diff options
Diffstat (limited to 'pack-bitmap-write.c')
| -rw-r--r-- | pack-bitmap-write.c | 91 |
1 files changed, 89 insertions, 2 deletions
diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c index 9b1be59f6d..2cfc92f287 100644 --- a/pack-bitmap-write.c +++ b/pack-bitmap-write.c @@ -651,13 +651,17 @@ static const struct object_id *oid_access(size_t pos, const void *table) static void write_selected_commits_v1(struct hashfile *f, struct pack_idx_entry **index, uint32_t index_nr, - uint32_t *commit_positions) + uint32_t *commit_positions, + off_t *offsets) { int i; for (i = 0; i < writer.selected_nr; ++i) { struct bitmapped_commit *stored = &writer.selected[i]; + if (offsets) + offsets[i] = hashfile_total(f); + hashwrite_be32(f, commit_positions[i]); hashwrite_u8(f, stored->xor_offset); hashwrite_u8(f, stored->flags); @@ -666,6 +670,81 @@ static void write_selected_commits_v1(struct hashfile *f, } } +static int table_cmp(const void *_va, const void *_vb, void *_data) +{ + uint32_t *commit_positions = _data; + uint32_t a = commit_positions[*(uint32_t *)_va]; + uint32_t b = commit_positions[*(uint32_t *)_vb]; + + if (a > b) + return 1; + else if (a < b) + return -1; + + return 0; +} + +static void write_lookup_table(struct hashfile *f, + struct pack_idx_entry **index, + uint32_t index_nr, + uint32_t *commit_positions, + off_t *offsets) +{ + uint32_t i; + uint32_t *table, *table_inv; + + ALLOC_ARRAY(table, writer.selected_nr); + ALLOC_ARRAY(table_inv, writer.selected_nr); + + for (i = 0; i < writer.selected_nr; i++) + table[i] = i; + + /* + * At the end of this sort table[j] = i means that the i'th + * bitmap corresponds to j'th bitmapped commit (among the selected + * commits) in lex order of OIDs. + */ + QSORT_S(table, writer.selected_nr, table_cmp, commit_positions); + + /* table_inv helps us discover that relationship (i'th bitmap + * to j'th commit by j = table_inv[i]) + */ + for (i = 0; i < writer.selected_nr; i++) + table_inv[table[i]] = i; + + trace2_region_enter("pack-bitmap-write", "writing_lookup_table", the_repository); + for (i = 0; i < writer.selected_nr; i++) { + struct bitmapped_commit *selected = &writer.selected[table[i]]; + uint32_t xor_offset = selected->xor_offset; + uint32_t xor_row; + + if (xor_offset) { + /* + * xor_index stores the index (in the bitmap entries) + * of the corresponding xor bitmap. But we need to convert + * this index into lookup table's index. So, table_inv[xor_index] + * gives us the index position w.r.t. the lookup table. + * + * If "k = table[i] - xor_offset" then the xor base is the k'th + * bitmap. `table_inv[k]` gives us the position of that bitmap + * in the lookup table. + */ + uint32_t xor_index = table[i] - xor_offset; + xor_row = table_inv[xor_index]; + } else { + xor_row = 0xffffffff; + } + + hashwrite_be32(f, commit_positions[table[i]]); + hashwrite_be64(f, (uint64_t)offsets[table[i]]); + hashwrite_be32(f, xor_row); + } + trace2_region_leave("pack-bitmap-write", "writing_lookup_table", the_repository); + + free(table); + free(table_inv); +} + static void write_hash_cache(struct hashfile *f, struct pack_idx_entry **index, uint32_t index_nr) @@ -693,6 +772,7 @@ void bitmap_writer_finish(struct pack_idx_entry **index, struct strbuf tmp_file = STRBUF_INIT; struct hashfile *f; uint32_t *commit_positions = NULL; + off_t *offsets = NULL; uint32_t i; struct bitmap_disk_header header; @@ -713,6 +793,9 @@ void bitmap_writer_finish(struct pack_idx_entry **index, dump_bitmap(f, writer.blobs); dump_bitmap(f, writer.tags); + if (options & BITMAP_OPT_LOOKUP_TABLE) + CALLOC_ARRAY(offsets, index_nr); + ALLOC_ARRAY(commit_positions, writer.selected_nr); for (i = 0; i < writer.selected_nr; i++) { @@ -725,7 +808,10 @@ void bitmap_writer_finish(struct pack_idx_entry **index, commit_positions[i] = commit_pos; } - write_selected_commits_v1(f, index, index_nr, commit_positions); + write_selected_commits_v1(f, index, index_nr, commit_positions, offsets); + + if (options & BITMAP_OPT_LOOKUP_TABLE) + write_lookup_table(f, index, index_nr, commit_positions, offsets); if (options & BITMAP_OPT_HASH_CACHE) write_hash_cache(f, index, index_nr); @@ -741,4 +827,5 @@ void bitmap_writer_finish(struct pack_idx_entry **index, strbuf_release(&tmp_file); free(commit_positions); + free(offsets); } |