[PATCH 03/15] handle_revision_arg: stop using "dotdot" as a generic pointer

[Jeff King <peff@peff.net>]

The handle_revision_arg() function has a "dotdot" variable
that it uses to find a ".." or "..." in the argument. If we
don't find one, we look for other marks, like "^!". But we
just keep re-using the "dotdot" variable, which is
confusing.

Let's introduce a separate "mark" variable that can be used
for these other marks. They still reuse the same variable,
but at least the name is no longer actively misleading.

Signed-off-by: Jeff King <peff@peff.net>
---
It may make sense to pull each of these into its own helper. I didn't
really look because they're so small, and because the return semantics
seemed confusing to me. Some of them return, and some of them keep
parsing. Some of them restore the NUL they overwrite, and some do not.

I didn't dig in to see if there are weird corner cases where they
misbehave.

 revision.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/revision.c b/revision.c
index b6031fb35..9c683874d 100644
--- a/revision.c
+++ b/revision.c
@@ -1433,6 +1433,7 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
 {
 	struct object_context oc;
 	char *dotdot;
+	char *mark;
 	struct object *object;
 	unsigned char sha1[20];
 	int local_flags;
@@ -1529,33 +1530,33 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
 		*dotdot = '.';
 	}
 
-	dotdot = strstr(arg, "^@");
-	if (dotdot && !dotdot[2]) {
-		*dotdot = 0;
+	mark = strstr(arg, "^@");
+	if (mark && !mark[2]) {
+		*mark = 0;
 		if (add_parents_only(revs, arg, flags, 0))
 			return 0;
-		*dotdot = '^';
+		*mark = '^';
 	}
-	dotdot = strstr(arg, "^!");
-	if (dotdot && !dotdot[2]) {
-		*dotdot = 0;
+	mark = strstr(arg, "^!");
+	if (mark && !mark[2]) {
+		*mark = 0;
 		if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), 0))
-			*dotdot = '^';
+			*mark = '^';
 	}
-	dotdot = strstr(arg, "^-");
-	if (dotdot) {
+	mark = strstr(arg, "^-");
+	if (mark) {
 		int exclude_parent = 1;
 
-		if (dotdot[2]) {
+		if (mark[2]) {
 			char *end;
-			exclude_parent = strtoul(dotdot + 2, &end, 10);
+			exclude_parent = strtoul(mark + 2, &end, 10);
 			if (*end != '\0' || !exclude_parent)
 				return -1;
 		}
 
-		*dotdot = 0;
+		*mark = 0;
 		if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), exclude_parent))
-			*dotdot = '^';
+			*mark = '^';
 	}
 
 	local_flags = 0;
-- 
2.13.0.219.g63f6bc368