| Message ID | patch-3.7-d7c14a1cad8-20220708T140354Z-avarab@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | xdiff: use standard alloc macros, share them via git-shared-util.h | expand |
Hi Ævar On 08/07/2022 15:20, Ævar Arnfjörð Bjarmason wrote: > Add "gently" versions of ALLOC_ARRAY(), CALLOC_ARRAY() etc. using the > naming convention G*() as a shorthand for "GENTLY_*()". It might be nicer just to call them ALLOC_ARRAY_GENTLY() etc. As the return value needs to be checked it would make sense to implement them as expressions as I have done for XDL_ALLOC_ARRAY() etc. > Nothing uses these functions yet, but as we'll see in subsequent > commit(s) we're able to convert things that need e.g. non-fatal > "ALLOC_GROW" behavior over to this. > > Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> > --- > git-shared-util.h | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/git-shared-util.h b/git-shared-util.h > index 7b4479a0f72..718a8e00732 100644 > --- a/git-shared-util.h > +++ b/git-shared-util.h > @@ -8,8 +8,11 @@ > #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 GALLOC_ARRAY(x, alloc) (x) = malloc(st_mult(sizeof(*(x)), (alloc))) > #define CALLOC_ARRAY(x, alloc) (x) = xcalloc((alloc), sizeof(*(x))) > +#define GCALLOC_ARRAY(x, alloc) (x) = calloc((alloc), sizeof(*(x))) > #define REALLOC_ARRAY(x, alloc) (x) = xrealloc((x), st_mult(sizeof(*(x)), (alloc))) > +#define GREALLOC_ARRAY(x, alloc) (x) = realloc((x), st_mult(sizeof(*(x)), (alloc))) > > #define COPY_ARRAY(dst, src, n) copy_array((dst), (src), (n), sizeof(*(dst)) + \ > BUILD_ASSERT_OR_ZERO(sizeof(*(dst)) == sizeof(*(src)))) > @@ -71,17 +74,25 @@ static inline void move_array(void *dst, const void *src, size_t n, size_t size) > * added niceties. > * > * DO NOT USE any expression with side-effect for 'x', 'nr', or 'alloc'. > + * > + * GALLOC_GROW() behaves like ALLOC_GROW(), except that in malloc() > + * failure we'll return NULL rather than dying. > */ > -#define ALLOC_GROW(x, nr, alloc) \ > +#define ALLOC_GROW_1(x, nr, alloc, gently) \ > do { \ > if ((nr) > alloc) { \ > if (alloc_nr(alloc) < (nr)) \ > alloc = (nr); \ > else \ > alloc = alloc_nr(alloc); \ > - REALLOC_ARRAY(x, alloc); \ This leaks the old allocation if realloc() fails because it overwrites the original pointer with NULL, that is particularly bad as if realloc() fails we're already short of memory. XDL_ALLOC_GROW() shows how a possible way to do this. Best Wishes Phillip > + if (gently) \ > + GREALLOC_ARRAY(x, alloc); \ > + else \ > + REALLOC_ARRAY(x, alloc); \ > } \ > } while (0) > +#define ALLOC_GROW(x, nr, alloc) ALLOC_GROW_1(x, nr, alloc, 0) > +#define GALLOC_GROW(x, nr, alloc) ALLOC_GROW_1(x, nr, alloc, 1) > > /* > * Similar to ALLOC_GROW but handles updating of the nr value and
diff --git a/git-shared-util.h b/git-shared-util.h index 7b4479a0f72..718a8e00732 100644 --- a/git-shared-util.h +++ b/git-shared-util.h @@ -8,8 +8,11 @@ #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 GALLOC_ARRAY(x, alloc) (x) = malloc(st_mult(sizeof(*(x)), (alloc))) #define CALLOC_ARRAY(x, alloc) (x) = xcalloc((alloc), sizeof(*(x))) +#define GCALLOC_ARRAY(x, alloc) (x) = calloc((alloc), sizeof(*(x))) #define REALLOC_ARRAY(x, alloc) (x) = xrealloc((x), st_mult(sizeof(*(x)), (alloc))) +#define GREALLOC_ARRAY(x, alloc) (x) = realloc((x), st_mult(sizeof(*(x)), (alloc))) #define COPY_ARRAY(dst, src, n) copy_array((dst), (src), (n), sizeof(*(dst)) + \ BUILD_ASSERT_OR_ZERO(sizeof(*(dst)) == sizeof(*(src)))) @@ -71,17 +74,25 @@ static inline void move_array(void *dst, const void *src, size_t n, size_t size) * added niceties. * * DO NOT USE any expression with side-effect for 'x', 'nr', or 'alloc'. + * + * GALLOC_GROW() behaves like ALLOC_GROW(), except that in malloc() + * failure we'll return NULL rather than dying. */ -#define ALLOC_GROW(x, nr, alloc) \ +#define ALLOC_GROW_1(x, nr, alloc, gently) \ do { \ if ((nr) > alloc) { \ if (alloc_nr(alloc) < (nr)) \ alloc = (nr); \ else \ alloc = alloc_nr(alloc); \ - REALLOC_ARRAY(x, alloc); \ + if (gently) \ + GREALLOC_ARRAY(x, alloc); \ + else \ + REALLOC_ARRAY(x, alloc); \ } \ } while (0) +#define ALLOC_GROW(x, nr, alloc) ALLOC_GROW_1(x, nr, alloc, 0) +#define GALLOC_GROW(x, nr, alloc) ALLOC_GROW_1(x, nr, alloc, 1) /* * Similar to ALLOC_GROW but handles updating of the nr value and
Add "gently" versions of ALLOC_ARRAY(), CALLOC_ARRAY() etc. using the naming convention G*() as a shorthand for "GENTLY_*()". Nothing uses these functions yet, but as we'll see in subsequent commit(s) we're able to convert things that need e.g. non-fatal "ALLOC_GROW" behavior over to this. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> --- git-shared-util.h | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)