[WebRTC] Add ScreenCapturerDifferWrapper to share Differ across ScreenCapturers

webrtc/modules/desktop_capture/screen_capturer_differ_wrapper_unittest.cc

Index: webrtc/modules/desktop_capture/screen_capturer_differ_wrapper_unittest.cc
diff --git a/webrtc/modules/desktop_capture/screen_capturer_differ_wrapper_unittest.cc b/webrtc/modules/desktop_capture/screen_capturer_differ_wrapper_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e667553b1474151980c38d6fcfb3365dda4ff9f5
--- /dev/null
+++ b/webrtc/modules/desktop_capture/screen_capturer_differ_wrapper_unittest.cc
@@ -0,0 +1,291 @@
+/*
+ *  Copyright (c) 2016 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/screen_capturer_differ_wrapper.h"
+
+#include <initializer_list>
+#include <memory>
+#include <utility>
+#include <vector>
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/base/random.h"
+#include "webrtc/base/timeutils.h"
+#include "webrtc/modules/desktop_capture/desktop_geometry.h"
+#include "webrtc/modules/desktop_capture/desktop_region.h"
+#include "webrtc/modules/desktop_capture/differ_block.h"
+#include "webrtc/modules/desktop_capture/fake_screen_capturer.h"
+#include "webrtc/modules/desktop_capture/screen_capturer_mock_objects.h"
+#include "webrtc/system_wrappers/include/cpu_features_wrapper.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+namespace {
+
+// Compares and asserts |frame|.updated_region() equals to |rects|. This
+// function does not care about the order of the |rects| and it does not expect
+// DesktopRegion to return an exact area for each rectangle in |rects|.
+template <template <typename, typename...> class T = std::initializer_list,
+          typename... Rect>
+void AssertUpdatedRegionIs(const DesktopFrame& frame,
+                           const T<DesktopRect, Rect...>& rects) {
+  DesktopRegion region;
+  for (const auto& rect : rects) {
+    region.AddRect(rect);
+  }
+  ASSERT_TRUE(frame.updated_region().Equals(region));
+}
+
+// Compares and asserts |frame|.updated_region() covers all rectangles in
+// |rects|, but does not cover areas other than a kBlockSize expansion. This
+// function does not care about the order of the |rects|, and it does not expect
+// DesktopRegion to return an exact area of each rectangle in |rects|.
+template <template <typename, typename...> class T = std::initializer_list,
+          typename... Rect>
+void AssertUpdatedRegionCovers(const DesktopFrame& frame,
+                               const T<DesktopRect, Rect...>& rects) {
+  DesktopRegion region;
+  for (const auto& rect : rects) {
+    region.AddRect(rect);
+  }
+
+  // Intersect of |rects| and |frame|.updated_region() should be |rects|. i.e.
+  // |frame|.updated_region() should be a superset of |rects|.
+  DesktopRegion intersect(region);
+  intersect.IntersectWith(frame.updated_region());
+  ASSERT_TRUE(region.Equals(intersect));
+
+  // Difference between |rects| and |frame|.updated_region() should not cover
+  // areas which have larger than twice of kBlockSize width and height.
+  //
+  // Explanation of the 'twice' of kBlockSize (indeed kBlockSize * 2 - 2) is
+  // following,
+  // (Each block in the following grid is a 8 x 8 pixels area. X means the real
+  // updated area, m means the updated area marked by
+  // ScreenCapturerDifferWrapper.)
+  // +---+---+---+---+---+---+---+---+
+  // | X | m | m | m | m | m | m | m |
+  // +---+---+---+---+---+---+---+---+
+  // | m | m | m | m | m | m | m | m |
+  // +---+---+---+---+---+---+---+---+
+  // | m | m | m | m | m | m | m | m |
+  // +---+---+---+---+---+---+---+---+
+  // | m | m | m | m | m | m | m | X |
+  // +---+---+---+---+---+---+---+---+
+  // The top left [0, 0] - [8, 8] and right bottom [56, 24] - [64, 32] blocks of
+  // this area are updated. But since ScreenCapturerDifferWrapper compares
+  // 32 x 32 blocks by default, this entire area is marked as updated. So the
+  // [8, 8] - [56, 32] is expected to be covered in the difference.
+  //
+  // But if [0, 0] - [8, 8] and [64, 24] - [72, 32] blocks are updated,
+  // +---+---+---+---+---+---+---+---+---+---+---+---+
+  // | X | m | m | m |   |   |   |   | m | m | m | m |
+  // +---+---+---+---+---+---+---+---+---+---+---+---+
+  // | m | m | m | m |   |   |   |   | m | m | m | m |
+  // +---+---+---+---+---+---+---+---+---+---+---+---+
+  // | m | m | m | m |   |   |   |   | m | m | m | m |
+  // +---+---+---+---+---+---+---+---+---+---+---+---+
+  // | m | m | m | m |   |   |   |   | X | m | m | m |
+  // +---+---+---+---+---+---+---+---+---+---+---+---+
+  // the [8, 8] - [64, 32] is not expected to be covered in the difference. As
+  // ScreenCapturerDifferWrapper should only mark [0, 0] - [32, 32] and
+  // [64, 0] - [96, 32] as updated.
+  DesktopRegion differ(frame.updated_region());
+  differ.Subtract(region);
+  for (DesktopRegion::Iterator it(differ); !it.IsAtEnd(); it.Advance()) {
+    ASSERT_TRUE(it.rect().width() <= kBlockSize * 2 - 2 ||
+                it.rect().height() <= kBlockSize * 2 - 2);
+  }
+}
+
+// Executes a ScreenCapturerDifferWrapper::Capture() and compares its output
+// DesktopFrame::updated_region() with |updated_region| if |check_result| is
+// true. If |exactly_match| is true, AssertUpdatedRegionIs() will be used,
+// otherwise AssertUpdatedRegionCovers() will be used.
+template <template <typename, typename...> class T = std::initializer_list,
+          typename... Rect>
+void ExecuteDifferWrapperCase(BlackWhiteDesktopFramePainter* frame_painter,
+                              ScreenCapturerDifferWrapper* capturer,
+                              MockScreenCapturerCallback* callback,
+                              const T<DesktopRect, Rect...>& updated_region,
+                              bool check_result,
+                              bool exactly_match) {
+  EXPECT_CALL(*callback,
+              OnCaptureResultPtr(DesktopCapturer::Result::SUCCESS, testing::_))
+      .Times(1)
+      .WillOnce(testing::Invoke([&updated_region, check_result, exactly_match](
+          DesktopCapturer::Result result,
+          std::unique_ptr<DesktopFrame>* frame) {
+        ASSERT_EQ(result, DesktopCapturer::Result::SUCCESS);
+        if (check_result) {
+          if (exactly_match) {
+            AssertUpdatedRegionIs(**frame, updated_region);
+          } else {
+            AssertUpdatedRegionCovers(**frame, updated_region);
+          }
+        }
+      }));
+  for (const auto& rect : updated_region) {
+    frame_painter->updated_region()->AddRect(rect);
+  }
+  capturer->Capture(DesktopRegion());
+}
+
+// Executes a ScreenCapturerDifferWrapper::Capture(), if updated_region() is not
+// set, this function will reset ScreenCapturerDifferWrapper internal
+// DesktopFrame into white.
+void ExecuteCapturer(ScreenCapturerDifferWrapper* capturer,
+                     MockScreenCapturerCallback* callback) {
+  EXPECT_CALL(*callback,
+              OnCaptureResultPtr(DesktopCapturer::Result::SUCCESS, testing::_))
+      .Times(1);
+  capturer->Capture(DesktopRegion());
+}
+
+void ExecuteDifferWrapperTest(bool with_hints,
+                              bool enlarge_updated_region,
+                              bool random_updated_region,
+                              bool check_result) {
+  const bool updated_region_should_exactly_match =
+      with_hints && !enlarge_updated_region && !random_updated_region;
+  BlackWhiteDesktopFramePainter frame_painter;
+  PainterDesktopFrameGenerator frame_generator;
+  frame_generator.set_desktop_frame_painter(&frame_painter);
+  std::unique_ptr<FakeScreenCapturer> fake(new FakeScreenCapturer());
+  fake->set_frame_generator(&frame_generator);
+  ScreenCapturerDifferWrapper capturer(std::move(fake));
+  MockScreenCapturerCallback callback;
+  frame_generator.set_provide_updated_region_hints(with_hints);
+  frame_generator.set_enlarge_updated_region(enlarge_updated_region);
+  frame_generator.set_add_random_updated_region(random_updated_region);
+
+  capturer.Start(&callback);
+
+  EXPECT_CALL(callback,
+              OnCaptureResultPtr(DesktopCapturer::Result::SUCCESS, testing::_))
+      .Times(1)
+      .WillOnce(testing::Invoke([](DesktopCapturer::Result result,
+                                   std::unique_ptr<DesktopFrame>* frame) {
+        ASSERT_EQ(result, DesktopCapturer::Result::SUCCESS);
+        AssertUpdatedRegionIs(**frame,
+                              {DesktopRect::MakeSize((*frame)->size())});
+      }));
+  capturer.Capture(DesktopRegion());
+
+  ExecuteDifferWrapperCase(&frame_painter, &capturer, &callback,
+                           {DesktopRect::MakeLTRB(100, 100, 200, 200),
+                            DesktopRect::MakeLTRB(300, 300, 400, 400)},
+                           check_result, updated_region_should_exactly_match);
+  ExecuteCapturer(&capturer, &callback);
+
+  ExecuteDifferWrapperCase(
+      &frame_painter, &capturer, &callback,
+      {DesktopRect::MakeLTRB(0, 0, 40, 40),
+       DesktopRect::MakeLTRB(0, frame_generator.size()->height() - 40, 40,
+                             frame_generator.size()->height()),
+       DesktopRect::MakeLTRB(frame_generator.size()->width() - 40, 0,
+                             frame_generator.size()->width(), 40),
+       DesktopRect::MakeLTRB(frame_generator.size()->width() - 40,
+                             frame_generator.size()->height() - 40,
+                             frame_generator.size()->width(),
+                             frame_generator.size()->height())},
+      check_result, updated_region_should_exactly_match);
+
+  Random random(rtc::TimeMillis());
+  // Fuzzing tests.
+  for (int i = 0; i < 1000; i++) {
+    if (enlarge_updated_region) {
+      frame_generator.set_enlarge_range(random.Rand(1, 50));
+    }
+    frame_generator.size()->set(random.Rand(500, 2000), random.Rand(500, 2000));
+    ExecuteCapturer(&capturer, &callback);
+    std::vector<DesktopRect> updated_region;
+    for (int j = random.Rand(50); j >= 0; j--) {
+      // At least a 1 x 1 updated region.
+      const int left = random.Rand(0, frame_generator.size()->width() - 2);
+      const int top = random.Rand(0, frame_generator.size()->height() - 2);
+      const int right = random.Rand(left + 1, frame_generator.size()->width());
+      const int bottom = random.Rand(top + 1, frame_generator.size()->height());
+      updated_region.push_back(DesktopRect::MakeLTRB(left, top, right, bottom));
+    }
+    ExecuteDifferWrapperCase(&frame_painter, &capturer, &callback,
+                             updated_region, check_result,
+                             updated_region_should_exactly_match);
+  }
+}
+
+}  // namespace
+
+TEST(ScreenCapturerDifferWrapperTest, CaptureWithoutHints) {
+  ExecuteDifferWrapperTest(false, false, false, true);
+}
+
+TEST(ScreenCapturerDifferWrapperTest, CaptureWithHints) {
+  ExecuteDifferWrapperTest(true, false, false, true);
+}
+
+TEST(ScreenCapturerDifferWrapperTest, CaptureWithEnlargedHints) {
+  ExecuteDifferWrapperTest(true, true, false, true);
+}
+
+TEST(ScreenCapturerDifferWrapperTest, CaptureWithRandomHints) {
+  ExecuteDifferWrapperTest(true, false, true, true);
+}
+
+TEST(ScreenCapturerDifferWrapperTest, CaptureWithEnlargedAndRandomHints) {
+  ExecuteDifferWrapperTest(true, true, true, true);
+}
+
+// When hints are provided, ScreenCapturerDifferWrapper has a slightly better
+// performance in current configuration, but not so significant. Following is
+// one run result.
+// [ RUN      ] DISABLED_CaptureWithoutHintsPerf
+// [       OK ] DISABLED_CaptureWithoutHintsPerf (7118 ms)
+// [ RUN      ] DISABLED_CaptureWithHintsPerf
+// [       OK ] DISABLED_CaptureWithHintsPerf (5580 ms)
+// [ RUN      ] DISABLED_CaptureWithEnlargedHintsPerf
+// [       OK ] DISABLED_CaptureWithEnlargedHintsPerf (5974 ms)
+// [ RUN      ] DISABLED_CaptureWithRandomHintsPerf
+// [       OK ] DISABLED_CaptureWithRandomHintsPerf (6184 ms)
+// [ RUN      ] DISABLED_CaptureWithEnlargedAndRandomHintsPerf
+// [       OK ] DISABLED_CaptureWithEnlargedAndRandomHintsPerf (6347 ms)
+TEST(ScreenCapturerDifferWrapperTest, DISABLED_CaptureWithoutHintsPerf) {
+  int64_t started = rtc::TimeMillis();
+  ExecuteDifferWrapperTest(false, false, false, false);
+  ASSERT_LE(rtc::TimeMillis() - started, 15000);
+}
+
+TEST(ScreenCapturerDifferWrapperTest, DISABLED_CaptureWithHintsPerf) {
+  int64_t started = rtc::TimeMillis();
+  ExecuteDifferWrapperTest(true, false, false, false);
+  ASSERT_LE(rtc::TimeMillis() - started, 15000);
+}
+
+TEST(ScreenCapturerDifferWrapperTest, DISABLED_CaptureWithEnlargedHintsPerf) {
+  int64_t started = rtc::TimeMillis();
+  ExecuteDifferWrapperTest(true, true, false, false);
+  ASSERT_LE(rtc::TimeMillis() - started, 15000);
+}
+
+TEST(ScreenCapturerDifferWrapperTest, DISABLED_CaptureWithRandomHintsPerf) {
+  int64_t started = rtc::TimeMillis();
+  ExecuteDifferWrapperTest(true, false, true, false);
+  ASSERT_LE(rtc::TimeMillis() - started, 15000);
+}
+
+TEST(ScreenCapturerDifferWrapperTest,
+     DISABLED_CaptureWithEnlargedAndRandomHintsPerf) {
+  int64_t started = rtc::TimeMillis();
+  ExecuteDifferWrapperTest(true, true, true, false);
+  ASSERT_LE(rtc::TimeMillis() - started, 15000);
+}
+
+}  // namespace webrtc