On 23 Jul 2016, at 10:14, Eric Wong <e@xxxxxxxxx> wrote:
> larsxschneider@xxxxxxxxx wrote:
>> Please note that the protocol filters do not support stream processing
>> with this implemenatation because the filter needs to know the length of
>> the result in advance. A protocol version 2 could address this in a
>> future patch.
>
> Would it be prudent to reuse pkt-line for this?
Peff suggested that, too, in $gmane/299902. However, this would make the
protocol a bit more complicated and it wouldn't buy us anything for Git
large file processing filters (my main motivation for this patch) as these
filters can't leverage streaming anyways.
>> +static void stop_protocol_filter(struct cmd2process *entry) {
>> + if (!entry)
>> + return;
>> + sigchain_push(SIGPIPE, SIG_IGN);
>> + close(entry->process.in);
>> + close(entry->process.out);
>> + sigchain_pop(SIGPIPE);
>> + finish_command(&entry->process);
>> + child_process_clear(&entry->process);
>> + hashmap_remove(&cmd_process_map, entry, NULL);
>> + free(entry);
>> +}
>> +
>> +static struct cmd2process *start_protocol_filter(const char *cmd)
>> +{
>> + int ret = 1;
>> + struct cmd2process *entry = NULL;
>> + struct child_process *process = NULL;
>
> These are unconditionally set below, so initializing to NULL
> may hide future bugs.
OK. I thought it is generally a good thing to initialize a pointer with
NULL. Can you explain to me how this might hide future bugs?
I will remove the initialization.
>> + struct strbuf nbuf = STRBUF_INIT;
>> + struct string_list split = STRING_LIST_INIT_NODUP;
>> + const char *argv[] = { NULL, NULL };
>> + const char *header = "git-filter-protocol\nversion";
>
> static const char header[] = "git-filter-protocol\nversion";
>
> ...might be smaller by avoiding the extra pointer
> (but compilers ought to be able to optimize it)
Agreed!
>> + entry = xmalloc(sizeof(*entry));
>> + hashmap_entry_init(entry, strhash(cmd));
>> + entry->cmd = cmd;
>> + process = &entry->process;
>
> <snip>
>
>> + ret &= strncmp(header, split.items[0].string, strlen(header)) == 0;
>
> starts_with() is probably more readable, here.
OK, will fix.
>> +static int apply_protocol_filter(const char *path, const char *src, size_t len,
>> + int fd, struct strbuf *dst, const char *cmd,
>> + const char *filter_type)
>> +{
>> + int ret = 1;
>> + struct cmd2process *entry = NULL;
>> + struct child_process *process = NULL;
>
> I would leave process initialized, here, since it should
> always be set below:
OK, will fix.
>> + struct stat fileStat;
>> + struct strbuf nbuf = STRBUF_INIT;
>> + size_t nbuf_len;
>> + char *strtol_end;
>> + char c;
>> +
>> + if (!cmd || !*cmd)
>> + return 0;
>> +
>> + if (!dst)
>> + return 1;
>> +
>> + if (!cmd_process_map_init) {
>> + cmd_process_map_init = 1;
>> + hashmap_init(&cmd_process_map, (hashmap_cmp_fn) cmd2process_cmp, 0);
>> + } else {
>> + entry = find_protocol_filter_entry(cmd);
>> + }
>> +
>> + if (!entry){
>> + entry = start_protocol_filter(cmd);
>> + if (!entry) {
>> + stop_protocol_filter(entry);
>
> stop_protocol_filter is a no-op, here, since entry is NULL
Oops - a result of my own refactoring :-) Thank you!
>> + return 0;
>> + }
>> + }
>> + process = &entry->process;
>> +
>> + sigchain_push(SIGPIPE, SIG_IGN);
>> + switch (entry->protocol) {
>> + case 1:
>> + if (fd >= 0 && !src) {
>> + ret &= fstat(fd, &fileStat) != -1;
>> + len = fileStat.st_size;
>
> There's a truncation bug when sizeof(size_t) < sizeof(off_t)
OK. What would you suggest to do in that case? Should we just let the
filter fail? Is there anything else we could do?
> (and mixedCase is inconsistent with our style)
OK, will fix.
>> + my $filelen = <STDIN>;
>> + chomp $filelen;
>> + print $debug " $filelen";
>> +
>> + $filelen = int($filelen);
>
> Calling int() here is unnecessary and may hide bugs if you
> forget to check $debug. Perhaps a regexp check is safer:
>
> $filelen =~ /\A\d+\z/ or die "bad filelen: $filelen\n";
OK, will fix!
Thanks for your review,
Lars
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