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| author | Junio C Hamano <gitster@pobox.com> | 2015-05-14 15:25:52 -0700 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2015-05-22 14:40:30 -0700 |
| commit | 862e730ec1c13f28bfb7c8c9ecb39bcc92dd0922 (patch) | |
| tree | 83f241cbdd890926053221fd0932ab6d47217108 /commit-slab.h | |
| parent | 282616c72d1d08a77ca4fe1186cb708c38408d87 (diff) | |
| download | git-862e730ec1c13f28bfb7c8c9ecb39bcc92dd0922.tar.gz | |
commit-slab: introduce slabname##_peek() functionjc/commit-slab
There is no API to ask "Does this commit have associated data in
slab?". If an application wants to (1) parse just a few commits at
the beginning of a process, (2) store data for only these commits,
and then (3) start processing many commits, taking into account the
data stored (for a few of them) in the slab, the application would
use slabname##_at() to allocate a space to store data in (2), but
there is no API other than slabname##_at() to use in step (3). This
allocates and wastes new space for these commits the caller is only
interested in checking if they have data stored in step (2).
Introduce slabname##_peek(), which is similar to slabname##_at() but
returns NULL when there is no data already associated to it in such
a use case.
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'commit-slab.h')
| -rw-r--r-- | commit-slab.h | 34 |
1 files changed, 29 insertions, 5 deletions
diff --git a/commit-slab.h b/commit-slab.h index 375c9c751a..9d12ce299c 100644 --- a/commit-slab.h +++ b/commit-slab.h @@ -15,7 +15,13 @@ * - int *indegree_at(struct indegree *, struct commit *); * * This function locates the data associated with the given commit in - * the indegree slab, and returns the pointer to it. + * the indegree slab, and returns the pointer to it. The location to + * store the data is allocated as necessary. + * + * - int *indegree_peek(struct indegree *, struct commit *); + * + * This function is similar to indegree_at(), but it will return NULL + * until a call to indegree_at() was made for the commit. * * - void init_indegree(struct indegree *); * void init_indegree_with_stride(struct indegree *, int); @@ -80,8 +86,9 @@ static MAYBE_UNUSED void clear_ ##slabname(struct slabname *s) \ s->slab = NULL; \ } \ \ -static MAYBE_UNUSED elemtype *slabname## _at(struct slabname *s, \ - const struct commit *c) \ +static MAYBE_UNUSED elemtype *slabname## _at_peek(struct slabname *s, \ + const struct commit *c, \ + int add_if_missing) \ { \ int nth_slab, nth_slot; \ \ @@ -90,6 +97,8 @@ static MAYBE_UNUSED elemtype *slabname## _at(struct slabname *s, \ \ if (s->slab_count <= nth_slab) { \ int i; \ + if (!add_if_missing) \ + return NULL; \ s->slab = xrealloc(s->slab, \ (nth_slab + 1) * sizeof(*s->slab)); \ stat_ ##slabname## realloc++; \ @@ -97,10 +106,25 @@ static MAYBE_UNUSED elemtype *slabname## _at(struct slabname *s, \ s->slab[i] = NULL; \ s->slab_count = nth_slab + 1; \ } \ - if (!s->slab[nth_slab]) \ + if (!s->slab[nth_slab]) { \ + if (!add_if_missing) \ + return NULL; \ s->slab[nth_slab] = xcalloc(s->slab_size, \ sizeof(**s->slab) * s->stride); \ - return &s->slab[nth_slab][nth_slot * s->stride]; \ + } \ + return &s->slab[nth_slab][nth_slot * s->stride]; \ +} \ + \ +static MAYBE_UNUSED elemtype *slabname## _at(struct slabname *s, \ + const struct commit *c) \ +{ \ + return slabname##_at_peek(s, c, 1); \ +} \ + \ +static MAYBE_UNUSED elemtype *slabname## _peek(struct slabname *s, \ + const struct commit *c) \ +{ \ + return slabname##_at_peek(s, c, 0); \ } \ \ static int stat_ ##slabname## realloc |