Merge branch 'maint'
[git/kusma.git] / object-refs.c
blob98ea10005a851c3879c6e65929e3e34068dc9e8b
1 #include "cache.h"
2 #include "object.h"
4 int track_object_refs = 0;
6 static unsigned int refs_hash_size, nr_object_refs;
7 static struct object_refs **refs_hash;
9 static unsigned int hash_obj(struct object *obj, unsigned int n)
11 unsigned int hash = *(unsigned int *)obj->sha1;
12 return hash % n;
15 static void insert_ref_hash(struct object_refs *ref, struct object_refs **hash, unsigned int size)
17 int j = hash_obj(ref->base, size);
19 while (hash[j]) {
20 j++;
21 if (j >= size)
22 j = 0;
24 hash[j] = ref;
27 static void grow_refs_hash(void)
29 int i;
30 int new_hash_size = (refs_hash_size + 1000) * 3 / 2;
31 struct object_refs **new_hash;
33 new_hash = xcalloc(new_hash_size, sizeof(struct object_refs *));
34 for (i = 0; i < refs_hash_size; i++) {
35 struct object_refs *ref = refs_hash[i];
36 if (!ref)
37 continue;
38 insert_ref_hash(ref, new_hash, new_hash_size);
40 free(refs_hash);
41 refs_hash = new_hash;
42 refs_hash_size = new_hash_size;
45 static void add_object_refs(struct object *obj, struct object_refs *ref)
47 int nr = nr_object_refs + 1;
49 if (nr > refs_hash_size * 2 / 3)
50 grow_refs_hash();
51 ref->base = obj;
52 insert_ref_hash(ref, refs_hash, refs_hash_size);
53 nr_object_refs = nr;
56 struct object_refs *lookup_object_refs(struct object *obj)
58 struct object_refs *ref;
59 int j;
61 /* nothing to lookup */
62 if (!refs_hash_size)
63 return NULL;
64 j = hash_obj(obj, refs_hash_size);
65 while ((ref = refs_hash[j]) != NULL) {
66 if (ref->base == obj)
67 break;
68 j++;
69 if (j >= refs_hash_size)
70 j = 0;
72 return ref;
75 struct object_refs *alloc_object_refs(unsigned count)
77 struct object_refs *refs;
78 size_t size = sizeof(*refs) + count*sizeof(struct object *);
80 refs = xcalloc(1, size);
81 refs->count = count;
82 return refs;
85 static int compare_object_pointers(const void *a, const void *b)
87 const struct object * const *pa = a;
88 const struct object * const *pb = b;
89 if (*pa == *pb)
90 return 0;
91 else if (*pa < *pb)
92 return -1;
93 else
94 return 1;
97 void set_object_refs(struct object *obj, struct object_refs *refs)
99 unsigned int i, j;
101 /* Do not install empty list of references */
102 if (refs->count < 1) {
103 free(refs);
104 return;
107 /* Sort the list and filter out duplicates */
108 qsort(refs->ref, refs->count, sizeof(refs->ref[0]),
109 compare_object_pointers);
110 for (i = j = 1; i < refs->count; i++) {
111 if (refs->ref[i] != refs->ref[i - 1])
112 refs->ref[j++] = refs->ref[i];
114 if (j < refs->count) {
115 /* Duplicates were found - reallocate list */
116 size_t size = sizeof(*refs) + j*sizeof(struct object *);
117 refs->count = j;
118 refs = xrealloc(refs, size);
121 for (i = 0; i < refs->count; i++)
122 refs->ref[i]->used = 1;
123 add_object_refs(obj, refs);
126 void mark_reachable(struct object *obj, unsigned int mask)
128 const struct object_refs *refs;
130 if (!track_object_refs)
131 die("cannot do reachability with object refs turned off");
132 /* If we've been here already, don't bother */
133 if (obj->flags & mask)
134 return;
135 obj->flags |= mask;
136 refs = lookup_object_refs(obj);
137 if (refs) {
138 unsigned i;
139 for (i = 0; i < refs->count; i++)
140 mark_reachable(refs->ref[i], mask);