData(provider);
-  DesktopFrame* frame = new BasicDesktopFrame(
-      DesktopSize(width, height));
+  std::unique_ptr<DesktopFrame> frame(
+      new BasicDesktopFrame(DesktopSize(width, height)));
 
   int src_stride = CGImageGetBytesPerRow(window_image);
   const uint8_t* src_data = CFDataGetBytePtr(cf_data);
   for (int y = 0; y < height; ++y) {
     memcpy(frame->data() + frame->stride() * y, src_data + src_stride * y,
            DesktopFrame::kBytesPerPixel * width);
   }
 
   CFRelease(cf_data);
   CFRelease(window_image);
 
   frame->mutable_updated_region()->SetRect(
       DesktopRect::MakeSize(frame->size()));
 
-  callback_->OnCaptureCompleted(frame);
+  callback_->OnCaptureCompleted(std::move(frame));
 
   if (full_screen_chrome_window_detector_)
     full_screen_chrome_window_detector_->UpdateWindowListIfNeeded(window_id_);
 }
 
 }  // namespace
 
 // static
 WindowCapturer* WindowCapturer::Create(const DesktopCaptureOptions& options) {
   return new WindowCapturerMac(options.full_screen_chrome_window_detector());
 }
 
 }  // namespace webrtc