From d6dead6bb15edc672b188bc2941ab02744a899bb Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <tridge@samba.org>
Date: Fri, 15 May 1998 07:34:19 +0000
Subject: [PATCH] added write buffering during the file list sending. This
 makes things a bit more efficient (less system calls)

---
 flist.c | 10 +++++++++-
 io.c    | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 rsync.h |  1 +
 3 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/flist.c b/flist.c
index 4c2e984c..d7da6e88 100644
--- a/flist.c
+++ b/flist.c
@@ -573,6 +573,10 @@ struct file_list *send_file_list(int f,int argc,char *argv[])
 						     flist->malloced);
 	if (!flist->files) out_of_memory("send_file_list");
 
+	if (f != -1) {
+		io_start_buffering(f);
+	}
+
 	for (i=0;i<argc;i++) {
 		char fname2[MAXPATHLEN];
 		char *fname = fname2;
@@ -658,7 +662,6 @@ struct file_list *send_file_list(int f,int argc,char *argv[])
 
 	if (f != -1) {
 		send_file_entry(NULL,f,0);
-		write_flush(f);
 	}
 
 	if (verbose && recurse && !am_server && f != -1)
@@ -677,6 +680,11 @@ struct file_list *send_file_list(int f,int argc,char *argv[])
 		write_int(f, io_error);
 	}
 
+	if (f != -1) {
+		io_end_buffering(f);
+		write_flush(f);
+	}
+
 	if (verbose > 2)
 		rprintf(FINFO,"send_file_list done\n");
 
diff --git a/io.c b/io.c
index 52c4cb14..1fafaa62 100644
--- a/io.c
+++ b/io.c
@@ -301,7 +301,7 @@ int write_file(int f,char *buf,int len)
 }
 
 
-static int writefd(int fd,char *buf,int len)
+static int writefd_unbuffered(int fd,char *buf,int len)
 {
   int total = 0;
   fd_set w_fds, r_fds;
@@ -375,6 +375,58 @@ static int writefd(int fd,char *buf,int len)
   return total;
 }
 
+static char *io_buffer;
+static int io_buffer_count;
+
+void io_start_buffering(int fd)
+{
+	io_buffer = (char *)malloc(IO_BUFFER_SIZE);
+	if (!io_buffer) out_of_memory("writefd");
+	io_buffer_count = 0;
+}
+
+void io_end_buffering(int fd)
+{
+	if (io_buffer_count) {
+		if (writefd_unbuffered(fd, io_buffer, 
+				       io_buffer_count) != 
+		    io_buffer_count) {
+			rprintf(FERROR,"write failed\n");
+			exit_cleanup(1);
+		}
+		io_buffer_count = 0;
+	}
+	free(io_buffer);
+	io_buffer = NULL;
+}
+
+static int writefd(int fd,char *buf,int len1)
+{
+	int len = len1;
+
+	if (!io_buffer) return writefd_unbuffered(fd, buf, len);
+
+	while (len) {
+		int n = MIN(len, IO_BUFFER_SIZE-io_buffer_count);
+		if (n > 0) {
+			memcpy(io_buffer+io_buffer_count, buf, n);
+			buf += n;
+			len -= n;
+			io_buffer_count += n;
+		}
+		
+		if (io_buffer_count == IO_BUFFER_SIZE) {
+			if (writefd_unbuffered(fd, io_buffer, 
+					       io_buffer_count) != 
+			    io_buffer_count) {
+				return -1;
+			}
+			io_buffer_count = 0;
+		}
+	}
+
+	return len1;
+}
 
 
 void write_int(int f,int32 x)
diff --git a/rsync.h b/rsync.h
index 13116707..187ef375 100644
--- a/rsync.h
+++ b/rsync.h
@@ -51,6 +51,7 @@
 #define WRITE_SIZE (32*1024)
 #define CHUNK_SIZE (32*1024)
 #define MAX_MAP_SIZE (4*1024*1024)
+#define IO_BUFFER_SIZE (4096)
 
 #define MAX_ARGS 1000
 
-- 
2.34.1