From 62ed9f801abe409d3f7c1cfa91287896187f2ac0 Mon Sep 17 00:00:00 2001
From: Martin Ling <martin-git@earth.li>
Date: Mon, 3 Jul 2017 20:55:13 +0100
Subject: [PATCH] windows: Break out helper function for awaiting previous
 write completion.

---
 serialport.c | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/serialport.c b/serialport.c
index db2aa43..1b71cdb 100644
--- a/serialport.c
+++ b/serialport.c
@@ -731,6 +731,27 @@ SP_API enum sp_return sp_drain(struct sp_port *port)
 #endif
 }
 
+#ifdef _WIN32
+static enum sp_return await_write_completion(struct sp_port *port)
+{
+	TRACE("%p", port);
+	DWORD bytes_written;
+	BOOL result;
+
+	/* Wait for previous non-blocking write to complete, if any. */
+	if (port->writing) {
+		DEBUG("Waiting for previous write to complete");
+		result = GetOverlappedResult(port->hdl, &port->write_ovl, &bytes_written, TRUE);
+		port->writing = 0;
+		if (!result)
+			RETURN_FAIL("Previous write failed to complete");
+		DEBUG("Previous write completed");
+	}
+
+	RETURN_OK();
+}
+#endif
+
 SP_API enum sp_return sp_blocking_write(struct sp_port *port, const void *buf,
                                         size_t count, unsigned int timeout_ms)
 {
@@ -753,17 +774,8 @@ SP_API enum sp_return sp_blocking_write(struct sp_port *port, const void *buf,
 
 #ifdef _WIN32
 	DWORD bytes_written = 0;
-	BOOL result;
 
-	/* Wait for previous non-blocking write to complete, if any. */
-	if (port->writing) {
-		DEBUG("Waiting for previous write to complete");
-		result = GetOverlappedResult(port->hdl, &port->write_ovl, &bytes_written, TRUE);
-		port->writing = 0;
-		if (!result)
-			RETURN_FAIL("Previous write failed to complete");
-		DEBUG("Previous write completed");
-	}
+	TRY(await_write_completion(port));
 
 	/* Set timeout. */
 	if (port->timeouts.WriteTotalTimeoutConstant != timeout_ms) {