Added connection management

src/ergodox.cpp

@@ -11,10 +11,10 @@ Ergodox::Ergodox(
 	product_id(product_id),
 	usage(usage),
 	usage_page(usage_page),
-	handle(NULL)
+	handle(NULL),
+	connected(false)
 {
 	hid_init();
-	open();
 }
 
 
@@ -54,21 +54,23 @@ Ergodox& Ergodox::init(
 // Instance is a static function variable,
 // and will be deleted at end of program.
 Ergodox::~Ergodox() {
-	close();
+	disconnect();
 	hid_exit();
 }
 
 
+
 /*
 Try to open this keyboard's hid device.
-Throws a runtime error if device is already open,
-or if we can't find a device with the given params.
+Throws a runtime error if device is already open.
 
 If we successfully open a device, this method sends a
 CMD_HELLO packet.
+
+@returns True if connection was successful, false otherwise.
 */
-void Ergodox::open() {
-	if (handle != NULL) {
+bool Ergodox::try_connect() {
+	if (connected) {
 		throw std::runtime_error("Device already open");
 	}
 
@@ -89,24 +91,47 @@ void Ergodox::open() {
 		cur_dev = cur_dev->next;
 	}
 
+	// Return false if connection failed
 	if (path_to_open) {
+		connected = true;
+
 		handle = hid_open_path(path_to_open);
+		hid_set_nonblocking(handle, 1);
 		hid_free_enumeration(devs);
+		write(CMD_HELLO, NULL, 0);
+
+		#define MAX_STR 255
+		wchar_t wstr[MAX_STR];
+
+
+		wprintf(L"\nConnected to device!\n");
+
+		// Read metadata
+		wstr[0] = 0x0000;
+		hid_get_manufacturer_string(handle, wstr, MAX_STR);
+		wprintf(L"Manufacturer String: %ls\n", wstr);
+
+		wstr[0] = 0x0000;
+		hid_get_product_string(handle, wstr, MAX_STR);
+		wprintf(L"Product String: %ls\n", wstr);
+
 	} else {
+		connected = false;
+
 		hid_free_enumeration(devs);
-		throw std::runtime_error("Could not open hid device");
+		return false;
 	}
 
-	hid_set_nonblocking(handle, 1);
-
-	write(CMD_HELLO, NULL, 0);
+	return connected;
 }
 
 
 // Close hid device if it is open.
-void Ergodox::close() {
+void Ergodox::disconnect() {
+	connected = false;
 	if (handle != NULL) {
 		hid_close(handle);
+		handle = NULL;
 	}
 }
 
@@ -116,14 +141,15 @@ Send data to Ergodox.
 
 @param cmd Command byte
 @param data Data to send
-@returns data_len Data length. Must be shorter than packet_size.
+@param data_len Data length. Must be shorter than packet_size.
+@returns True if successful, false otherwise.
 */
-int Ergodox::write(uint8_t cmd, const uint8_t* data, uint8_t data_len) const {
-	if (handle == NULL) {
-		throw std::runtime_error("Cannot write, device is not open!");
-	}
-
-	if (data_len > packet_size) {
+bool Ergodox::write(uint8_t cmd, const uint8_t* data, uint8_t data_len) {
+	if (!connected) {
+		throw std::runtime_error("Not connected, cannot write!");
+	} else if (handle == NULL) {
+		throw std::runtime_error("Tried to write a null handle, something is very wrong.");
+	} else if (data_len > packet_size) {
 		throw std::runtime_error("Data length exceeds packet size");
 	}
 
@@ -138,7 +164,15 @@ int Ergodox::write(uint8_t cmd, const uint8_t* data, uint8_t data_len) const {
 	// Copy data into rest of packet
 	std::copy(data, data + data_len, packet + 2);
 
-	return hid_write(handle, packet, packet_size + 1);
+	ssize_t res;
+	res = hid_write(handle, packet, packet_size + 1);
+
+	if (res < 0) {
+		wprintf(L"Lost device, disconnecting.\n");
+		disconnect();
+		return false;
+	}
+	return true;
 }
 
 
@@ -148,16 +182,21 @@ Read data from Ergodox into read_buf. If a CMD_SEND_STATE packet is received, pr
 @returns True if a new command was received, false otherwise.
 */
 bool Ergodox::read() {
-	if (handle == NULL) {
-		throw std::runtime_error("Cannot write, device is not open!");
+	if (!connected) {
+		throw std::runtime_error("Not connected, cannot read!");
+	} else if (handle == NULL) {
+		throw std::runtime_error("Tried to read a null handle, something is very wrong.");
 	}
+
 	ssize_t res;
 	res = hid_read(handle, read_buf, packet_size);
 
 	if (res == 0) {
 		return false;
 	} else if (res < 0) {
-		throw std::runtime_error("Read failed.");
+		wprintf(L"Lost device, disconnecting.\n");
+		disconnect();
+		return false;
 	}
 
 	switch(read_buf[0]) {
@@ -173,5 +212,11 @@ bool Ergodox::read() {
 			return false;
 	}
 
-	return res > 0;
+	return true;
+}
+
+
+// Simple connectivity check
+void Ergodox::test_connection() {
+	write(CMD_RUTHERE, NULL, 0);
 }