deduplicate test helper

src/benchmark/benchmark_ipc_channel.cpp

@@ -23,53 +23,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 TEST_CASE("benchmark_ipc_channel")
 {
-	// same as in test_threading.cpp (TODO: remove duplication)
+	auto end_a_thread_b_p = make_test_ipc_channel([](IPCChannelEnd end_b) {
-	struct IPCChannelResourcesSingleProcess final : public IPCChannelResources
-	{
-		void cleanupLast() noexcept override
-		{
-			delete data.shared;
-#ifdef IPC_CHANNEL_IMPLEMENTATION_WIN32
-			CloseHandle(data.sem_b);
-			CloseHandle(data.sem_a);
-#endif
-		}
-
-		void cleanupNotLast() noexcept override
-		{
-			// nothing to do (i.e. no unmapping needed)
-		}
-
-		~IPCChannelResourcesSingleProcess() override { cleanup(); }
-	};
-
-	auto resource_data = [] {
-		auto shared = new IPCChannelShared();
-
-#ifdef IPC_CHANNEL_IMPLEMENTATION_WIN32
-		HANDLE sem_a = CreateSemaphoreA(nullptr, 0, 1, nullptr);
-		REQUIRE(sem_a != INVALID_HANDLE_VALUE);
-
-		HANDLE sem_b = CreateSemaphoreA(nullptr, 0, 1, nullptr);
-		REQUIRE(sem_b != INVALID_HANDLE_VALUE);
-
-		return IPCChannelResources::Data{shared, sem_a, sem_b};
-#else
-		return IPCChannelResources::Data{shared};
-#endif
-	}();
-
-	auto resources_first = std::make_unique<IPCChannelResourcesSingleProcess>();
-	resources_first->setFirst(resource_data);
-
-	IPCChannelEnd end_a = IPCChannelEnd::makeA(std::move(resources_first));
-
 		// echos back messages. stops if "" is sent
-	std::thread thread_b([=] {
-		auto resources_second = std::make_unique<IPCChannelResourcesSingleProcess>();
-		resources_second->setSecond(resource_data);
-		IPCChannelEnd end_b = IPCChannelEnd::makeB(std::move(resources_second));
-
 		for (;;) {
 			end_b.recv();
 			end_b.send(end_b.getRecvData(), end_b.getRecvSize());
@@ -77,6 +32,9 @@ TEST_CASE("benchmark_ipc_channel")
 				break;
 		}
 	});
+	// Can't use structured bindings before C++20, because of lamda captures below.
+	auto end_a = std::move(end_a_thread_b_p.first);
+	auto thread_b = std::move(end_a_thread_b_p.second);
 
 	BENCHMARK("simple_call_1", i) {
 		char buf[16] = {};

src/threading/ipc_channel.cpp

@@ -353,3 +353,36 @@ bool IPCChannelEnd::recvWithTimeout(int timeout_ms) noexcept
 	}
 	return true;
 }
+
+std::pair<IPCChannelEnd, std::thread> make_test_ipc_channel(
+		const std::function<void(IPCChannelEnd)> &fun)
+{
+	auto resource_data = [] {
+		auto shared = new IPCChannelShared();
+
+#ifdef IPC_CHANNEL_IMPLEMENTATION_WIN32
+		HANDLE sem_a = CreateSemaphoreA(nullptr, 0, 1, nullptr);
+		HANDLE sem_b = CreateSemaphoreA(nullptr, 0, 1, nullptr);
+		FATAL_ERROR_IF(!sem_a || !sem_b, "CreateSemaphoreA failed");
+
+		return IPCChannelResources::Data{shared, sem_a, sem_b};
+#else
+		return IPCChannelResources::Data{shared};
+#endif
+	}();
+
+	auto resources_first = std::make_unique<IPCChannelResourcesSingleProcess>();
+	resources_first->setFirst(resource_data);
+
+	IPCChannelEnd end_a = IPCChannelEnd::makeA(std::move(resources_first));
+
+	std::thread thread_b([=] {
+		auto resources_second = std::make_unique<IPCChannelResourcesSingleProcess>();
+		resources_second->setSecond(resource_data);
+		IPCChannelEnd end_b = IPCChannelEnd::makeB(std::move(resources_second));
+
+		fun(std::move(end_b));
+	});
+
+	return {std::move(end_a), std::move(thread_b)};
+}

src/threading/ipc_channel.h

@@ -25,6 +25,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <memory>
 #include <vector>
 #include <atomic>
+#include <thread>
+#include <functional>
 
 #if defined(_WIN32)
 #define IPC_CHANNEL_IMPLEMENTATION_WIN32
@@ -256,3 +258,29 @@ private:
 	// (this buffer only grows)
 	std::vector<u8> m_large_recv = std::vector<u8>(IPC_CHANNEL_MSG_SIZE);
 };
+
+// For testing purposes
+struct IPCChannelResourcesSingleProcess final : public IPCChannelResources
+{
+	void cleanupLast() noexcept override
+	{
+		delete data.shared;
+#ifdef IPC_CHANNEL_IMPLEMENTATION_WIN32
+		CloseHandle(data.sem_b);
+		CloseHandle(data.sem_a);
+#endif
+	}
+
+	void cleanupNotLast() noexcept override
+	{
+		// nothing to do (i.e. no unmapping needed)
+	}
+
+	~IPCChannelResourcesSingleProcess() override { cleanup(); }
+};
+
+// For testing
+// Returns one end and a thread holding the other end. The thread will execute
+// fun, and pass it the other end.
+std::pair<IPCChannelEnd, std::thread> make_test_ipc_channel(
+		const std::function<void(IPCChannelEnd)> &fun);

src/unittest/test_threading.cpp

@@ -236,52 +236,8 @@ void TestThreading::testTLS()
 
 void TestThreading::testIPCChannel()
 {
-	struct IPCChannelResourcesSingleProcess final : public IPCChannelResources
+	auto [end_a, thread_b] = make_test_ipc_channel([](IPCChannelEnd end_b) {
-	{
-		void cleanupLast() noexcept override
-		{
-			delete data.shared;
-#ifdef IPC_CHANNEL_IMPLEMENTATION_WIN32
-			CloseHandle(data.sem_b);
-			CloseHandle(data.sem_a);
-#endif
-		}
-
-		void cleanupNotLast() noexcept override
-		{
-			// nothing to do (i.e. no unmapping needed)
-		}
-
-		~IPCChannelResourcesSingleProcess() override { cleanup(); }
-	};
-
-	auto resource_data = [] {
-		auto shared = new IPCChannelShared();
-
-#ifdef IPC_CHANNEL_IMPLEMENTATION_WIN32
-		HANDLE sem_a = CreateSemaphoreA(nullptr, 0, 1, nullptr);
-		UASSERT(sem_a != INVALID_HANDLE_VALUE);
-
-		HANDLE sem_b = CreateSemaphoreA(nullptr, 0, 1, nullptr);
-		UASSERT(sem_b != INVALID_HANDLE_VALUE);
-
-		return IPCChannelResources::Data{shared, sem_a, sem_b};
-#else
-		return IPCChannelResources::Data{shared};
-#endif
-	}();
-
-	auto resources_first = std::make_unique<IPCChannelResourcesSingleProcess>();
-	resources_first->setFirst(resource_data);
-
-	IPCChannelEnd end_a = IPCChannelEnd::makeA(std::move(resources_first));
-
 		// echos back messages. stops if "" is sent
-	std::thread thread_b([=] {
-		auto resources_second = std::make_unique<IPCChannelResourcesSingleProcess>();
-		resources_second->setSecond(resource_data);
-		IPCChannelEnd end_b = IPCChannelEnd::makeB(std::move(resources_second));
-
 		for (;;) {
 			UASSERT(end_b.recvWithTimeout(-1));
 			UASSERT(end_b.sendWithTimeout(end_b.getRecvData(), end_b.getRecvSize(), -1));