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Commit30cdc33fba(pack-bitmap: save "have" bitmap from walk, 2018-08-21) introduced a new function for looking at the "have" side of a bitmap walk. Because it only makes sense to do so after we've finished the walk, we added an extra safety assertion, making sure that bitmap_git->result is non-NULL. However, this safety is misguided. It was trying to catch the case where we had called prepare_bitmap_walk() to give us a "struct bitmap_index", but had not yet called traverse_bitmap_commit_list() to walk it. But all of the interesting computation (including setting up the result and "have" bitmaps) happens in the first function! The latter function only delivers the result to a callback function. So the case we were worried about is impossible; if you get a non-NULL result from prepare_bitmap_walk(), then its "have" field will be fully formed. But much worse, traverse_bitmap_commit_list() actually frees the result field as it finishes. Which means that this assertion is worse than useless: it's almost guaranteed to trigger! Our test suite didn't catch this because the function isn't actually exercised at all. The only caller comes from6a1e32d532(pack-objects: reuse on-disk deltas for thin "have" objects, 2018-08-21), and that's triggered only when you fetch or push history that contains an object with a base that is found deep in history. Our test suite fetches and pushes either don't use bitmaps, or use too-small example repositories. But any reasonably-sized real-world push or fetch (with bitmaps) would trigger this. This patch drops the harmful assertion and tweaks the docstring for the function to make the precondition clear. The tests need to be improved to exercise this new pack-objects feature, but we'll do that in a separate commit. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
77 lines
2.3 KiB
C
77 lines
2.3 KiB
C
#ifndef PACK_BITMAP_H
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#define PACK_BITMAP_H
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#include "ewah/ewok.h"
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#include "khash.h"
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#include "pack-objects.h"
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struct commit;
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struct rev_info;
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struct bitmap_disk_header {
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char magic[4];
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uint16_t version;
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uint16_t options;
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uint32_t entry_count;
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unsigned char checksum[20];
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};
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static const char BITMAP_IDX_SIGNATURE[] = {'B', 'I', 'T', 'M'};
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#define NEEDS_BITMAP (1u<<22)
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enum pack_bitmap_opts {
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BITMAP_OPT_FULL_DAG = 1,
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BITMAP_OPT_HASH_CACHE = 4,
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};
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enum pack_bitmap_flags {
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BITMAP_FLAG_REUSE = 0x1
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};
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typedef int (*show_reachable_fn)(
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const struct object_id *oid,
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enum object_type type,
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int flags,
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uint32_t hash,
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struct packed_git *found_pack,
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off_t found_offset);
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struct bitmap_index;
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struct bitmap_index *prepare_bitmap_git(void);
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void count_bitmap_commit_list(struct bitmap_index *, uint32_t *commits,
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uint32_t *trees, uint32_t *blobs, uint32_t *tags);
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void traverse_bitmap_commit_list(struct bitmap_index *,
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show_reachable_fn show_reachable);
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void test_bitmap_walk(struct rev_info *revs);
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struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs);
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int reuse_partial_packfile_from_bitmap(struct bitmap_index *,
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struct packed_git **packfile,
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uint32_t *entries, off_t *up_to);
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int rebuild_existing_bitmaps(struct bitmap_index *, struct packing_data *mapping,
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khash_sha1 *reused_bitmaps, int show_progress);
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void free_bitmap_index(struct bitmap_index *);
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/*
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* After a traversal has been performed by prepare_bitmap_walk(), this can be
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* queried to see if a particular object was reachable from any of the
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* objects flagged as UNINTERESTING.
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*/
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int bitmap_has_sha1_in_uninteresting(struct bitmap_index *, const unsigned char *sha1);
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void bitmap_writer_show_progress(int show);
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void bitmap_writer_set_checksum(unsigned char *sha1);
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void bitmap_writer_build_type_index(struct packing_data *to_pack,
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struct pack_idx_entry **index,
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uint32_t index_nr);
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void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack);
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void bitmap_writer_select_commits(struct commit **indexed_commits,
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unsigned int indexed_commits_nr, int max_bitmaps);
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void bitmap_writer_build(struct packing_data *to_pack);
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void bitmap_writer_finish(struct pack_idx_entry **index,
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uint32_t index_nr,
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const char *filename,
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uint16_t options);
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#endif
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