Changed the prerelease-protocol support to use an idiom that will not

slow down the initial version handshake between the two sides.

diff --git a/compat.c b/compat.c
index 0cfb78f..c5eee15 100644 (file)
--- a/compat.c
+++ b/compat.c
@@ -49,11 +49,41 @@ extern int need_messages_from_generator;
 extern int delete_mode, delete_before, delete_during, delete_after;
 extern int delete_excluded;
 extern int make_backups;
+extern char *shell_cmd; /* contains VER.SUB string if client is a pre-release */
 extern char *backup_dir, *backup_suffix;
 extern char *partial_dir;
 extern char *dest_option;
 extern struct filter_list_struct filter_list;
 
+/* The server makes sure that if either side only supports a pre-release
+ * version of a protocol, that both sides must speak a compatible version
+ * of that protocol for it to be advertised as available. */
+static void check_sub_protocol(void)
+{
+       char *dot;
+       int their_protocol, their_sub;
+       int our_sub = protocol_version < PROTOCOL_VERSION ? 0 : SUBPROTOCOL_VERSION;
+
+       if (!shell_cmd || !(dot = strchr(shell_cmd, '.'))
+        || !(their_protocol = atoi(shell_cmd))
+        || !(their_sub = atoi(dot+1))) {
+               if (our_sub)
+                       protocol_version--;
+               return;
+       }
+
+       if (their_protocol < protocol_version) {
+               if (their_sub)
+                       protocol_version = their_protocol - 1;
+               return;
+       }
+
+       if (their_protocol > protocol_version)
+               their_sub = 0; /* 0 == final version */
+       if (their_sub != our_sub)
+               protocol_version--;
+}
+
 void setup_protocol(int f_out,int f_in)
 {
        if (am_sender)
@@ -70,27 +100,16 @@ void setup_protocol(int f_out,int f_in)
                preserve_xattrs = ++file_extra_cnt;
 
        if (remote_protocol == 0) {
+               if (am_server && !local_server)
+                       check_sub_protocol();
                if (!read_batch)
                        write_int(f_out, protocol_version);
                remote_protocol = read_int(f_in);
                if (protocol_version > remote_protocol)
                        protocol_version = remote_protocol;
-               /* CVS support: fallback to finalized protocol if incompatible */
-               if (protocol_version >= 30) {
-                       int theirsub, oursub = SUBPROTOCOL_VERSION;
-                       if (!read_batch)
-                               write_varint(f_out, oursub);
-                       theirsub = read_varint(f_in);
-                       if (remote_protocol > PROTOCOL_VERSION)
-                               theirsub = 0; /* 0 == final version */
-                       if (protocol_version < PROTOCOL_VERSION)
-                               oursub = 0;
-                       if (theirsub != oursub)
-                               protocol_version--;
-               }
        }
        if (read_batch && remote_protocol > protocol_version) {
-               rprintf(FERROR, "The protocol version in the batch file is too new (%d > %d).\n",
+               rprintf(FERROR, "The protocol version in the batch file is too new (%d > %d).\n",
                        remote_protocol, protocol_version);
                exit_cleanup(RERR_PROTOCOL);
        }

diff --git a/io.c b/io.c
index 571f1ff..a7603ff 100644 (file)
--- a/io.c
+++ b/io.c
@@ -1715,11 +1715,6 @@ void start_write_batch(int fd)
         * actual communication so far depends on whether a daemon
         * is involved. */
        write_int(batch_fd, protocol_version);
-       if (protocol_version >= 30) {
-               int sub = protocol_version == PROTOCOL_VERSION
-                       ? SUBPROTOCOL_VERSION : 0;
-               write_varint(batch_fd, sub);
-       }
        write_int(batch_fd, checksum_seed);
 
        if (am_sender)

diff --git a/options.c b/options.c
index a269a51..4a9b28f 100644 (file)
--- a/options.c
+++ b/options.c
@@ -1650,6 +1650,13 @@ void server_options(char **args,int *argc)
 
        argstr[x] = '\0';
 
+       /* If we're speaking a pre-release version of a protocol, we tell
+        * the server about this by (ab)using the -e option. */
+       if (SUBPROTOCOL_VERSION && protocol_version == PROTOCOL_VERSION) {
+               x += snprintf(argstr+x, sizeof argstr - x,
+                             "e%d.%d", PROTOCOL_VERSION, SUBPROTOCOL_VERSION);
+       }
+
        if (x != 1)
                args[ac++] = argstr;