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[git/git.git] / pack-objects.c
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1#include "cache.h"
2#include "object.h"
3#include "pack.h"
4#include "pack-objects.h"
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5#include "packfile.h"
6#include "config.h"
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7
8static uint32_t locate_object_entry_hash(struct packing_data *pdata,
5e7ac680 9 const struct object_id *oid,
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10 int *found)
11{
039dc71a 12 uint32_t i, mask = (pdata->index_size - 1);
2834bc27 13
d40abc8e 14 i = oidhash(oid) & mask;
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15
16 while (pdata->index[i] > 0) {
17 uint32_t pos = pdata->index[i] - 1;
18
5e7ac680 19 if (oideq(oid, &pdata->objects[pos].idx.oid)) {
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20 *found = 1;
21 return i;
22 }
23
24 i = (i + 1) & mask;
25 }
26
27 *found = 0;
28 return i;
29}
30
31static 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
42static 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
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51 free(pdata->index);
52 pdata->index = xcalloc(pdata->index_size, sizeof(*pdata->index));
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53
54 entry = pdata->objects;
55
56 for (i = 0; i < pdata->nr_objects; i++) {
57 int found;
e6a492b7 58 uint32_t ix = locate_object_entry_hash(pdata,
5e7ac680 59 &entry->idx.oid,
e6a492b7 60 &found);
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61
62 if (found)
033abf97 63 BUG("Duplicate object in hash");
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64
65 pdata->index[ix] = i + 1;
66 entry++;
67 }
68}
69
70struct object_entry *packlist_find(struct packing_data *pdata,
3df28cae 71 const struct object_id *oid,
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72 uint32_t *index_pos)
73{
74 uint32_t i;
75 int found;
76
77 if (!pdata->index_size)
78 return NULL;
79
5e7ac680 80 i = locate_object_entry_hash(pdata, oid, &found);
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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
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91static 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;
7c141127 102 for (p = get_all_packs(pdata->repo); p; p = p->next, cnt++) {
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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 */
c409d108 122void oe_map_new_pack(struct packing_data *pack)
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123{
124 uint32_t i;
125
126 REALLOC_ARRAY(pack->in_pack, pack->nr_alloc);
127
128 for (i = 0; i < pack->nr_objects; i++)
129 pack->in_pack[i] = oe_in_pack(pack, pack->objects + i);
130
131 FREE_AND_NULL(pack->in_pack_by_idx);
132}
133
134/* assume pdata is already zero'd by caller */
7c141127 135void prepare_packing_data(struct repository *r, struct packing_data *pdata)
43fa44fa 136{
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137 pdata->repo = r;
138
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139 if (git_env_bool("GIT_TEST_FULL_IN_PACK_ARRAY", 0)) {
140 /*
141 * do not initialize in_pack_by_idx[] to force the
142 * slow path in oe_in_pack()
143 */
144 } else {
145 prepare_in_pack_by_idx(pdata);
146 }
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147
148 pdata->oe_size_limit = git_env_ulong("GIT_TEST_OE_SIZE",
149 1U << OE_SIZE_BITS);
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150 pdata->oe_delta_size_limit = git_env_ulong("GIT_TEST_OE_DELTA_SIZE",
151 1UL << OE_DELTA_SIZE_BITS);
edb673cf 152 init_recursive_mutex(&pdata->odb_lock);
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153}
154
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155struct object_entry *packlist_alloc(struct packing_data *pdata,
156 const unsigned char *sha1,
157 uint32_t index_pos)
158{
159 struct object_entry *new_entry;
160
161 if (pdata->nr_objects >= pdata->nr_alloc) {
162 pdata->nr_alloc = (pdata->nr_alloc + 1024) * 3 / 2;
2756ca43 163 REALLOC_ARRAY(pdata->objects, pdata->nr_alloc);
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164
165 if (!pdata->in_pack_by_idx)
166 REALLOC_ARRAY(pdata->in_pack, pdata->nr_alloc);
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167 if (pdata->delta_size)
168 REALLOC_ARRAY(pdata->delta_size, pdata->nr_alloc);
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169
170 if (pdata->tree_depth)
171 REALLOC_ARRAY(pdata->tree_depth, pdata->nr_alloc);
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172
173 if (pdata->layer)
174 REALLOC_ARRAY(pdata->layer, pdata->nr_alloc);
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175 }
176
177 new_entry = pdata->objects + pdata->nr_objects++;
178
179 memset(new_entry, 0, sizeof(*new_entry));
e6a492b7 180 hashcpy(new_entry->idx.oid.hash, sha1);
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181
182 if (pdata->index_size * 3 <= pdata->nr_objects * 4)
183 rehash_objects(pdata);
184 else
185 pdata->index[index_pos] = pdata->nr_objects;
186
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187 if (pdata->in_pack)
188 pdata->in_pack[pdata->nr_objects - 1] = NULL;
189
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190 if (pdata->tree_depth)
191 pdata->tree_depth[pdata->nr_objects - 1] = 0;
192
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193 if (pdata->layer)
194 pdata->layer[pdata->nr_objects - 1] = 0;
195
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196 return new_entry;
197}
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198
199void oe_set_delta_ext(struct packing_data *pdata,
200 struct object_entry *delta,
201 const unsigned char *sha1)
202{
203 struct object_entry *base;
204
205 ALLOC_GROW(pdata->ext_bases, pdata->nr_ext + 1, pdata->alloc_ext);
206 base = &pdata->ext_bases[pdata->nr_ext++];
207 memset(base, 0, sizeof(*base));
208 hashcpy(base->idx.oid.hash, sha1);
209
210 /* These flags mark that we are not part of the actual pack output. */
211 base->preferred_base = 1;
212 base->filled = 1;
213
214 delta->ext_base = 1;
215 delta->delta_idx = base - pdata->ext_bases + 1;
216}