Implement difference clip rects with window rectangles

tests/WindowRectanglesTest.cpp

Index: tests/WindowRectanglesTest.cpp
diff --git a/tests/WindowRectanglesTest.cpp b/tests/WindowRectanglesTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..d569f1d7aa2320fdae27d3896e5cf9ec3a8819ec
--- /dev/null
+++ b/tests/WindowRectanglesTest.cpp
@@ -0,0 +1,92 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkTypes.h"
+#include "Test.h"
+
+#if SK_SUPPORT_GPU
+
+#include "GrWindowRectangles.h"
+
+static SkIRect next_irect(SkRandom& r) {
+    return {r.nextS(), r.nextS(), r.nextS(), r.nextS()};
+}
+
+DEF_TEST(WindowRectangles, reporter) {
+    SkRandom r;
+
+    SkIRect windowData[GrWindowRectangles::kMaxWindows];
+    for (int i = 0; i < GrWindowRectangles::kMaxWindows; ++i) {
+        windowData[i] = next_irect(r);
+    }
+
+    GrWindowRectangles wr;
+    for (int i = 0; i < GrWindowRectangles::kMaxWindows - 1; ++i) {
+        REPORTER_ASSERT(reporter, wr.count() == i);
+        REPORTER_ASSERT(reporter, !memcmp(wr.data(), windowData, i * sizeof(SkIRect)));
+
+        GrWindowRectangles wr2(wr);
+        REPORTER_ASSERT(reporter, wr2 == wr);
+        REPORTER_ASSERT(reporter, wr2.mode() == wr.mode());
+        REPORTER_ASSERT(reporter, wr2.count() == wr.count());
+        REPORTER_ASSERT(reporter, !memcmp(wr2.data(), wr.data(), i * sizeof(SkIRect)));
+
+        wr.addWindow(windowData[i]);
+    }
+
+    SkASSERT(wr.count() == GrWindowRectangles::kMaxWindows - 1);
+    {
+        GrWindowRectangles A(wr), B(wr);
+        REPORTER_ASSERT(reporter, B == A);
+        REPORTER_ASSERT(reporter, B.data() == A.data()); // Should use copy-on-write.
+
+        A.addWindow(windowData[GrWindowRectangles::kMaxWindows - 1]);
+        REPORTER_ASSERT(reporter, B.data() != A.data());
+        REPORTER_ASSERT(reporter, B != A);
+
+        B.addWindow(SkIRect::MakeLargest());
+        REPORTER_ASSERT(reporter, B != A);
+
+        REPORTER_ASSERT(reporter, !memcmp(A.data(), windowData,
+                                          GrWindowRectangles::kMaxWindows * sizeof(SkIRect)));
+        REPORTER_ASSERT(reporter, !memcmp(B.data(), windowData,
+                                          (GrWindowRectangles::kMaxWindows - 1) * sizeof(SkIRect)));
+        REPORTER_ASSERT(reporter,
+                        B.data()[GrWindowRectangles::kMaxWindows - 1] == SkIRect::MakeLargest());
+    }
+    {
+        GrWindowRectangles A(wr), B(wr);
+        REPORTER_ASSERT(reporter, B == A);
+        REPORTER_ASSERT(reporter, B.data() == A.data()); // Should use copy-on-write.
+
+        A.addWindow(windowData[GrWindowRectangles::kMaxWindows - 1]);
+        B.addWindow(windowData[GrWindowRectangles::kMaxWindows - 1]);
+        REPORTER_ASSERT(reporter, B == A);
+        REPORTER_ASSERT(reporter, B.data() != A.data());
+        REPORTER_ASSERT(reporter, !memcmp(B.data(), A.data(),
+                                          GrWindowRectangles::kMaxWindows * sizeof(SkIRect)));
+        REPORTER_ASSERT(reporter, !memcmp(A.data(), windowData,
+                                          GrWindowRectangles::kMaxWindows * sizeof(SkIRect)));
+    }
+
+    GrWindowRectangles wrI(GrWindowRectangles::Mode::kInclusive);
+    for (int i = 0; i < wr.count(); ++i) {
+        wrI.addWindow(windowData[i]);
+    }
+    REPORTER_ASSERT(reporter, wrI != wr);
+    REPORTER_ASSERT(reporter, wrI.mode() != wr.mode());
+    REPORTER_ASSERT(reporter, wrI.count() == wr.count());
+    REPORTER_ASSERT(reporter, !memcmp(wrI.data(), wr.data(), wr.count() * sizeof(SkIRect)));
+
+    wr.reset(GrWindowRectangles::Mode::kInclusive);
+    for (int i = 0; i < wrI.count(); ++i) {
+        wr.addWindow(windowData[i]);
+    }
+    REPORTER_ASSERT(reporter, wrI == wr);
+}
+
+#endif