pack-objects: move read mutex to packing_data struct
[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
e3ff0683 19 if (hasheq(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;
454ea2e4 102 for (p = get_all_packs(the_repository); 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 */
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 pdata->oe_delta_size_limit = git_env_ulong("GIT_TEST_OE_DELTA_SIZE",
150 1UL << OE_DELTA_SIZE_BITS);
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151#ifndef NO_PTHREADS
152 pthread_mutex_init(&pdata->lock, NULL);
459307b1 153 init_recursive_mutex(&pdata->read_lock);
34204c81 154#endif
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155}
156
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157struct object_entry *packlist_alloc(struct packing_data *pdata,
158 const unsigned char *sha1,
159 uint32_t index_pos)
160{
161 struct object_entry *new_entry;
162
163 if (pdata->nr_objects >= pdata->nr_alloc) {
164 pdata->nr_alloc = (pdata->nr_alloc + 1024) * 3 / 2;
2756ca43 165 REALLOC_ARRAY(pdata->objects, pdata->nr_alloc);
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166
167 if (!pdata->in_pack_by_idx)
168 REALLOC_ARRAY(pdata->in_pack, pdata->nr_alloc);
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169 if (pdata->delta_size)
170 REALLOC_ARRAY(pdata->delta_size, pdata->nr_alloc);
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171
172 if (pdata->tree_depth)
173 REALLOC_ARRAY(pdata->tree_depth, pdata->nr_alloc);
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174
175 if (pdata->layer)
176 REALLOC_ARRAY(pdata->layer, pdata->nr_alloc);
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177 }
178
179 new_entry = pdata->objects + pdata->nr_objects++;
180
181 memset(new_entry, 0, sizeof(*new_entry));
e6a492b7 182 hashcpy(new_entry->idx.oid.hash, sha1);
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183
184 if (pdata->index_size * 3 <= pdata->nr_objects * 4)
185 rehash_objects(pdata);
186 else
187 pdata->index[index_pos] = pdata->nr_objects;
188
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189 if (pdata->in_pack)
190 pdata->in_pack[pdata->nr_objects - 1] = NULL;
191
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192 if (pdata->tree_depth)
193 pdata->tree_depth[pdata->nr_objects - 1] = 0;
194
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195 if (pdata->layer)
196 pdata->layer[pdata->nr_objects - 1] = 0;
197
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198 return new_entry;
199}
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200
201void oe_set_delta_ext(struct packing_data *pdata,
202 struct object_entry *delta,
203 const unsigned char *sha1)
204{
205 struct object_entry *base;
206
207 ALLOC_GROW(pdata->ext_bases, pdata->nr_ext + 1, pdata->alloc_ext);
208 base = &pdata->ext_bases[pdata->nr_ext++];
209 memset(base, 0, sizeof(*base));
210 hashcpy(base->idx.oid.hash, sha1);
211
212 /* These flags mark that we are not part of the actual pack output. */
213 base->preferred_base = 1;
214 base->filled = 1;
215
216 delta->ext_base = 1;
217 delta->delta_idx = base - pdata->ext_bases + 1;
218}