Base ObserverList: Add basic support for standard C++ iterators.

base/observer_list_unittest.cc

Index: base/observer_list_unittest.cc
diff --git a/base/observer_list_unittest.cc b/base/observer_list_unittest.cc
index 097a2ed28b15490b3f1f36daca349aa199645858..e0f701167f5aa34d2b2079bf8d6b05730f071594 100644
--- a/base/observer_list_unittest.cc
+++ b/base/observer_list_unittest.cc
@@ -22,13 +22,17 @@ class Foo {
  public:
   virtual void Observe(int x) = 0;
   virtual ~Foo() {}
+  virtual int GetValue() const { return 0; }
 };
 
 class Adder : public Foo {
  public:
   explicit Adder(int scaler) : total(0), scaler_(scaler) {}
-  void Observe(int x) override { total += x * scaler_; }
   ~Adder() override {}
+
+  void Observe(int x) override { total += x * scaler_; }
+  int GetValue() const override { return total; }
+
   int total;
 
  private:
@@ -37,16 +41,28 @@ class Adder : public Foo {
 
 class Disrupter : public Foo {
  public:
+  Disrupter(ObserverList<Foo>* list, Foo* doomed, bool remove_self)
+      : list_(list), doomed_(doomed), remove_self_(remove_self) {}
   Disrupter(ObserverList<Foo>* list, Foo* doomed)
-      : list_(list),
-        doomed_(doomed) {
-  }
+      : Disrupter(list, doomed, false) {}
+  Disrupter(ObserverList<Foo>* list, bool remove_self)
+      : Disrupter(list, nullptr, remove_self) {}
+
   ~Disrupter() override {}
-  void Observe(int x) override { list_->RemoveObserver(doomed_); }
+
+  void Observe(int x) override {
+    if (remove_self_)
+      list_->RemoveObserver(this);
+    if (doomed_)
+      list_->RemoveObserver(doomed_);
+  }
+
+  void SetDoomed(Foo* doomed) { doomed_ = doomed; }
 
  private:
   ObserverList<Foo>* list_;
   Foo* doomed_;
+  bool remove_self_;
 };
 
 class ThreadSafeDisrupter : public Foo {
@@ -112,8 +128,6 @@ class AddRemoveThread : public PlatformThread::Delegate,
         FROM_HERE,
         base::Bind(&AddRemoveThread::AddTask, weak_factory_.GetWeakPtr()));
     RunLoop().Run();
-    //LOG(ERROR) << "Loop 0x" << std::hex << loop_ << " done. " <<
-    //    count_observes_ << ", " << count_addtask_;
     delete loop_;
     loop_ = reinterpret_cast<MessageLoop*>(0xdeadbeef);
     delete this;
@@ -176,6 +190,8 @@ class AddRemoveThread : public PlatformThread::Delegate,
   base::WeakPtrFactory<AddRemoveThread> weak_factory_;
 };
 
+}  // namespace
+
 TEST(ObserverListTest, BasicTest) {
   ObserverList<Foo> observer_list;
   Adder a(1), b(-1), c(1), d(-1), e(-1);
@@ -205,6 +221,48 @@ TEST(ObserverListTest, BasicTest) {
   EXPECT_EQ(0, e.total);
 }
 
+TEST(ObserverListTest, DisruptSelf) {
+  ObserverList<Foo> observer_list;
+  Adder a(1), b(-1), c(1), d(-1);
+  Disrupter evil(&observer_list, true);
+
+  observer_list.AddObserver(&a);
+  observer_list.AddObserver(&b);
+
+  FOR_EACH_OBSERVER(Foo, observer_list, Observe(10));
+
+  observer_list.AddObserver(&evil);
+  observer_list.AddObserver(&c);
+  observer_list.AddObserver(&d);
+
+  FOR_EACH_OBSERVER(Foo, observer_list, Observe(10));
+
+  EXPECT_EQ(20, a.total);
+  EXPECT_EQ(-20, b.total);
+  EXPECT_EQ(10, c.total);
+  EXPECT_EQ(-10, d.total);
+}
+
+TEST(ObserverListTest, DisruptBefore) {
+  ObserverList<Foo> observer_list;
+  Adder a(1), b(-1), c(1), d(-1);
+  Disrupter evil(&observer_list, &b);
+
+  observer_list.AddObserver(&a);
+  observer_list.AddObserver(&b);
+  observer_list.AddObserver(&evil);
+  observer_list.AddObserver(&c);
+  observer_list.AddObserver(&d);
+
+  FOR_EACH_OBSERVER(Foo, observer_list, Observe(10));
+  FOR_EACH_OBSERVER(Foo, observer_list, Observe(10));
+
+  EXPECT_EQ(20, a.total);
+  EXPECT_EQ(-10, b.total);
+  EXPECT_EQ(20, c.total);
+  EXPECT_EQ(-20, d.total);
+}
+
 TEST(ObserverListThreadSafeTest, BasicTest) {
   MessageLoop loop;
 
@@ -541,5 +599,266 @@ TEST(ObserverListTest, IteratorOutlivesList) {
   // of scope.
 }
 
-}  // namespace
+TEST(ObserverListTest, BasicStdIterator) {
+  using FooList = ObserverList<Foo>;
+  FooList observer_list;
+
+  // An optimization: begin() and end() do not involve weak pointers on
+  // empty list.
+  EXPECT_FALSE(observer_list.begin().list_);
+  EXPECT_FALSE(observer_list.end().list_);
+
+  // Iterate over empty list: no effect, no crash.
+  for (auto& i : observer_list)
+    i.Observe(10);
+
+  Adder a(1), b(-1), c(1), d(-1);
+
+  observer_list.AddObserver(&a);
+  observer_list.AddObserver(&b);
+  observer_list.AddObserver(&c);
+  observer_list.AddObserver(&d);
+
+  for (FooList::iterator i = observer_list.begin(), e = observer_list.end();
+       i != e; ++i)
+    i->Observe(1);
+
+  EXPECT_EQ(1, a.total);
+  EXPECT_EQ(-1, b.total);
+  EXPECT_EQ(1, c.total);
+  EXPECT_EQ(-1, d.total);
+
+  // Check an iteration over a 'const view' for a given container.
+  const FooList& const_list = observer_list;
+  for (FooList::const_iterator i = const_list.begin(), e = const_list.end();
+       i != e; ++i) {
+    EXPECT_EQ(1, std::abs(i->GetValue()));
+  }
+
+  for (const auto& o : const_list)
+    EXPECT_EQ(1, std::abs(o.GetValue()));
+}
+
+TEST(ObserverListTest, StdIteratorRemoveItself) {
+  ObserverList<Foo> observer_list;
+  Adder a(1), b(-1), c(1), d(-1);
+  Disrupter disrupter(&observer_list, true);
+
+  observer_list.AddObserver(&a);
+  observer_list.AddObserver(&b);
+  observer_list.AddObserver(&disrupter);
+  observer_list.AddObserver(&c);
+  observer_list.AddObserver(&d);
+
+  for (auto& o : observer_list)
+    o.Observe(1);
+
+  for (auto& o : observer_list)
+    o.Observe(10);
+
+  EXPECT_EQ(11, a.total);
+  EXPECT_EQ(-11, b.total);
+  EXPECT_EQ(11, c.total);
+  EXPECT_EQ(-11, d.total);
+}
+
+TEST(ObserverListTest, StdIteratorRemoveBefore) {
+  ObserverList<Foo> observer_list;
+  Adder a(1), b(-1), c(1), d(-1);
+  Disrupter disrupter(&observer_list, &b);
+
+  observer_list.AddObserver(&a);
+  observer_list.AddObserver(&b);
+  observer_list.AddObserver(&disrupter);
+  observer_list.AddObserver(&c);
+  observer_list.AddObserver(&d);
+
+  for (auto& o : observer_list)
+    o.Observe(1);
+
+  for (auto& o : observer_list)
+    o.Observe(10);
+
+  EXPECT_EQ(11, a.total);
+  EXPECT_EQ(-1, b.total);
+  EXPECT_EQ(11, c.total);
+  EXPECT_EQ(-11, d.total);
+}
+
+TEST(ObserverListTest, StdIteratorRemoveAfter) {
+  ObserverList<Foo> observer_list;
+  Adder a(1), b(-1), c(1), d(-1);
+  Disrupter disrupter(&observer_list, &c);
+
+  observer_list.AddObserver(&a);
+  observer_list.AddObserver(&b);
+  observer_list.AddObserver(&disrupter);
+  observer_list.AddObserver(&c);
+  observer_list.AddObserver(&d);
+
+  for (auto& o : observer_list)
+    o.Observe(1);
+
+  for (auto& o : observer_list)
+    o.Observe(10);
+
+  EXPECT_EQ(11, a.total);
+  EXPECT_EQ(-11, b.total);
+  EXPECT_EQ(0, c.total);
+  EXPECT_EQ(-11, d.total);
+}
+
+TEST(ObserverListTest, StdIteratorRemoveAfterFront) {
+  ObserverList<Foo> observer_list;
+  Adder a(1), b(-1), c(1), d(-1);
+  Disrupter disrupter(&observer_list, &a);
+
+  observer_list.AddObserver(&a);
+  observer_list.AddObserver(&disrupter);
+  observer_list.AddObserver(&b);
+  observer_list.AddObserver(&c);
+  observer_list.AddObserver(&d);
+
+  for (auto& o : observer_list)
+    o.Observe(1);
+
+  for (auto& o : observer_list)
+    o.Observe(10);
+
+  EXPECT_EQ(1, a.total);
+  EXPECT_EQ(-11, b.total);
+  EXPECT_EQ(11, c.total);
+  EXPECT_EQ(-11, d.total);
+}
+
+TEST(ObserverListTest, StdIteratorRemoveBeforeBack) {
+  ObserverList<Foo> observer_list;
+  Adder a(1), b(-1), c(1), d(-1);
+  Disrupter disrupter(&observer_list, &d);
+
+  observer_list.AddObserver(&a);
+  observer_list.AddObserver(&b);
+  observer_list.AddObserver(&c);
+  observer_list.AddObserver(&disrupter);
+  observer_list.AddObserver(&d);
+
+  for (auto& o : observer_list)
+    o.Observe(1);
+
+  for (auto& o : observer_list)
+    o.Observe(10);
+
+  EXPECT_EQ(11, a.total);
+  EXPECT_EQ(-11, b.total);
+  EXPECT_EQ(11, c.total);
+  EXPECT_EQ(0, d.total);
+}
+
+TEST(ObserverListTest, StdIteratorRemoveFront) {
+  using FooList = ObserverList<Foo>;
+  FooList observer_list;
+  Adder a(1), b(-1), c(1), d(-1);
+  Disrupter disrupter(&observer_list, true);
+
+  observer_list.AddObserver(&disrupter);
+  observer_list.AddObserver(&a);
+  observer_list.AddObserver(&b);
+  observer_list.AddObserver(&c);
+  observer_list.AddObserver(&d);
+
+  bool test_disruptor = true;
+  for (FooList::iterator i = observer_list.begin(), e = observer_list.end();
+       i != e; ++i) {
+    i->Observe(1);
+    // Check that second call to i->Observe() would crash here.
+    if (test_disruptor) {
+      EXPECT_FALSE(i.GetCurrent());
+      test_disruptor = false;
+    }
+  }
+
+  for (auto& o : observer_list)
+    o.Observe(10);
+
+  EXPECT_EQ(11, a.total);
+  EXPECT_EQ(-11, b.total);
+  EXPECT_EQ(11, c.total);
+  EXPECT_EQ(-11, d.total);
+}
+
+TEST(ObserverListTest, StdIteratorRemoveBack) {
+  ObserverList<Foo> observer_list;
+  Adder a(1), b(-1), c(1), d(-1);
+  Disrupter disrupter(&observer_list, true);
+
+  observer_list.AddObserver(&a);
+  observer_list.AddObserver(&b);
+  observer_list.AddObserver(&c);
+  observer_list.AddObserver(&d);
+  observer_list.AddObserver(&disrupter);
+
+  for (auto& o : observer_list)
+    o.Observe(1);
+
+  for (auto& o : observer_list)
+    o.Observe(10);
+
+  EXPECT_EQ(11, a.total);
+  EXPECT_EQ(-11, b.total);
+  EXPECT_EQ(11, c.total);
+  EXPECT_EQ(-11, d.total);
+}
+
+TEST(ObserverListTest, Multipass) {
+  ObserverList<Foo> observer_list;
+  Adder a(1), b(-1), c(1), d(-1);
+  Disrupter disrupter(&observer_list, true);
+
+  observer_list.AddObserver(&disrupter);
+  observer_list.AddObserver(&a);
+  observer_list.AddObserver(&b);
+  observer_list.AddObserver(&c);
+  observer_list.AddObserver(&d);
+
+  for (auto& o : observer_list) {
+    o.Observe(10);
+
+    for (auto& o : observer_list)
+      o.Observe(1);
+  }
+
+  EXPECT_EQ(15, a.total);
+  EXPECT_EQ(-15, b.total);
+  EXPECT_EQ(15, c.total);
+  EXPECT_EQ(-15, d.total);
+}
+
+TEST(ObserverListTest, NonCompactList) {
+  ObserverList<Foo> observer_list;
+  Adder a(1), b(-1);
+
+  Disrupter disrupter1(&observer_list, true);
+  Disrupter disrupter2(&observer_list, true);
+
+  // Disrupt itself and another guy.
+  disrupter1.SetDoomed(&disrupter2);
+
+  observer_list.AddObserver(&disrupter1);
+  observer_list.AddObserver(&disrupter2);
+  observer_list.AddObserver(&a);
+  observer_list.AddObserver(&b);
+
+  for (auto& o : observer_list) {
+    // Get the { nullptr, nullptr, &a, &b } non-compact list
+    // on the first inner pass.
+    o.Observe(10);
+
+    for (auto& o : observer_list)
+      o.Observe(1);
+  }
+
+  EXPECT_EQ(13, a.total);
+  EXPECT_EQ(-13, b.total);
+}
+
 }  // namespace base