Re: [PATCH] MinGW readdir reimplementation to support d_type
- From
Johannes Sixt <j6t@kdbg.org>
- Date
- Apr 11, 2009, 21:44 UTC
- Message-ID
- <49E10F5A.9010400@kdbg.org>
- In-Reply-To
- <49DEFA30.1000101@gmail.com>
Marius Storm-Olsen schrieb:
Show 39 quoted lines
> Johannes Sixt said the following on 09.04.2009 22:34:
>> Marius Storm-Olsen schrieb:
>>> +struct mingw_dirent
>>> +{
>>> + long d_ino; /* Always zero. */
>>> + union {
>>> + unsigned short d_reclen; /* Always zero. */
>>> + unsigned char d_type; /* Reimplementation adds this */
>>> + };
>>
>> VERY sneaky! I was wondering why you could get away without replacing
>> opendir and closedir, and why you still defined a replacement
>> mingw_DIR that contains the replacement mingw_dirent, until I noticed
>> this unnamed union.
>>
>> Since we don't use d_reclen anywhere in the code, wouldn't you get
>> away with
>>
>> #define d_type d_reclen
>>
>> unless the type (short vs. char) makes a difference. Or would you say
>> that doing that would be even more sneaky?
>
> I'm sure it could be done just with a define. However, given the
> remaining unused variables, I was wondering about also packing in
> permission bits and file modification time in there, to optimize the
> status checking even further. That way, on Windows, we would only need
> one 'readdir' pass to check the whole repository, with no lstats
> whatsoever. So, this was patch was a 'primer' for that, hence the union
> with a proper uchar for the d_type.
>
> However, that would also mean a significant change in the status
> checking code, as it first lstat's ever file in the index, then uses
> read_directory + lstat's for others. I guess that'll be too big of a
> change in core code, so the vision is moot?
>
> I'd be ok to just use the define, provided that it compiles cleanly of
> course, if the above seems too ambitious. :-) I kinda feel like the
> current code is more clean though :)With a comment in the commit message, it would have been clear, perhaps.
I'll carry this in my (private) tree for a while with the below squashed in to avoid a lot of warnings.
-- Hannes
diff --git a/compat/mingw.h b/compat/mingw.h index 104b310..16ec76b 100644 --- a/compat/mingw.h +++ b/compat/mingw.h @@ -260,4 +260,5 @@ struct mingw_dirent }; #define dirent mingw_dirent #define readdir(x) mingw_readdir(x) +struct dirent *mingw_readdir(DIR *dir); #endif // !NO_MINGW_REPLACE_READDIR