grep: update boundary variable for pre-context

Function context can be bigger than -A/-B/-C context.  To find the
beginning of the combined context we search backwards.  Currently we
check at each loop iteration what we're looking for and determine the
effective upper boundary based on that.

Simplify this a bit by setting the variable "from" to the lowest unshown
line number up front if we're looking for a function line and set it
back to the required -B/-C context line number when we find one.  This
prepares the ground for the next patch; no functional change intended.

Signed-off-by: Rene Scharfe <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: rscharfe

grep.c

@@ -1479,20 +1479,21 @@ static void show_funcname_line(struct grep_opt *opt, struct grep_source *gs,
 static void show_pre_context(struct grep_opt *opt, struct grep_source *gs,
 			     char *bol, char *end, unsigned lno)
 {
-	unsigned cur = lno, from = 1, funcname_lno = 0;
+	unsigned cur = lno, from = 1, funcname_lno = 0, orig_from;
 	int funcname_needed = !!opt->funcname;
 
-	if (opt->funcbody && !match_funcname(opt, gs, bol, end))
-		funcname_needed = 2;
-
 	if (opt->pre_context < lno)
 		from = lno - opt->pre_context;
 	if (from <= opt->last_shown)
 		from = opt->last_shown + 1;
+	orig_from = from;
+	if (opt->funcbody && !match_funcname(opt, gs, bol, end)) {
+		funcname_needed = 1;
+		from = opt->last_shown + 1;
+	}
 
 	/* Rewind. */
-	while (bol > gs->buf &&
-	       cur > (funcname_needed == 2 ? opt->last_shown + 1 : from)) {
+	while (bol > gs->buf && cur > from) {
 		char *eol = --bol;
 
 		while (bol > gs->buf && bol[-1] != '\n')
@@ -1501,6 +1502,7 @@ static void show_pre_context(struct grep_opt *opt, struct grep_source *gs,
 		if (funcname_needed && match_funcname(opt, gs, bol, eol)) {
 			funcname_lno = cur;
 			funcname_needed = 0;
+			from = orig_from;
 		}
 	}