Fix #288

src/client/client.d

@@ -30,13 +30,14 @@ import std.conv;
 import std.string;
 import std.experimental.logger;
 
-import msgpack;
 import common.messages;
 import common.dcd_version;
 import common.socket;
 
 int main(string[] args)
 {
+	sharedLog.fatalHandler = () {};
+
 	size_t cursorPos = size_t.max;
 	string[] importPaths;
 	ushort port = 9166;
@@ -106,24 +107,12 @@ int main(string[] args)
 
 	if (query)
 	{
-		try
+		if (serverIsRunning(useTCP, socketFile, port))
 		{
-			Socket socket = createSocket(socketFile, port);
-			scope (exit) { socket.shutdown(SocketShutdown.BOTH); socket.close(); }
-			request.kind = RequestKind.query;
-			if (sendRequest(socket, request))
-			{
-				const AutocompleteResponse response = getResponse(socket);
-				if (response.completionType == "ack")
-				{
-					writeln("Server is running");
-					return 0;
-				}
-				else
-					throw new Exception("");
-			}
+			writeln("Server is running");
+			return 0;
 		}
-		catch (Exception ex)
+		else
 		{
 			writeln("Server is not running");
 			return 1;
@@ -328,39 +317,10 @@ Socket createSocket(string socketFile, ushort port)
 	return socket;
 }
 
-/**
- * Returns: true on success
- */
-bool sendRequest(Socket socket, AutocompleteRequest request)
-{
-	ubyte[] message = msgpack.pack(request);
-	ubyte[] messageBuffer = new ubyte[message.length + message.length.sizeof];
-	auto messageLength = message.length;
-	messageBuffer[0 .. size_t.sizeof] = (cast(ubyte*) &messageLength)[0 .. size_t.sizeof];
-	messageBuffer[size_t.sizeof .. $] = message[];
-	return socket.send(messageBuffer) == messageBuffer.length;
-}
-
-/**
- * Gets the response from the server
- */
-AutocompleteResponse getResponse(Socket socket)
-{
-	ubyte[1024 * 16] buffer;
-	auto bytesReceived = socket.receive(buffer);
-	if (bytesReceived == Socket.ERROR)
-		throw new Exception("Incorrect number of bytes received");
-	if (bytesReceived == 0)
-		throw new Exception("Server closed the connection, 0 bytes received");
-	AutocompleteResponse response;
-	msgpack.unpack(buffer[0..bytesReceived], response);
-	return response;
-}
-
 void printDocResponse(AutocompleteResponse response)
 {
 	import std.array: join;
-    response.docComments.join(r"\n\n").writeln;
+	response.docComments.join(r"\n\n").writeln;
 }
 
 void printLocationResponse(AutocompleteResponse response)

src/common/messages.d

@@ -18,6 +18,9 @@
 
 module common.messages;
 
+import std.socket;
+import msgpack;
+
 /**
  * The type of completion list being returned
  */
@@ -157,3 +160,69 @@ struct AutocompleteResponse
 	 */
 	string[] importPaths;
 }
+
+/**
+ * Returns: true on success
+ */
+bool sendRequest(Socket socket, AutocompleteRequest request)
+{
+	ubyte[] message = msgpack.pack(request);
+	ubyte[] messageBuffer = new ubyte[message.length + message.length.sizeof];
+	auto messageLength = message.length;
+	messageBuffer[0 .. size_t.sizeof] = (cast(ubyte*) &messageLength)[0 .. size_t.sizeof];
+	messageBuffer[size_t.sizeof .. $] = message[];
+	return socket.send(messageBuffer) == messageBuffer.length;
+}
+
+/**
+ * Gets the response from the server
+ */
+AutocompleteResponse getResponse(Socket socket)
+{
+	ubyte[1024 * 16] buffer;
+	auto bytesReceived = socket.receive(buffer);
+	if (bytesReceived == Socket.ERROR)
+		throw new Exception("Incorrect number of bytes received");
+	if (bytesReceived == 0)
+		throw new Exception("Server closed the connection, 0 bytes received");
+	AutocompleteResponse response;
+	msgpack.unpack(buffer[0..bytesReceived], response);
+	return response;
+}
+
+/**
+ * Returns: true if a server instance is running
+ * Params:
+ *     useTCP = `true` to check a TCP port, `false` for UNIX domain socket
+ *     socketFile = the file name for the UNIX domain socket
+ *     port = the TCP port
+ */
+bool serverIsRunning(bool useTCP, string socketFile, ushort port)
+{
+	scope (failure)
+		return false;
+	AutocompleteRequest request;
+	request.kind = RequestKind.query;
+	Socket socket;
+	scope (exit)
+	{
+		socket.shutdown(SocketShutdown.BOTH);
+		socket.close();
+	}
+	if (useTCP)
+	{
+		socket = new TcpSocket(AddressFamily.INET);
+		socket.connect(new InternetAddress("localhost", port));
+	}
+	else
+	{
+		socket = new Socket(AddressFamily.UNIX, SocketType.STREAM);
+		socket.connect(new UnixAddress(socketFile));
+	}
+	socket.setOption(SocketOptionLevel.SOCKET, SocketOption.RCVTIMEO, dur!"seconds"(5));
+	socket.blocking = true;
+	if (sendRequest(socket, request))
+		return getResponse(socket).completionType == "ack";
+	else
+		return false;
+}

src/server/server.d

@@ -73,6 +73,8 @@ int main(string[] args)
 		string socketFile = generateSocketName();
 	}
 
+	sharedLog.fatalHandler = () {};
+
 	try
 	{
 		getopt(args, "port|p", &port, "I", &importPaths, "help|h", &help,
@@ -86,6 +88,8 @@ int main(string[] args)
 		return 1;
 	}
 
+	globalLogLevel = level;
+
 	if (printVersion)
 	{
 		version (Windows)
@@ -109,7 +113,11 @@ int main(string[] args)
 		return 1;
 	}
 
-	globalLogLevel = level;
+	if (serverIsRunning(useTCP, socketFile,  port))
+	{
+		fatal("Another instance of DCD-server is already running");
+		return 1;
+	}
 
 	info("Starting up...");
 	StopWatch sw = StopWatch(AutoStart.yes);