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authorÆvar Arnfjörð Bjarmason <avarab@gmail.com>2017-06-15 21:06:59 (GMT)
committerJunio C Hamano <gitster@pobox.com>2017-06-15 21:56:39 (GMT)
commit481df65f4f72582369eea8d002070c5dff38f8e6 (patch)
treea3fb4da57f398d6d6fd9530997384b933afd9ad2
parent97e2ff464302565877a00b8a9aa6a2d85bd1445e (diff)
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git-compat-util: add a FREE_AND_NULL() wrapper around free(ptr); ptr = NULL
Add a FREE_AND_NULL() wrapper marco for the common pattern of freeing a pointer and assigning NULL to it right afterwards. The implementation is similar to the (currently unused) XDL_PTRFREE macro in xdiff/xmacros.h added in commit 3443546f6e ("Use a *real* built-in diff generator", 2006-03-24). The only difference is that free() is called unconditionally, see [1]. See [2] for a suggested alternative which does this via a function instead of a macro. As covered in replies to that message, while it's a viable approach, it would introduce caveats which this approach doesn't have, so that potential change is left to a future follow-up change. This merely allows us to translate exactly what we're doing now to a less verbose & idiomatic form using a macro, while guaranteeing that we don't introduce any functional changes. 1. <alpine.DEB.2.20.1608301948310.129229@virtualbox> (http://public-inbox.org/git/alpine.DEB.2.20.1608301948310.129229@virtualbox/) 2. <20170610032143.GA7880@starla> (https://public-inbox.org/git/20170610032143.GA7880@starla/) Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--git-compat-util.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/git-compat-util.h b/git-compat-util.h
index 51ba4e6..047172d 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -808,6 +808,12 @@ extern char *xgetcwd(void);
extern FILE *fopen_for_writing(const char *path);
extern FILE *fopen_or_warn(const char *path, const char *mode);
+/*
+ * FREE_AND_NULL(ptr) is like free(ptr) followed by ptr = NULL. Note
+ * that ptr is used twice, so don't pass e.g. ptr++.
+ */
+#define FREE_AND_NULL(p) do { free(p); (p) = NULL; } while (0)
+
#define ALLOC_ARRAY(x, alloc) (x) = xmalloc(st_mult(sizeof(*(x)), (alloc)))
#define REALLOC_ARRAY(x, alloc) (x) = xrealloc((x), st_mult(sizeof(*(x)), (alloc)))