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// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/cancelable_callback.h"
#include <memory>
#include "base/functional/bind.h"
#include "base/functional/callback_helpers.h"
#include "base/location.h"
#include "base/memory/ref_counted.h"
#include "base/run_loop.h"
#include "base/task/single_thread_task_runner.h"
#include "base/test/task_environment.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
namespace {
class TestRefCounted : public RefCountedThreadSafe<TestRefCounted> {
private:
friend class RefCountedThreadSafe<TestRefCounted>;
~TestRefCounted() = default;
};
void Increment(int* count) { (*count)++; }
void IncrementBy(int* count, int n) { (*count) += n; }
void RefCountedParam(const scoped_refptr<TestRefCounted>& ref_counted) {}
void OnMoveOnlyReceived(int* value, std::unique_ptr<int> result) {
*value = *result;
}
// Cancel().
// - Callback can be run multiple times.
// - After Cancel(), Run() completes but has no effect.
TEST(CancelableCallbackTest, Cancel) {
int count = 0;
CancelableRepeatingClosure cancelable(
base::BindRepeating(&Increment, base::Unretained(&count)));
base::RepeatingClosure callback = cancelable.callback();
callback.Run();
EXPECT_EQ(1, count);
callback.Run();
EXPECT_EQ(2, count);
cancelable.Cancel();
callback.Run();
EXPECT_EQ(2, count);
}
// Cancel() called multiple times.
// - Cancel() cancels all copies of the wrapped callback.
// - Calling Cancel() more than once has no effect.
// - After Cancel(), callback() returns a null callback.
TEST(CancelableCallbackTest, MultipleCancel) {
int count = 0;
CancelableRepeatingClosure cancelable(
base::BindRepeating(&Increment, base::Unretained(&count)));
base::RepeatingClosure callback1 = cancelable.callback();
base::RepeatingClosure callback2 = cancelable.callback();
cancelable.Cancel();
callback1.Run();
EXPECT_EQ(0, count);
callback2.Run();
EXPECT_EQ(0, count);
// Calling Cancel() again has no effect.
cancelable.Cancel();
// callback() of a cancelled callback is null.
base::RepeatingClosure callback3 = cancelable.callback();
EXPECT_TRUE(callback3.is_null());
}
// CancelableRepeatingCallback destroyed before callback is run.
// - Destruction of CancelableRepeatingCallback cancels outstanding callbacks.
TEST(CancelableCallbackTest, CallbackCanceledOnDestruction) {
int count = 0;
base::RepeatingClosure callback;
{
CancelableRepeatingClosure cancelable(
base::BindRepeating(&Increment, base::Unretained(&count)));
callback = cancelable.callback();
callback.Run();
EXPECT_EQ(1, count);
}
callback.Run();
EXPECT_EQ(1, count);
}
// Cancel() called on bound closure with a RefCounted parameter.
// - Cancel drops wrapped callback (and, implicitly, its bound arguments).
TEST(CancelableCallbackTest, CancelDropsCallback) {
scoped_refptr<TestRefCounted> ref_counted = new TestRefCounted;
EXPECT_TRUE(ref_counted->HasOneRef());
CancelableOnceClosure cancelable(
base::BindOnce(RefCountedParam, ref_counted));
EXPECT_FALSE(cancelable.IsCancelled());
EXPECT_TRUE(ref_counted.get());
EXPECT_FALSE(ref_counted->HasOneRef());
// There is only one reference to |ref_counted| after the Cancel().
cancelable.Cancel();
EXPECT_TRUE(cancelable.IsCancelled());
EXPECT_TRUE(ref_counted.get());
EXPECT_TRUE(ref_counted->HasOneRef());
}
// Reset().
// - Reset() replaces the existing wrapped callback with a new callback.
// - Reset() deactivates outstanding callbacks.
TEST(CancelableCallbackTest, Reset) {
int count = 0;
CancelableRepeatingClosure cancelable(
base::BindRepeating(&Increment, base::Unretained(&count)));
base::RepeatingClosure callback = cancelable.callback();
callback.Run();
EXPECT_EQ(1, count);
callback.Run();
EXPECT_EQ(2, count);
cancelable.Reset(
base::BindRepeating(&IncrementBy, base::Unretained(&count), 3));
EXPECT_FALSE(cancelable.IsCancelled());
// The stale copy of the cancelable callback is non-null.
ASSERT_FALSE(callback.is_null());
// The stale copy of the cancelable callback is no longer active.
callback.Run();
EXPECT_EQ(2, count);
base::RepeatingClosure callback2 = cancelable.callback();
ASSERT_FALSE(callback2.is_null());
callback2.Run();
EXPECT_EQ(5, count);
}
// IsCanceled().
// - Cancel() transforms the CancelableOnceCallback into a cancelled state.
TEST(CancelableCallbackTest, IsNull) {
CancelableOnceClosure cancelable;
EXPECT_TRUE(cancelable.IsCancelled());
int count = 0;
cancelable.Reset(base::BindOnce(&Increment, base::Unretained(&count)));
EXPECT_FALSE(cancelable.IsCancelled());
cancelable.Cancel();
EXPECT_TRUE(cancelable.IsCancelled());
}
// CancelableRepeatingCallback posted to a task environment with PostTask.
// - Posted callbacks can be cancelled.
TEST(CancelableCallbackTest, PostTask) {
test::TaskEnvironment task_environment;
int count = 0;
CancelableRepeatingClosure cancelable(
base::BindRepeating(&Increment, base::Unretained(&count)));
SingleThreadTaskRunner::GetCurrentDefault()->PostTask(FROM_HERE,
cancelable.callback());
RunLoop().RunUntilIdle();
EXPECT_EQ(1, count);
SingleThreadTaskRunner::GetCurrentDefault()->PostTask(FROM_HERE,
cancelable.callback());
// Cancel before running the tasks.
cancelable.Cancel();
RunLoop().RunUntilIdle();
// Callback never ran due to cancellation; count is the same.
EXPECT_EQ(1, count);
}
// CancelableRepeatingCallback can be used with move-only types.
TEST(CancelableCallbackTest, MoveOnlyType) {
const int kExpectedResult = 42;
int result = 0;
CancelableRepeatingCallback<void(std::unique_ptr<int>)> cb(
base::BindRepeating(&OnMoveOnlyReceived, base::Unretained(&result)));
cb.callback().Run(std::make_unique<int>(kExpectedResult));
EXPECT_EQ(kExpectedResult, result);
}
} // namespace
} // namespace base
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