Re: [PATCH v8 11/11] convert: add filter.<driver>.process option

[Lars Schneider <larsxschneider@gmail.com>]

> On 27 Sep 2016, at 17:37, Jakub Narębski <jnareb@gmail.com> wrote:
> 
> Part second of the review of 11/11.
> 
> W dniu 20.09.2016 o 21:02, larsxschneider@gmail.com pisze:
> 
>> +
>> +	if (!drv->process && (CAP_CLEAN & wanted_capability) && drv->clean)
> 
> This is just a very minor nitpicking, but wouldn't it be easier
> to read with those checks reordered?
> 
>  +	if ((wanted_capability & CAP_CLEAN) && !drv->process && drv->clean)

OK


>> +
>> +	if (start_command(process)) {
>> +		error("cannot fork to run external filter '%s'", cmd);
>> +		kill_multi_file_filter(hashmap, entry);
>> +		return NULL;
>> +	}
> 
> I guess there is a reason why we init hashmap entry, try to start
> external process, then kill entry of unable to start, instead of
> trying to start external process, and adding hashmap entry when
> we succeed?

Yes. This way I can reuse the kill_multi_file_filter() function.


>> +
>> +	sigchain_push(SIGPIPE, SIG_IGN);
> 
> I guess that this is here to handle errors writing to filter
> by ourself, isn't it?

Yes.


>> +		error("external filter '%s' does not support long running filter protocol", cmd);
> 
> We could have described the error here better.
> 
>  +		error("external filter '%s' does not support filter protocol version 2", cmd);

OK


>> +static void read_multi_file_filter_values(int fd, struct strbuf *status) {
> 
> This is more
> 
>  +static void read_multi_file_filter_status(int fd, struct strbuf *status) {
> 
> It doesn't read arbitrary values, it examines 'metadata' from
> filter for "status=<foo>" lines.

True!


>> +		if (pair[0] && pair[0]->len && pair[1]) {
>> +			if (!strcmp(pair[0]->buf, "status=")) {
>> +				strbuf_reset(status);
>> +				strbuf_addbuf(status, pair[1]);
>> +			}
> 
> So it is last status=<foo> line wins behavior?

Correct.


> 
>> +		}
> 
> Shouldn't we free 'struct strbuf **pair', maybe allocated by the
> strbuf_split_str() function, and reset to NULL?

True. strbuf_list_free() should be enough.


>> 
>> +	fflush(NULL);
> 
> Why this fflush(NULL) is needed here?

This flushes all open output streams. The single filter does the same.


>> 
>> +	if (fd >= 0 && !src) {
>> +		if (fstat(fd, &file_stat) == -1)
>> +			return 0;
>> +		len = xsize_t(file_stat.st_size);
>> +	}
> 
> Errr... is it necessary?  The protocol no longer provides size=<n>
> hint, and neither uses such hint if provided.

We require the size in write_packetized_from_buf() later.


>> +
>> +	err = strlen(filter_type) > PKTLINE_DATA_MAXLEN;
>> +	if (err)
>> +		goto done;
> 
> Errr... this should never happen.  We control which capabilities
> we pass, it can be only "clean" or "smudge", nothing else. Those
> would always be shorter than PKTLINE_DATA_MAXLEN.
> 
> Never mind that that is "command=smudge\n" etc. that needs to
> be shorter that PKTLINE_DATA_MAXLEN!
> 
> So, IMHO it should be at most assert, and needs to be corrected
> anyway.

OK!


> This should never happen, PATH_MAX everywhere is much shorter
> than PKTLINE_DATA_MAXLEN / LARGE_PACKET_MAX.  Or is it?
> 
> Anyway, we should probably explain or warn
> 
>   		error("path name too long: '%s'", path);

OK


>> +			/*
>> +			 * Something went wrong with the protocol filter.
>> +			 * Force shutdown and restart if another blob requires filtering!
> 
> Is this exclamation mark '!' here necessary?
> 

No.


Thanks,
Lars