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#include <library/cpp/testing/gtest/gtest.h>
#include <library/cpp/yt/memory/function_view.h>
#include <util/generic/string.h>
#include <util/string/cast.h>
namespace NYT {
namespace {
////////////////////////////////////////////////////////////////////////////////
struct TNoCopy
{
int Value = 42;
TNoCopy() = default;
TNoCopy(const TNoCopy&) = delete;
TNoCopy(TNoCopy&&)
{ }
};
int Foo()
{
return 42;
}
int& Bar()
{
static int bar = 0;
return bar;
}
const TNoCopy& ImmutBar()
{
static TNoCopy bar = {};
return bar;
}
TString Baz(const int& x)
{
return ToString(x);
}
void NoExFoo() noexcept
{ }
struct TCallable
{
int InvocationCount = 0;
mutable int ConstInvocationCount = 0;
void operator()() &
{
++InvocationCount;
}
void operator()() const &
{
++ConstInvocationCount;
}
};
////////////////////////////////////////////////////////////////////////////////
TEST(TFunctionViewTest, JustWorks)
{
auto stackLambda = [] (int val) {
return val + 1;
};
{
TFunctionView<int(int)> view(stackLambda);
EXPECT_EQ(view(42), 43);
}
}
TEST(TFunctionViewTest, FreeFunction)
{
TFunctionView<int()> view(Foo);
EXPECT_EQ(view(), 42);
}
TEST(TFunctionViewTest, RefReturn)
{
TFunctionView<int&()> view(Bar);
++view();
EXPECT_EQ(view(), 1);
TFunctionView<const TNoCopy&()> immut_view(ImmutBar);
EXPECT_EQ(immut_view().Value, 42);
}
TEST(TFunctionViewTest, RefArgument)
{
TFunctionView<TString(const int&)> view(Baz);
EXPECT_EQ(view(77), TString("77"));
}
TEST(TFunctionViewTest, NoExcept)
{
TFunctionView<void() noexcept> view(NoExFoo);
static_assert(std::is_nothrow_invocable_r_v<void, decltype(view)>);
view();
}
TEST(TFunctionViewTest, CVOverloads)
{
TCallable callable;
TFunctionView<void()> view(callable);
// NB: & overload overshadows every other overload.
// const auto& viewRef = view;
// viewRef();
view();
EXPECT_EQ(callable.InvocationCount, 1);
EXPECT_EQ(callable.ConstInvocationCount, 0);
}
TEST(TFunctionViewTest, CopyView)
{
int counter = 0;
auto lambda = [&counter] {
++counter;
};
TFunctionView<void()> view1(lambda);
TFunctionView<void()> view2 = view1;
view1();
EXPECT_EQ(counter, 1);
view2();
EXPECT_EQ(counter, 2);
view1();
EXPECT_EQ(counter, 3);
}
TEST(TFunctionViewTest, AssignView)
{
int counter = 0;
auto lambda = [&counter] {
++counter;
};
TFunctionView<void()> view(lambda);
view();
EXPECT_EQ(counter, 1);
{
auto innerCounter = 0;
auto lambda = [&innerCounter] {
++innerCounter;
};
view = lambda;
view();
EXPECT_EQ(counter, 1);
EXPECT_EQ(innerCounter, 1);
}
// NB: Even though object is dead view will remain "valid".
// Be careful with lifetimes!
EXPECT_TRUE(view.IsValid());
}
TEST(TFunctionViewTest, ReleaseSemantics)
{
int counter = 0;
auto lambda = [&counter] {
++counter;
};
TFunctionView<void()> view1(lambda);
view1();
EXPECT_EQ(counter, 1);
TFunctionView view2 = view1.Release();
EXPECT_FALSE(view1.IsValid());
EXPECT_TRUE(view2.IsValid());
view2();
EXPECT_EQ(counter, 2);
}
////////////////////////////////////////////////////////////////////////////////
} // namespace
} // namespace NYT
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