diff options
Diffstat (limited to 'third_party/git/pack-objects.c')
| -rw-r--r-- | third_party/git/pack-objects.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/third_party/git/pack-objects.c b/third_party/git/pack-objects.c new file mode 100644 index 0000000000..52560293b6 --- /dev/null +++ b/third_party/git/pack-objects.c @@ -0,0 +1,216 @@ +#include "cache.h" +#include "object.h" +#include "pack.h" +#include "pack-objects.h" +#include "packfile.h" +#include "config.h" + +static uint32_t locate_object_entry_hash(struct packing_data *pdata, + const struct object_id *oid, + int *found) +{ + uint32_t i, mask = (pdata->index_size - 1); + + i = oidhash(oid) & mask; + + while (pdata->index[i] > 0) { + uint32_t pos = pdata->index[i] - 1; + + if (oideq(oid, &pdata->objects[pos].idx.oid)) { + *found = 1; + return i; + } + + i = (i + 1) & mask; + } + + *found = 0; + return i; +} + +static inline uint32_t closest_pow2(uint32_t v) +{ + v = v - 1; + v |= v >> 1; + v |= v >> 2; + v |= v >> 4; + v |= v >> 8; + v |= v >> 16; + return v + 1; +} + +static void rehash_objects(struct packing_data *pdata) +{ + uint32_t i; + struct object_entry *entry; + + pdata->index_size = closest_pow2(pdata->nr_objects * 3); + if (pdata->index_size < 1024) + pdata->index_size = 1024; + + free(pdata->index); + pdata->index = xcalloc(pdata->index_size, sizeof(*pdata->index)); + + entry = pdata->objects; + + for (i = 0; i < pdata->nr_objects; i++) { + int found; + uint32_t ix = locate_object_entry_hash(pdata, + &entry->idx.oid, + &found); + + if (found) + BUG("Duplicate object in hash"); + + pdata->index[ix] = i + 1; + entry++; + } +} + +struct object_entry *packlist_find(struct packing_data *pdata, + const struct object_id *oid, + uint32_t *index_pos) +{ + uint32_t i; + int found; + + if (!pdata->index_size) + return NULL; + + i = locate_object_entry_hash(pdata, oid, &found); + + if (index_pos) + *index_pos = i; + + if (!found) + return NULL; + + return &pdata->objects[pdata->index[i] - 1]; +} + +static void prepare_in_pack_by_idx(struct packing_data *pdata) +{ + struct packed_git **mapping, *p; + int cnt = 0, nr = 1U << OE_IN_PACK_BITS; + + ALLOC_ARRAY(mapping, nr); + /* + * oe_in_pack() on an all-zero'd object_entry + * (i.e. in_pack_idx also zero) should return NULL. + */ + mapping[cnt++] = NULL; + for (p = get_all_packs(pdata->repo); p; p = p->next, cnt++) { + if (cnt == nr) { + free(mapping); + return; + } + p->index = cnt; + mapping[cnt] = p; + } + pdata->in_pack_by_idx = mapping; +} + +/* + * A new pack appears after prepare_in_pack_by_idx() has been + * run. This is likely a race. + * + * We could map this new pack to in_pack_by_idx[] array, but then we + * have to deal with full array anyway. And since it's hard to test + * this fall back code, just stay simple and fall back to using + * in_pack[] array. + */ +void oe_map_new_pack(struct packing_data *pack) +{ + uint32_t i; + + REALLOC_ARRAY(pack->in_pack, pack->nr_alloc); + + for (i = 0; i < pack->nr_objects; i++) + pack->in_pack[i] = oe_in_pack(pack, pack->objects + i); + + FREE_AND_NULL(pack->in_pack_by_idx); +} + +/* assume pdata is already zero'd by caller */ +void prepare_packing_data(struct repository *r, struct packing_data *pdata) +{ + pdata->repo = r; + + if (git_env_bool("GIT_TEST_FULL_IN_PACK_ARRAY", 0)) { + /* + * do not initialize in_pack_by_idx[] to force the + * slow path in oe_in_pack() + */ + } else { + prepare_in_pack_by_idx(pdata); + } + + pdata->oe_size_limit = git_env_ulong("GIT_TEST_OE_SIZE", + 1U << OE_SIZE_BITS); + pdata->oe_delta_size_limit = git_env_ulong("GIT_TEST_OE_DELTA_SIZE", + 1UL << OE_DELTA_SIZE_BITS); + init_recursive_mutex(&pdata->odb_lock); +} + +struct object_entry *packlist_alloc(struct packing_data *pdata, + const unsigned char *sha1, + uint32_t index_pos) +{ + struct object_entry *new_entry; + + if (pdata->nr_objects >= pdata->nr_alloc) { + pdata->nr_alloc = (pdata->nr_alloc + 1024) * 3 / 2; + REALLOC_ARRAY(pdata->objects, pdata->nr_alloc); + + if (!pdata->in_pack_by_idx) + REALLOC_ARRAY(pdata->in_pack, pdata->nr_alloc); + if (pdata->delta_size) + REALLOC_ARRAY(pdata->delta_size, pdata->nr_alloc); + + if (pdata->tree_depth) + REALLOC_ARRAY(pdata->tree_depth, pdata->nr_alloc); + + if (pdata->layer) + REALLOC_ARRAY(pdata->layer, pdata->nr_alloc); + } + + new_entry = pdata->objects + pdata->nr_objects++; + + memset(new_entry, 0, sizeof(*new_entry)); + hashcpy(new_entry->idx.oid.hash, sha1); + + if (pdata->index_size * 3 <= pdata->nr_objects * 4) + rehash_objects(pdata); + else + pdata->index[index_pos] = pdata->nr_objects; + + if (pdata->in_pack) + pdata->in_pack[pdata->nr_objects - 1] = NULL; + + if (pdata->tree_depth) + pdata->tree_depth[pdata->nr_objects - 1] = 0; + + if (pdata->layer) + pdata->layer[pdata->nr_objects - 1] = 0; + + return new_entry; +} + +void oe_set_delta_ext(struct packing_data *pdata, + struct object_entry *delta, + const unsigned char *sha1) +{ + struct object_entry *base; + + ALLOC_GROW(pdata->ext_bases, pdata->nr_ext + 1, pdata->alloc_ext); + base = &pdata->ext_bases[pdata->nr_ext++]; + memset(base, 0, sizeof(*base)); + hashcpy(base->idx.oid.hash, sha1); + + /* These flags mark that we are not part of the actual pack output. */ + base->preferred_base = 1; + base->filled = 1; + + delta->ext_base = 1; + delta->delta_idx = base - pdata->ext_bases + 1; +} |