* - 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);
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; \
\
\
if (s->slab_count <= nth_slab) { \
int i; \
+ if (!add_if_missing) \
+ return NULL; \
REALLOC_ARRAY(s->slab, nth_slab + 1); \
stat_ ##slabname## realloc++; \
for (i = s->slab_count; i <= nth_slab; i++) \
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