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
locate_object_entry_hash(struct packing_data * pdata,const struct object_id * oid,int * found)8 static uint32_t locate_object_entry_hash(struct packing_data *pdata,
9 const struct object_id *oid,
10 int *found)
11 {
12 uint32_t i, mask = (pdata->index_size - 1);
13
14 i = oidhash(oid) & mask;
15
16 while (pdata->index[i] > 0) {
17 uint32_t pos = pdata->index[i] - 1;
18
19 if (oideq(oid, &pdata->objects[pos].idx.oid)) {
20 *found = 1;
21 return i;
22 }
23
24 i = (i + 1) & mask;
25 }
26
27 *found = 0;
28 return i;
29 }
30
closest_pow2(uint32_t v)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
rehash_objects(struct packing_data * pdata)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,
60 &found);
61
62 if (found)
63 BUG("Duplicate object in hash");
64
65 pdata->index[ix] = i + 1;
66 entry++;
67 }
68 }
69
packlist_find(struct packing_data * pdata,const struct object_id * oid)70 struct object_entry *packlist_find(struct packing_data *pdata,
71 const struct object_id *oid)
72 {
73 uint32_t i;
74 int found;
75
76 if (!pdata->index_size)
77 return NULL;
78
79 i = locate_object_entry_hash(pdata, oid, &found);
80
81 if (!found)
82 return NULL;
83
84 return &pdata->objects[pdata->index[i] - 1];
85 }
86
prepare_in_pack_by_idx(struct packing_data * pdata)87 static void prepare_in_pack_by_idx(struct packing_data *pdata)
88 {
89 struct packed_git **mapping, *p;
90 int cnt = 0, nr = 1U << OE_IN_PACK_BITS;
91
92 ALLOC_ARRAY(mapping, nr);
93 /*
94 * oe_in_pack() on an all-zero'd object_entry
95 * (i.e. in_pack_idx also zero) should return NULL.
96 */
97 mapping[cnt++] = NULL;
98 for (p = get_all_packs(pdata->repo); p; p = p->next, cnt++) {
99 if (cnt == nr) {
100 free(mapping);
101 return;
102 }
103 p->index = cnt;
104 mapping[cnt] = p;
105 }
106 pdata->in_pack_by_idx = mapping;
107 }
108
109 /*
110 * A new pack appears after prepare_in_pack_by_idx() has been
111 * run. This is likely a race.
112 *
113 * We could map this new pack to in_pack_by_idx[] array, but then we
114 * have to deal with full array anyway. And since it's hard to test
115 * this fall back code, just stay simple and fall back to using
116 * in_pack[] array.
117 */
oe_map_new_pack(struct packing_data * pack)118 void oe_map_new_pack(struct packing_data *pack)
119 {
120 uint32_t i;
121
122 if (pack->in_pack)
123 BUG("packing_data has already been converted to pack array");
124
125 ALLOC_ARRAY(pack->in_pack, pack->nr_alloc);
126
127 for (i = 0; i < pack->nr_objects; i++)
128 pack->in_pack[i] = oe_in_pack(pack, pack->objects + i);
129
130 FREE_AND_NULL(pack->in_pack_by_idx);
131 }
132
133 /* assume pdata is already zero'd by caller */
prepare_packing_data(struct repository * r,struct packing_data * pdata)134 void prepare_packing_data(struct repository *r, struct packing_data *pdata)
135 {
136 pdata->repo = r;
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 init_recursive_mutex(&pdata->odb_lock);
152 }
153
packlist_alloc(struct packing_data * pdata,const struct object_id * oid)154 struct object_entry *packlist_alloc(struct packing_data *pdata,
155 const struct object_id *oid)
156 {
157 struct object_entry *new_entry;
158
159 if (pdata->nr_objects >= pdata->nr_alloc) {
160 pdata->nr_alloc = (pdata->nr_alloc + 1024) * 3 / 2;
161 REALLOC_ARRAY(pdata->objects, pdata->nr_alloc);
162
163 if (!pdata->in_pack_by_idx)
164 REALLOC_ARRAY(pdata->in_pack, pdata->nr_alloc);
165 if (pdata->delta_size)
166 REALLOC_ARRAY(pdata->delta_size, pdata->nr_alloc);
167
168 if (pdata->tree_depth)
169 REALLOC_ARRAY(pdata->tree_depth, pdata->nr_alloc);
170
171 if (pdata->layer)
172 REALLOC_ARRAY(pdata->layer, pdata->nr_alloc);
173 }
174
175 new_entry = pdata->objects + pdata->nr_objects++;
176
177 memset(new_entry, 0, sizeof(*new_entry));
178 oidcpy(&new_entry->idx.oid, oid);
179
180 if (pdata->index_size * 3 <= pdata->nr_objects * 4)
181 rehash_objects(pdata);
182 else {
183 int found;
184 uint32_t pos = locate_object_entry_hash(pdata,
185 &new_entry->idx.oid,
186 &found);
187 if (found)
188 BUG("duplicate object inserted into hash");
189 pdata->index[pos] = pdata->nr_objects;
190 }
191
192 if (pdata->in_pack)
193 pdata->in_pack[pdata->nr_objects - 1] = NULL;
194
195 if (pdata->tree_depth)
196 pdata->tree_depth[pdata->nr_objects - 1] = 0;
197
198 if (pdata->layer)
199 pdata->layer[pdata->nr_objects - 1] = 0;
200
201 return new_entry;
202 }
203
oe_set_delta_ext(struct packing_data * pdata,struct object_entry * delta,const unsigned char * sha1)204 void oe_set_delta_ext(struct packing_data *pdata,
205 struct object_entry *delta,
206 const unsigned char *sha1)
207 {
208 struct object_entry *base;
209
210 ALLOC_GROW(pdata->ext_bases, pdata->nr_ext + 1, pdata->alloc_ext);
211 base = &pdata->ext_bases[pdata->nr_ext++];
212 memset(base, 0, sizeof(*base));
213 hashcpy(base->idx.oid.hash, sha1);
214
215 /* These flags mark that we are not part of the actual pack output. */
216 base->preferred_base = 1;
217 base->filled = 1;
218
219 delta->ext_base = 1;
220 delta->delta_idx = base - pdata->ext_bases + 1;
221 }
222