Merge branch 'jk/uploadpack-packobjectshook-fix' into maint
[git] / pack-objects.c
1 #include "cache.h"
2 #include "object.h"
3 #include "pack.h"
4 #include "pack-objects.h"
5 #include "packfile.h"
6 #include "config.h"
7
8 static uint32_t locate_object_entry_hash(struct packing_data *pdata,
9                                          const unsigned char *sha1,
10                                          int *found)
11 {
12         uint32_t i, mask = (pdata->index_size - 1);
13
14         i = sha1hash(sha1) & mask;
15
16         while (pdata->index[i] > 0) {
17                 uint32_t pos = pdata->index[i] - 1;
18
19                 if (!hashcmp(sha1, pdata->objects[pos].idx.oid.hash)) {
20                         *found = 1;
21                         return i;
22                 }
23
24                 i = (i + 1) & mask;
25         }
26
27         *found = 0;
28         return i;
29 }
30
31 static inline uint32_t closest_pow2(uint32_t v)
32 {
33         v = v - 1;
34         v |= v >> 1;
35         v |= v >> 2;
36         v |= v >> 4;
37         v |= v >> 8;
38         v |= v >> 16;
39         return v + 1;
40 }
41
42 static void rehash_objects(struct packing_data *pdata)
43 {
44         uint32_t i;
45         struct object_entry *entry;
46
47         pdata->index_size = closest_pow2(pdata->nr_objects * 3);
48         if (pdata->index_size < 1024)
49                 pdata->index_size = 1024;
50
51         free(pdata->index);
52         pdata->index = xcalloc(pdata->index_size, sizeof(*pdata->index));
53
54         entry = pdata->objects;
55
56         for (i = 0; i < pdata->nr_objects; i++) {
57                 int found;
58                 uint32_t ix = locate_object_entry_hash(pdata,
59                                                        entry->idx.oid.hash,
60                                                        &found);
61
62                 if (found)
63                         BUG("Duplicate object in hash");
64
65                 pdata->index[ix] = i + 1;
66                 entry++;
67         }
68 }
69
70 struct object_entry *packlist_find(struct packing_data *pdata,
71                                    const unsigned char *sha1,
72                                    uint32_t *index_pos)
73 {
74         uint32_t i;
75         int found;
76
77         if (!pdata->index_size)
78                 return NULL;
79
80         i = locate_object_entry_hash(pdata, sha1, &found);
81
82         if (index_pos)
83                 *index_pos = i;
84
85         if (!found)
86                 return NULL;
87
88         return &pdata->objects[pdata->index[i] - 1];
89 }
90
91 static void prepare_in_pack_by_idx(struct packing_data *pdata)
92 {
93         struct packed_git **mapping, *p;
94         int cnt = 0, nr = 1U << OE_IN_PACK_BITS;
95
96         ALLOC_ARRAY(mapping, nr);
97         /*
98          * oe_in_pack() on an all-zero'd object_entry
99          * (i.e. in_pack_idx also zero) should return NULL.
100          */
101         mapping[cnt++] = NULL;
102         for (p = get_packed_git(the_repository); p; p = p->next, cnt++) {
103                 if (cnt == nr) {
104                         free(mapping);
105                         return;
106                 }
107                 p->index = cnt;
108                 mapping[cnt] = p;
109         }
110         pdata->in_pack_by_idx = mapping;
111 }
112
113 /*
114  * A new pack appears after prepare_in_pack_by_idx() has been
115  * run. This is likely a race.
116  *
117  * We could map this new pack to in_pack_by_idx[] array, but then we
118  * have to deal with full array anyway. And since it's hard to test
119  * this fall back code, just stay simple and fall back to using
120  * in_pack[] array.
121  */
122 void oe_map_new_pack(struct packing_data *pack,
123                      struct packed_git *p)
124 {
125         uint32_t i;
126
127         REALLOC_ARRAY(pack->in_pack, pack->nr_alloc);
128
129         for (i = 0; i < pack->nr_objects; i++)
130                 pack->in_pack[i] = oe_in_pack(pack, pack->objects + i);
131
132         FREE_AND_NULL(pack->in_pack_by_idx);
133 }
134
135 /* assume pdata is already zero'd by caller */
136 void prepare_packing_data(struct packing_data *pdata)
137 {
138         if (git_env_bool("GIT_TEST_FULL_IN_PACK_ARRAY", 0)) {
139                 /*
140                  * do not initialize in_pack_by_idx[] to force the
141                  * slow path in oe_in_pack()
142                  */
143         } else {
144                 prepare_in_pack_by_idx(pdata);
145         }
146
147         pdata->oe_size_limit = git_env_ulong("GIT_TEST_OE_SIZE",
148                                              1U << OE_SIZE_BITS);
149         pdata->oe_delta_size_limit = git_env_ulong("GIT_TEST_OE_DELTA_SIZE",
150                                                    1UL << OE_DELTA_SIZE_BITS);
151 #ifndef NO_PTHREADS
152         pthread_mutex_init(&pdata->lock, NULL);
153 #endif
154 }
155
156 struct object_entry *packlist_alloc(struct packing_data *pdata,
157                                     const unsigned char *sha1,
158                                     uint32_t index_pos)
159 {
160         struct object_entry *new_entry;
161
162         if (pdata->nr_objects >= pdata->nr_alloc) {
163                 pdata->nr_alloc = (pdata->nr_alloc  + 1024) * 3 / 2;
164                 REALLOC_ARRAY(pdata->objects, pdata->nr_alloc);
165
166                 if (!pdata->in_pack_by_idx)
167                         REALLOC_ARRAY(pdata->in_pack, pdata->nr_alloc);
168                 if (pdata->delta_size)
169                         REALLOC_ARRAY(pdata->delta_size, pdata->nr_alloc);
170         }
171
172         new_entry = pdata->objects + pdata->nr_objects++;
173
174         memset(new_entry, 0, sizeof(*new_entry));
175         hashcpy(new_entry->idx.oid.hash, sha1);
176
177         if (pdata->index_size * 3 <= pdata->nr_objects * 4)
178                 rehash_objects(pdata);
179         else
180                 pdata->index[index_pos] = pdata->nr_objects;
181
182         if (pdata->in_pack)
183                 pdata->in_pack[pdata->nr_objects - 1] = NULL;
184
185         return new_entry;
186 }