t5320: tests for delta islands
[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,
9 const unsigned char *sha1,
10 int *found)
11{
039dc71a 12 uint32_t i, mask = (pdata->index_size - 1);
2834bc27 13
039dc71a 14 i = sha1hash(sha1) & mask;
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15
16 while (pdata->index[i] > 0) {
17 uint32_t pos = pdata->index[i] - 1;
18
e6a492b7 19 if (!hashcmp(sha1, pdata->objects[pos].idx.oid.hash)) {
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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,
59 entry->idx.oid.hash,
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,
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
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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;
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 */
122void 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 */
136void 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 }
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146
147 pdata->oe_size_limit = git_env_ulong("GIT_TEST_OE_SIZE",
148 1U << OE_SIZE_BITS);
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149}
150
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151struct object_entry *packlist_alloc(struct packing_data *pdata,
152 const unsigned char *sha1,
153 uint32_t index_pos)
154{
155 struct object_entry *new_entry;
156
157 if (pdata->nr_objects >= pdata->nr_alloc) {
158 pdata->nr_alloc = (pdata->nr_alloc + 1024) * 3 / 2;
2756ca43 159 REALLOC_ARRAY(pdata->objects, pdata->nr_alloc);
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160
161 if (!pdata->in_pack_by_idx)
162 REALLOC_ARRAY(pdata->in_pack, pdata->nr_alloc);
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163 }
164
165 new_entry = pdata->objects + pdata->nr_objects++;
166
167 memset(new_entry, 0, sizeof(*new_entry));
e6a492b7 168 hashcpy(new_entry->idx.oid.hash, sha1);
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169
170 if (pdata->index_size * 3 <= pdata->nr_objects * 4)
171 rehash_objects(pdata);
172 else
173 pdata->index[index_pos] = pdata->nr_objects;
174
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175 if (pdata->in_pack)
176 pdata->in_pack[pdata->nr_objects - 1] = NULL;
177
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178 return new_entry;
179}