Add skia::RefPtr class to wrap ref counted classes from Skia.

skia/ext/refptr_unittest.cc

+// Copyright 2012 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 "skia/ext/refptr.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace skia {
+namespace {
+
+TEST(RefPtrTest, ReferenceCounting) {
+  SkRefCnt* ref = new SkRefCnt();
+  EXPECT_EQ(1, ref->getRefCnt());
+
+  {
+    // Adopt the reference from the caller on creation.
+    RefPtr<SkRefCnt> refptr1 = AdoptRef(ref);
+    EXPECT_EQ(1, ref->getRefCnt());
+    EXPECT_EQ(1, refptr1->getRefCnt());
+
+    EXPECT_EQ(ref, &*refptr1);
+    EXPECT_EQ(ref, refptr1.get());
+
+    {
+      // Take a second reference for the second instance.
+      RefPtr<SkRefCnt> refptr2(refptr1);
+      EXPECT_EQ(2, ref->getRefCnt());
+
+      RefPtr<SkRefCnt> refptr3;
+      EXPECT_FALSE(refptr3);
+
+      // Take a third reference for the third instance.
+      refptr3 = refptr1;
+      EXPECT_EQ(3, ref->getRefCnt());
+
+      // Same object, so should have the same refcount.
+      refptr2 = refptr3;
+      EXPECT_EQ(3, ref->getRefCnt());
+
+      // Drop the object from refptr2, so it should lose its reference.
+      EXPECT_TRUE(refptr2);
+      refptr2.clear();
+      EXPECT_EQ(2, ref->getRefCnt());
+
+      EXPECT_FALSE(refptr2);
+      EXPECT_EQ(NULL, refptr2.get());
+
+      EXPECT_TRUE(refptr3);
+      EXPECT_EQ(2, refptr3->getRefCnt());
+      EXPECT_EQ(ref, &*refptr3);
+      EXPECT_EQ(ref, refptr3.get());
+    }
+
+    // Drop a reference when the third object is destroyed.
+    EXPECT_EQ(1, ref->getRefCnt());
+  }
+}
+
+TEST(RefPtrTest, Construct) {
+  SkRefCnt* ref = new SkRefCnt();
+  EXPECT_EQ(1, ref->getRefCnt());
+
+  // Adopt the reference from the caller on creation.
+  RefPtr<SkRefCnt> refptr1(AdoptRef(ref));
+  EXPECT_EQ(1, ref->getRefCnt());
+  EXPECT_EQ(1, refptr1->getRefCnt());
+
+  EXPECT_EQ(ref, &*refptr1);
+  EXPECT_EQ(ref, refptr1.get());
+
+  RefPtr<SkRefCnt> refptr2(refptr1);
+  EXPECT_EQ(2, ref->getRefCnt());
+}
+
+TEST(RefPtrTest, DeclareAndAssign) {
+  SkRefCnt* ref = new SkRefCnt();
+  EXPECT_EQ(1, ref->getRefCnt());
+
+  // Adopt the reference from the caller on creation.
+  RefPtr<SkRefCnt> refptr1 = AdoptRef(ref);
+  EXPECT_EQ(1, ref->getRefCnt());
+  EXPECT_EQ(1, refptr1->getRefCnt());
+
+  EXPECT_EQ(ref, &*refptr1);
+  EXPECT_EQ(ref, refptr1.get());
+
+  RefPtr<SkRefCnt> refptr2 = refptr1;
+  EXPECT_EQ(2, ref->getRefCnt());
+}
+
+TEST(RefPtrTest, Assign) {
+  SkRefCnt* ref = new SkRefCnt();
+  EXPECT_EQ(1, ref->getRefCnt());
+
+  // Adopt the reference from the caller on creation.
+  RefPtr<SkRefCnt> refptr1;
+  refptr1 = AdoptRef(ref);
+  EXPECT_EQ(1, ref->getRefCnt());
+  EXPECT_EQ(1, refptr1->getRefCnt());
+
+  EXPECT_EQ(ref, &*refptr1);
+  EXPECT_EQ(ref, refptr1.get());
+
+  RefPtr<SkRefCnt> refptr2;
+  refptr2 = refptr1;
+  EXPECT_EQ(2, ref->getRefCnt());
+}
+
+class Subclass : public SkRefCnt {};
+
+TEST(RefPtrTest, Upcast) {
+  RefPtr<Subclass> child = AdoptRef(new Subclass());
+  EXPECT_EQ(1, child->getRefCnt());
+
+  RefPtr<SkRefCnt> parent = child;
+  EXPECT_TRUE(child);
+  EXPECT_TRUE(parent);
+
+  EXPECT_EQ(2, child->getRefCnt());
+  EXPECT_EQ(2, parent->getRefCnt());
+}
+
+}  // namespace
+}  // namespace skia