Add a CallbackRegistry class to base/ to manage callbacks

base/callback_list_unittest.cc

+// Copyright 2013 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 "base/callback_list.h"
+
+#include <vector>
+
+#include "base/bind_helpers.h"
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace {
+
+class Listener {
+ public:
+  Listener() : total_(0), scaler_(1) {}
+  explicit Listener(int scaler) : total_(0), scaler_(scaler) {}
+  void IncrementTotal() { total_++; }
+  void MultiplyTotal(const int& x) { total_ += x * scaler_; }
+
+  int total_;
+ private:
+  int scaler_;
+  DISALLOW_COPY_AND_ASSIGN(Listener);
+};
+
+class Remover {
+ public:
+  Remover() : total_(0), removal_cb_(base::Closure()) {}
+  void IncrementTotalAndRemove() {
+    total_++;
+    removal_cb_.Run();
+  }
+  void SetCallback(const base::Closure& cb) { removal_cb_ = cb; }
+
+  int total_;
+ private:
+  base::Closure removal_cb_;
+  DISALLOW_COPY_AND_ASSIGN(Remover);
+};
+
+class Adder {
+ public:
+  explicit Adder(CallbackList<void>* cb_list)
+      : added_(false),
+        total_(0),
+        cb_list_(cb_list) {}
+  void AddCallback() {
+    if (!added_) {
+      added_ = true;
+      cb_list_->Add(
+          base::Bind(&Adder::IncrementTotal, base::Unretained(this)));
+    }
+  }
+  void IncrementTotal() { total_++; }
+
+  bool added_;
+  int total_;
+ private:
+  CallbackList<void>* cb_list_;
+  DISALLOW_COPY_AND_ASSIGN(Adder);
+};
+
+class Clearer {
+ public:
+  explicit Clearer(CallbackList<void>* cb_list)
+      : added_(false),
+        total_(0),
+        cb_list_(cb_list) {}
+  void ClearListAndAddCallback() {
+    cb_list_->Clear();
+    cb_list_->Add(
+        base::Bind(&Clearer::IncrementTotal, base::Unretained(this)));
+    added_ = true;
+  }
+  void IncrementTotal() { total_++; }
+
+  bool added_;
+  int total_;
+ private:
+  CallbackList<void>* cb_list_;
+  DISALLOW_COPY_AND_ASSIGN(Clearer);
+};
+
+// Sanity check that closures added to the list will be run, and those removed
+// from the list will not be run.
+TEST(CallbackListTest, BasicTest) {
+  CallbackList<void> cb_list;
+  Listener a, b, c;
+
+  base::Closure remove_a = cb_list.Add(
+      base::Bind(&Listener::IncrementTotal, base::Unretained(&a)));
+  base::Closure remove_b = cb_list.Add(
+      base::Bind(&Listener::IncrementTotal, base::Unretained(&b)));
+
+  EXPECT_FALSE(remove_a.is_null());
+  EXPECT_FALSE(remove_b.is_null());
+
+  cb_list.Run();
+
+  EXPECT_EQ(1, a.total_);
+  EXPECT_EQ(1, b.total_);
+
+  remove_b.Run();
+
+  base::Closure remove_c = cb_list.Add(
+      base::Bind(&Listener::IncrementTotal, base::Unretained(&c)));
+
+  cb_list.Run();
+
+  EXPECT_EQ(2, a.total_);
+  EXPECT_EQ(1, b.total_);
+  EXPECT_EQ(1, c.total_);
+
+  remove_a.Run();
+  remove_b.Run();
+  remove_c.Run();
+}
+
+// Sanity check that callbacks with details added to the list will be run, with
+// the correct details, and those removed from the list will not be run.
+TEST(CallbackListTest, BasicTestWithParams) {
+  CallbackList<int> cb_list;
+  Listener a(1), b(-1), c(1);
+
+  base::Closure remove_a = cb_list.Add(
+      base::Bind(&Listener::MultiplyTotal, base::Unretained(&a)));
+  base::Closure remove_b = cb_list.Add(
+      base::Bind(&Listener::MultiplyTotal, base::Unretained(&b)));
+
+  EXPECT_FALSE(remove_a.is_null());
+  EXPECT_FALSE(remove_b.is_null());
+
+  cb_list.Run(10);
+
+  EXPECT_EQ(10, a.total_);
+  EXPECT_EQ(-10, b.total_);
+
+  remove_b.Run();
+
+  base::Closure remove_c = cb_list.Add(
+      base::Bind(&Listener::MultiplyTotal, base::Unretained(&c)));
+
+  cb_list.Run(10);
+
+  EXPECT_EQ(20, a.total_);
+  EXPECT_EQ(-10, b.total_);
+  EXPECT_EQ(10, c.total_);
+
+  remove_a.Run();
+  remove_b.Run();
+  remove_c.Run();
+}
+
+// Test the a callback can remove itself or a different callback from the list
+// during iteration without invalidating the iterator.
+TEST(CallbackListTest, RemoveCallbacksDuringIteration) {
+  CallbackList<void> cb_list;
+  Listener a, b;
+  Remover remover_1, remover_2;
+
+  base::Closure remover_1_cb = cb_list.Add(
+      base::Bind(&Remover::IncrementTotalAndRemove,
+          base::Unretained(&remover_1)));
+  base::Closure remover_2_cb = cb_list.Add(
+      base::Bind(&Remover::IncrementTotalAndRemove,
+          base::Unretained(&remover_2)));
+  base::Closure a_cb = cb_list.Add(
+      base::Bind(&Listener::IncrementTotal, base::Unretained(&a)));
+  base::Closure b_cb = cb_list.Add(
+      base::Bind(&Listener::IncrementTotal, base::Unretained(&b)));
+
+  // |remover_1| will remove itself.
+  remover_1.SetCallback(remover_1_cb);
+  // |remover_2| will remove a.
+  remover_2.SetCallback(a_cb);
+
+  cb_list.Run();
+
+  // |remover_1| runs once (and removes itself), |remover_2| runs once (and
+  // removes a), |a| never runs, and |b| runs once.
+  EXPECT_EQ(1, remover_1.total_);
+  EXPECT_EQ(1, remover_2.total_);
+  EXPECT_EQ(0, a.total_);
+  EXPECT_EQ(1, b.total_);
+
+  cb_list.Run();
+
+  // Only |remover_2| and |b| run this time.
+  EXPECT_EQ(1, remover_1.total_);
+  EXPECT_EQ(2, remover_2.total_);
+  EXPECT_EQ(0, a.total_);
+  EXPECT_EQ(2, b.total_);
+}
+
+// Test that a callback can add another callback to the list durning iteration
+// without invalidating the iterator.
+// - If the CallbackNotificationType is |CALLBACKS_NOTIFY_ALL|, the newly added
+//   callback will be run on the current iteration.
+// - All other callbacks in the list will be run as well.
+TEST(CallbackListTest, AddCallbacksDuringIteration) {
+  CallbackList<void> cb_list;
+  Adder a(&cb_list);
+  Listener b;
+  cb_list.Add(
+      base::Bind(&Adder::AddCallback, base::Unretained(&a)));
+  cb_list.Add(
+      base::Bind(&Listener::IncrementTotal, base::Unretained(&b)));
+
+  cb_list.Run();
+
+  EXPECT_EQ(1, a.total_);
+  EXPECT_EQ(1, b.total_);
+  EXPECT_TRUE(a.added_);
+
+  cb_list.Run();
+
+  EXPECT_EQ(2, a.total_);
+  EXPECT_EQ(2, b.total_);
+}
+
+
+// Test that if we clear the list during iteration, no callbacks are run after
+// the one that did the clearing.
+TEST(CallbackListTest, ClearCallbacksDuringIteration) {
+  CallbackList<void> cb_list;
+  Clearer a(&cb_list);
+  Listener b;
+  cb_list.Add(
+      base::Bind(&Clearer::ClearListAndAddCallback, base::Unretained(&a)));
+  cb_list.Add(
+      base::Bind(&Listener::IncrementTotal, base::Unretained(&b)));
+
+  cb_list.Run();
+
+  EXPECT_EQ(1, a.total_);
+  // |b| never runs because we cleared the list first.
+  EXPECT_EQ(0, b.total_);
+  EXPECT_TRUE(a.added_);
+}
+
+// Test that if the iterator outlives the list (that is, for some reason or
+// we delete the list mid-iteration) then:
+// - no callbacks run after deletion.
+// - the list is cleaned up properly (there will be memory errors if this is not
+//   the case).
+TEST(CallbackListTest, IteratorOutlivesList) {
+  CallbackList<void>* cl = new CallbackList<void>();
+
+  cl->Add(Bind(&DeletePointer<CallbackList<void> >, cl));
+  cl->Add(Bind(&CallbackList<void>::Clear, Unretained(cl)));
+  Listener a;
+  cl->Add(Bind(&Listener::IncrementTotal, base::Unretained(&a)));
+
+  cl->Run();
+
+  // |a| never gets called, as |cb_list| got deleted first.
+  EXPECT_EQ(0, a.total_);
+}
+
+}  // namespace
+}  // namespace base