Correct alignment in ContiguousContainer::appendByMoving()

third_party/WebKit/Source/platform/graphics/ContiguousContainerTest.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform/graphics/ContiguousContainer.h"
 
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "wtf/TypeTraits.h"
 
@@ skipping 506 matching lines @@
     // Clearing should restore the capacity of the container to the same as a
     // newly allocated one (without reserved capacity requested).
     ContiguousContainer<Point2D, kPointAlignment> list(kMaxPointSize);
     size_t emptyCapacity = list.capacityInBytes();
     list.allocateAndConstruct<Point2D>();
     list.allocateAndConstruct<Point2D>();
     list.clear();
     EXPECT_EQ(emptyCapacity, list.capacityInBytes());
 }
 
+TEST(ContiguousContainerTest, Alignment)
+{
+    const size_t maxAlign = WTF_ALIGN_OF(long double);
+    ContiguousContainer<Point2D, maxAlign> list(kMaxPointSize);
+
+    list.allocateAndConstruct<Point2D>();
+    EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (maxAlign - 1));
+    list.allocateAndConstruct<Point2D>();
+    EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (maxAlign - 1));
+    list.allocateAndConstruct<Point3D>();
+    EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (maxAlign - 1));
+    list.allocateAndConstruct<Point3D>();
+    EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (maxAlign - 1));
+    list.allocateAndConstruct<Point2D>();
+    EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (maxAlign - 1));
+
+    list.appendByMoving(list[0], sizeof(Point2D));
+    EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (maxAlign - 1));
+    list.appendByMoving(list[1], sizeof(Point2D));
+    EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (maxAlign - 1));
+    list.appendByMoving(list[2], sizeof(Point3D));
+    EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (maxAlign - 1));
+    list.appendByMoving(list[3], sizeof(Point3D));
+    EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (maxAlign - 1));
+    list.appendByMoving(list[4], sizeof(Point2D));
+    EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (maxAlign - 1));
+}
+
 } // namespace
 } // namespace blink