Re: [WIP RFC 4/5] upload-pack: refactor writing of "packfile" line

From: Jonathan Tan <jonathantanmy@google.com>
Date: Dec 6, 2018, 23:25 UTC
Message-ID: <20181206232538.141378-1-jonathantanmy@google.com>
In-Reply-To: <xmqqzhtj88nw.fsf@gitster-ct.c.googlers.com>

Show 15 quoted lines

> Jonathan Tan <jonathantanmy@google.com> writes:
> 
> > @@ -126,6 +129,12 @@ static int read_pack_objects_stdout(int outfd, struct output_state *os)
> >  	}
> >  	os->used += readsz;
> >  
> > +	if (!os->packfile_started) {
> > +		os->packfile_started = 1;
> > +		if (use_protocol_v2)
> > +			packet_write_fmt(1, "packfile\n");
> 
> If we fix this function so that the only byte in the buffer is held
> back without emitted when os->used == 1 as I alluded to, this may
> have to be done a bit later, as with such a change, it is no longer
> guaranteed that send_client_data() will be called after this point.

I'm not sure what you mean about there being no guarantee that send_client_data() is not called - in create_pack_file(), there is an "if (output_state.used > 0)" line (previously "if (0 <= buffered)") that outputs anything remaining.

Show 5 quoted lines

> Isn't progress output that goes to the channel #2 pretty much
> independent from the payload stream that carries the pkt-line 
> command like "packfile" plus the raw pack stream?  It somehow
> feels like an oxymoron to _buffer_ progress indicator, as it
> defeats the whole point of progress report to buffer it.

Yes, it is - I don't fully like this part of the design. I alluded to a similar issue (keepalive) in the toplevel email [1] and that it might be better if the server can send sideband throughout the whole response - perhaps that should be investigated first. If we had sideband throughout the whole response, we wouldn't need to buffer the progress indicator.

[1] https://public-inbox.org/git/cover.1543879256.git.jonathantanmy@google.com/