Fix libpq compression when no compression algorithms are avaiable

Author: knizhnik

src/common/zpq_stream.c

@@ -440,7 +440,8 @@ zpq_write(ZpqStream *zs, void const *buf, size_t size, size_t* processed)
 void
 zpq_free(ZpqStream *zs)
 {
-	zpq_algorithms[zpq_algorithm_impl].free(zs);
+	if (zs)
+		zpq_algorithms[zpq_algorithm_impl].free(zs);
 }
 
 char const*
@@ -453,7 +454,7 @@ zpq_error(ZpqStream *zs)
 size_t
 zpq_buffered(ZpqStream *zs)
 {
-	return zpq_algorithms[zpq_algorithm_impl].buffered(zs);
+	return zs ? zpq_algorithms[zpq_algorithm_impl].buffered(zs) : 0;
 }
 
 /*

src/interfaces/libpq/fe-connect.c

@@ -431,12 +431,10 @@ pgthreadlock_t pg_g_threadlock = default_threadlock;
 void
 pqDropConnection(PGconn *conn, bool flushInput)
 {
-	if (conn->zstream)
-	{
-		/* Release compression streams */
-		zpq_free(conn->zstream);
-		conn->zstream = NULL;
-	}
+	/* Release compression streams */
+	zpq_free(conn->zstream);
+	conn->zstream = NULL;
+
 	/* Drop any SSL state */
 	pqsecure_close(conn);
 

src/interfaces/libpq/fe-misc.c

@@ -898,7 +898,7 @@ pqSendSome(PGconn *conn, int len)
 	}
 
 	/* while there's still data to send */
-	while (len > 0 || (conn->zstream && zpq_buffered(conn->zstream)))
+	while (len > 0 || zpq_buffered(conn->zstream))
 	{
 		int			sent;
 		size_t      processed = 0;
@@ -964,7 +964,7 @@ pqSendSome(PGconn *conn, int len)
 			remaining -= sent;
 		}
 
-		if (len > 0 || sent < 0 || (conn->zstream && zpq_buffered(conn->zstream)))
+		if (len > 0 || sent < 0 || zpq_buffered(conn->zstream))
 		{
 			/*
 			 * We didn't send it all, wait till we can send more.