pack-revindex: prepare for incremental MIDX bitmaps

Prepare the reverse index machinery to handle object lookups in an
incremental MIDX bitmap. These changes are broken out across a few
functions:

  - load_midx_revindex() learns to use the appropriate MIDX filename
    depending on whether the given 'struct multi_pack_index *' is
    incremental or not.

  - pack_pos_to_midx() and midx_to_pack_pos() now both take in a global
    object position in the MIDX pseudo-pack order, and find the
    earliest containing MIDX (similar to midx.c::midx_for_object().

  - midx_pack_order_cmp() adjusts its call to pack_pos_to_midx() by the
    number of objects in the base (since 'vb - midx->revindx_data' is
    relative to the containing MIDX, and pack_pos_to_midx() expects a
    global position).

    Likewise, this function adjusts its output by adding
    m->num_objects_in_base to return a global position out through the
    `*pos` pointer.

Together, these changes are sufficient to use the multi-pack index's
reverse index format for incremental multi-pack reachability bitmaps.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Acked-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/pack-bitmap.c b/pack-bitmap.c
index 6406953d3223719b01dcb255a3f69965d578cf26..87f3b5cf4de76d36afb12b2df9e981f8ab1739f5 100644 (file)
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -170,6 +170,15 @@ static struct ewah_bitmap *read_bitmap_1(struct bitmap_index *index)
        return read_bitmap(index->map, index->map_size, &index->map_pos);
 }
 
+static uint32_t bitmap_num_objects_total(struct bitmap_index *index)
+{
+       if (index->midx) {
+               struct multi_pack_index *m = index->midx;
+               return m->num_objects + m->num_objects_in_base;
+       }
+       return index->pack->num_objects;
+}
+
 static uint32_t bitmap_num_objects(struct bitmap_index *index)
 {
        if (index->midx)
@@ -924,7 +933,7 @@ static inline int bitmap_position_extended(struct bitmap_index *bitmap_git,
 
        if (pos < kh_end(positions)) {
                int bitmap_pos = kh_value(positions, pos);
-               return bitmap_pos + bitmap_num_objects(bitmap_git);
+               return bitmap_pos + bitmap_num_objects_total(bitmap_git);
        }
 
        return -1;
@@ -992,7 +1001,7 @@ static int ext_index_add_object(struct bitmap_index *bitmap_git,
                bitmap_pos = kh_value(eindex->positions, hash_pos);
        }
 
-       return bitmap_pos + bitmap_num_objects(bitmap_git);
+       return bitmap_pos + bitmap_num_objects_total(bitmap_git);
 }
 
 struct bitmap_show_data {
@@ -1342,11 +1351,17 @@ struct ewah_bitmap *pseudo_merge_bitmap_for_commit(struct bitmap_index *bitmap_g
                if (pos < 0 || pos >= bitmap_num_objects(bitmap_git))
                        goto done;
 
+               /*
+                * Use bitmap-relative positions instead of offsetting
+                * by bitmap_git->num_objects_in_base because we use
+                * this to find a match in pseudo_merge_for_parents(),
+                * and pseudo-merge groups cannot span multiple bitmap
+                * layers.
+                */
                bitmap_set(parents, pos);
        }
 
-       match = pseudo_merge_for_parents(&bitmap_git->pseudo_merges,
-                                               parents);
+       match = pseudo_merge_for_parents(&bitmap_git->pseudo_merges, parents);
 
 done:
        bitmap_free(parents);
@@ -1500,7 +1515,9 @@ static void show_extended_objects(struct bitmap_index *bitmap_git,
        for (i = 0; i < eindex->count; ++i) {
                struct object *obj;
 
-               if (!bitmap_get(objects, st_add(bitmap_num_objects(bitmap_git), i)))
+               if (!bitmap_get(objects,
+                               st_add(bitmap_num_objects_total(bitmap_git),
+                                      i)))
                        continue;
 
                obj = eindex->objects[i];
@@ -1679,7 +1696,7 @@ static void filter_bitmap_exclude_type(struct bitmap_index *bitmap_git,
         * them individually.
         */
        for (i = 0; i < eindex->count; i++) {
-               size_t pos = st_add(i, bitmap_num_objects(bitmap_git));
+               size_t pos = st_add(i, bitmap_num_objects_total(bitmap_git));
                if (eindex->objects[i]->type == type &&
                    bitmap_get(to_filter, pos) &&
                    !bitmap_get(tips, pos))
@@ -1705,7 +1722,7 @@ static unsigned long get_size_by_pos(struct bitmap_index *bitmap_git,
 
        oi.sizep = &size;
 
-       if (pos < bitmap_num_objects(bitmap_git)) {
+       if (pos < bitmap_num_objects_total(bitmap_git)) {
                struct packed_git *pack;
                off_t ofs;
 
@@ -1728,8 +1745,9 @@ static unsigned long get_size_by_pos(struct bitmap_index *bitmap_git,
                        die(_("unable to get size of %s"), oid_to_hex(&oid));
                }
        } else {
+               size_t eindex_pos = pos - bitmap_num_objects_total(bitmap_git);
                struct eindex *eindex = &bitmap_git->ext_index;
-               struct object *obj = eindex->objects[pos - bitmap_num_objects(bitmap_git)];
+               struct object *obj = eindex->objects[eindex_pos];
                if (oid_object_info_extended(bitmap_repo(bitmap_git), &obj->oid,
                                             &oi, 0) < 0)
                        die(_("unable to get size of %s"), oid_to_hex(&obj->oid));
@@ -1882,7 +1900,7 @@ static void filter_packed_objects_from_bitmap(struct bitmap_index *bitmap_git,
        uint32_t objects_nr;
        size_t i, pos;
 
-       objects_nr = bitmap_num_objects(bitmap_git);
+       objects_nr = bitmap_num_objects_total(bitmap_git);
        pos = objects_nr / BITS_IN_EWORD;
 
        if (pos > result->word_alloc)
@@ -2419,7 +2437,7 @@ static uint32_t count_object_type(struct bitmap_index *bitmap_git,
        for (i = 0; i < eindex->count; ++i) {
                if (eindex->objects[i]->type == type &&
                    bitmap_get(objects,
-                              st_add(bitmap_num_objects(bitmap_git), i)))
+                              st_add(bitmap_num_objects_total(bitmap_git), i)))
                        count++;
        }
 
@@ -2820,7 +2838,7 @@ uint32_t *create_bitmap_mapping(struct bitmap_index *bitmap_git,
                BUG("rebuild_existing_bitmaps: missing required rev-cache "
                    "extension");
 
-       num_objects = bitmap_num_objects(bitmap_git);
+       num_objects = bitmap_num_objects_total(bitmap_git);
        CALLOC_ARRAY(reposition, num_objects);
 
        for (i = 0; i < num_objects; ++i) {
@@ -2963,7 +2981,8 @@ static off_t get_disk_usage_for_extended(struct bitmap_index *bitmap_git)
                struct object *obj = eindex->objects[i];
 
                if (!bitmap_get(result,
-                               st_add(bitmap_num_objects(bitmap_git), i)))
+                               st_add(bitmap_num_objects_total(bitmap_git),
+                                      i)))
                        continue;
 
                if (oid_object_info_extended(bitmap_repo(bitmap_git), &obj->oid,

diff --git a/pack-revindex.c b/pack-revindex.c
index d3832478d99edffae17db0bbe85aa981c1a3ad30..d3faab6a37de2dbdd039c022b9cc9eb95874a97b 100644 (file)
--- a/pack-revindex.c
+++ b/pack-revindex.c
@@ -383,8 +383,14 @@ int load_midx_revindex(struct multi_pack_index *m)
        trace2_data_string("load_midx_revindex", the_repository,
                           "source", "rev");
 
-       get_midx_filename_ext(m->repo->hash_algo, &revindex_name, m->object_dir,
-                             get_midx_checksum(m), MIDX_EXT_REV);
+       if (m->has_chain)
+               get_split_midx_filename_ext(m->repo->hash_algo, &revindex_name,
+                                           m->object_dir, get_midx_checksum(m),
+                                           MIDX_EXT_REV);
+       else
+               get_midx_filename_ext(m->repo->hash_algo, &revindex_name,
+                                     m->object_dir, get_midx_checksum(m),
+                                     MIDX_EXT_REV);
 
        ret = load_revindex_from_disk(revindex_name.buf,
                                      m->num_objects,
@@ -471,11 +477,15 @@ off_t pack_pos_to_offset(struct packed_git *p, uint32_t pos)
 
 uint32_t pack_pos_to_midx(struct multi_pack_index *m, uint32_t pos)
 {
+       while (m && pos < m->num_objects_in_base)
+               m = m->base_midx;
+       if (!m)
+               BUG("NULL multi-pack-index for object position: %"PRIu32, pos);
        if (!m->revindex_data)
                BUG("pack_pos_to_midx: reverse index not yet loaded");
-       if (m->num_objects <= pos)
+       if (m->num_objects + m->num_objects_in_base <= pos)
                BUG("pack_pos_to_midx: out-of-bounds object at %"PRIu32, pos);
-       return get_be32(m->revindex_data + pos);
+       return get_be32(m->revindex_data + pos - m->num_objects_in_base);
 }
 
 struct midx_pack_key {
@@ -491,7 +501,8 @@ static int midx_pack_order_cmp(const void *va, const void *vb)
        const struct midx_pack_key *key = va;
        struct multi_pack_index *midx = key->midx;
 
-       uint32_t versus = pack_pos_to_midx(midx, (uint32_t*)vb - (const uint32_t *)midx->revindex_data);
+       size_t pos = (uint32_t *)vb - (const uint32_t *)midx->revindex_data;
+       uint32_t versus = pack_pos_to_midx(midx, pos + midx->num_objects_in_base);
        uint32_t versus_pack = nth_midxed_pack_int_id(midx, versus);
        off_t versus_offset;
 
@@ -529,9 +540,9 @@ static int midx_key_to_pack_pos(struct multi_pack_index *m,
 {
        uint32_t *found;
 
-       if (key->pack >= m->num_packs)
+       if (key->pack >= m->num_packs + m->num_packs_in_base)
                BUG("MIDX pack lookup out of bounds (%"PRIu32" >= %"PRIu32")",
-                   key->pack, m->num_packs);
+                   key->pack, m->num_packs + m->num_packs_in_base);
        /*
         * The preferred pack sorts first, so determine its identifier by
         * looking at the first object in pseudo-pack order.
@@ -551,7 +562,8 @@ static int midx_key_to_pack_pos(struct multi_pack_index *m,
        if (!found)
                return -1;
 
-       *pos = found - m->revindex_data;
+       *pos = (found - m->revindex_data) + m->num_objects_in_base;
+
        return 0;
 }
 
@@ -559,9 +571,13 @@ int midx_to_pack_pos(struct multi_pack_index *m, uint32_t at, uint32_t *pos)
 {
        struct midx_pack_key key;
 
+       while (m && at < m->num_objects_in_base)
+               m = m->base_midx;
+       if (!m)
+               BUG("NULL multi-pack-index for object position: %"PRIu32, at);
        if (!m->revindex_data)
                BUG("midx_to_pack_pos: reverse index not yet loaded");
-       if (m->num_objects <= at)
+       if (m->num_objects + m->num_objects_in_base <= at)
                BUG("midx_to_pack_pos: out-of-bounds object at %"PRIu32, at);
 
        key.pack = nth_midxed_pack_int_id(m, at);