--- flist.c	16 Sep 2005 05:52:54 -0000	1.303
+++ flist.c	16 Sep 2005 16:41:25 -0000
@@ -36,6 +36,7 @@ extern int am_daemon;
 extern int am_sender;
 extern int do_progress;
 extern int always_checksum;
+extern int pre_checksum;
 extern int module_id;
 extern int ignore_errors;
 extern int numeric_ids;
@@ -716,6 +717,16 @@ static struct file_struct *receive_file_
 			sum = empty_sum;
 		}
 		read_buf(f, sum, slen);
+		if (pre_checksum) {
+			char sum2[MD4_SUM_LENGTH];
+			STRUCT_STAT st;
+			char *fname = f_name(file);
+			if (stat(fname, &st) == 0 && st.st_size == file_length) {
+				file_checksum(fname, sum2, st.st_size);
+				if (memcmp(sum, sum2, slen) != 0)
+					file->flags |= FLAG_SUM_DIFFERS;
+			}
+		}
 	}
 
 	if (!preserve_perms) {
--- generator.c	6 Sep 2005 18:12:38 -0000	1.222
+++ generator.c	16 Sep 2005 16:41:25 -0000
@@ -67,6 +67,7 @@ extern int ignore_timeout;
 extern int protocol_version;
 extern int fuzzy_basis;
 extern int always_checksum;
+extern int pre_checksum;
 extern char *partial_dir;
 extern char *basis_dir[];
 extern int compare_dest;
@@ -358,7 +359,8 @@ void itemize(struct file_struct *file, i
 
 
 /* Perform our quick-check heuristic for determining if a file is unchanged. */
-static int unchanged_file(char *fn, struct file_struct *file, STRUCT_STAT *st)
+static int unchanged_file(char *fn, int fnamecmp_type, struct file_struct *file,
+			  STRUCT_STAT *st)
 {
 	if (st->st_size != file->length)
 		return 0;
@@ -367,6 +369,8 @@ static int unchanged_file(char *fn, stru
 	   of the file time to determine whether to sync */
 	if (always_checksum && S_ISREG(st->st_mode)) {
 		char sum[MD4_SUM_LENGTH];
+		if (pre_checksum && fnamecmp_type == FNAMECMP_FNAME)
+			return !(file->flags & FLAG_SUM_DIFFERS);
 		file_checksum(fn, sum, st->st_size);
 		return memcmp(sum, file->u.sum, protocol_version < 21 ? 2
 							: MD4_SUM_LENGTH) == 0;
@@ -913,7 +917,7 @@ static void recv_generator(char *fname, 
 				match_level = 1;
 				/* FALL THROUGH */
 			case 1:
-				if (!unchanged_file(fnamecmpbuf, file, &st))
+				if (!unchanged_file(fnamecmpbuf, 0, file, &st))
 					continue;
 				best_match = i;
 				match_level = 2;
@@ -1044,7 +1048,7 @@ static void recv_generator(char *fname, 
 		;
 	else if (fnamecmp_type == FNAMECMP_FUZZY)
 		;
-	else if (unchanged_file(fnamecmp, file, &st)) {
+	else if (unchanged_file(fnamecmp, fnamecmp_type, file, &st)) {
 		if (fnamecmp_type == FNAMECMP_FNAME) {
 			if (itemizing) {
 				itemize(file, ndx, real_ret, &real_st,
--- main.c	16 Sep 2005 16:40:30 -0000	1.277
+++ main.c	16 Sep 2005 16:41:25 -0000
@@ -45,6 +45,7 @@ extern int copy_links;
 extern int keep_dirlinks;
 extern int preserve_hard_links;
 extern int protocol_version;
+extern int always_checksum;
 extern int recurse;
 extern int relative_paths;
 extern int rsync_port;
@@ -60,8 +61,10 @@ extern char *filesfrom_host;
 extern char *rsync_path;
 extern char *shell_cmd;
 extern char *batch_name;
+extern char curr_dir[MAXPATHLEN];
 
 int local_server = 0;
+int pre_checksum = 0;
 struct file_list *the_file_list;
 
 /* There's probably never more than at most 2 outstanding child processes,
@@ -613,6 +616,7 @@ static void do_server_recv(int f_in, int
 	struct file_list *flist;
 	char *local_name = NULL;
 	char *dir = NULL;
+	char olddir[sizeof curr_dir];
 	int save_verbose = verbose;
 
 	if (filesfrom_fd >= 0) {
@@ -657,6 +661,10 @@ static void do_server_recv(int f_in, int
 		filesfrom_fd = -1;
 	}
 
+	strlcpy(olddir, curr_dir, sizeof olddir);
+	if (always_checksum && argc > 0)
+		pre_checksum = push_dir(argv[0]);
+
 	flist = recv_file_list(f_in);
 	verbose = save_verbose;
 	if (!flist) {
@@ -665,6 +673,9 @@ static void do_server_recv(int f_in, int
 	}
 	the_file_list = flist;
 
+	if (pre_checksum)
+		pop_dir(olddir);
+
 	if (argc > 0)
 		local_name = get_local_name(flist,argv[0]);
 
@@ -713,6 +724,7 @@ int client_run(int f_in, int f_out, pid_
 {
 	struct file_list *flist = NULL;
 	int status = 0, status2 = 0;
+	char olddir[sizeof curr_dir];
 	char *local_name = NULL;
 
 	cleanup_child_pid = pid;
@@ -784,11 +796,18 @@ int client_run(int f_in, int f_out, pid_
 		filesfrom_fd = -1;
 	}
 
+	strlcpy(olddir, curr_dir, sizeof olddir);
+	if (always_checksum)
+		pre_checksum = push_dir(argv[0]);
+
 	if (write_batch && !am_server)
 		start_write_batch(f_in);
 	flist = recv_file_list(f_in);
 	the_file_list = flist;
 
+	if (pre_checksum)
+		pop_dir(olddir);
+
 	if (flist && flist->count > 0) {
 		local_name = get_local_name(flist, argv[0]);
 
--- rsync.h	29 Jul 2005 18:31:03 -0000	1.265
+++ rsync.h	16 Sep 2005 16:41:26 -0000
@@ -64,6 +64,7 @@
 #define FLAG_DEL_HERE (1<<3)	/* receiver/generator */
 #define FLAG_SENT (1<<3)	/* sender */
 #define FLAG_HLINK_TOL (1<<4)	/* receiver/generator */
+#define FLAG_SUM_DIFFERS (1<<5)	/* receiver/generator */
 
 /* update this if you make incompatible changes */
 #define PROTOCOL_VERSION 29