Remove "refs" field from "struct object"
[git/git.git] / object-refs.c
1 #include "cache.h"
2 #include "object.h"
3
4 int track_object_refs = 0;
5
6 static unsigned int refs_hash_size, nr_object_refs;
7 static struct object_refs **refs_hash;
8
9 static unsigned int hash_obj(struct object *obj, unsigned int n)
10 {
11 unsigned int hash = *(unsigned int *)obj->sha1;
12 return hash % n;
13 }
14
15 static void grow_refs_hash(void)
16 {
17 int i;
18 int new_hash_size = (refs_hash_size + 1000) * 3 / 2;
19 struct object_refs **new_hash;
20
21 new_hash = calloc(new_hash_size, sizeof(struct object_refs *));
22 for (i = 0; i < refs_hash_size; i++) {
23 int j;
24 struct object_refs *ref = refs_hash[i];
25 if (!ref)
26 continue;
27 j = hash_obj(ref->base, new_hash_size);
28 new_hash[j] = ref;
29 }
30 free(refs_hash);
31 refs_hash = new_hash;
32 refs_hash_size = new_hash_size;
33 }
34
35 static void insert_ref_hash(struct object_refs *ref)
36 {
37 int j = hash_obj(ref->base, refs_hash_size);
38
39 while (refs_hash[j]) {
40 j++;
41 if (j >= refs_hash_size)
42 j = 0;
43 }
44 refs_hash[j] = ref;
45 }
46
47 static void add_object_refs(struct object *obj, struct object_refs *ref)
48 {
49 int nr = nr_object_refs + 1;
50
51 if (nr > refs_hash_size * 2 / 3)
52 grow_refs_hash();
53 ref->base = obj;
54 insert_ref_hash(ref);
55 nr_object_refs = nr;
56 }
57
58 struct object_refs *lookup_object_refs(struct object *obj)
59 {
60 int j = hash_obj(obj, refs_hash_size);
61 struct object_refs *ref;
62
63 while ((ref = refs_hash[j]) != NULL) {
64 if (ref->base == obj)
65 break;
66 j++;
67 if (j >= refs_hash_size)
68 j = 0;
69 }
70 return ref;
71 }
72
73 struct object_refs *alloc_object_refs(unsigned count)
74 {
75 struct object_refs *refs;
76 size_t size = sizeof(*refs) + count*sizeof(struct object *);
77
78 refs = xcalloc(1, size);
79 refs->count = count;
80 return refs;
81 }
82
83 static int compare_object_pointers(const void *a, const void *b)
84 {
85 const struct object * const *pa = a;
86 const struct object * const *pb = b;
87 if (*pa == *pb)
88 return 0;
89 else if (*pa < *pb)
90 return -1;
91 else
92 return 1;
93 }
94
95 void set_object_refs(struct object *obj, struct object_refs *refs)
96 {
97 unsigned int i, j;
98
99 /* Do not install empty list of references */
100 if (refs->count < 1) {
101 free(refs);
102 return;
103 }
104
105 /* Sort the list and filter out duplicates */
106 qsort(refs->ref, refs->count, sizeof(refs->ref[0]),
107 compare_object_pointers);
108 for (i = j = 1; i < refs->count; i++) {
109 if (refs->ref[i] != refs->ref[i - 1])
110 refs->ref[j++] = refs->ref[i];
111 }
112 if (j < refs->count) {
113 /* Duplicates were found - reallocate list */
114 size_t size = sizeof(*refs) + j*sizeof(struct object *);
115 refs->count = j;
116 refs = xrealloc(refs, size);
117 }
118
119 for (i = 0; i < refs->count; i++)
120 refs->ref[i]->used = 1;
121 add_object_refs(obj, refs);
122 }
123
124 void mark_reachable(struct object *obj, unsigned int mask)
125 {
126 const struct object_refs *refs;
127
128 if (!track_object_refs)
129 die("cannot do reachability with object refs turned off");
130 /* If we've been here already, don't bother */
131 if (obj->flags & mask)
132 return;
133 obj->flags |= mask;
134 refs = lookup_object_refs(obj);
135 if (refs) {
136 unsigned i;
137 for (i = 0; i < refs->count; i++)
138 mark_reachable(refs->ref[i], mask);
139 }
140 }
141
142