pack-objects.c

   1 #include "git-compat-util.h"
   2 #include "alloc.h"
   3 #include "object.h"
   4 #include "pack.h"
   5 #include "pack-objects.h"
   6 #include "packfile.h"
   7 #include "config.h"
   8
   9 static uint32_t locate_object_entry_hash(struct packing_data *pdata,
  10                                          const struct object_id *oid,
  11                                          int *found)
  12 {
  13         uint32_t i, mask = (pdata->index_size - 1);
  14
  15         i = oidhash(oid) & mask;
  16
  17         while (pdata->index[i] > 0) {
  18                 uint32_t pos = pdata->index[i] - 1;
  19
  20                 if (oideq(oid, &pdata->objects[pos].idx.oid)) {
  21                         *found = 1;
  22                         return i;
  23                 }
  24
  25                 i = (i + 1) & mask;
  26         }
  27
  28         *found = 0;
  29         return i;
  30 }
  31
  32 static inline uint32_t closest_pow2(uint32_t v)
  33 {
  34         v = v - 1;
  35         v |= v >> 1;
  36         v |= v >> 2;
  37         v |= v >> 4;
  38         v |= v >> 8;
  39         v |= v >> 16;
  40         return v + 1;
  41 }
  42
  43 static void rehash_objects(struct packing_data *pdata)
  44 {
  45         uint32_t i;
  46         struct object_entry *entry;
  47
  48         pdata->index_size = closest_pow2(pdata->nr_objects * 3);
  49         if (pdata->index_size < 1024)
  50                 pdata->index_size = 1024;
  51
  52         free(pdata->index);
  53         CALLOC_ARRAY(pdata->index, pdata->index_size);
  54
  55         entry = pdata->objects;
  56
  57         for (i = 0; i < pdata->nr_objects; i++) {
  58                 int found;
  59                 uint32_t ix = locate_object_entry_hash(pdata,
  60                                                        &entry->idx.oid,
  61                                                        &found);
  62
  63                 if (found)
  64                         BUG("Duplicate object in hash");
  65
  66                 pdata->index[ix] = i + 1;
  67                 entry++;
  68         }
  69 }
  70
  71 struct object_entry *packlist_find(struct packing_data *pdata,
  72                                    const struct object_id *oid)
  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, oid, &found);
  81
  82         if (!found)
  83                 return NULL;
  84
  85         return &pdata->objects[pdata->index[i] - 1];
  86 }
  87
  88 static void prepare_in_pack_by_idx(struct packing_data *pdata)
  89 {
  90         struct packed_git **mapping, *p;
  91         int cnt = 0, nr = 1U << OE_IN_PACK_BITS;
  92
  93         ALLOC_ARRAY(mapping, nr);
  94         /*
  95          * oe_in_pack() on an all-zero'd object_entry
  96          * (i.e. in_pack_idx also zero) should return NULL.
  97          */
  98         mapping[cnt++] = NULL;
  99         for (p = get_all_packs(pdata->repo); p; p = p->next, cnt++) {
 100                 if (cnt == nr) {
 101                         free(mapping);
 102                         return;
 103                 }
 104                 p->index = cnt;
 105                 mapping[cnt] = p;
 106         }
 107         pdata->in_pack_by_idx = mapping;
 108 }
 109
 110 /*
 111  * A new pack appears after prepare_in_pack_by_idx() has been
 112  * run. This is likely a race.
 113  *
 114  * We could map this new pack to in_pack_by_idx[] array, but then we
 115  * have to deal with full array anyway. And since it's hard to test
 116  * this fall back code, just stay simple and fall back to using
 117  * in_pack[] array.
 118  */
 119 void oe_map_new_pack(struct packing_data *pack)
 120 {
 121         uint32_t i;
 122
 123         if (pack->in_pack)
 124                 BUG("packing_data has already been converted to pack array");
 125
 126         ALLOC_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 */
 135 void prepare_packing_data(struct repository *r, struct packing_data *pdata)
 136 {
 137         pdata->repo = r;
 138
 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         }
 147
 148         pdata->oe_size_limit = git_env_ulong("GIT_TEST_OE_SIZE",
 149                                              1U << OE_SIZE_BITS);
 150         pdata->oe_delta_size_limit = git_env_ulong("GIT_TEST_OE_DELTA_SIZE",
 151                                                    1UL << OE_DELTA_SIZE_BITS);
 152         init_recursive_mutex(&pdata->odb_lock);
 153 }
 154
 155 struct object_entry *packlist_alloc(struct packing_data *pdata,
 156                                     const struct object_id *oid)
 157 {
 158         struct object_entry *new_entry;
 159
 160         if (pdata->nr_objects >= pdata->nr_alloc) {
 161                 pdata->nr_alloc = (pdata->nr_alloc  + 1024) * 3 / 2;
 162                 REALLOC_ARRAY(pdata->objects, pdata->nr_alloc);
 163
 164                 if (!pdata->in_pack_by_idx)
 165                         REALLOC_ARRAY(pdata->in_pack, pdata->nr_alloc);
 166                 if (pdata->delta_size)
 167                         REALLOC_ARRAY(pdata->delta_size, pdata->nr_alloc);
 168
 169                 if (pdata->tree_depth)
 170                         REALLOC_ARRAY(pdata->tree_depth, pdata->nr_alloc);
 171
 172                 if (pdata->layer)
 173                         REALLOC_ARRAY(pdata->layer, pdata->nr_alloc);
 174
 175                 if (pdata->cruft_mtime)
 176                         REALLOC_ARRAY(pdata->cruft_mtime, pdata->nr_alloc);
 177         }
 178
 179         new_entry = pdata->objects + pdata->nr_objects++;
 180
 181         memset(new_entry, 0, sizeof(*new_entry));
 182         oidcpy(&new_entry->idx.oid, oid);
 183
 184         if (pdata->index_size * 3 <= pdata->nr_objects * 4)
 185                 rehash_objects(pdata);
 186         else {
 187                 int found;
 188                 uint32_t pos = locate_object_entry_hash(pdata,
 189                                                         &new_entry->idx.oid,
 190                                                         &found);
 191                 if (found)
 192                         BUG("duplicate object inserted into hash");
 193                 pdata->index[pos] = pdata->nr_objects;
 194         }
 195
 196         if (pdata->in_pack)
 197                 pdata->in_pack[pdata->nr_objects - 1] = NULL;
 198
 199         if (pdata->tree_depth)
 200                 pdata->tree_depth[pdata->nr_objects - 1] = 0;
 201
 202         if (pdata->layer)
 203                 pdata->layer[pdata->nr_objects - 1] = 0;
 204
 205         if (pdata->cruft_mtime)
 206                 pdata->cruft_mtime[pdata->nr_objects - 1] = 0;
 207
 208         return new_entry;
 209 }
 210
 211 void oe_set_delta_ext(struct packing_data *pdata,
 212                       struct object_entry *delta,
 213                       const struct object_id *oid)
 214 {
 215         struct object_entry *base;
 216
 217         ALLOC_GROW(pdata->ext_bases, pdata->nr_ext + 1, pdata->alloc_ext);
 218         base = &pdata->ext_bases[pdata->nr_ext++];
 219         memset(base, 0, sizeof(*base));
 220         oidcpy(&base->idx.oid, oid);
 221
 222         /* These flags mark that we are not part of the actual pack output. */
 223         base->preferred_base = 1;
 224         base->filled = 1;
 225
 226         delta->ext_base = 1;
 227         delta->delta_idx = base - pdata->ext_bases + 1;
 228 }