base/cancelable_callback_unittest.cc

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/cancelable_callback.h"
   6
   7 #include <memory>
   8
   9 #include "base/bind.h"
  10 #include "base/bind_helpers.h"
  11 #include "base/location.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "base/run_loop.h"
  14 #include "base/single_thread_task_runner.h"
  15 #include "base/test/scoped_task_environment.h"
  16 #include "base/threading/thread_task_runner_handle.h"
  17 #include "testing/gtest/include/gtest/gtest.h"
  18
  19 namespace base {
  20 namespace {
  21
  22 class TestRefCounted : public RefCountedThreadSafe<TestRefCounted> {
  23  private:
  24   friend class RefCountedThreadSafe<TestRefCounted>;
  25   ~TestRefCounted() = default;
  26   ;
  27 };
  28
  29 void Increment(int* count) { (*count)++; }
  30 void IncrementBy(int* count, int n) { (*count) += n; }
  31 void RefCountedParam(const scoped_refptr<TestRefCounted>& ref_counted) {}
  32
  33 void OnMoveOnlyReceived(int* value, std::unique_ptr<int> result) {
  34   *value = *result;
  35 }
  36
  37 // Cancel().
  38 //  - Callback can be run multiple times.
  39 //  - After Cancel(), Run() completes but has no effect.
  40 TEST(CancelableCallbackTest, Cancel) {
  41   int count = 0;
  42   CancelableClosure cancelable(
  43       base::Bind(&Increment, base::Unretained(&count)));
  44
  45   base::Closure callback = cancelable.callback();
  46   callback.Run();
  47   EXPECT_EQ(1, count);
  48
  49   callback.Run();
  50   EXPECT_EQ(2, count);
  51
  52   cancelable.Cancel();
  53   callback.Run();
  54   EXPECT_EQ(2, count);
  55 }
  56
  57 // Cancel() called multiple times.
  58 //  - Cancel() cancels all copies of the wrapped callback.
  59 //  - Calling Cancel() more than once has no effect.
  60 //  - After Cancel(), callback() returns a null callback.
  61 TEST(CancelableCallbackTest, MultipleCancel) {
  62   int count = 0;
  63   CancelableClosure cancelable(
  64       base::Bind(&Increment, base::Unretained(&count)));
  65
  66   base::Closure callback1 = cancelable.callback();
  67   base::Closure callback2 = cancelable.callback();
  68   cancelable.Cancel();
  69
  70   callback1.Run();
  71   EXPECT_EQ(0, count);
  72
  73   callback2.Run();
  74   EXPECT_EQ(0, count);
  75
  76   // Calling Cancel() again has no effect.
  77   cancelable.Cancel();
  78
  79   // callback() of a cancelled callback is null.
  80   base::Closure callback3 = cancelable.callback();
  81   EXPECT_TRUE(callback3.is_null());
  82 }
  83
  84 // CancelableCallback destroyed before callback is run.
  85 //  - Destruction of CancelableCallback cancels outstanding callbacks.
  86 TEST(CancelableCallbackTest, CallbackCanceledOnDestruction) {
  87   int count = 0;
  88   base::Closure callback;
  89
  90   {
  91     CancelableClosure cancelable(
  92         base::Bind(&Increment, base::Unretained(&count)));
  93
  94     callback = cancelable.callback();
  95     callback.Run();
  96     EXPECT_EQ(1, count);
  97   }
  98
  99   callback.Run();
 100   EXPECT_EQ(1, count);
 101 }
 102
 103 // Cancel() called on bound closure with a RefCounted parameter.
 104 //  - Cancel drops wrapped callback (and, implicitly, its bound arguments).
 105 TEST(CancelableCallbackTest, CancelDropsCallback) {
 106   scoped_refptr<TestRefCounted> ref_counted = new TestRefCounted;
 107   EXPECT_TRUE(ref_counted->HasOneRef());
 108
 109   CancelableClosure cancelable(base::Bind(RefCountedParam, ref_counted));
 110   EXPECT_FALSE(cancelable.IsCancelled());
 111   EXPECT_TRUE(ref_counted.get());
 112   EXPECT_FALSE(ref_counted->HasOneRef());
 113
 114   // There is only one reference to |ref_counted| after the Cancel().
 115   cancelable.Cancel();
 116   EXPECT_TRUE(cancelable.IsCancelled());
 117   EXPECT_TRUE(ref_counted.get());
 118   EXPECT_TRUE(ref_counted->HasOneRef());
 119 }
 120
 121 // Reset().
 122 //  - Reset() replaces the existing wrapped callback with a new callback.
 123 //  - Reset() deactivates outstanding callbacks.
 124 TEST(CancelableCallbackTest, Reset) {
 125   int count = 0;
 126   CancelableClosure cancelable(
 127       base::Bind(&Increment, base::Unretained(&count)));
 128
 129   base::Closure callback = cancelable.callback();
 130   callback.Run();
 131   EXPECT_EQ(1, count);
 132
 133   callback.Run();
 134   EXPECT_EQ(2, count);
 135
 136   cancelable.Reset(
 137       base::Bind(&IncrementBy, base::Unretained(&count), 3));
 138   EXPECT_FALSE(cancelable.IsCancelled());
 139
 140   // The stale copy of the cancelable callback is non-null.
 141   ASSERT_FALSE(callback.is_null());
 142
 143   // The stale copy of the cancelable callback is no longer active.
 144   callback.Run();
 145   EXPECT_EQ(2, count);
 146
 147   base::Closure callback2 = cancelable.callback();
 148   ASSERT_FALSE(callback2.is_null());
 149
 150   callback2.Run();
 151   EXPECT_EQ(5, count);
 152 }
 153
 154 // IsCanceled().
 155 //  - Cancel() transforms the CancelableCallback into a cancelled state.
 156 TEST(CancelableCallbackTest, IsNull) {
 157   CancelableClosure cancelable;
 158   EXPECT_TRUE(cancelable.IsCancelled());
 159
 160   int count = 0;
 161   cancelable.Reset(base::Bind(&Increment,
 162                               base::Unretained(&count)));
 163   EXPECT_FALSE(cancelable.IsCancelled());
 164
 165   cancelable.Cancel();
 166   EXPECT_TRUE(cancelable.IsCancelled());
 167 }
 168
 169 // CancelableCallback posted to a task environment with PostTask.
 170 //  - Posted callbacks can be cancelled.
 171 TEST(CancelableCallbackTest, PostTask) {
 172   test::ScopedTaskEnvironment scoped_task_environment;
 173
 174   int count = 0;
 175   CancelableClosure cancelable(base::Bind(&Increment,
 176                                            base::Unretained(&count)));
 177
 178   ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE, cancelable.callback());
 179   RunLoop().RunUntilIdle();
 180
 181   EXPECT_EQ(1, count);
 182
 183   ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE, cancelable.callback());
 184
 185   // Cancel before running the tasks.
 186   cancelable.Cancel();
 187   RunLoop().RunUntilIdle();
 188
 189   // Callback never ran due to cancellation; count is the same.
 190   EXPECT_EQ(1, count);
 191 }
 192
 193 // CancelableCallback can be used with move-only types.
 194 TEST(CancelableCallbackTest, MoveOnlyType) {
 195   const int kExpectedResult = 42;
 196
 197   int result = 0;
 198   CancelableCallback<void(std::unique_ptr<int>)> cb(
 199       base::Bind(&OnMoveOnlyReceived, base::Unretained(&result)));
 200   cb.callback().Run(std::make_unique<int>(kExpectedResult));
 201
 202   EXPECT_EQ(kExpectedResult, result);
 203 }
 204
 205 }  // namespace
 206 }  // namespace base