give priority to progress messages

In theory it is possible for sideband channel #2 to be delayed if
pack data is quick to come up for sideband channel #1.  And because
data for channel #2 is read only 128 bytes at a time while pack data
is read 8192 bytes at a time, it is possible for many pack blocks to
be sent to the client before the progress message fifo is emptied,
making the situation even worse.  This would result in totally garbled
progress display on the client's console as local progress gets mixed
with partial remote progress lines.

Let's prevent such situations by giving transmission priority to
progress messages over pack data at all times.

Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-upload-archive.c b/builtin-upload-archive.c
index f6c4c0f149801c2d423f7ed1740a6fe9b03cf8df..58f6b8f3779e55154b3d598f39bfee32eba3c545 100644 (file)
--- a/builtin-upload-archive.c
+++ b/builtin-upload-archive.c
@@ -132,7 +132,6 @@ int cmd_upload_archive(int argc, const char **argv, const char *prefix)
 
        while (1) {
                struct pollfd pfd[2];
-               ssize_t processed[2] = { 0, 0 };
                int status;
 
                pfd[0].fd = fd1[0];
@@ -147,15 +146,14 @@ int cmd_upload_archive(int argc, const char **argv, const char *prefix)
                        }
                        continue;
                }
-               if (pfd[0].revents & POLLIN)
-                       /* Data stream ready */
-                       processed[0] = process_input(pfd[0].fd, 1);
                if (pfd[1].revents & POLLIN)
                        /* Status stream ready */
-                       processed[1] = process_input(pfd[1].fd, 2);
-               /* Always finish to read data when available */
-               if (processed[0] || processed[1])
-                       continue;
+                       if (process_input(pfd[1].fd, 2))
+                               continue;
+               if (pfd[0].revents & POLLIN)
+                       /* Data stream ready */
+                       if (process_input(pfd[0].fd, 1))
+                               continue;
 
                if (waitpid(writer, &status, 0) < 0)
                        error_clnt("%s", lostchild);

diff --git a/upload-pack.c b/upload-pack.c
index b98b1d61c127de6368d24cc3c3b16a054724ed74..8734f1d1b958f0ddbe1f88b783f1fbfb6003814f 100644 (file)
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -218,6 +218,23 @@ static void create_pack_file(void)
                        }
                        continue;
                }
+               if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
+                       /* Status ready; we ship that in the side-band
+                        * or dump to the standard error.
+                        */
+                       sz = xread(pack_objects.err, progress,
+                                 sizeof(progress));
+                       if (0 < sz)
+                               send_client_data(2, progress, sz);
+                       else if (sz == 0) {
+                               close(pack_objects.err);
+                               pack_objects.err = -1;
+                       }
+                       else
+                               goto fail;
+                       /* give priority to status messages */
+                       continue;
+               }
                if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
                        /* Data ready; we keep the last byte to ourselves
                         * in case we detect broken rev-list, so that we
@@ -255,21 +272,6 @@ static void create_pack_file(void)
                        if (sz < 0)
                                goto fail;
                }
-               if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
-                       /* Status ready; we ship that in the side-band
-                        * or dump to the standard error.
-                        */
-                       sz = xread(pack_objects.err, progress,
-                                 sizeof(progress));
-                       if (0 < sz)
-                               send_client_data(2, progress, sz);
-                       else if (sz == 0) {
-                               close(pack_objects.err);
-                               pack_objects.err = -1;
-                       }
-                       else
-                               goto fail;
-               }
        }
 
        if (finish_command(&pack_objects)) {