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authorDerrick Stolee <dstolee@microsoft.com>2019-12-13 18:09:53 (GMT)
committerJunio C Hamano <gitster@pobox.com>2019-12-13 20:01:02 (GMT)
commit190a65f9db8db9d87d54351429f7879fcb4ad608 (patch)
tree69147479da50321ae236a5910783c6d7a62e365f /builtin/sparse-checkout.c
parentcff4e9138d8df45e3b6199171092ee781cdadaeb (diff)
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sparse-checkout: respect core.ignoreCase in cone mode
When a user uses the sparse-checkout feature in cone mode, they add patterns using "git sparse-checkout set <dir1> <dir2> ..." or by using "--stdin" to provide the directories line-by-line over stdin. This behaviour naturally looks a lot like the way a user would type "git add <dir1> <dir2> ..." If core.ignoreCase is enabled, then "git add" will match the input using a case-insensitive match. Do the same for the sparse-checkout feature. Perform case-insensitive checks while updating the skip-worktree bits during unpack_trees(). This is done by changing the hash algorithm and hashmap comparison methods to optionally use case- insensitive methods. When this is enabled, there is a small performance cost in the hashing algorithm. To tease out the worst possible case, the following was run on a repo with a deep directory structure: git ls-tree -d -r --name-only HEAD | git sparse-checkout set --stdin The 'set' command was timed with core.ignoreCase disabled or enabled. For the repo with a deep history, the numbers were core.ignoreCase=false: 62s core.ignoreCase=true: 74s (+19.3%) For reproducibility, the equivalent test on the Linux kernel repository had these numbers: core.ignoreCase=false: 3.1s core.ignoreCase=true: 3.6s (+16%) Now, this is not an entirely fair comparison, as most users will define their sparse cone using more shallow directories, and the performance improvement from eb42feca97 ("unpack-trees: hash less in cone mode" 2019-11-21) can remove most of the hash cost. For a more realistic test, drop the "-r" from the ls-tree command to store only the first-level directories. In that case, the Linux kernel repository takes 0.2-0.25s in each case, and the deep repository takes one second, plus or minus 0.05s, in each case. Thus, we _can_ demonstrate a cost to this change, but it is unlikely to matter to any reasonable sparse-checkout cone. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'builtin/sparse-checkout.c')
-rw-r--r--builtin/sparse-checkout.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index a542d61..5d62f7a 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -313,7 +313,10 @@ static void insert_recursive_pattern(struct pattern_list *pl, struct strbuf *pat
struct pattern_entry *e = xmalloc(sizeof(*e));
e->patternlen = path->len;
e->pattern = strbuf_detach(path, NULL);
- hashmap_entry_init(&e->ent, memhash(e->pattern, e->patternlen));
+ hashmap_entry_init(&e->ent,
+ ignore_case ?
+ strihash(e->pattern) :
+ strhash(e->pattern));
hashmap_add(&pl->recursive_hashmap, &e->ent);
@@ -329,7 +332,10 @@ static void insert_recursive_pattern(struct pattern_list *pl, struct strbuf *pat
e = xmalloc(sizeof(struct pattern_entry));
e->patternlen = newlen;
e->pattern = xstrndup(oldpattern, newlen);
- hashmap_entry_init(&e->ent, memhash(e->pattern, e->patternlen));
+ hashmap_entry_init(&e->ent,
+ ignore_case ?
+ strihash(e->pattern) :
+ strhash(e->pattern));
if (!hashmap_get_entry(&pl->parent_hashmap, e, ent, NULL))
hashmap_add(&pl->parent_hashmap, &e->ent);