Bring in a reduced/simplified version of Chromium's base::WeakPtr to //mojo/edk/util.

mojo/edk/util/weak_ptr_unittest.cc

+// Copyright 2016 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 "mojo/edk/util/weak_ptr.h"
+
+#include <utility>
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace mojo {
+namespace util {
+namespace {
+
+TEST(WeakPtrTest, Basic) {
+  int data = 0;
+  WeakPtrFactory<int> factory(&data);
+  WeakPtr<int> ptr = factory.GetWeakPtr();
+  EXPECT_EQ(&data, ptr.get());
+}
+
+TEST(WeakPtrTest, CopyConstruction) {
+  int data = 0;
+  WeakPtrFactory<int> factory(&data);
+  WeakPtr<int> ptr = factory.GetWeakPtr();
+  WeakPtr<int> ptr2(ptr);
+  EXPECT_EQ(&data, ptr.get());
+  EXPECT_EQ(&data, ptr2.get());
+}
+
+TEST(WeakPtrTest, MoveConstruction) {
+  int data = 0;
+  WeakPtrFactory<int> factory(&data);
+  WeakPtr<int> ptr = factory.GetWeakPtr();
+  WeakPtr<int> ptr2(std::move(ptr));
+  EXPECT_EQ(nullptr, ptr.get());
+  EXPECT_EQ(&data, ptr2.get());
+}
+
+TEST(WeakPtrTest, CopyAssignment) {
+  int data = 0;
+  WeakPtrFactory<int> factory(&data);
+  WeakPtr<int> ptr = factory.GetWeakPtr();
+  WeakPtr<int> ptr2;
+  EXPECT_EQ(nullptr, ptr2.get());
+  ptr2 = ptr;
+  EXPECT_EQ(&data, ptr.get());
+  EXPECT_EQ(&data, ptr2.get());
+}
+
+TEST(WeakPtrTest, MoveAssignment) {
+  int data = 0;
+  WeakPtrFactory<int> factory(&data);
+  WeakPtr<int> ptr = factory.GetWeakPtr();
+  WeakPtr<int> ptr2;
+  EXPECT_EQ(nullptr, ptr2.get());
+  ptr2 = std::move(ptr);
+  EXPECT_EQ(nullptr, ptr.get());
+  EXPECT_EQ(&data, ptr2.get());
+}
+
+TEST(WeakPtrTest, Testable) {
+  int data = 0;
+  WeakPtrFactory<int> factory(&data);
+  WeakPtr<int> ptr;
+  EXPECT_EQ(nullptr, ptr.get());
+  EXPECT_FALSE(ptr);
+  ptr = factory.GetWeakPtr();
+  EXPECT_EQ(&data, ptr.get());
+  EXPECT_TRUE(ptr);
+}
+
+TEST(WeakPtrTest, OutOfScope) {
+  WeakPtr<int> ptr;
+  EXPECT_EQ(nullptr, ptr.get());
+  {
+    int data = 0;
+    WeakPtrFactory<int> factory(&data);
+    ptr = factory.GetWeakPtr();
+  }
+  EXPECT_EQ(nullptr, ptr.get());
+}
+
+TEST(WeakPtrTest, Multiple) {
+  WeakPtr<int> a;
+  WeakPtr<int> b;
+  {
+    int data = 0;
+    WeakPtrFactory<int> factory(&data);
+    a = factory.GetWeakPtr();
+    b = factory.GetWeakPtr();
+    EXPECT_EQ(&data, a.get());
+    EXPECT_EQ(&data, b.get());
+  }
+  EXPECT_EQ(nullptr, a.get());
+  EXPECT_EQ(nullptr, b.get());
+}
+
+TEST(WeakPtrTest, MultipleStaged) {
+  WeakPtr<int> a;
+  {
+    int data = 0;
+    WeakPtrFactory<int> factory(&data);
+    a = factory.GetWeakPtr();
+    { WeakPtr<int> b = factory.GetWeakPtr(); }
+    EXPECT_NE(a.get(), nullptr);
+  }
+  EXPECT_EQ(nullptr, a.get());
+}
+
+struct Base {
+  double member = 0.;
+};
+struct Derived : public Base {};
+
+TEST(WeakPtrTest, Dereference) {
+  Base data;
+  data.member = 123456.;
+  WeakPtrFactory<Base> factory(&data);
+  WeakPtr<Base> ptr = factory.GetWeakPtr();
+  EXPECT_EQ(&data, ptr.get());
+  EXPECT_EQ(data.member, (*ptr).member);
+  EXPECT_EQ(data.member, ptr->member);
+}
+
+TEST(WeakPtrTest, UpcastCopyConstruction) {
+  Derived data;
+  WeakPtrFactory<Derived> factory(&data);
+  WeakPtr<Derived> ptr = factory.GetWeakPtr();
+  WeakPtr<Base> ptr2(ptr);
+  EXPECT_EQ(&data, ptr.get());
+  EXPECT_EQ(&data, ptr2.get());
+}
+
+TEST(WeakPtrTest, UpcastMoveConstruction) {
+  Derived data;
+  WeakPtrFactory<Derived> factory(&data);
+  WeakPtr<Derived> ptr = factory.GetWeakPtr();
+  WeakPtr<Base> ptr2(std::move(ptr));
+  EXPECT_EQ(nullptr, ptr.get());
+  EXPECT_EQ(&data, ptr2.get());
+}
+
+TEST(WeakPtrTest, UpcastCopyAssignment) {
+  Derived data;
+  WeakPtrFactory<Derived> factory(&data);
+  WeakPtr<Derived> ptr = factory.GetWeakPtr();
+  WeakPtr<Base> ptr2;
+  EXPECT_EQ(nullptr, ptr2.get());
+  ptr2 = ptr;
+  EXPECT_EQ(&data, ptr.get());
+  EXPECT_EQ(&data, ptr2.get());
+}
+
+TEST(WeakPtrTest, UpcastMoveAssignment) {
+  Derived data;
+  WeakPtrFactory<Derived> factory(&data);
+  WeakPtr<Derived> ptr = factory.GetWeakPtr();
+  WeakPtr<Base> ptr2;
+  EXPECT_EQ(nullptr, ptr2.get());
+  ptr2 = std::move(ptr);
+  EXPECT_EQ(nullptr, ptr.get());
+  EXPECT_EQ(&data, ptr2.get());
+}
+
+TEST(WeakPtrTest, InvalidateWeakPtrs) {
+  int data = 0;
+  WeakPtrFactory<int> factory(&data);
+  WeakPtr<int> ptr = factory.GetWeakPtr();
+  EXPECT_EQ(&data, ptr.get());
+  EXPECT_TRUE(factory.HasWeakPtrs());
+  factory.InvalidateWeakPtrs();
+  EXPECT_EQ(nullptr, ptr.get());
+  EXPECT_FALSE(factory.HasWeakPtrs());
+
+  // Test that the factory can create new weak pointers after a
+  // |InvalidateWeakPtrs()| call, and that they remain valid until the next
+  // |InvalidateWeakPtrs()| call.
+  WeakPtr<int> ptr2 = factory.GetWeakPtr();
+  EXPECT_EQ(&data, ptr2.get());
+  EXPECT_TRUE(factory.HasWeakPtrs());
+  factory.InvalidateWeakPtrs();
+  EXPECT_EQ(nullptr, ptr2.get());
+  EXPECT_FALSE(factory.HasWeakPtrs());
+}
+
+TEST(WeakPtrTest, HasWeakPtrs) {
+  int data = 0;
+  WeakPtrFactory<int> factory(&data);
+  {
+    WeakPtr<int> ptr = factory.GetWeakPtr();
+    EXPECT_TRUE(factory.HasWeakPtrs());
+  }
+  EXPECT_FALSE(factory.HasWeakPtrs());
+}
+
+// TODO(vtl): Copy/convert the various threaded tests from Chromium's
+// //base/memory/weak_ptr_unittest.cc.
+
+}  // namespace
+}  // namespace util
+}  // namespace mojo