make timeout explicit

src/threading/ipc_channel.cpp

@@ -284,7 +284,7 @@ bool IPCChannelEnd::sendLarge(const void *data, size_t size, int timeout_ms) noe
 	return true;
 }
 
-bool IPCChannelEnd::recv(int timeout_ms) noexcept
+bool IPCChannelEnd::recvWithTimeout(int timeout_ms) noexcept
 {
 #if defined(IPC_CHANNEL_IMPLEMENTATION_WIN32)
 	DWORD timeout = get_timeout(timeout_ms);
@@ -329,7 +329,7 @@ bool IPCChannelEnd::recv(int timeout_ms) noexcept
 #endif
 				return false;
 		} while (size > IPC_CHANNEL_MSG_SIZE);
-		memcpy(recv_data, m_in->data, size);
+		memcpy(recv_data, m_in->data, size); //TODO: memcpy volatile save?
 	}
 	return true;
 }

src/threading/ipc_channel.h

@@ -168,7 +168,9 @@ public:
 	// If send, recv, or exchange return false (=timeout), stop using the channel. <--- TODO:why?
 	// Note: timeouts may be for receiving any response, not a whole message.
 
-	bool send(const void *data, size_t size, int timeout_ms = -1) noexcept
+	// Returns false on timeout
+	[[nodiscard]]
+	bool sendWithTimeout(const void *data, size_t size, int timeout_ms) noexcept
 	{
 		if (size <= IPC_CHANNEL_MSG_SIZE) {
 			sendSmall(data, size);
@@ -178,14 +180,40 @@ public:
 		}
 	}
 
-	bool recv(int timeout_ms = -1) noexcept;
+	// Same as above
-
+	void send(const void *data, size_t size) noexcept
-	bool exchange(const void *data, size_t size, int timeout_ms = -1) noexcept
 	{
-		return send(data, size, timeout_ms) && recv(timeout_ms);
+		(void)sendWithTimeout(data, size, -1);
+	}
+
+	// Returns false on timeout.
+	// Otherwise returns true, and data is available via getRecvData().
+	[[nodiscard]]
+	bool recvWithTimeout(int timeout_ms) noexcept;
+
+	// Same as above
+	void recv() noexcept
+	{
+		(void)recvWithTimeout(-1);
+	}
+
+	// Returns false on timeout
+	// Otherwise returns true, and data is available via getRecvData().
+	[[nodiscard]]
+	bool exchangeWithTimeout(const void *data, size_t size, int timeout_ms) noexcept
+	{
+		return sendWithTimeout(data, size, timeout_ms)
+				&& recvWithTimeout(timeout_ms);
+	}
+
+	// Same as above
+	void exchange(const void *data, size_t size) noexcept
+	{
+		(void)exchangeWithTimeout(data, size, -1);
 	}
 
 	// Get the content of the last received message
+	// TODO: u8 *, or string_view?
 	inline const void *getRecvData() const noexcept { return m_large_recv.data(); }
 	inline size_t getRecvSize() const noexcept { return m_recv_size; }
 
@@ -208,6 +236,7 @@ private:
 	{}
 #endif
 
+	// TODO: u8 *, or string_view?
 	void sendSmall(const void *data, size_t size) noexcept;
 
 	// returns false on timeout

src/unittest/test_threading.cpp

@@ -282,25 +282,26 @@ void TestThreading::testIPCChannel()
 		IPCChannelEnd end_b = IPCChannelEnd::makeB(std::move(resources_second));
 
 		for (;;) {
-			UASSERT(end_b.recv());
+			UASSERT(end_b.recvWithTimeout(-1));
-			UASSERT(end_b.send(end_b.getRecvData(), end_b.getRecvSize()));
+			UASSERT(end_b.sendWithTimeout(end_b.getRecvData(), end_b.getRecvSize(), -1));
 			if (end_b.getRecvSize() == 0)
 				break;
 		}
 	});
 
 	char buf[20000] = {};
-	for (int i = sizeof(buf); i > 0; i -= 1000) {
+	for (int i = sizeof(buf); i > 0; i -= 100) {
 		buf[i - 1] = 123;
-		UASSERT(end_a.exchange(buf, i));
+		UASSERT(end_a.exchangeWithTimeout(buf, i, -1));
 		UASSERTEQ(int, end_a.getRecvSize(), i);
 		UASSERTEQ(int, ((const char *)end_a.getRecvData())[i - 1], 123);
 	}
 
-	UASSERT(end_a.exchange(buf, 0));
+	UASSERT(end_a.exchangeWithTimeout(buf, 0, -1));
 	UASSERTEQ(int, end_a.getRecvSize(), 0);
 
 	thread_b.join();
 
-	UASSERT(!end_a.exchange(buf, 0, 1000));
+	// other side dead ==> should time out
+	UASSERT(!end_a.exchangeWithTimeout(buf, 0, 200));
 }