If two consecutive patterns share the same "base" and we just compared
base against pathname last time, we can just reuse the last comparison
result.
This optmization is made with read_directory() in mind. Notice that
all exclude patterns share the same "base" pointer, which is basebuf[]
from "struct dir" (given indirectly by prep_exclude()) and patterns
from the same .gitignore will stay in the same order. This opens an
opportunity for this optimization when there are a lot of patterns in
subdirectories-with-long-path-name/.gitignore.
Other users of excluded_from_list() unlikely take advantage of this,
unless add_excludes() learns to pre-compare two consecutive bases and
save the result, so excluded_from_list() can perform a cheap "are
these two bases the same" check.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
---
I haven't put more thought/work on optimizing the big top .gitignore
case yet. But something like this is probably worth doing anyway.
Pathspec might use the same optimization. If a user does (notice no
quotes)
git something long/path/to/here/*.[ch]
we would need to compare "long/path/to/here" all over again (I
haven't checked the code though).
dir.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/dir.c b/dir.c
index 94fe9f8..2964076 100644
--- a/dir.c
+++ b/dir.c
@@ -511,6 +511,7 @@ int excluded_from_list(const char *pathname,
struct exclude_list *el)
{
int i;
+ int last_basecmp = el->nr, basecmp_result;
if (!el->nr)
return -1; /* undefined */
@@ -552,9 +553,25 @@ int excluded_from_list(const char *pathname,
prefix--;
}
- if (pathlen < x->baselen ||
- (x->baselen && pathname[x->baselen-1] != '/') ||
- strncmp_icase(pathname, x->base, x->baselen))
+ if (i < el->nr - 1 &&
+ last_basecmp == i + 1 &&
+ x->base == el->excludes[last_basecmp]->base &&
+ x->baselen == el->excludes[last_basecmp]->baselen)
+ /*
+ * we have the same "base" as last time and
+ * last time we came here too (i.e. no break
+ * or continue from the above code), reuse
+ * basecmp_result
+ */
+ ;
+ else
+ /* anything other than zero is ok, we don't
+ really care about the sorting order */
+ basecmp_result = pathlen < x->baselen ||
+ (x->baselen && pathname[x->baselen - 1] != '/') ||
+ strncmp_icase(pathname, x->base, x->baselen);
+ last_basecmp = i;
+ if (basecmp_result)
continue;
namelen = x->baselen ? pathlen - x->baselen : pathlen;
--
1.7.11.rc1.185.g281ad67
--
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