Client: fix and normalize receive operations

There was a bug: in epoll net provider, in case of EAGAIN the
connection was marked as having data to decode, which is wrong.

Fix it by simple check that the connection has input data.

Implement this part int libev net provider similarly.

Part of #28

src/Client/EpollNetProvider.hpp

@@ -222,17 +222,17 @@ EpollNetProvider<BUFFER, NETWORK>::recv(Conn_t &conn)
 	size_t iov_cnt = 0;
 	/* Get IO vectors array pointing to the input buffer. */
 	struct iovec *iov = inBufferToIOV(conn, total, &iov_cnt);
-	int has_read_bytes = NETWORK::recvall(conn.getSocket(), iov, iov_cnt, true);
-	if (has_read_bytes < 0) {
+	ssize_t rcvd = NETWORK::recvall(conn.getSocket(), iov, iov_cnt, true);
+	hasNotRecvBytes(conn, total - (rcvd < 0 ? 0 : rcvd));
+	if (rcvd < 0) {
 		//Don't consider EWOULDBLOCK to be an error.
 		if (netWouldBlock(errno))
 			return 0;
 		conn.setError(std::string("Failed to receive response: ") +
 					  strerror(errno), errno);
 		return -1;
 	}
-	hasNotRecvBytes(conn, total - has_read_bytes);
-	return total - has_read_bytes;
+	return 0;
 }
 
 template<class BUFFER, class NETWORK>
@@ -296,9 +296,9 @@ EpollNetProvider<BUFFER, NETWORK>::wait(int timeout)
 			 * becomes ready to decode.
 			 */
 			int rc = recv(conn);
-			if (rc < 0)
+			if (rc != 0)
 				return -1;
-			if (rc == 0)
+			if (hasDataToDecode(conn))
 				m_Connector.readyToDecode(conn);
 		}
 

src/Client/LibevNetProvider.hpp

@@ -129,17 +129,17 @@ connectionReceive(Connection<BUFFER,  LibevNetProvider<BUFFER, NETWORK>> &conn)
 	size_t iov_cnt = 0;
 	struct iovec *iov =
 		inBufferToIOV(conn, total, &iov_cnt);
-	int read_bytes = NETWORK::recvall(conn.getSocket(), iov, iov_cnt, true);
-	hasNotRecvBytes(conn, total - read_bytes);
-	if (read_bytes < 0) {
+	ssize_t rcvd = NETWORK::recvall(conn.getSocket(), iov, iov_cnt, true);
+	hasNotRecvBytes(conn, total - (rcvd < 0 ? 0 : rcvd));
+	if (rcvd < 0) {
 		if (netWouldBlock(errno)) {
-			return 1;
+			return 0;
 		}
 		conn.setError(std::string("Failed to receive response: ") +
 			       strerror(errno));
 		return -1;
 	}
-	return total - read_bytes;
+	return 0;
 }
 
 template<class BUFFER, class NETWORK>
@@ -158,9 +158,9 @@ recv_cb(struct ev_loop *loop, struct ev_io *watcher, int /* revents */)
 	timerDisable(loop, waitWatcher->timer);
 	int rc = connectionReceive(conn);
 	Connector_t *connector = waitWatcher->connector;
-	if (rc < 0)
+	if (rc != 0)
 		return;
-	if (rc == 0)
+	if (hasDataToDecode(conn))
 		connector->readyToDecode(conn);
 }