Refactor receivelog.c parameters

Much cruft had accumulated over time with a large number of parameters
passed down between functions very deep. With this refactoring, instead
introduce a StreamCtl structure that holds the parameters, and pass around
a pointer to this structure instead. This makes it much easier to add or
remove fields that are needed deeper down in the implementation without
having to modify every function header in the file.

Patch by me after much nagging from Andres
Reviewed by Craig Ringer and Daniel Gustafsson

Author: mhagander

src/bin/pg_basebackup/pg_basebackup.c

@@ -372,10 +372,20 @@ typedef struct
 static int
 LogStreamerMain(logstreamer_param *param)
 {
-	if (!ReceiveXlogStream(param->bgconn, param->startptr, param->timeline,
-						   param->sysidentifier, param->xlogdir,
-						   reached_end_position, standby_message_timeout,
-						   NULL, false, true))
+	StreamCtl	stream;
+
+	MemSet(&stream, sizeof(stream), 0);
+	stream.startpos = param->startptr;
+	stream.timeline = param->timeline;
+	stream.sysidentifier = param->sysidentifier;
+	stream.stream_stop = reached_end_position;
+	stream.standby_message_timeout = standby_message_timeout;
+	stream.synchronous = false;
+	stream.mark_done = true;
+	stream.basedir = param->xlogdir;
+	stream.partial_suffix = NULL;
+
+	if (!ReceiveXlogStream(param->bgconn, &stream))
 
 		/*
 		 * Any errors will already have been reported in the function process,

src/bin/pg_basebackup/pg_receivexlog.c

@@ -276,10 +276,11 @@ FindStreamingStart(uint32 *tli)
 static void
 StreamLog(void)
 {
-	XLogRecPtr	startpos,
-				serverpos;
-	TimeLineID	starttli,
-				servertli;
+	XLogRecPtr	serverpos;
+	TimeLineID	servertli;
+	StreamCtl	stream;
+
+	MemSet(&stream, 0, sizeof(stream));
 
 	/*
 	 * Connect in replication mode to the server
@@ -311,30 +312,35 @@ StreamLog(void)
 	/*
 	 * Figure out where to start streaming.
 	 */
-	startpos = FindStreamingStart(&starttli);
-	if (startpos == InvalidXLogRecPtr)
+	stream.startpos = FindStreamingStart(&stream.timeline);
+	if (stream.startpos == InvalidXLogRecPtr)
 	{
-		startpos = serverpos;
-		starttli = servertli;
+		stream.startpos = serverpos;
+		stream.timeline = servertli;
 	}
 
 	/*
 	 * Always start streaming at the beginning of a segment
 	 */
-	startpos -= startpos % XLOG_SEG_SIZE;
+	stream.startpos -= stream.startpos % XLOG_SEG_SIZE;
 
 	/*
 	 * Start the replication
 	 */
 	if (verbose)
 		fprintf(stderr,
 				_("%s: starting log streaming at %X/%X (timeline %u)\n"),
-				progname, (uint32) (startpos >> 32), (uint32) startpos,
-				starttli);
+		progname, (uint32) (stream.startpos >> 32), (uint32) stream.startpos,
+				stream.timeline);
+
+	stream.stream_stop = stop_streaming;
+	stream.standby_message_timeout = standby_message_timeout;
+	stream.synchronous = synchronous;
+	stream.mark_done = false;
+	stream.basedir = basedir;
+	stream.partial_suffix = ".partial";
 
-	ReceiveXlogStream(conn, startpos, starttli, NULL, basedir,
-					  stop_streaming, standby_message_timeout, ".partial",
-					  synchronous, false);
+	ReceiveXlogStream(conn, &stream);
 
 	PQfinish(conn);
 	conn = NULL;