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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include <vespa/vespalib/coro/lazy.h>
#include <vespa/vespalib/coro/sync_wait.h>
#include <vespa/vespalib/coro/schedule.h>
#include <vespa/vespalib/util/size_literals.h>
#include <vespa/vespalib/util/require.h>
#include <vespa/vespalib/util/threadstackexecutor.h>
#include <vespa/vespalib/gtest/gtest.h>
#include <mutex>
#include <thread>
using vespalib::Executor;
using vespalib::coro::Lazy;
using vespalib::coro::ScheduleFailedException;
using vespalib::coro::schedule;
using vespalib::coro::sync_wait;
using vespalib::coro::try_schedule;
Lazy<int> make_lazy(int value) {
co_return value;
}
Lazy<int> async_add_values(int a, int b) {
auto lazy_a = make_lazy(a);
auto lazy_b = make_lazy(b);
co_return (co_await lazy_a + co_await lazy_b);
}
Lazy<int> async_sum(Lazy<int> a, Lazy<int> b) {
co_return (co_await a + co_await b);
}
Lazy<std::unique_ptr<int>> move_only_int() {
co_return std::make_unique<int>(123);
}
Lazy<int> extract_rvalue() {
auto res = co_await move_only_int();
co_return *res;
}
Lazy<int> will_throw() {
REQUIRE_FAILED("failed on purpose");
co_return 123;
}
template<typename T>
Lazy<T> forward_value(Lazy<T> value) {
co_return co_await std::move(value);
}
template <typename T>
Lazy<std::pair<bool,T>> try_schedule_on(Executor &executor, Lazy<T> value) {
std::cerr << "switching from thread " << std::this_thread::get_id() << std::endl;
bool accepted = co_await try_schedule(executor);
std::cerr << "........... to thread " << std::this_thread::get_id() << std::endl;
co_return std::make_pair(accepted, co_await value);
}
template <typename T>
Lazy<T> schedule_on(Executor &executor, Lazy<T> value) {
std::cerr << "switching from thread " << std::this_thread::get_id() << std::endl;
co_await schedule(executor);
std::cerr << "........... to thread " << std::this_thread::get_id() << std::endl;
co_return co_await value;
}
TEST(LazyTest, simple_lazy_value) {
auto lazy = make_lazy(42);
auto result = sync_wait(lazy);
EXPECT_EQ(result, 42);
}
TEST(LazyTest, async_sum_of_async_values) {
auto lazy = async_add_values(10, 20);
auto result = sync_wait(lazy);
EXPECT_EQ(result, 30);
}
TEST(LazyTest, async_sum_of_external_async_values) {
auto a = make_lazy(100);
auto b = make_lazy(200);
auto lazy = async_sum(std::move(a), std::move(b));
auto result = sync_wait(lazy);
EXPECT_EQ(result, 300);
}
TEST(LazyTest, extract_rvalue_from_lazy_in_coroutine) {
auto lazy = extract_rvalue();
auto result = sync_wait(lazy);
EXPECT_EQ(result, 123);
}
TEST(LazyTest, extract_rvalue_from_lazy_in_sync_wait) {
auto result = sync_wait(move_only_int());
EXPECT_EQ(*result, 123);
}
TEST(LazyTest, calculate_result_in_another_thread) {
vespalib::ThreadStackExecutor executor(1, 128_Ki);
auto result = sync_wait(try_schedule_on(executor, make_lazy(7)));
EXPECT_EQ(result.first, true);
EXPECT_EQ(result.second, 7);
auto result2 = sync_wait(schedule_on(executor, make_lazy(8)));
EXPECT_EQ(result2, 8);
}
TEST(LazyTest, exceptions_are_propagated) {
vespalib::ThreadStackExecutor executor(1, 128_Ki);
auto lazy = try_schedule_on(executor, forward_value(will_throw()));
EXPECT_THROW(sync_wait(lazy), vespalib::RequireFailedException);
}
TEST(LazyTest, not_able_to_switch_thread_if_executor_is_shut_down) {
vespalib::ThreadStackExecutor executor(1, 128_Ki);
executor.shutdown();
auto result = sync_wait(try_schedule_on(executor, make_lazy(7)));
EXPECT_EQ(result.first, false);
EXPECT_EQ(result.second, 7);
auto lazy = schedule_on(executor, make_lazy(8));
EXPECT_THROW(sync_wait(lazy), ScheduleFailedException);
}
GTEST_MAIN_RUN_ALL_TESTS()
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