midx: write object ids in a chunk
Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Derrick Stolee committed
Jul 12, 2018 at 15:39 UTC
0d5b3a5ef72383f3b6fe93793be3bbd107a88eaa
5 files changed
+53
-5
Documentation/technical/pack-format.txt
+4
@@ -302,6 +302,10 @@ CHUNK DATA:
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name. This is the only chunk not guaranteed to be a multiple of four
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bytes in length, so should be the last chunk for alignment reasons.
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+ OID Lookup (ID: {'O', 'I', 'D', 'L'})
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+ The OIDs for all objects in the MIDX are stored in lexicographic
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+ order in this chunk.
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+
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(This section intentionally left incomplete.)
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TRAILER:
midx.c
+44
-3
@@ -18,9 +18,10 @@
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#define MIDX_HASH_LEN 20
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#define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + MIDX_HASH_LEN)
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-#define MIDX_MAX_CHUNKS 1
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+#define MIDX_MAX_CHUNKS 2
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#define MIDX_CHUNK_ALIGNMENT 4
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#define MIDX_CHUNKID_PACKNAMES 0x504e414d /* "PNAM" */
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+#define MIDX_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
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#define MIDX_CHUNKLOOKUP_WIDTH (sizeof(uint32_t) + sizeof(uint64_t))
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static char *get_midx_filename(const char *object_dir)
@@ -101,6 +102,10 @@ struct multi_pack_index *load_multi_pack_index(const char *object_dir)
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m->chunk_pack_names = m->data + chunk_offset;
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break;
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+ case MIDX_CHUNKID_OIDLOOKUP:
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+ m->chunk_oid_lookup = m->data + chunk_offset;
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+ break;
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+
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case 0:
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die(_("terminating multi-pack-index chunk id appears earlier than expected"));
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break;
@@ -116,6 +121,8 @@ struct multi_pack_index *load_multi_pack_index(const char *object_dir)
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if (!m->chunk_pack_names)
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die(_("multi-pack-index missing required pack-name chunk"));
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+ if (!m->chunk_oid_lookup)
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+ die(_("multi-pack-index missing required OID lookup chunk"));
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m->pack_names = xcalloc(m->num_packs, sizeof(*m->pack_names));
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@@ -382,6 +389,32 @@ static size_t write_midx_pack_names(struct hashfile *f,
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return written;
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}
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+static size_t write_midx_oid_lookup(struct hashfile *f, unsigned char hash_len,
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+ struct pack_midx_entry *objects,
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+ uint32_t nr_objects)
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+{
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+ struct pack_midx_entry *list = objects;
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+ uint32_t i;
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+ size_t written = 0;
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+
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+ for (i = 0; i < nr_objects; i++) {
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+ struct pack_midx_entry *obj = list++;
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+
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+ if (i < nr_objects - 1) {
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+ struct pack_midx_entry *next = list;
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+ if (oidcmp(&obj->oid, &next->oid) >= 0)
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+ BUG("OIDs not in order: %s >= %s",
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+ oid_to_hex(&obj->oid),
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+ oid_to_hex(&next->oid));
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+ }
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+
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+ hashwrite(f, obj->oid.hash, (int)hash_len);
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+ written += hash_len;
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+ }
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+
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+ return written;
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+}
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+
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int write_midx_file(const char *object_dir)
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{
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unsigned char cur_chunk, num_chunks = 0;
@@ -428,7 +461,7 @@ int write_midx_file(const char *object_dir)
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FREE_AND_NULL(midx_name);
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cur_chunk = 0;
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- num_chunks = 1;
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+ num_chunks = 2;
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written = write_midx_header(f, num_chunks, packs.nr);
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@@ -436,9 +469,13 @@ int write_midx_file(const char *object_dir)
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chunk_offsets[cur_chunk] = written + (num_chunks + 1) * MIDX_CHUNKLOOKUP_WIDTH;
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cur_chunk++;
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- chunk_ids[cur_chunk] = 0;
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+ chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDLOOKUP;
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chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + packs.pack_name_concat_len;
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+ cur_chunk++;
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+ chunk_ids[cur_chunk] = 0;
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+ chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_HASH_LEN;
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+
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for (i = 0; i <= num_chunks; i++) {
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if (i && chunk_offsets[i] < chunk_offsets[i - 1])
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BUG("incorrect chunk offsets: %"PRIu64" before %"PRIu64,
@@ -468,6 +505,10 @@ int write_midx_file(const char *object_dir)
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written += write_midx_pack_names(f, packs.names, packs.nr);
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break;
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+ case MIDX_CHUNKID_OIDLOOKUP:
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+ written += write_midx_oid_lookup(f, MIDX_HASH_LEN, entries, nr_entries);
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+ break;
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+
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default:
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BUG("trying to write unknown chunk id %"PRIx32,
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chunk_ids[i]);
midx.h
+1
@@ -15,6 +15,7 @@ struct multi_pack_index {
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uint32_t num_objects;
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const unsigned char *chunk_pack_names;
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+ const unsigned char *chunk_oid_lookup;
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const char **pack_names;
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char object_dir[FLEX_ARRAY];
t/helper/test-read-midx.c
+2
@@ -22,6 +22,8 @@ static int read_midx_file(const char *object_dir)
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if (m->chunk_pack_names)
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printf(" pack-names");
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+ if (m->chunk_oid_lookup)
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+ printf(" oid-lookup");
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printf("\n");
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t/t5319-multi-pack-index.sh
+2
-2
@@ -7,8 +7,8 @@ midx_read_expect () {
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NUM_PACKS=$1
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{
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cat <<-EOF &&
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- header: 4d494458 1 1 $NUM_PACKS
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- chunks: pack-names
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+ header: 4d494458 1 2 $NUM_PACKS
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+ chunks: pack-names oid-lookup
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packs:
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EOF
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if test $NUM_PACKS -ge 1