work around buggy S_ISxxx(m) implementations

There are buggy implementations of S_ISxxx(m) macros on some platforms
(e.g. NetBSD).  The issue is that NetBSD doesn't take care to wrap its
macro arguments in parentheses, so on Linux and sane systems we have
S_ISREG(m) defined as something like:

    (((m) & S_IFMT) == S_IFREG)

But on NetBSD:

    ((m & _S_IFMT) == _S_IFREG)

Since a caller in builtin/diff.c called our macro as `S_IFREG | 0644'
this bug introduced a logic error on NetBSD, since the precedence of
bit-wise & is higher than | in C.

[jc: took change description from Ævar Arnfjörð Bjarmason's patch]

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
René Scharfe 2010-10-04 12:53:11 +02:00 committed by Junio C Hamano
parent 349362cc20
commit b90d9b8895

13
cache.h
View File

@ -277,9 +277,16 @@ static inline int ce_to_dtype(const struct cache_entry *ce)
else
return DT_UNKNOWN;
}
#define canon_mode(mode) \
(S_ISREG(mode) ? (S_IFREG | ce_permissions(mode)) : \
S_ISLNK(mode) ? S_IFLNK : S_ISDIR(mode) ? S_IFDIR : S_IFGITLINK)
static inline unsigned int canon_mode(unsigned int mode)
{
if (S_ISREG(mode))
return S_IFREG | ce_permissions(mode);
if (S_ISLNK(mode))
return S_IFLNK;
if (S_ISDIR(mode))
return S_IFDIR;
return S_IFGITLINK;
}
#define flexible_size(STRUCT,len) ((offsetof(struct STRUCT,name) + (len) + 8) & ~7)
#define cache_entry_size(len) flexible_size(cache_entry,len)