From 013fd7ada3c81cec8f0c48427c77394028707c2e Mon Sep 17 00:00:00 2001 From: Jeff King Date: Fri, 5 Apr 2019 14:06:04 -0400 Subject: [PATCH] midx: check both pack and index names for containment MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit A midx file (and the struct we parse from it) contains a list of all of the covered packfiles, mentioned by their ".idx" names (e.g., "pack-1234.idx", etc). And thus calls to midx_contains_pack() expect callers to provide the idx name. This works for most of the calls, but the one in open_packed_git_1() tries to feed a packed_git->pack_name, which is the ".pack" name, meaning we'll never find a match (even if the pack is covered by the midx). We can fix this by converting the ".pack" to ".idx" in the caller. However, that requires allocating a new string. Instead, let's make midx_contains_pack() a bit friendlier, and allow it take _either_ the .pack or .idx variant. All cleverness in the matching code is credited to René. Bugs are mine. There's no test here, because while this does fix _a_ bug, it's masked by another bug in that same caller. That will be covered (with a test) in the next patch. Helped-by: René Scharfe Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- midx.c | 36 ++++++++++++++++++++++++++++++++++-- midx.h | 2 +- 2 files changed, 35 insertions(+), 3 deletions(-) diff --git a/midx.c b/midx.c index 8a505fd423..0ceca1938f 100644 --- a/midx.c +++ b/midx.c @@ -307,7 +307,39 @@ int fill_midx_entry(const struct object_id *oid, struct pack_entry *e, struct mu return nth_midxed_pack_entry(m, e, pos); } -int midx_contains_pack(struct multi_pack_index *m, const char *idx_name) +/* Match "foo.idx" against either "foo.pack" _or_ "foo.idx". */ +static int cmp_idx_or_pack_name(const char *idx_or_pack_name, + const char *idx_name) +{ + /* Skip past any initial matching prefix. */ + while (*idx_name && *idx_name == *idx_or_pack_name) { + idx_name++; + idx_or_pack_name++; + } + + /* + * If we didn't match completely, we may have matched "pack-1234." and + * be left with "idx" and "pack" respectively, which is also OK. We do + * not have to check for "idx" and "idx", because that would have been + * a complete match (and in that case these strcmps will be false, but + * we'll correctly return 0 from the final strcmp() below. + * + * Technically this matches "fooidx" and "foopack", but we'd never have + * such names in the first place. + */ + if (!strcmp(idx_name, "idx") && !strcmp(idx_or_pack_name, "pack")) + return 0; + + /* + * This not only checks for a complete match, but also orders based on + * the first non-identical character, which means our ordering will + * match a raw strcmp(). That makes it OK to use this to binary search + * a naively-sorted list. + */ + return strcmp(idx_or_pack_name, idx_name); +} + +int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name) { uint32_t first = 0, last = m->num_packs; @@ -317,7 +349,7 @@ int midx_contains_pack(struct multi_pack_index *m, const char *idx_name) int cmp; current = m->pack_names[mid]; - cmp = strcmp(idx_name, current); + cmp = cmp_idx_or_pack_name(idx_or_pack_name, current); if (!cmp) return 1; if (cmp > 0) { diff --git a/midx.h b/midx.h index 774f652530..26dd042d63 100644 --- a/midx.h +++ b/midx.h @@ -43,7 +43,7 @@ struct object_id *nth_midxed_object_oid(struct object_id *oid, struct multi_pack_index *m, uint32_t n); int fill_midx_entry(const struct object_id *oid, struct pack_entry *e, struct multi_pack_index *m); -int midx_contains_pack(struct multi_pack_index *m, const char *idx_name); +int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name); int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local); int write_midx_file(const char *object_dir); -- 2.48.1