Added connection management

src/commands.h

@@ -1,8 +1,20 @@
 #pragma once
 
 // Sent by host when connection is initiated.
+//
+// Packet structure:
+// Data:		| cmd |
+// # of Bytes:	|  1  |
 #define CMD_HELLO 0x00
 
+// Sent periodically by host to test connection.
+// Keyboard should ignore this command.
+//
+// Packet structure:
+// Data:		| cmd |
+// # of Bytes:	|  1  |
+#define CMD_RUTHERE 0x01
+
 // Send keyboard state to host.
 //
 // Packet structure:
@@ -13,7 +25,7 @@
 // 0x00: RGBMatrix disabled
 // 0x01: normal animation, no HID data.
 // 0x02: FFT Animation
-#define CMD_SEND_STATE 0x01
+#define CMD_SEND_STATE 0x02
 
 
 // Animation data. Sent by host.
@@ -27,7 +39,7 @@
 //
 // data:
 // Animation data. Content depends on data type.
-#define CMD_ANIM_DATA 0x02
+#define CMD_ANIM_DATA 0x03
 
 // Data for FFT animation.
 // Data segment consists of 10 bits, each representing the height of a column.

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);
 }

src/ergodox.hpp

@@ -32,15 +32,22 @@ class Ergodox {
 
 		~Ergodox();
 
-		int write(uint8_t cmd, const uint8_t* data, uint8_t data_len) const;
+		bool try_connect();
+		void disconnect();
+		void test_connection();
 
 		bool read();
+		bool write(uint8_t cmd, const uint8_t* data, uint8_t data_len);
+
 
 		// Read buffer, len = packet_size.
 		// Filled by read().
 		uint8_t read_buf[RAW_EPSIZE];
 
+
+		// Getter methods
 		uint8_t get_animation_mode() const { return animation_mode; }
+		bool is_connected() const { return connected; }
 
 	private:
 		Ergodox(
@@ -55,14 +62,16 @@ class Ergodox {
 		//Ergodox(Ergodox& other);
 		//Ergodox& operator=(Ergodox& other);
 
-		void open();
-		void close();
-
 		// HID device.
 		// NULL if not opened.
 		hid_device* handle;
 
 		// Keyboard state variables.
 		// Updated by read().
+
+		// Which animation is the keyboard running right now?
+		// See CMD_SEND_STATE in commands.h for docs.
 		uint8_t animation_mode;
+		// Are we connected to a keyboard right now?
+		bool connected;
 };

src/main.cpp

@@ -5,6 +5,9 @@
 // For reading FIFO
 #include <fcntl.h>
 #include <unistd.h>
+// For sleep
+#include <chrono>
+#include <thread>
 
 // Local files
 #include "utility/bitmap.hpp"
@@ -82,37 +85,57 @@ int main(int argc, char *argv[]) {
 	);
 
 	// Write buffer
-	uint8_t hid_buf[12];
+	uint8_t hid_buf[Dox.packet_size];
+
+	wprintf(L"Trying to connect...\n");
+	while (!Dox.is_connected()) {
+		Dox.try_connect();
+		std::this_thread::sleep_for(std::chrono::milliseconds(500));
+	}
+
 
 	while (1) {
 
+		if (Dox.is_connected()) {
+			if (Dox.get_animation_mode() == 0x02) {
+				buf.update();
+				fft.update(buf);
 
-		if (Dox.get_animation_mode() == 0x02) {
-			buf.update();
-			fft.update(buf);
+				hid_buf[0] = CMD_ANIM_DATA_fft;
+				for (size_t i = 0; i < 10; i++) {
+					// Get height from fft, apply bottom_skip
+					ssize_t h = fft.get_output()[i] - bottom_skip;
 
-			hid_buf[0] = CMD_ANIM_DATA_fft;
-			for (size_t i = 0; i < 10; i++) {
-				// Get height from fft, apply bottom_skip
-				ssize_t h = fft.get_output()[i] - bottom_skip;
+					// Enforce max and min
+					// max implicitly enforces top_skip
+					h = h>kb_resolution ? kb_resolution : h;
+					h = h<0 ? 0 : h;
 
-				// Enforce max and min
-				// max implicitly enforces top_skip
-				h = h>kb_resolution ? kb_resolution : h;
-				h = h<0 ? 0 : h;
-
-				hid_buf[i + 1] = h;
+					hid_buf[i + 1] = h;
+				}
 			}
-			Dox.write(CMD_ANIM_DATA, hid_buf, 13);
-		}
 
-		// Read a packet if there is a packet to read
-		if (Dox.read()) {
-			uint8_t cmd = Dox.read_buf[0];
+			Dox.write(CMD_ANIM_DATA, hid_buf, Dox.packet_size);
 
-			switch(cmd) {
-				case CMD_SEND_STATE:
-					break;
+			// Dox.write might detect that we've been disconnected,
+			// and Dox.read will fail if we are.
+			// This check prevents it from doing that, and instead jumps to reconnect.
+			if (!Dox.is_connected()) { continue; }
+
+			// Read a packet if there is a packet to read
+			if (Dox.read()) {
+				uint8_t cmd = Dox.read_buf[0];
+
+				switch(cmd) {
+					case CMD_SEND_STATE:
+						break;
+				}
+			}
+		} else {
+			wprintf(L"Trying to connect...\n");
+			while (!Dox.is_connected()) {
+				Dox.try_connect();
+				std::this_thread::sleep_for(std::chrono::milliseconds(500));
 			}
 		}
 	}