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