From 8ebfaf896690c8be6832ccb32780c2b83630b357 Mon Sep 17 00:00:00 2001
From: Martin Ling <martin-git@earth.li>
Date: Wed, 6 May 2015 20:18:37 +0100
Subject: [PATCH] windows: restart_wait_if_needed(): Inline receive buffer
 check.

This removes all the debug spam arising from calling sp_input_waiting().
---
 serialport.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/serialport.c b/serialport.c
index ab263a9..bae37ed 100644
--- a/serialport.c
+++ b/serialport.c
@@ -921,19 +921,16 @@ SP_API enum sp_return sp_nonblocking_write(struct sp_port *port,
 /* Restart wait operation if buffer was emptied. */
 static enum sp_return restart_wait_if_needed(struct sp_port *port, unsigned int bytes_read)
 {
-	int ret, bytes_remaining;
+	DWORD errors;
+	COMSTAT comstat;
 
 	if (bytes_read == 0)
 		RETURN_OK();
 
-	ret = sp_input_waiting(port);
+	if (ClearCommError(port->hdl, &errors, &comstat) == 0)
+		RETURN_FAIL("ClearCommError() failed");
 
-	if (ret < 0)
-		RETURN_CODEVAL(ret);
-
-	bytes_remaining = ret;
-
-	if (bytes_remaining == 0)
+	if (comstat.cbInQue == 0)
 		TRY(restart_wait(port));
 
 	RETURN_OK();