midx: use chunk-format read API
Instead of parsing the table of contents directly, use the chunk-format API methods read_table_of_contents() and pair_chunk(). In particular, we can use the return value of pair_chunk() to generate an error when a required chunk is missing. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Derrick Stolee committed
Feb 18, 2021 at 14:07 UTC
6ab3b8b8b8dc94c8e4caefb1d368cc704e70d38b
2 files changed
+29
-50
midx.c
+26
-47
@@ -28,7 +28,6 @@
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#define MIDX_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
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#define MIDX_CHUNKID_OBJECTOFFSETS 0x4f4f4646 /* "OOFF" */
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#define MIDX_CHUNKID_LARGEOFFSETS 0x4c4f4646 /* "LOFF" */
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-#define MIDX_CHUNKLOOKUP_WIDTH (sizeof(uint32_t) + sizeof(uint64_t))
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#define MIDX_CHUNK_FANOUT_SIZE (sizeof(uint32_t) * 256)
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#define MIDX_CHUNK_OFFSET_WIDTH (2 * sizeof(uint32_t))
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#define MIDX_CHUNK_LARGE_OFFSET_WIDTH (sizeof(uint64_t))
@@ -53,6 +52,19 @@ static char *get_midx_filename(const char *object_dir)
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return xstrfmt("%s/pack/multi-pack-index", object_dir);
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}
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+static int midx_read_oid_fanout(const unsigned char *chunk_start,
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+ size_t chunk_size, void *data)
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+{
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+ struct multi_pack_index *m = data;
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+ m->chunk_oid_fanout = (uint32_t *)chunk_start;
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+
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+ if (chunk_size != 4 * 256) {
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+ error(_("multi-pack-index OID fanout is of the wrong size"));
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+ return 1;
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+ }
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+ return 0;
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+}
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+
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struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local)
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{
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struct multi_pack_index *m = NULL;
@@ -64,6 +76,7 @@ struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local
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char *midx_name = get_midx_filename(object_dir);
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uint32_t i;
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const char *cur_pack_name;
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+ struct chunkfile *cf = NULL;
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fd = git_open(midx_name);
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@@ -113,58 +126,23 @@ struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local
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m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
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- for (i = 0; i < m->num_chunks; i++) {
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- uint32_t chunk_id = get_be32(m->data + MIDX_HEADER_SIZE +
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- MIDX_CHUNKLOOKUP_WIDTH * i);
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- uint64_t chunk_offset = get_be64(m->data + MIDX_HEADER_SIZE + 4 +
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- MIDX_CHUNKLOOKUP_WIDTH * i);
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-
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- if (chunk_offset >= m->data_len)
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- die(_("invalid chunk offset (too large)"));
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-
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- switch (chunk_id) {
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- case MIDX_CHUNKID_PACKNAMES:
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- m->chunk_pack_names = m->data + chunk_offset;
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- break;
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-
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- case MIDX_CHUNKID_OIDFANOUT:
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- m->chunk_oid_fanout = (uint32_t *)(m->data + chunk_offset);
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- break;
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-
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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 MIDX_CHUNKID_OBJECTOFFSETS:
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- m->chunk_object_offsets = m->data + chunk_offset;
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- break;
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-
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- case MIDX_CHUNKID_LARGEOFFSETS:
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- m->chunk_large_offsets = 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;
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-
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- default:
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- /*
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- * Do nothing on unrecognized chunks, allowing future
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- * extensions to add optional chunks.
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- */
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- break;
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- }
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- }
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+ cf = init_chunkfile(NULL);
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- if (!m->chunk_pack_names)
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+ if (read_table_of_contents(cf, m->data, midx_size,
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+ MIDX_HEADER_SIZE, m->num_chunks))
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+ goto cleanup_fail;
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+
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+ if (pair_chunk(cf, MIDX_CHUNKID_PACKNAMES, &m->chunk_pack_names) == CHUNK_NOT_FOUND)
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die(_("multi-pack-index missing required pack-name chunk"));
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- if (!m->chunk_oid_fanout)
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+ if (read_chunk(cf, MIDX_CHUNKID_OIDFANOUT, midx_read_oid_fanout, m) == CHUNK_NOT_FOUND)
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die(_("multi-pack-index missing required OID fanout chunk"));
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- if (!m->chunk_oid_lookup)
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+ if (pair_chunk(cf, MIDX_CHUNKID_OIDLOOKUP, &m->chunk_oid_lookup) == CHUNK_NOT_FOUND)
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die(_("multi-pack-index missing required OID lookup chunk"));
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- if (!m->chunk_object_offsets)
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+ if (pair_chunk(cf, MIDX_CHUNKID_OBJECTOFFSETS, &m->chunk_object_offsets) == CHUNK_NOT_FOUND)
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die(_("multi-pack-index missing required object offsets chunk"));
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+ pair_chunk(cf, MIDX_CHUNKID_LARGEOFFSETS, &m->chunk_large_offsets);
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+
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m->num_objects = ntohl(m->chunk_oid_fanout[255]);
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m->pack_names = xcalloc(m->num_packs, sizeof(*m->pack_names));
@@ -190,6 +168,7 @@ struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local
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cleanup_fail:
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free(m);
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free(midx_name);
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+ free(cf);
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if (midx_map)
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munmap(midx_map, midx_size);
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if (0 <= fd)
t/t5319-multi-pack-index.sh
+3
-3
@@ -314,12 +314,12 @@ test_expect_success 'verify bad OID version' '
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test_expect_success 'verify truncated chunk count' '
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corrupt_midx_and_verify $MIDX_BYTE_CHUNK_COUNT "\01" $objdir \
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- "missing required"
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+ "final chunk has non-zero id"
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'
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test_expect_success 'verify extended chunk count' '
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corrupt_midx_and_verify $MIDX_BYTE_CHUNK_COUNT "\07" $objdir \
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- "terminating multi-pack-index chunk id appears earlier than expected"
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+ "terminating chunk id appears earlier than expected"
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'
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test_expect_success 'verify missing required chunk' '
@@ -329,7 +329,7 @@ test_expect_success 'verify missing required chunk' '
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test_expect_success 'verify invalid chunk offset' '
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corrupt_midx_and_verify $MIDX_BYTE_CHUNK_OFFSET "\01" $objdir \
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- "invalid chunk offset (too large)"
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+ "improper chunk offset(s)"
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'
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test_expect_success 'verify packnames out of order' '