Re: [PATCH 12/12] receive-pack: send keepalives during quiet periods

On Sat, Jul 16, 2016 at 12:56 AM, Jeff King [off-list ref] wrote:

quoted

quoted

+               if (use_keepalive == KEEPALIVE_AFTER_NUL && !keepalive_active) {
+                       const char *p = memchr(data, '\0', sz);
+                       if (p) {
+                               /*
+                                * The NUL tells us to start sending keepalives. Make
+                                * sure we send any other data we read along
+                                * with it.
+                                */
+                               keepalive_active = 1;
+                               send_sideband(1, 2, data, p - data, use_sideband);
+                               send_sideband(1, 2, p + 1, sz - (p - data + 1), use_sideband);
+                               continue;

Oh, I see why the turn_on_keepalive_on_NUL doesn't work as well as I thought.
I wonder if we can use a better read function, that would stop reading at a NUL,
and return early instead?

How would you do that, if not by read()ing a byte at a time (which is
inefficient)? Otherwise you have to deal with the leftovers (after the
NUL) in your buffer. It's one of the reasons I went with a single-byte
signal, because otherwise it gets rather complicated to do robustly.

I do not question the concept of a single NUL byte, but rather the
implementation,
i.e. if we had an xread_until_nul you would not need to have a double
send_sideband
here?

-Peff