Add support for WeakPtr<T>

webrtc/base/weak_ptr_unittest.cc

+/*
+ *  Copyright 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 <string>
+
+#include "webrtc/base/gunit.h"
+#include "webrtc/base/task_queue.h"
+#include "webrtc/base/weak_ptr.h"
+
+namespace rtc {
+
+namespace {
+
+struct Base {
+  std::string member;
+};
+struct Derived : public Base {};
+
+struct Target {};
+
+struct Arrow {
+  WeakPtr<Target> target;
+};
+
+struct TargetWithFactory : public Target {
+  TargetWithFactory() : factory(this) {}
+  WeakPtrFactory<Target> factory;
+};
+
+}  // namespace
+
+TEST(WeakPtrFactoryTest, Basic) {
+  int data;
+  WeakPtrFactory<int> factory(&data);
+  WeakPtr<int> ptr = factory.GetWeakPtr();
+  EXPECT_EQ(&data, ptr.get());
+}
+
+TEST(WeakPtrFactoryTest, Comparison) {
+  int data;
+  WeakPtrFactory<int> factory(&data);
+  WeakPtr<int> ptr = factory.GetWeakPtr();
+  WeakPtr<int> ptr2 = ptr;
+  EXPECT_EQ(ptr.get(), ptr2.get());
+}
+
+TEST(WeakPtrFactoryTest, Move) {
+  int data;
+  WeakPtrFactory<int> factory(&data);
+  WeakPtr<int> ptr = factory.GetWeakPtr();
+  WeakPtr<int> ptr2 = factory.GetWeakPtr();
+  WeakPtr<int> ptr3 = std::move(ptr2);
+  EXPECT_NE(ptr.get(), ptr2.get());
+  EXPECT_EQ(ptr.get(), ptr3.get());
+}
+
+TEST(WeakPtrFactoryTest, OutOfScope) {
+  WeakPtr<int> ptr;
+  EXPECT_EQ(nullptr, ptr.get());
+  {
+    int data;
+    WeakPtrFactory<int> factory(&data);
+    ptr = factory.GetWeakPtr();
+    EXPECT_EQ(&data, ptr.get());
+  }
+  EXPECT_EQ(nullptr, ptr.get());
+}
+
+TEST(WeakPtrFactoryTest, Multiple) {
+  WeakPtr<int> a, b;
+  {
+    int data;
+    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(WeakPtrFactoryTest, MultipleStaged) {
+  WeakPtr<int> a;
+  {
+    int data;
+    WeakPtrFactory<int> factory(&data);
+    a = factory.GetWeakPtr();
+    { WeakPtr<int> b = factory.GetWeakPtr(); }
+    EXPECT_NE(nullptr, a.get());
+  }
+  EXPECT_EQ(nullptr, a.get());
+}
+
+TEST(WeakPtrFactoryTest, 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(WeakPtrFactoryTest, UpCast) {
+  Derived data;
+  WeakPtrFactory<Derived> factory(&data);
+  WeakPtr<Base> ptr = factory.GetWeakPtr();
+  ptr = factory.GetWeakPtr();
+  EXPECT_EQ(ptr.get(), &data);
+}
+
+TEST(WeakPtrTest, DefaultConstructor) {
+  WeakPtr<int> ptr;
+  EXPECT_EQ(nullptr, ptr.get());
+}
+
+TEST(WeakPtrFactoryTest, BooleanTesting) {
+  int data;
+  WeakPtrFactory<int> factory(&data);
+
+  WeakPtr<int> ptr_to_an_instance = factory.GetWeakPtr();
+  EXPECT_TRUE(ptr_to_an_instance);
+  EXPECT_FALSE(!ptr_to_an_instance);
+
+  if (ptr_to_an_instance) {
+  } else {
+    ADD_FAILURE() << "Pointer to an instance should result in true.";
+  }
+
+  if (!ptr_to_an_instance) {  // check for operator!().
+    ADD_FAILURE() << "Pointer to an instance should result in !x being false.";
+  }
+
+  WeakPtr<int> null_ptr;
+  EXPECT_FALSE(null_ptr);
+  EXPECT_TRUE(!null_ptr);
+
+  if (null_ptr) {
+    ADD_FAILURE() << "Null pointer should result in false.";
+  }
+
+  if (!null_ptr) {  // check for operator!().
+  } else {
+    ADD_FAILURE() << "Null pointer should result in !x being true.";
+  }
+}
+
+TEST(WeakPtrFactoryTest, ComparisonToNull) {
+  int data;
+  WeakPtrFactory<int> factory(&data);
+
+  WeakPtr<int> ptr_to_an_instance = factory.GetWeakPtr();
+  EXPECT_NE(nullptr, ptr_to_an_instance);
+  EXPECT_NE(ptr_to_an_instance, nullptr);
+
+  WeakPtr<int> null_ptr;
+  EXPECT_EQ(null_ptr, nullptr);
+  EXPECT_EQ(nullptr, null_ptr);
+}
+
+TEST(WeakPtrTest, InvalidateWeakPtrs) {
+  int data;
+  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 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;
+  WeakPtrFactory<int> factory(&data);
+  {
+    WeakPtr<int> ptr = factory.GetWeakPtr();
+    EXPECT_TRUE(factory.HasWeakPtrs());
+  }
+  EXPECT_FALSE(factory.HasWeakPtrs());
+}
+
+template <class T>
+std::unique_ptr<T> NewObjectCreatedOnTaskQueue() {
+  std::unique_ptr<T> obj;
+  TaskQueue queue("NewObjectCreatedOnTaskQueue");
+  Event event(false, false);
+  queue.PostTask([&event, &obj] {
+    obj.reset(new T());
+    event.Set();
+  });
+  EXPECT_TRUE(event.Wait(1000));
+  return obj;
+}
+
+TEST(WeakPtrTest, ObjectAndWeakPtrOnDifferentThreads) {
+  // Test that it is OK to create an object with a WeakPtrFactory one thread,
+  // but use it on another.  This tests that we do not trip runtime checks that
+  // ensure that a WeakPtr is not used by multiple threads.
+  std::unique_ptr<TargetWithFactory> target(
+      NewObjectCreatedOnTaskQueue<TargetWithFactory>());
+  WeakPtr<Target> weak_ptr = target->factory.GetWeakPtr();
+  EXPECT_EQ(target.get(), weak_ptr.get());
+}
+
+TEST(WeakPtrTest, WeakPtrInitiateAndUseOnDifferentThreads) {
+  // Test that it is OK to create an object that has a WeakPtr member on one
+  // thread, but use it on another.  This tests that we do not trip runtime
+  // checks that ensure that a WeakPtr is not used by multiple threads.
+  std::unique_ptr<Arrow> arrow(NewObjectCreatedOnTaskQueue<Arrow>());
+  TargetWithFactory target;
+  arrow->target = target.factory.GetWeakPtr();
+  EXPECT_EQ(&target, arrow->target.get());
+}
+
+}  // namespace rtc