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From: Junio C Hamano <gitster@pobox•com>
To: David Michael <fedora.dm0@gmail•com>
Cc: git@vger•kernel.org
Subject: Re: [PATCH] compat: convert modes to use portable file type values
Date: Sun, 30 Nov 2014 19:11:39 -0800	[thread overview]
Message-ID: <xmqq8uisrrmc.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <87vblxl8ah.fsf@gmail.com> (David Michael's message of "Sat, 29 Nov 2014 21:41:10 -0500")

David Michael <fedora.dm0@gmail•com> writes:

> This is my most recent attempt at solving the problem of z/OS using
> different file type values than every other OS.  I believe it should be
> safe as long as the file type bits don't ever need to be converted back
> to their native values (and I didn't see any instances of that).
>
> I've been testing it by making commits to the same repositories on
> different operating systems and pushing those changes around, and so far
> there have been no issues.
>
> Can anyone foresee any problems with this method?

I cannot offhand comment on the last question above, but the
reliance on exact S_IFxxx bit assignment was identified as a
potential problem from very early days of Git that we have known
about but didn't have need to address on any system that mattered.

This is a long overdue issue and I am happy to see it getting
tackled.  The patch seems to be a sensible implementation of your
design decision to use the one-way conversion.

> diff --git a/compat/stat.c b/compat/stat.c
> new file mode 100644
> index 0000000..0ff1f2f
> --- /dev/null
> +++ b/compat/stat.c
> @@ -0,0 +1,49 @@
> +#define _POSIX_SOURCE
> +#include <stddef.h>    /* NULL         */
> +#include <sys/stat.h>  /* *stat, S_IS* */
> +#include <sys/types.h> /* mode_t       */
> +
> +static inline mode_t mode_native_to_git(mode_t native_mode)
> +{
> +	if (S_ISREG(native_mode))
> +		return 0100000 | (native_mode & 07777);
> +	else if (S_ISDIR(native_mode))
> +		return 0040000 | (native_mode & 07777);
> +	else if (S_ISLNK(native_mode))
> +		return 0120000 | (native_mode & 07777);
> +	else if (S_ISBLK(native_mode))
> +		return 0060000 | (native_mode & 07777);
> +	else if (S_ISCHR(native_mode))
> +		return 0020000 | (native_mode & 07777);
> +	else if (S_ISFIFO(native_mode))
> +		return 0010000 | (native_mode & 07777);
> +	else /* Non-standard type bits were given. */
> +		return native_mode & 07777;
> +}

next prev parent reply	other threads:[~2014-12-01  3:11 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-30  2:41 [PATCH] compat: convert modes to use portable file type values David Michael
2014-11-30 20:16 ` Torsten Bögershausen
2014-12-01  3:40   ` David Michael
2014-12-01  5:55     ` Torsten Bögershausen
2014-12-01 12:48       ` David Michael
2014-12-01 17:46         ` David Michael
2014-12-01  3:11 ` Junio C Hamano [this message]
2014-12-01 14:44 ` Duy Nguyen
2014-12-01 17:49   ` David Michael
2014-12-01 17:57     ` Junio C Hamano
2014-12-01 19:10       ` David Michael
2014-12-01 20:09         ` Junio C Hamano

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