From: Thomas Adam <thomas@xteddy.org>
To: Jakub Narebski <jnareb@gmail.com>
Cc: git@vger.kernel.org,
"John 'Warthog9' Hawley" <warthog9@kernel.org>,
Petr Baudis <pasky@ucw.cz>,
admin@repo.or.cz
Subject: Re: [PATCHv5 03/17] gitweb/lib - Very simple file based cache
Date: Thu, 7 Oct 2010 00:12:43 +0100 [thread overview]
Message-ID: <AANLkTikVmHgk=jLCs11tJ7yhUL4H2gnM_pKkXOJSxYq7@mail.gmail.com> (raw)
In-Reply-To: <201010070100.33478.jnareb@gmail.com>
Hi --
On 7 October 2010 00:00, Jakub Narebski <jnareb@gmail.com> wrote:
> Thank you very much for those comments on code.
Sure.
> On the other hand this way scope where "no strict 'refs';" is active
> is limited... but I guess having "no strict 'refs';" outside loop would
> be better.
Definitely.
>>
>> > + my $file = $self->path_to_key($key);
>> > + return undef unless (defined $file && -f $file);
>>
>> PBP (Perl Best Practises) will tell you that explicitly returning
>> undef is discouraged -- "undef" should be reserved for those errors
>> you cannot handle, not ones you don't want to.
>
> Well, Perl Best Practices are practices; sometimes there is good reason
> to not take them into account (though probably not in this case).
Do not ever underestimate Conway's book, Jakub -- seriously. It's
not a Bible, sure, but to ignore it or otherwise eschew its advise is
to shoot yourself in the foot. :)
> I should really have run gitweb, caching modules and tests through
> perlcritic...
And your other patches. :)
>> > + last if $read_cnt == 0;
>> > + $size_left -= $read_cnt;
>> > + #last if $size_left <= 0;
>> > + }
>> > +
>> > + close $read_fh
>> > + or die "Couldn't close file '$file' opened for reading: $!";
>> > + return $buf;
>> > +}
>>
>> "use Carp;" would be more useful here, and hence croak() and confess().
>
> For a web application we usually do not want to have too detailed error
> message present to client (to web browser) to avoid leaking of sensitive
> information.
Unless we use fatalstobrowser, it will still end up in Apache's error
log. I don't see a problem here.
>> > + # ensure that directory leading to cache file exists
>> > + if (!-d $dir) {
>> > + eval { mkpath($dir, 0, 0777); 1 }
>> > + or die "Couldn't create leading directory '$dir' (mkpath): $!";
>> > + }
>>
>> Why is this eval()ed? It will still return false and set $! appropriately.
>
> IIRC mkpath *dies on error*, rather than returning false. For better
> error handling we would need to use make_path, but File::Path 2.0+
> is in [stable] core only since Perl 5.10.
Umm, maybe. I've not verified this, but we shouldn't rely on this either.
> I don't want to code too defensively, but perhaps check for this is in
> order... though what we should do if $code is not code reference?
confess() ahem, or otherwise die() since it's a complete fail here.
Appropriate logging is necessary here.
>>
>> unless( defined $code and ref $code eq 'CODE' )
>
> "ref($code) eq 'CODE'" would be enough; 'undef' is not reference, and
> ref(undef) returns "".
Sure, but it still assumes $code is a reference, and there's no
guarantee of that in the code path.
>> {
>> ....
>> }
>>
>> Wouldn't it be easier to eval{} this and check $@?
>
> So the answer is no.
Fantastic! :)
-- Thomas Adam
next prev parent reply other threads:[~2010-10-06 23:13 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-06 22:01 [PATCHv5 00/17] gitweb: Simple file based output caching Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 01/17] t/test-lib.sh: Export also GIT_BUILD_DIR in test_external Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 02/17] gitweb: Prepare for splitting gitweb Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 03/17] gitweb/lib - Very simple file based cache Jakub Narebski
2010-10-06 22:41 ` Thomas Adam
2010-10-06 22:44 ` Ævar Arnfjörð Bjarmason
2010-10-06 22:46 ` Thomas Adam
2010-10-06 22:47 ` Ævar Arnfjörð Bjarmason
2010-10-06 23:00 ` Jakub Narebski
2010-10-06 23:12 ` Thomas Adam [this message]
2010-10-06 23:32 ` Jakub Narebski
2010-10-06 22:57 ` Ævar Arnfjörð Bjarmason
2010-10-06 23:46 ` Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 04/17] gitweb/lib - Stat-based cache expiration Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 05/17] gitweb/lib - Regenerate entry if the cache file has size of 0 Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 06/17] gitweb/lib - Simple select(FH) based output capture Jakub Narebski
2010-10-06 22:52 ` Thomas Adam
2010-10-06 23:22 ` Jakub Narebski
2010-10-06 23:03 ` Ævar Arnfjörð Bjarmason
2010-10-06 23:26 ` Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 07/17] gitweb/lib - Cache captured output (using get/set) Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 08/17] gitweb: Add optional output caching Jakub Narebski
2010-10-06 22:46 ` Ævar Arnfjörð Bjarmason
2010-10-06 23:06 ` Jakub Narebski
2010-10-06 23:16 ` Ævar Arnfjörð Bjarmason
2010-10-06 22:01 ` [PATCHv5 09/17] gitweb/lib - Adaptive cache expiration time Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 10/21] gitweb/lib - Use CHI compatibile (compute method) caching interface Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 11/17] gitweb/lib - Use locking to avoid 'cache miss stampede' problem Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 12/17] gitweb/lib - No need for File::Temp when locking Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 13/17] gitweb/lib - Serve stale data when waiting for filling cache Jakub Narebski
2010-10-06 22:01 ` [PATCHv5 14/17] gitweb/lib - Regenerate (refresh) cache in background Jakub Narebski
2010-10-06 22:02 ` [PATCHv5 15/17] gitweb: Introduce %actions_info, gathering information about actions Jakub Narebski
2010-10-06 22:02 ` [PATCHv5/RFC 16/17] gitweb: Show appropriate "Generating..." page when regenerating cache Jakub Narebski
2010-10-06 22:02 ` [PATCHv5/RFC 17/17] gitweb: Add startup delay to activity indicator for cache Jakub Narebski
2010-10-06 22:02 ` [RFC/PATCHv5 18/17] gitweb/lib - Add clear() and size() methods to caching interface Jakub Narebski
2010-10-06 22:56 ` Thomas Adam
2010-10-06 22:02 ` [RFC PATCHv5 19/17] gitweb: Add beginnings of cache administration page Jakub Narebski
2010-10-06 22:02 ` [PoC PATCHv5 20/17] gitweb/lib - Benchmarking GitwebCache::SimpleFileCache (in t/9603/) Jakub Narebski
2010-10-06 22:02 ` [PoC PATCHv5 21/17] gitweb/lib - Alternate ways of capturing output Jakub Narebski
2010-10-10 20:32 ` [RFD] Possible improvements for output caching in gitweb Jakub Narebski
2010-10-24 21:34 ` [PATCHv5 00/17] gitweb: Simple file based output caching J.H.
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