grep: factor test for \0 in grep patterns into a function

Factor the test for \0 in grep patterns into a function. Since commit
9eceddeec6 ("Use kwset in grep", 2011-08-21) any pattern containing a
\0 is considered fixed as regcomp() can't handle it.

This change makes later changes that make use of either has_null() or
is_fixed() (but not both) smaller.

While I'm at it make the comment conform to the style guide, i.e. add
an opening "/*\n".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/grep.c b/grep.c
index bf6c249..18306bc 100644 (file)
--- a/grep.c
+++ b/grep.c
@@ -321,6 +321,18 @@ static NORETURN void compile_regexp_failed(const struct grep_pat *p,
        die("%s'%s': %s", where, p->pattern, error);
 }
 
+static int has_null(const char *s, size_t len)
+{
+       /*
+        * regcomp cannot accept patterns with NULs so when using it
+        * we consider any pattern containing a NUL fixed.
+        */
+       if (memchr(s, 0, len))
+               return 1;
+
+       return 0;
+}
+
 #ifdef USE_LIBPCRE
 static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
 {
@@ -394,12 +406,6 @@ static int is_fixed(const char *s, size_t len)
 {
        size_t i;
 
-       /* regcomp cannot accept patterns with NULs so we
-        * consider any pattern containing a NUL fixed.
-        */
-       if (memchr(s, 0, len))
-               return 1;
-
        for (i = 0; i < len; i++) {
                if (is_regex_special(s[i]))
                        return 0;
@@ -451,7 +457,9 @@ static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
         * simple string match using kws.  p->fixed tells us if we
         * want to use kws.
         */
-       if (opt->fixed || is_fixed(p->pattern, p->patternlen))
+       if (opt->fixed ||
+           has_null(p->pattern, p->patternlen) ||
+           is_fixed(p->pattern, p->patternlen))
                p->fixed = !icase || ascii_only;
        else
                p->fixed = 0;