grep: don't call regexec() for fixed strings
Add the new flag "fixed" to struct grep_pat and set it if the pattern
is doesn't contain any regex control characters in addition to if the
flag -F/--fixed-strings was specified.
This gives a nice speed up on msysgit, where regexec() seems to be
extra slow. Before (best of five runs):
$ time git grep grep v1.6.1 >/dev/null
real 0m0.552s
user 0m0.000s
sys 0m0.000s
$ time git grep -F grep v1.6.1 >/dev/null
real 0m0.170s
user 0m0.000s
sys 0m0.015s
With the patch:
$ time git grep grep v1.6.1 >/dev/null
real 0m0.173s
user 0m0.000s
sys 0m0.000s
The difference is much smaller on Linux, but still measurable.
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/grep.h b/grep.h
index 45a222d..5102ce3 100644
--- a/grep.h
+++ b/grep.h
@@ -30,6 +30,7 @@
const char *pattern;
enum grep_header_field field;
regex_t regexp;
+ unsigned fixed:1;
};
enum grep_expr_node {
