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-rw-r--r--midx.c918
1 files changed, 918 insertions, 0 deletions
diff --git a/midx.c b/midx.c
new file mode 100644
index 0000000..19b7df3
--- /dev/null
+++ b/midx.c
@@ -0,0 +1,918 @@
+#include "cache.h"
+#include "config.h"
+#include "csum-file.h"
+#include "dir.h"
+#include "lockfile.h"
+#include "packfile.h"
+#include "object-store.h"
+#include "sha1-lookup.h"
+#include "midx.h"
+
+#define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
+#define MIDX_VERSION 1
+#define MIDX_BYTE_FILE_VERSION 4
+#define MIDX_BYTE_HASH_VERSION 5
+#define MIDX_BYTE_NUM_CHUNKS 6
+#define MIDX_BYTE_NUM_PACKS 8
+#define MIDX_HASH_VERSION 1
+#define MIDX_HEADER_SIZE 12
+#define MIDX_HASH_LEN 20
+#define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + MIDX_HASH_LEN)
+
+#define MIDX_MAX_CHUNKS 5
+#define MIDX_CHUNK_ALIGNMENT 4
+#define MIDX_CHUNKID_PACKNAMES 0x504e414d /* "PNAM" */
+#define MIDX_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
+#define MIDX_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
+#define MIDX_CHUNKID_OBJECTOFFSETS 0x4f4f4646 /* "OOFF" */
+#define MIDX_CHUNKID_LARGEOFFSETS 0x4c4f4646 /* "LOFF" */
+#define MIDX_CHUNKLOOKUP_WIDTH (sizeof(uint32_t) + sizeof(uint64_t))
+#define MIDX_CHUNK_FANOUT_SIZE (sizeof(uint32_t) * 256)
+#define MIDX_CHUNK_OFFSET_WIDTH (2 * sizeof(uint32_t))
+#define MIDX_CHUNK_LARGE_OFFSET_WIDTH (sizeof(uint64_t))
+#define MIDX_LARGE_OFFSET_NEEDED 0x80000000
+
+static char *get_midx_filename(const char *object_dir)
+{
+ return xstrfmt("%s/pack/multi-pack-index", object_dir);
+}
+
+struct multi_pack_index *load_multi_pack_index(const char *object_dir)
+{
+ struct multi_pack_index *m = NULL;
+ int fd;
+ struct stat st;
+ size_t midx_size;
+ void *midx_map = NULL;
+ uint32_t hash_version;
+ char *midx_name = get_midx_filename(object_dir);
+ uint32_t i;
+ const char *cur_pack_name;
+
+ fd = git_open(midx_name);
+
+ if (fd < 0)
+ goto cleanup_fail;
+ if (fstat(fd, &st)) {
+ error_errno(_("failed to read %s"), midx_name);
+ goto cleanup_fail;
+ }
+
+ midx_size = xsize_t(st.st_size);
+
+ if (midx_size < MIDX_MIN_SIZE) {
+ error(_("multi-pack-index file %s is too small"), midx_name);
+ goto cleanup_fail;
+ }
+
+ FREE_AND_NULL(midx_name);
+
+ midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
+
+ FLEX_ALLOC_MEM(m, object_dir, object_dir, strlen(object_dir));
+ m->fd = fd;
+ m->data = midx_map;
+ m->data_len = midx_size;
+
+ m->signature = get_be32(m->data);
+ if (m->signature != MIDX_SIGNATURE) {
+ error(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
+ m->signature, MIDX_SIGNATURE);
+ goto cleanup_fail;
+ }
+
+ m->version = m->data[MIDX_BYTE_FILE_VERSION];
+ if (m->version != MIDX_VERSION) {
+ error(_("multi-pack-index version %d not recognized"),
+ m->version);
+ goto cleanup_fail;
+ }
+
+ hash_version = m->data[MIDX_BYTE_HASH_VERSION];
+ if (hash_version != MIDX_HASH_VERSION) {
+ error(_("hash version %u does not match"), hash_version);
+ goto cleanup_fail;
+ }
+ m->hash_len = MIDX_HASH_LEN;
+
+ m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
+
+ m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
+
+ for (i = 0; i < m->num_chunks; i++) {
+ uint32_t chunk_id = get_be32(m->data + MIDX_HEADER_SIZE +
+ MIDX_CHUNKLOOKUP_WIDTH * i);
+ uint64_t chunk_offset = get_be64(m->data + MIDX_HEADER_SIZE + 4 +
+ MIDX_CHUNKLOOKUP_WIDTH * i);
+
+ switch (chunk_id) {
+ case MIDX_CHUNKID_PACKNAMES:
+ m->chunk_pack_names = m->data + chunk_offset;
+ break;
+
+ case MIDX_CHUNKID_OIDFANOUT:
+ m->chunk_oid_fanout = (uint32_t *)(m->data + chunk_offset);
+ break;
+
+ case MIDX_CHUNKID_OIDLOOKUP:
+ m->chunk_oid_lookup = m->data + chunk_offset;
+ break;
+
+ case MIDX_CHUNKID_OBJECTOFFSETS:
+ m->chunk_object_offsets = m->data + chunk_offset;
+ break;
+
+ case MIDX_CHUNKID_LARGEOFFSETS:
+ m->chunk_large_offsets = m->data + chunk_offset;
+ break;
+
+ case 0:
+ die(_("terminating multi-pack-index chunk id appears earlier than expected"));
+ break;
+
+ default:
+ /*
+ * Do nothing on unrecognized chunks, allowing future
+ * extensions to add optional chunks.
+ */
+ break;
+ }
+ }
+
+ if (!m->chunk_pack_names)
+ die(_("multi-pack-index missing required pack-name chunk"));
+ if (!m->chunk_oid_fanout)
+ die(_("multi-pack-index missing required OID fanout chunk"));
+ if (!m->chunk_oid_lookup)
+ die(_("multi-pack-index missing required OID lookup chunk"));
+ if (!m->chunk_object_offsets)
+ die(_("multi-pack-index missing required object offsets chunk"));
+
+ m->num_objects = ntohl(m->chunk_oid_fanout[255]);
+
+ m->pack_names = xcalloc(m->num_packs, sizeof(*m->pack_names));
+ m->packs = xcalloc(m->num_packs, sizeof(*m->packs));
+
+ cur_pack_name = (const char *)m->chunk_pack_names;
+ for (i = 0; i < m->num_packs; i++) {
+ m->pack_names[i] = cur_pack_name;
+
+ cur_pack_name += strlen(cur_pack_name) + 1;
+
+ if (i && strcmp(m->pack_names[i], m->pack_names[i - 1]) <= 0) {
+ error(_("multi-pack-index pack names out of order: '%s' before '%s'"),
+ m->pack_names[i - 1],
+ m->pack_names[i]);
+ goto cleanup_fail;
+ }
+ }
+
+ return m;
+
+cleanup_fail:
+ free(m);
+ free(midx_name);
+ if (midx_map)
+ munmap(midx_map, midx_size);
+ if (0 <= fd)
+ close(fd);
+ return NULL;
+}
+
+static void close_midx(struct multi_pack_index *m)
+{
+ uint32_t i;
+ munmap((unsigned char *)m->data, m->data_len);
+ close(m->fd);
+ m->fd = -1;
+
+ for (i = 0; i < m->num_packs; i++) {
+ if (m->packs[i]) {
+ close_pack(m->packs[i]);
+ free(m->packs);
+ }
+ }
+ FREE_AND_NULL(m->packs);
+ FREE_AND_NULL(m->pack_names);
+}
+
+static int prepare_midx_pack(struct multi_pack_index *m, uint32_t pack_int_id)
+{
+ struct strbuf pack_name = STRBUF_INIT;
+
+ if (pack_int_id >= m->num_packs)
+ BUG("bad pack-int-id");
+
+ if (m->packs[pack_int_id])
+ return 0;
+
+ strbuf_addf(&pack_name, "%s/pack/%s", m->object_dir,
+ m->pack_names[pack_int_id]);
+
+ m->packs[pack_int_id] = add_packed_git(pack_name.buf, pack_name.len, 1);
+ strbuf_release(&pack_name);
+ return !m->packs[pack_int_id];
+}
+
+int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result)
+{
+ return bsearch_hash(oid->hash, m->chunk_oid_fanout, m->chunk_oid_lookup,
+ MIDX_HASH_LEN, result);
+}
+
+struct object_id *nth_midxed_object_oid(struct object_id *oid,
+ struct multi_pack_index *m,
+ uint32_t n)
+{
+ if (n >= m->num_objects)
+ return NULL;
+
+ hashcpy(oid->hash, m->chunk_oid_lookup + m->hash_len * n);
+ return oid;
+}
+
+static off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos)
+{
+ const unsigned char *offset_data;
+ uint32_t offset32;
+
+ offset_data = m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH;
+ offset32 = get_be32(offset_data + sizeof(uint32_t));
+
+ if (m->chunk_large_offsets && offset32 & MIDX_LARGE_OFFSET_NEEDED) {
+ if (sizeof(offset32) < sizeof(uint64_t))
+ die(_("multi-pack-index stores a 64-bit offset, but off_t is too small"));
+
+ offset32 ^= MIDX_LARGE_OFFSET_NEEDED;
+ return get_be64(m->chunk_large_offsets + sizeof(uint64_t) * offset32);
+ }
+
+ return offset32;
+}
+
+static uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos)
+{
+ return get_be32(m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH);
+}
+
+static int nth_midxed_pack_entry(struct multi_pack_index *m, struct pack_entry *e, uint32_t pos)
+{
+ uint32_t pack_int_id;
+ struct packed_git *p;
+
+ if (pos >= m->num_objects)
+ return 0;
+
+ pack_int_id = nth_midxed_pack_int_id(m, pos);
+
+ if (prepare_midx_pack(m, pack_int_id))
+ die(_("error preparing packfile from multi-pack-index"));
+ p = m->packs[pack_int_id];
+
+ /*
+ * We are about to tell the caller where they can locate the
+ * requested object. We better make sure the packfile is
+ * still here and can be accessed before supplying that
+ * answer, as it may have been deleted since the MIDX was
+ * loaded!
+ */
+ if (!is_pack_valid(p))
+ return 0;
+
+ e->offset = nth_midxed_offset(m, pos);
+ e->p = p;
+
+ return 1;
+}
+
+int fill_midx_entry(const struct object_id *oid, struct pack_entry *e, struct multi_pack_index *m)
+{
+ uint32_t pos;
+
+ if (!bsearch_midx(oid, m, &pos))
+ return 0;
+
+ return nth_midxed_pack_entry(m, e, pos);
+}
+
+int midx_contains_pack(struct multi_pack_index *m, const char *idx_name)
+{
+ uint32_t first = 0, last = m->num_packs;
+
+ while (first < last) {
+ uint32_t mid = first + (last - first) / 2;
+ const char *current;
+ int cmp;
+
+ current = m->pack_names[mid];
+ cmp = strcmp(idx_name, current);
+ if (!cmp)
+ return 1;
+ if (cmp > 0) {
+ first = mid + 1;
+ continue;
+ }
+ last = mid;
+ }
+
+ return 0;
+}
+
+int prepare_multi_pack_index_one(struct repository *r, const char *object_dir)
+{
+ struct multi_pack_index *m = r->objects->multi_pack_index;
+ struct multi_pack_index *m_search;
+ int config_value;
+
+ if (repo_config_get_bool(r, "core.multipackindex", &config_value) ||
+ !config_value)
+ return 0;
+
+ for (m_search = m; m_search; m_search = m_search->next)
+ if (!strcmp(object_dir, m_search->object_dir))
+ return 1;
+
+ r->objects->multi_pack_index = load_multi_pack_index(object_dir);
+
+ if (r->objects->multi_pack_index) {
+ r->objects->multi_pack_index->next = m;
+ return 1;
+ }
+
+ return 0;
+}
+
+static size_t write_midx_header(struct hashfile *f,
+ unsigned char num_chunks,
+ uint32_t num_packs)
+{
+ unsigned char byte_values[4];
+
+ hashwrite_be32(f, MIDX_SIGNATURE);
+ byte_values[0] = MIDX_VERSION;
+ byte_values[1] = MIDX_HASH_VERSION;
+ byte_values[2] = num_chunks;
+ byte_values[3] = 0; /* unused */
+ hashwrite(f, byte_values, sizeof(byte_values));
+ hashwrite_be32(f, num_packs);
+
+ return MIDX_HEADER_SIZE;
+}
+
+struct pack_list {
+ struct packed_git **list;
+ char **names;
+ uint32_t nr;
+ uint32_t alloc_list;
+ uint32_t alloc_names;
+ size_t pack_name_concat_len;
+ struct multi_pack_index *m;
+};
+
+static void add_pack_to_midx(const char *full_path, size_t full_path_len,
+ const char *file_name, void *data)
+{
+ struct pack_list *packs = (struct pack_list *)data;
+
+ if (ends_with(file_name, ".idx")) {
+ if (packs->m && midx_contains_pack(packs->m, file_name))
+ return;
+
+ ALLOC_GROW(packs->list, packs->nr + 1, packs->alloc_list);
+ ALLOC_GROW(packs->names, packs->nr + 1, packs->alloc_names);
+
+ packs->list[packs->nr] = add_packed_git(full_path,
+ full_path_len,
+ 0);
+
+ if (!packs->list[packs->nr]) {
+ warning(_("failed to add packfile '%s'"),
+ full_path);
+ return;
+ }
+
+ if (open_pack_index(packs->list[packs->nr])) {
+ warning(_("failed to open pack-index '%s'"),
+ full_path);
+ close_pack(packs->list[packs->nr]);
+ FREE_AND_NULL(packs->list[packs->nr]);
+ return;
+ }
+
+ packs->names[packs->nr] = xstrdup(file_name);
+ packs->pack_name_concat_len += strlen(file_name) + 1;
+ packs->nr++;
+ }
+}
+
+struct pack_pair {
+ uint32_t pack_int_id;
+ char *pack_name;
+};
+
+static int pack_pair_compare(const void *_a, const void *_b)
+{
+ struct pack_pair *a = (struct pack_pair *)_a;
+ struct pack_pair *b = (struct pack_pair *)_b;
+ return strcmp(a->pack_name, b->pack_name);
+}
+
+static void sort_packs_by_name(char **pack_names, uint32_t nr_packs, uint32_t *perm)
+{
+ uint32_t i;
+ struct pack_pair *pairs;
+
+ ALLOC_ARRAY(pairs, nr_packs);
+
+ for (i = 0; i < nr_packs; i++) {
+ pairs[i].pack_int_id = i;
+ pairs[i].pack_name = pack_names[i];
+ }
+
+ QSORT(pairs, nr_packs, pack_pair_compare);
+
+ for (i = 0; i < nr_packs; i++) {
+ pack_names[i] = pairs[i].pack_name;
+ perm[pairs[i].pack_int_id] = i;
+ }
+
+ free(pairs);
+}
+
+struct pack_midx_entry {
+ struct object_id oid;
+ uint32_t pack_int_id;
+ time_t pack_mtime;
+ uint64_t offset;
+};
+
+static int midx_oid_compare(const void *_a, const void *_b)
+{
+ const struct pack_midx_entry *a = (const struct pack_midx_entry *)_a;
+ const struct pack_midx_entry *b = (const struct pack_midx_entry *)_b;
+ int cmp = oidcmp(&a->oid, &b->oid);
+
+ if (cmp)
+ return cmp;
+
+ if (a->pack_mtime > b->pack_mtime)
+ return -1;
+ else if (a->pack_mtime < b->pack_mtime)
+ return 1;
+
+ return a->pack_int_id - b->pack_int_id;
+}
+
+static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
+ uint32_t *pack_perm,
+ struct pack_midx_entry *e,
+ uint32_t pos)
+{
+ if (pos >= m->num_objects)
+ return 1;
+
+ nth_midxed_object_oid(&e->oid, m, pos);
+ e->pack_int_id = pack_perm[nth_midxed_pack_int_id(m, pos)];
+ e->offset = nth_midxed_offset(m, pos);
+
+ /* consider objects in midx to be from "old" packs */
+ e->pack_mtime = 0;
+ return 0;
+}
+
+static void fill_pack_entry(uint32_t pack_int_id,
+ struct packed_git *p,
+ uint32_t cur_object,
+ struct pack_midx_entry *entry)
+{
+ if (!nth_packed_object_oid(&entry->oid, p, cur_object))
+ die(_("failed to locate object %d in packfile"), cur_object);
+
+ entry->pack_int_id = pack_int_id;
+ entry->pack_mtime = p->mtime;
+
+ entry->offset = nth_packed_object_offset(p, cur_object);
+}
+
+/*
+ * It is possible to artificially get into a state where there are many
+ * duplicate copies of objects. That can create high memory pressure if
+ * we are to create a list of all objects before de-duplication. To reduce
+ * this memory pressure without a significant performance drop, automatically
+ * group objects by the first byte of their object id. Use the IDX fanout
+ * tables to group the data, copy to a local array, then sort.
+ *
+ * Copy only the de-duplicated entries (selected by most-recent modified time
+ * of a packfile containing the object).
+ */
+static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
+ struct packed_git **p,
+ uint32_t *perm,
+ uint32_t nr_packs,
+ uint32_t *nr_objects)
+{
+ uint32_t cur_fanout, cur_pack, cur_object;
+ uint32_t alloc_fanout, alloc_objects, total_objects = 0;
+ struct pack_midx_entry *entries_by_fanout = NULL;
+ struct pack_midx_entry *deduplicated_entries = NULL;
+ uint32_t start_pack = m ? m->num_packs : 0;
+
+ for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++)
+ total_objects += p[cur_pack]->num_objects;
+
+ /*
+ * As we de-duplicate by fanout value, we expect the fanout
+ * slices to be evenly distributed, with some noise. Hence,
+ * allocate slightly more than one 256th.
+ */
+ alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16;
+
+ ALLOC_ARRAY(entries_by_fanout, alloc_fanout);
+ ALLOC_ARRAY(deduplicated_entries, alloc_objects);
+ *nr_objects = 0;
+
+ for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) {
+ uint32_t nr_fanout = 0;
+
+ if (m) {
+ uint32_t start = 0, end;
+
+ if (cur_fanout)
+ start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
+ end = ntohl(m->chunk_oid_fanout[cur_fanout]);
+
+ for (cur_object = start; cur_object < end; cur_object++) {
+ ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
+ nth_midxed_pack_midx_entry(m, perm,
+ &entries_by_fanout[nr_fanout],
+ cur_object);
+ nr_fanout++;
+ }
+ }
+
+ for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) {
+ uint32_t start = 0, end;
+
+ if (cur_fanout)
+ start = get_pack_fanout(p[cur_pack], cur_fanout - 1);
+ end = get_pack_fanout(p[cur_pack], cur_fanout);
+
+ for (cur_object = start; cur_object < end; cur_object++) {
+ ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
+ fill_pack_entry(perm[cur_pack], p[cur_pack], cur_object, &entries_by_fanout[nr_fanout]);
+ nr_fanout++;
+ }
+ }
+
+ QSORT(entries_by_fanout, nr_fanout, midx_oid_compare);
+
+ /*
+ * The batch is now sorted by OID and then mtime (descending).
+ * Take only the first duplicate.
+ */
+ for (cur_object = 0; cur_object < nr_fanout; cur_object++) {
+ if (cur_object && !oidcmp(&entries_by_fanout[cur_object - 1].oid,
+ &entries_by_fanout[cur_object].oid))
+ continue;
+
+ ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects);
+ memcpy(&deduplicated_entries[*nr_objects],
+ &entries_by_fanout[cur_object],
+ sizeof(struct pack_midx_entry));
+ (*nr_objects)++;
+ }
+ }
+
+ free(entries_by_fanout);
+ return deduplicated_entries;
+}
+
+static size_t write_midx_pack_names(struct hashfile *f,
+ char **pack_names,
+ uint32_t num_packs)
+{
+ uint32_t i;
+ unsigned char padding[MIDX_CHUNK_ALIGNMENT];
+ size_t written = 0;
+
+ for (i = 0; i < num_packs; i++) {
+ size_t writelen = strlen(pack_names[i]) + 1;
+
+ if (i && strcmp(pack_names[i], pack_names[i - 1]) <= 0)
+ BUG("incorrect pack-file order: %s before %s",
+ pack_names[i - 1],
+ pack_names[i]);
+
+ hashwrite(f, pack_names[i], writelen);
+ written += writelen;
+ }
+
+ /* add padding to be aligned */
+ i = MIDX_CHUNK_ALIGNMENT - (written % MIDX_CHUNK_ALIGNMENT);
+ if (i < MIDX_CHUNK_ALIGNMENT) {
+ memset(padding, 0, sizeof(padding));
+ hashwrite(f, padding, i);
+ written += i;
+ }
+
+ return written;
+}
+
+static size_t write_midx_oid_fanout(struct hashfile *f,
+ struct pack_midx_entry *objects,
+ uint32_t nr_objects)
+{
+ struct pack_midx_entry *list = objects;
+ struct pack_midx_entry *last = objects + nr_objects;
+ uint32_t count = 0;
+ uint32_t i;
+
+ /*
+ * Write the first-level table (the list is sorted,
+ * but we use a 256-entry lookup to be able to avoid
+ * having to do eight extra binary search iterations).
+ */
+ for (i = 0; i < 256; i++) {
+ struct pack_midx_entry *next = list;
+
+ while (next < last && next->oid.hash[0] == i) {
+ count++;
+ next++;
+ }
+
+ hashwrite_be32(f, count);
+ list = next;
+ }
+
+ return MIDX_CHUNK_FANOUT_SIZE;
+}
+
+static size_t write_midx_oid_lookup(struct hashfile *f, unsigned char hash_len,
+ struct pack_midx_entry *objects,
+ uint32_t nr_objects)
+{
+ struct pack_midx_entry *list = objects;
+ uint32_t i;
+ size_t written = 0;
+
+ for (i = 0; i < nr_objects; i++) {
+ struct pack_midx_entry *obj = list++;
+
+ if (i < nr_objects - 1) {
+ struct pack_midx_entry *next = list;
+ if (oidcmp(&obj->oid, &next->oid) >= 0)
+ BUG("OIDs not in order: %s >= %s",
+ oid_to_hex(&obj->oid),
+ oid_to_hex(&next->oid));
+ }
+
+ hashwrite(f, obj->oid.hash, (int)hash_len);
+ written += hash_len;
+ }
+
+ return written;
+}
+
+static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_needed,
+ struct pack_midx_entry *objects, uint32_t nr_objects)
+{
+ struct pack_midx_entry *list = objects;
+ uint32_t i, nr_large_offset = 0;
+ size_t written = 0;
+
+ for (i = 0; i < nr_objects; i++) {
+ struct pack_midx_entry *obj = list++;
+
+ hashwrite_be32(f, obj->pack_int_id);
+
+ if (large_offset_needed && obj->offset >> 31)
+ hashwrite_be32(f, MIDX_LARGE_OFFSET_NEEDED | nr_large_offset++);
+ else if (!large_offset_needed && obj->offset >> 32)
+ BUG("object %s requires a large offset (%"PRIx64") but the MIDX is not writing large offsets!",
+ oid_to_hex(&obj->oid),
+ obj->offset);
+ else
+ hashwrite_be32(f, (uint32_t)obj->offset);
+
+ written += MIDX_CHUNK_OFFSET_WIDTH;
+ }
+
+ return written;
+}
+
+static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset,
+ struct pack_midx_entry *objects, uint32_t nr_objects)
+{
+ struct pack_midx_entry *list = objects;
+ size_t written = 0;
+
+ while (nr_large_offset) {
+ struct pack_midx_entry *obj = list++;
+ uint64_t offset = obj->offset;
+
+ if (!(offset >> 31))
+ continue;
+
+ hashwrite_be32(f, offset >> 32);
+ hashwrite_be32(f, offset & 0xffffffffUL);
+ written += 2 * sizeof(uint32_t);
+
+ nr_large_offset--;
+ }
+
+ return written;
+}
+
+int write_midx_file(const char *object_dir)
+{
+ unsigned char cur_chunk, num_chunks = 0;
+ char *midx_name;
+ uint32_t i;
+ struct hashfile *f = NULL;
+ struct lock_file lk;
+ struct pack_list packs;
+ uint32_t *pack_perm = NULL;
+ uint64_t written = 0;
+ uint32_t chunk_ids[MIDX_MAX_CHUNKS + 1];
+ uint64_t chunk_offsets[MIDX_MAX_CHUNKS + 1];
+ uint32_t nr_entries, num_large_offsets = 0;
+ struct pack_midx_entry *entries = NULL;
+ int large_offsets_needed = 0;
+
+ midx_name = get_midx_filename(object_dir);
+ if (safe_create_leading_directories(midx_name)) {
+ UNLEAK(midx_name);
+ die_errno(_("unable to create leading directories of %s"),
+ midx_name);
+ }
+
+ packs.m = load_multi_pack_index(object_dir);
+
+ packs.nr = 0;
+ packs.alloc_list = packs.m ? packs.m->num_packs : 16;
+ packs.alloc_names = packs.alloc_list;
+ packs.list = NULL;
+ packs.names = NULL;
+ packs.pack_name_concat_len = 0;
+ ALLOC_ARRAY(packs.list, packs.alloc_list);
+ ALLOC_ARRAY(packs.names, packs.alloc_names);
+
+ if (packs.m) {
+ for (i = 0; i < packs.m->num_packs; i++) {
+ ALLOC_GROW(packs.list, packs.nr + 1, packs.alloc_list);
+ ALLOC_GROW(packs.names, packs.nr + 1, packs.alloc_names);
+
+ packs.list[packs.nr] = NULL;
+ packs.names[packs.nr] = xstrdup(packs.m->pack_names[i]);
+ packs.pack_name_concat_len += strlen(packs.names[packs.nr]) + 1;
+ packs.nr++;
+ }
+ }
+
+ for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &packs);
+
+ if (packs.m && packs.nr == packs.m->num_packs)
+ goto cleanup;
+
+ if (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT)
+ packs.pack_name_concat_len += MIDX_CHUNK_ALIGNMENT -
+ (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT);
+
+ ALLOC_ARRAY(pack_perm, packs.nr);
+ sort_packs_by_name(packs.names, packs.nr, pack_perm);
+
+ entries = get_sorted_entries(packs.m, packs.list, pack_perm, packs.nr, &nr_entries);
+
+ for (i = 0; i < nr_entries; i++) {
+ if (entries[i].offset > 0x7fffffff)
+ num_large_offsets++;
+ if (entries[i].offset > 0xffffffff)
+ large_offsets_needed = 1;
+ }
+
+ hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR);
+ f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
+ FREE_AND_NULL(midx_name);
+
+ if (packs.m)
+ close_midx(packs.m);
+
+ cur_chunk = 0;
+ num_chunks = large_offsets_needed ? 5 : 4;
+
+ written = write_midx_header(f, num_chunks, packs.nr);
+
+ chunk_ids[cur_chunk] = MIDX_CHUNKID_PACKNAMES;
+ chunk_offsets[cur_chunk] = written + (num_chunks + 1) * MIDX_CHUNKLOOKUP_WIDTH;
+
+ cur_chunk++;
+ chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDFANOUT;
+ chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + packs.pack_name_concat_len;
+
+ cur_chunk++;
+ chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDLOOKUP;
+ chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + MIDX_CHUNK_FANOUT_SIZE;
+
+ cur_chunk++;
+ chunk_ids[cur_chunk] = MIDX_CHUNKID_OBJECTOFFSETS;
+ chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_HASH_LEN;
+
+ cur_chunk++;
+ chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_CHUNK_OFFSET_WIDTH;
+ if (large_offsets_needed) {
+ chunk_ids[cur_chunk] = MIDX_CHUNKID_LARGEOFFSETS;
+
+ cur_chunk++;
+ chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] +
+ num_large_offsets * MIDX_CHUNK_LARGE_OFFSET_WIDTH;
+ }
+
+ chunk_ids[cur_chunk] = 0;
+
+ for (i = 0; i <= num_chunks; i++) {
+ if (i && chunk_offsets[i] < chunk_offsets[i - 1])
+ BUG("incorrect chunk offsets: %"PRIu64" before %"PRIu64,
+ chunk_offsets[i - 1],
+ chunk_offsets[i]);
+
+ if (chunk_offsets[i] % MIDX_CHUNK_ALIGNMENT)
+ BUG("chunk offset %"PRIu64" is not properly aligned",
+ chunk_offsets[i]);
+
+ hashwrite_be32(f, chunk_ids[i]);
+ hashwrite_be32(f, chunk_offsets[i] >> 32);
+ hashwrite_be32(f, chunk_offsets[i]);
+
+ written += MIDX_CHUNKLOOKUP_WIDTH;
+ }
+
+ for (i = 0; i < num_chunks; i++) {
+ if (written != chunk_offsets[i])
+ BUG("incorrect chunk offset (%"PRIu64" != %"PRIu64") for chunk id %"PRIx32,
+ chunk_offsets[i],
+ written,
+ chunk_ids[i]);
+
+ switch (chunk_ids[i]) {
+ case MIDX_CHUNKID_PACKNAMES:
+ written += write_midx_pack_names(f, packs.names, packs.nr);
+ break;
+
+ case MIDX_CHUNKID_OIDFANOUT:
+ written += write_midx_oid_fanout(f, entries, nr_entries);
+ break;
+
+ case MIDX_CHUNKID_OIDLOOKUP:
+ written += write_midx_oid_lookup(f, MIDX_HASH_LEN, entries, nr_entries);
+ break;
+
+ case MIDX_CHUNKID_OBJECTOFFSETS:
+ written += write_midx_object_offsets(f, large_offsets_needed, entries, nr_entries);
+ break;
+
+ case MIDX_CHUNKID_LARGEOFFSETS:
+ written += write_midx_large_offsets(f, num_large_offsets, entries, nr_entries);
+ break;
+
+ default:
+ BUG("trying to write unknown chunk id %"PRIx32,
+ chunk_ids[i]);
+ }
+ }
+
+ if (written != chunk_offsets[num_chunks])
+ BUG("incorrect final offset %"PRIu64" != %"PRIu64,
+ written,
+ chunk_offsets[num_chunks]);
+
+ finalize_hashfile(f, NULL, CSUM_FSYNC | CSUM_HASH_IN_STREAM);
+ commit_lock_file(&lk);
+
+cleanup:
+ for (i = 0; i < packs.nr; i++) {
+ if (packs.list[i]) {
+ close_pack(packs.list[i]);
+ free(packs.list[i]);
+ }
+ free(packs.names[i]);
+ }
+
+ free(packs.list);
+ free(packs.names);
+ free(entries);
+ free(pack_perm);
+ free(midx_name);
+ return 0;
+}
+
+void clear_midx_file(const char *object_dir)
+{
+ char *midx = get_midx_filename(object_dir);
+
+ if (remove_path(midx)) {
+ UNLEAK(midx);
+ die(_("failed to clear multi-pack-index at %s"), midx);
+ }
+
+ free(midx);
+}