]> git.ipfire.org Git - thirdparty/git.git/blobdiff - midx.c
Merge branch 'jk/escaped-wildcard-dwim'
[thirdparty/git.git] / midx.c
diff --git a/midx.c b/midx.c
index 2a6a24fcd7eff1a074c37e6c556f2143ef134c19..37ec28623af67f01ec6fbc2f42c6e727eddbdaf4 100644 (file)
--- a/midx.c
+++ b/midx.c
@@ -8,6 +8,8 @@
 #include "sha1-lookup.h"
 #include "midx.h"
 #include "progress.h"
+#include "trace2.h"
+#include "run-command.h"
 
 #define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
 #define MIDX_VERSION 1
@@ -17,8 +19,7 @@
 #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_MIN_SIZE (MIDX_HEADER_SIZE + the_hash_algo->rawsz)
 
 #define MIDX_MAX_CHUNKS 5
 #define MIDX_CHUNK_ALIGNMENT 4
@@ -33,6 +34,8 @@
 #define MIDX_CHUNK_LARGE_OFFSET_WIDTH (sizeof(uint64_t))
 #define MIDX_LARGE_OFFSET_NEEDED 0x80000000
 
+#define PACK_EXPIRED UINT_MAX
+
 static char *get_midx_filename(const char *object_dir)
 {
        return xstrfmt("%s/pack/multi-pack-index", object_dir);
@@ -70,7 +73,7 @@ struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local
 
        midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 
-       FLEX_ALLOC_MEM(m, object_dir, object_dir, strlen(object_dir));
+       FLEX_ALLOC_STR(m, object_dir, object_dir);
        m->fd = fd;
        m->data = midx_map;
        m->data_len = midx_size;
@@ -89,7 +92,7 @@ struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local
        hash_version = m->data[MIDX_BYTE_HASH_VERSION];
        if (hash_version != MIDX_HASH_VERSION)
                die(_("hash version %u does not match"), hash_version);
-       m->hash_len = MIDX_HASH_LEN;
+       m->hash_len = the_hash_algo->rawsz;
 
        m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
 
@@ -164,6 +167,9 @@ struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local
                              m->pack_names[i]);
        }
 
+       trace2_data_intmax("midx", the_repository, "load/num_packs", m->num_packs);
+       trace2_data_intmax("midx", the_repository, "load/num_objects", m->num_objects);
+
        return m;
 
 cleanup_fail:
@@ -188,18 +194,17 @@ void close_midx(struct multi_pack_index *m)
        m->fd = -1;
 
        for (i = 0; i < m->num_packs; i++) {
-               if (m->packs[i]) {
-                       close_pack(m->packs[i]);
-                       free(m->packs[i]);
-               }
+               if (m->packs[i])
+                       m->packs[i]->multi_pack_index = 0;
        }
        FREE_AND_NULL(m->packs);
        FREE_AND_NULL(m->pack_names);
 }
 
-int prepare_midx_pack(struct multi_pack_index *m, uint32_t pack_int_id)
+int prepare_midx_pack(struct repository *r, struct multi_pack_index *m, uint32_t pack_int_id)
 {
        struct strbuf pack_name = STRBUF_INIT;
+       struct packed_git *p;
 
        if (pack_int_id >= m->num_packs)
                die(_("bad pack-int-id: %u (%u total packs)"),
@@ -211,15 +216,24 @@ int prepare_midx_pack(struct multi_pack_index *m, uint32_t pack_int_id)
        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, m->local);
+       p = add_packed_git(pack_name.buf, pack_name.len, m->local);
        strbuf_release(&pack_name);
-       return !m->packs[pack_int_id];
+
+       if (!p)
+               return 1;
+
+       p->multi_pack_index = 1;
+       m->packs[pack_int_id] = p;
+       install_packed_git(r, p);
+       list_add_tail(&p->mru, &r->objects->packed_git_mru);
+
+       return 0;
 }
 
 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);
+                           the_hash_algo->rawsz, result);
 }
 
 struct object_id *nth_midxed_object_oid(struct object_id *oid,
@@ -257,7 +271,10 @@ 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)
+static int nth_midxed_pack_entry(struct repository *r,
+                                struct multi_pack_index *m,
+                                struct pack_entry *e,
+                                uint32_t pos)
 {
        uint32_t pack_int_id;
        struct packed_git *p;
@@ -267,7 +284,7 @@ static int nth_midxed_pack_entry(struct multi_pack_index *m, struct pack_entry *
 
        pack_int_id = nth_midxed_pack_int_id(m, pos);
 
-       if (prepare_midx_pack(m, pack_int_id))
+       if (prepare_midx_pack(r, m, pack_int_id))
                die(_("error preparing packfile from multi-pack-index"));
        p = m->packs[pack_int_id];
 
@@ -297,17 +314,52 @@ static int nth_midxed_pack_entry(struct multi_pack_index *m, struct pack_entry *
        return 1;
 }
 
-int fill_midx_entry(const struct object_id *oid, struct pack_entry *e, struct multi_pack_index *m)
+int fill_midx_entry(struct repository * r,
+                   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);
+       return nth_midxed_pack_entry(r, m, e, pos);
+}
+
+/* Match "foo.idx" against either "foo.pack" _or_ "foo.idx". */
+static int cmp_idx_or_pack_name(const char *idx_or_pack_name,
+                               const char *idx_name)
+{
+       /* Skip past any initial matching prefix. */
+       while (*idx_name && *idx_name == *idx_or_pack_name) {
+               idx_name++;
+               idx_or_pack_name++;
+       }
+
+       /*
+        * If we didn't match completely, we may have matched "pack-1234." and
+        * be left with "idx" and "pack" respectively, which is also OK. We do
+        * not have to check for "idx" and "idx", because that would have been
+        * a complete match (and in that case these strcmps will be false, but
+        * we'll correctly return 0 from the final strcmp() below.
+        *
+        * Technically this matches "fooidx" and "foopack", but we'd never have
+        * such names in the first place.
+        */
+       if (!strcmp(idx_name, "idx") && !strcmp(idx_or_pack_name, "pack"))
+               return 0;
+
+       /*
+        * This not only checks for a complete match, but also orders based on
+        * the first non-identical character, which means our ordering will
+        * match a raw strcmp(). That makes it OK to use this to binary search
+        * a naively-sorted list.
+        */
+       return strcmp(idx_or_pack_name, idx_name);
 }
 
-int midx_contains_pack(struct multi_pack_index *m, const char *idx_name)
+int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name)
 {
        uint32_t first = 0, last = m->num_packs;
 
@@ -317,7 +369,7 @@ int midx_contains_pack(struct multi_pack_index *m, const char *idx_name)
                int cmp;
 
                current = m->pack_names[mid];
-               cmp = strcmp(idx_name, current);
+               cmp = cmp_idx_or_pack_name(idx_or_pack_name, current);
                if (!cmp)
                        return 1;
                if (cmp > 0) {
@@ -377,14 +429,27 @@ static size_t write_midx_header(struct hashfile *f,
        return MIDX_HEADER_SIZE;
 }
 
+struct pack_info {
+       uint32_t orig_pack_int_id;
+       char *pack_name;
+       struct packed_git *p;
+       unsigned expired : 1;
+};
+
+static int pack_info_compare(const void *_a, const void *_b)
+{
+       struct pack_info *a = (struct pack_info *)_a;
+       struct pack_info *b = (struct pack_info *)_b;
+       return strcmp(a->pack_name, b->pack_name);
+}
+
 struct pack_list {
-       struct packed_git **list;
-       char **names;
+       struct pack_info *info;
        uint32_t nr;
-       uint32_t alloc_list;
-       uint32_t alloc_names;
-       size_t pack_name_concat_len;
+       uint32_t alloc;
        struct multi_pack_index *m;
+       struct progress *progress;
+       unsigned pack_paths_checked;
 };
 
 static void add_pack_to_midx(const char *full_path, size_t full_path_len,
@@ -393,70 +458,37 @@ static void add_pack_to_midx(const char *full_path, size_t full_path_len,
        struct pack_list *packs = (struct pack_list *)data;
 
        if (ends_with(file_name, ".idx")) {
+               display_progress(packs->progress, ++packs->pack_paths_checked);
                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);
+               ALLOC_GROW(packs->info, packs->nr + 1, packs->alloc);
 
-               packs->list[packs->nr] = add_packed_git(full_path,
-                                                       full_path_len,
-                                                       0);
+               packs->info[packs->nr].p = add_packed_git(full_path,
+                                                         full_path_len,
+                                                         0);
 
-               if (!packs->list[packs->nr]) {
+               if (!packs->info[packs->nr].p) {
                        warning(_("failed to add packfile '%s'"),
                                full_path);
                        return;
                }
 
-               if (open_pack_index(packs->list[packs->nr])) {
+               if (open_pack_index(packs->info[packs->nr].p)) {
                        warning(_("failed to open pack-index '%s'"),
                                full_path);
-                       close_pack(packs->list[packs->nr]);
-                       FREE_AND_NULL(packs->list[packs->nr]);
+                       close_pack(packs->info[packs->nr].p);
+                       FREE_AND_NULL(packs->info[packs->nr].p);
                        return;
                }
 
-               packs->names[packs->nr] = xstrdup(file_name);
-               packs->pack_name_concat_len += strlen(file_name) + 1;
+               packs->info[packs->nr].pack_name = xstrdup(file_name);
+               packs->info[packs->nr].orig_pack_int_id = packs->nr;
+               packs->info[packs->nr].expired = 0;
                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;
@@ -482,7 +514,6 @@ static int midx_oid_compare(const void *_a, const void *_b)
 }
 
 static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
-                                     uint32_t *pack_perm,
                                      struct pack_midx_entry *e,
                                      uint32_t pos)
 {
@@ -490,7 +521,7 @@ static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
                return 1;
 
        nth_midxed_object_oid(&e->oid, m, pos);
-       e->pack_int_id = pack_perm[nth_midxed_pack_int_id(m, pos)];
+       e->pack_int_id = nth_midxed_pack_int_id(m, pos);
        e->offset = nth_midxed_offset(m, pos);
 
        /* consider objects in midx to be from "old" packs */
@@ -524,8 +555,7 @@ static void fill_pack_entry(uint32_t pack_int_id,
  * 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,
+                                                 struct pack_info *info,
                                                  uint32_t nr_packs,
                                                  uint32_t *nr_objects)
 {
@@ -536,7 +566,7 @@ static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
        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;
+               total_objects += info[cur_pack].p->num_objects;
 
        /*
         * As we de-duplicate by fanout value, we expect the fanout
@@ -561,7 +591,7 @@ static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
 
                        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,
+                               nth_midxed_pack_midx_entry(m,
                                                           &entries_by_fanout[nr_fanout],
                                                           cur_object);
                                nr_fanout++;
@@ -572,12 +602,12 @@ static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
                        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);
+                               start = get_pack_fanout(info[cur_pack].p, cur_fanout - 1);
+                       end = get_pack_fanout(info[cur_pack].p, 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]);
+                               fill_pack_entry(cur_pack, info[cur_pack].p, cur_object, &entries_by_fanout[nr_fanout]);
                                nr_fanout++;
                        }
                }
@@ -606,7 +636,7 @@ static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
 }
 
 static size_t write_midx_pack_names(struct hashfile *f,
-                                   char **pack_names,
+                                   struct pack_info *info,
                                    uint32_t num_packs)
 {
        uint32_t i;
@@ -614,14 +644,18 @@ static size_t write_midx_pack_names(struct hashfile *f,
        size_t written = 0;
 
        for (i = 0; i < num_packs; i++) {
-               size_t writelen = strlen(pack_names[i]) + 1;
+               size_t writelen;
 
-               if (i && strcmp(pack_names[i], pack_names[i - 1]) <= 0)
+               if (info[i].expired)
+                       continue;
+
+               if (i && strcmp(info[i].pack_name, info[i - 1].pack_name) <= 0)
                        BUG("incorrect pack-file order: %s before %s",
-                           pack_names[i - 1],
-                           pack_names[i]);
+                           info[i - 1].pack_name,
+                           info[i].pack_name);
 
-               hashwrite(f, pack_names[i], writelen);
+               writelen = strlen(info[i].pack_name) + 1;
+               hashwrite(f, info[i].pack_name, writelen);
                written += writelen;
        }
 
@@ -692,6 +726,7 @@ static size_t write_midx_oid_lookup(struct hashfile *f, unsigned char hash_len,
 }
 
 static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_needed,
+                                       uint32_t *perm,
                                        struct pack_midx_entry *objects, uint32_t nr_objects)
 {
        struct pack_midx_entry *list = objects;
@@ -701,7 +736,12 @@ static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_nee
        for (i = 0; i < nr_objects; i++) {
                struct pack_midx_entry *obj = list++;
 
-               hashwrite_be32(f, obj->pack_int_id);
+               if (perm[obj->pack_int_id] == PACK_EXPIRED)
+                       BUG("object %s is in an expired pack with int-id %d",
+                           oid_to_hex(&obj->oid),
+                           obj->pack_int_id);
+
+               hashwrite_be32(f, perm[obj->pack_int_id]);
 
                if (large_offset_needed && obj->offset >> 31)
                        hashwrite_be32(f, MIDX_LARGE_OFFSET_NEEDED | nr_large_offset++);
@@ -747,7 +787,8 @@ static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_off
        return written;
 }
 
-int write_midx_file(const char *object_dir)
+static int write_midx_internal(const char *object_dir, struct multi_pack_index *m,
+                              struct string_list *packs_to_drop, unsigned flags)
 {
        unsigned char cur_chunk, num_chunks = 0;
        char *midx_name;
@@ -761,7 +802,11 @@ int write_midx_file(const char *object_dir)
        uint64_t chunk_offsets[MIDX_MAX_CHUNKS + 1];
        uint32_t nr_entries, num_large_offsets = 0;
        struct pack_midx_entry *entries = NULL;
+       struct progress *progress = NULL;
        int large_offsets_needed = 0;
+       int pack_name_concat_len = 0;
+       int dropped_packs = 0;
+       int result = 0;
 
        midx_name = get_midx_filename(object_dir);
        if (safe_create_leading_directories(midx_name)) {
@@ -770,42 +815,41 @@ int write_midx_file(const char *object_dir)
                          midx_name);
        }
 
-       packs.m = load_multi_pack_index(object_dir, 1);
+       if (m)
+               packs.m = m;
+       else
+               packs.m = load_multi_pack_index(object_dir, 1);
 
        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);
+       packs.alloc = packs.m ? packs.m->num_packs : 16;
+       packs.info = NULL;
+       ALLOC_ARRAY(packs.info, packs.alloc);
 
        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);
+                       ALLOC_GROW(packs.info, packs.nr + 1, packs.alloc);
 
-                       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.info[packs.nr].orig_pack_int_id = i;
+                       packs.info[packs.nr].pack_name = xstrdup(packs.m->pack_names[i]);
+                       packs.info[packs.nr].p = NULL;
+                       packs.info[packs.nr].expired = 0;
                        packs.nr++;
                }
        }
 
+       packs.pack_paths_checked = 0;
+       if (flags & MIDX_PROGRESS)
+               packs.progress = start_progress(_("Adding packfiles to multi-pack-index"), 0);
+       else
+               packs.progress = NULL;
+
        for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &packs);
+       stop_progress(&packs.progress);
 
-       if (packs.m && packs.nr == packs.m->num_packs)
+       if (packs.m && packs.nr == packs.m->num_packs && !packs_to_drop)
                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);
+       entries = get_sorted_entries(packs.m, packs.info, packs.nr, &nr_entries);
 
        for (i = 0; i < nr_entries; i++) {
                if (entries[i].offset > 0x7fffffff)
@@ -814,6 +858,61 @@ int write_midx_file(const char *object_dir)
                        large_offsets_needed = 1;
        }
 
+       QSORT(packs.info, packs.nr, pack_info_compare);
+
+       if (packs_to_drop && packs_to_drop->nr) {
+               int drop_index = 0;
+               int missing_drops = 0;
+
+               for (i = 0; i < packs.nr && drop_index < packs_to_drop->nr; i++) {
+                       int cmp = strcmp(packs.info[i].pack_name,
+                                        packs_to_drop->items[drop_index].string);
+
+                       if (!cmp) {
+                               drop_index++;
+                               packs.info[i].expired = 1;
+                       } else if (cmp > 0) {
+                               error(_("did not see pack-file %s to drop"),
+                                     packs_to_drop->items[drop_index].string);
+                               drop_index++;
+                               missing_drops++;
+                               i--;
+                       } else {
+                               packs.info[i].expired = 0;
+                       }
+               }
+
+               if (missing_drops) {
+                       result = 1;
+                       goto cleanup;
+               }
+       }
+
+       /*
+        * pack_perm stores a permutation between pack-int-ids from the
+        * previous multi-pack-index to the new one we are writing:
+        *
+        * pack_perm[old_id] = new_id
+        */
+       ALLOC_ARRAY(pack_perm, packs.nr);
+       for (i = 0; i < packs.nr; i++) {
+               if (packs.info[i].expired) {
+                       dropped_packs++;
+                       pack_perm[packs.info[i].orig_pack_int_id] = PACK_EXPIRED;
+               } else {
+                       pack_perm[packs.info[i].orig_pack_int_id] = i - dropped_packs;
+               }
+       }
+
+       for (i = 0; i < packs.nr; i++) {
+               if (!packs.info[i].expired)
+                       pack_name_concat_len += strlen(packs.info[i].pack_name) + 1;
+       }
+
+       if (pack_name_concat_len % MIDX_CHUNK_ALIGNMENT)
+               pack_name_concat_len += MIDX_CHUNK_ALIGNMENT -
+                                       (pack_name_concat_len % MIDX_CHUNK_ALIGNMENT);
+
        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);
@@ -824,14 +923,14 @@ int write_midx_file(const char *object_dir)
        cur_chunk = 0;
        num_chunks = large_offsets_needed ? 5 : 4;
 
-       written = write_midx_header(f, num_chunks, packs.nr);
+       written = write_midx_header(f, num_chunks, packs.nr - dropped_packs);
 
        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;
+       chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + pack_name_concat_len;
 
        cur_chunk++;
        chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDLOOKUP;
@@ -839,7 +938,7 @@ int write_midx_file(const char *object_dir)
 
        cur_chunk++;
        chunk_ids[cur_chunk] = MIDX_CHUNKID_OBJECTOFFSETS;
-       chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_HASH_LEN;
+       chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * the_hash_algo->rawsz;
 
        cur_chunk++;
        chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_CHUNK_OFFSET_WIDTH;
@@ -870,6 +969,9 @@ int write_midx_file(const char *object_dir)
                written += MIDX_CHUNKLOOKUP_WIDTH;
        }
 
+       if (flags & MIDX_PROGRESS)
+               progress = start_progress(_("Writing chunks to multi-pack-index"),
+                                         num_chunks);
        for (i = 0; i < num_chunks; i++) {
                if (written != chunk_offsets[i])
                        BUG("incorrect chunk offset (%"PRIu64" != %"PRIu64") for chunk id %"PRIx32,
@@ -879,7 +981,7 @@ int write_midx_file(const char *object_dir)
 
                switch (chunk_ids[i]) {
                        case MIDX_CHUNKID_PACKNAMES:
-                               written += write_midx_pack_names(f, packs.names, packs.nr);
+                               written += write_midx_pack_names(f, packs.info, packs.nr);
                                break;
 
                        case MIDX_CHUNKID_OIDFANOUT:
@@ -887,11 +989,11 @@ int write_midx_file(const char *object_dir)
                                break;
 
                        case MIDX_CHUNKID_OIDLOOKUP:
-                               written += write_midx_oid_lookup(f, MIDX_HASH_LEN, entries, nr_entries);
+                               written += write_midx_oid_lookup(f, the_hash_algo->rawsz, entries, nr_entries);
                                break;
 
                        case MIDX_CHUNKID_OBJECTOFFSETS:
-                               written += write_midx_object_offsets(f, large_offsets_needed, entries, nr_entries);
+                               written += write_midx_object_offsets(f, large_offsets_needed, pack_perm, entries, nr_entries);
                                break;
 
                        case MIDX_CHUNKID_LARGEOFFSETS:
@@ -902,7 +1004,10 @@ int write_midx_file(const char *object_dir)
                                BUG("trying to write unknown chunk id %"PRIx32,
                                    chunk_ids[i]);
                }
+
+               display_progress(progress, i + 1);
        }
+       stop_progress(&progress);
 
        if (written != chunk_offsets[num_chunks])
                BUG("incorrect final offset %"PRIu64" != %"PRIu64,
@@ -914,24 +1019,28 @@ int write_midx_file(const char *object_dir)
 
 cleanup:
        for (i = 0; i < packs.nr; i++) {
-               if (packs.list[i]) {
-                       close_pack(packs.list[i]);
-                       free(packs.list[i]);
+               if (packs.info[i].p) {
+                       close_pack(packs.info[i].p);
+                       free(packs.info[i].p);
                }
-               free(packs.names[i]);
+               free(packs.info[i].pack_name);
        }
 
-       free(packs.list);
-       free(packs.names);
+       free(packs.info);
        free(entries);
        free(pack_perm);
        free(midx_name);
-       return 0;
+       return result;
+}
+
+int write_midx_file(const char *object_dir, unsigned flags)
+{
+       return write_midx_internal(object_dir, NULL, NULL, flags);
 }
 
 void clear_midx_file(struct repository *r)
 {
-       char *midx = get_midx_filename(r->objects->objectdir);
+       char *midx = get_midx_filename(r->objects->odb->path);
 
        if (r->objects && r->objects->multi_pack_index) {
                close_midx(r->objects->multi_pack_index);
@@ -958,20 +1067,53 @@ static void midx_report(const char *fmt, ...)
        va_end(ap);
 }
 
-int verify_midx_file(const char *object_dir)
+struct pair_pos_vs_id
+{
+       uint32_t pos;
+       uint32_t pack_int_id;
+};
+
+static int compare_pair_pos_vs_id(const void *_a, const void *_b)
+{
+       struct pair_pos_vs_id *a = (struct pair_pos_vs_id *)_a;
+       struct pair_pos_vs_id *b = (struct pair_pos_vs_id *)_b;
+
+       return b->pack_int_id - a->pack_int_id;
+}
+
+/*
+ * Limit calls to display_progress() for performance reasons.
+ * The interval here was arbitrarily chosen.
+ */
+#define SPARSE_PROGRESS_INTERVAL (1 << 12)
+#define midx_display_sparse_progress(progress, n) \
+       do { \
+               uint64_t _n = (n); \
+               if ((_n & (SPARSE_PROGRESS_INTERVAL - 1)) == 0) \
+                       display_progress(progress, _n); \
+       } while (0)
+
+int verify_midx_file(struct repository *r, const char *object_dir, unsigned flags)
 {
+       struct pair_pos_vs_id *pairs = NULL;
        uint32_t i;
-       struct progress *progress;
+       struct progress *progress = NULL;
        struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
        verify_midx_error = 0;
 
        if (!m)
                return 0;
 
+       if (flags & MIDX_PROGRESS)
+               progress = start_progress(_("Looking for referenced packfiles"),
+                                         m->num_packs);
        for (i = 0; i < m->num_packs; i++) {
-               if (prepare_midx_pack(m, i))
+               if (prepare_midx_pack(r, m, i))
                        midx_report("failed to load pack in position %d", i);
+
+               display_progress(progress, i + 1);
        }
+       stop_progress(&progress);
 
        for (i = 0; i < 255; i++) {
                uint32_t oid_fanout1 = ntohl(m->chunk_oid_fanout[i]);
@@ -982,6 +1124,9 @@ int verify_midx_file(const char *object_dir)
                                    i, oid_fanout1, oid_fanout2, i + 1);
        }
 
+       if (flags & MIDX_PROGRESS)
+               progress = start_sparse_progress(_("Verifying OID order in multi-pack-index"),
+                                                m->num_objects - 1);
        for (i = 0; i < m->num_objects - 1; i++) {
                struct object_id oid1, oid2;
 
@@ -991,18 +1136,49 @@ int verify_midx_file(const char *object_dir)
                if (oidcmp(&oid1, &oid2) >= 0)
                        midx_report(_("oid lookup out of order: oid[%d] = %s >= %s = oid[%d]"),
                                    i, oid_to_hex(&oid1), oid_to_hex(&oid2), i + 1);
+
+               midx_display_sparse_progress(progress, i + 1);
        }
+       stop_progress(&progress);
 
-       progress = start_progress(_("Verifying object offsets"), m->num_objects);
+       /*
+        * Create an array mapping each object to its packfile id.  Sort it
+        * to group the objects by packfile.  Use this permutation to visit
+        * each of the objects and only require 1 packfile to be open at a
+        * time.
+        */
+       ALLOC_ARRAY(pairs, m->num_objects);
+       for (i = 0; i < m->num_objects; i++) {
+               pairs[i].pos = i;
+               pairs[i].pack_int_id = nth_midxed_pack_int_id(m, i);
+       }
+
+       if (flags & MIDX_PROGRESS)
+               progress = start_sparse_progress(_("Sorting objects by packfile"),
+                                                m->num_objects);
+       display_progress(progress, 0); /* TODO: Measure QSORT() progress */
+       QSORT(pairs, m->num_objects, compare_pair_pos_vs_id);
+       stop_progress(&progress);
+
+       if (flags & MIDX_PROGRESS)
+               progress = start_sparse_progress(_("Verifying object offsets"), m->num_objects);
        for (i = 0; i < m->num_objects; i++) {
                struct object_id oid;
                struct pack_entry e;
                off_t m_offset, p_offset;
 
-               nth_midxed_object_oid(&oid, m, i);
-               if (!fill_midx_entry(&oid, &e, m)) {
+               if (i > 0 && pairs[i-1].pack_int_id != pairs[i].pack_int_id &&
+                   m->packs[pairs[i-1].pack_int_id])
+               {
+                       close_pack_fd(m->packs[pairs[i-1].pack_int_id]);
+                       close_pack_index(m->packs[pairs[i-1].pack_int_id]);
+               }
+
+               nth_midxed_object_oid(&oid, m, pairs[i].pos);
+
+               if (!fill_midx_entry(r, &oid, &e, m)) {
                        midx_report(_("failed to load pack entry for oid[%d] = %s"),
-                                   i, oid_to_hex(&oid));
+                                   pairs[i].pos, oid_to_hex(&oid));
                        continue;
                }
 
@@ -1017,11 +1193,228 @@ int verify_midx_file(const char *object_dir)
 
                if (m_offset != p_offset)
                        midx_report(_("incorrect object offset for oid[%d] = %s: %"PRIx64" != %"PRIx64),
-                                   i, oid_to_hex(&oid), m_offset, p_offset);
+                                   pairs[i].pos, oid_to_hex(&oid), m_offset, p_offset);
 
-               display_progress(progress, i + 1);
+               midx_display_sparse_progress(progress, i + 1);
        }
        stop_progress(&progress);
 
+       free(pairs);
+
        return verify_midx_error;
 }
+
+int expire_midx_packs(struct repository *r, const char *object_dir, unsigned flags)
+{
+       uint32_t i, *count, result = 0;
+       struct string_list packs_to_drop = STRING_LIST_INIT_DUP;
+       struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
+       struct progress *progress = NULL;
+
+       if (!m)
+               return 0;
+
+       count = xcalloc(m->num_packs, sizeof(uint32_t));
+
+       if (flags & MIDX_PROGRESS)
+               progress = start_progress(_("Counting referenced objects"),
+                                         m->num_objects);
+       for (i = 0; i < m->num_objects; i++) {
+               int pack_int_id = nth_midxed_pack_int_id(m, i);
+               count[pack_int_id]++;
+               display_progress(progress, i + 1);
+       }
+       stop_progress(&progress);
+
+       if (flags & MIDX_PROGRESS)
+               progress = start_progress(_("Finding and deleting unreferenced packfiles"),
+                                         m->num_packs);
+       for (i = 0; i < m->num_packs; i++) {
+               char *pack_name;
+               display_progress(progress, i + 1);
+
+               if (count[i])
+                       continue;
+
+               if (prepare_midx_pack(r, m, i))
+                       continue;
+
+               if (m->packs[i]->pack_keep)
+                       continue;
+
+               pack_name = xstrdup(m->packs[i]->pack_name);
+               close_pack(m->packs[i]);
+
+               string_list_insert(&packs_to_drop, m->pack_names[i]);
+               unlink_pack_path(pack_name, 0);
+               free(pack_name);
+       }
+       stop_progress(&progress);
+
+       free(count);
+
+       if (packs_to_drop.nr)
+               result = write_midx_internal(object_dir, m, &packs_to_drop, flags);
+
+       string_list_clear(&packs_to_drop, 0);
+       return result;
+}
+
+struct repack_info {
+       timestamp_t mtime;
+       uint32_t referenced_objects;
+       uint32_t pack_int_id;
+};
+
+static int compare_by_mtime(const void *a_, const void *b_)
+{
+       const struct repack_info *a, *b;
+
+       a = (const struct repack_info *)a_;
+       b = (const struct repack_info *)b_;
+
+       if (a->mtime < b->mtime)
+               return -1;
+       if (a->mtime > b->mtime)
+               return 1;
+       return 0;
+}
+
+static int fill_included_packs_all(struct multi_pack_index *m,
+                                  unsigned char *include_pack)
+{
+       uint32_t i;
+
+       for (i = 0; i < m->num_packs; i++)
+               include_pack[i] = 1;
+
+       return m->num_packs < 2;
+}
+
+static int fill_included_packs_batch(struct repository *r,
+                                    struct multi_pack_index *m,
+                                    unsigned char *include_pack,
+                                    size_t batch_size)
+{
+       uint32_t i, packs_to_repack;
+       size_t total_size;
+       struct repack_info *pack_info = xcalloc(m->num_packs, sizeof(struct repack_info));
+
+       for (i = 0; i < m->num_packs; i++) {
+               pack_info[i].pack_int_id = i;
+
+               if (prepare_midx_pack(r, m, i))
+                       continue;
+
+               pack_info[i].mtime = m->packs[i]->mtime;
+       }
+
+       for (i = 0; batch_size && i < m->num_objects; i++) {
+               uint32_t pack_int_id = nth_midxed_pack_int_id(m, i);
+               pack_info[pack_int_id].referenced_objects++;
+       }
+
+       QSORT(pack_info, m->num_packs, compare_by_mtime);
+
+       total_size = 0;
+       packs_to_repack = 0;
+       for (i = 0; total_size < batch_size && i < m->num_packs; i++) {
+               int pack_int_id = pack_info[i].pack_int_id;
+               struct packed_git *p = m->packs[pack_int_id];
+               size_t expected_size;
+
+               if (!p)
+                       continue;
+               if (open_pack_index(p) || !p->num_objects)
+                       continue;
+
+               expected_size = (size_t)(p->pack_size
+                                        * pack_info[i].referenced_objects);
+               expected_size /= p->num_objects;
+
+               if (expected_size >= batch_size)
+                       continue;
+
+               packs_to_repack++;
+               total_size += expected_size;
+               include_pack[pack_int_id] = 1;
+       }
+
+       free(pack_info);
+
+       if (total_size < batch_size || packs_to_repack < 2)
+               return 1;
+
+       return 0;
+}
+
+int midx_repack(struct repository *r, const char *object_dir, size_t batch_size, unsigned flags)
+{
+       int result = 0;
+       uint32_t i;
+       unsigned char *include_pack;
+       struct child_process cmd = CHILD_PROCESS_INIT;
+       struct strbuf base_name = STRBUF_INIT;
+       struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
+
+       if (!m)
+               return 0;
+
+       include_pack = xcalloc(m->num_packs, sizeof(unsigned char));
+
+       if (batch_size) {
+               if (fill_included_packs_batch(r, m, include_pack, batch_size))
+                       goto cleanup;
+       } else if (fill_included_packs_all(m, include_pack))
+               goto cleanup;
+
+       argv_array_push(&cmd.args, "pack-objects");
+
+       strbuf_addstr(&base_name, object_dir);
+       strbuf_addstr(&base_name, "/pack/pack");
+       argv_array_push(&cmd.args, base_name.buf);
+
+       if (flags & MIDX_PROGRESS)
+               argv_array_push(&cmd.args, "--progress");
+       else
+               argv_array_push(&cmd.args, "-q");
+
+       strbuf_release(&base_name);
+
+       cmd.git_cmd = 1;
+       cmd.in = cmd.out = -1;
+
+       if (start_command(&cmd)) {
+               error(_("could not start pack-objects"));
+               result = 1;
+               goto cleanup;
+       }
+
+       for (i = 0; i < m->num_objects; i++) {
+               struct object_id oid;
+               uint32_t pack_int_id = nth_midxed_pack_int_id(m, i);
+
+               if (!include_pack[pack_int_id])
+                       continue;
+
+               nth_midxed_object_oid(&oid, m, i);
+               xwrite(cmd.in, oid_to_hex(&oid), the_hash_algo->hexsz);
+               xwrite(cmd.in, "\n", 1);
+       }
+       close(cmd.in);
+
+       if (finish_command(&cmd)) {
+               error(_("could not finish pack-objects"));
+               result = 1;
+               goto cleanup;
+       }
+
+       result = write_midx_internal(object_dir, m, NULL, flags);
+       m = NULL;
+
+cleanup:
+       if (m)
+               close_midx(m);
+       free(include_pack);
+       return result;
+}