handle_revision_arg: hoist ".." check out of range parsing

Since 003c84f6d (specifying ranges: we did not mean to make
".." an empty set, 2011-05-02), we treat the argument ".."
specially. We detect it by noticing that both sides of the
range are empty, and that this is a non-symmetric two-dot
range.

While correct, this makes the code overly complicated. We
can just detect ".." up front before we try to do further
parsing. This avoids having to de-munge the NUL from dotdot,
and lets us eliminate an extra const array (which we needed
only to do direct pointer comparisons).

It also removes the one code path from the range-parsing
conditional that requires us to return -1. That will make it
simpler to pull the dotdot parsing out into its own
function.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/revision.c b/revision.c
index c98804ac02e3a84e3a22c9e73c3b943d37cea567..2664f08879a384d7243afb1387a1059efe086e20 100644 (file)
--- a/revision.c
+++ b/revision.c
@@ -1443,6 +1443,14 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
 
        flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;
 
+       if (!cant_be_filename && !strcmp(arg, "..")) {
+               /*
+                * Just ".."?  That is not a range but the
+                * pathspec for the parent directory.
+                */
+               return -1;
+       }
+
        dotdot = strstr(arg, "..");
        if (dotdot) {
                unsigned char from_sha1[20];
@@ -1450,27 +1458,15 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
                const char *this = arg;
                int symmetric = *next == '.';
                unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
-               static const char head_by_default[] = "HEAD";
                unsigned int a_flags;
 
                *dotdot = 0;
                next += symmetric;
 
                if (!*next)
-                       next = head_by_default;
+                       next = "HEAD";
                if (dotdot == arg)
-                       this = head_by_default;
-               if (this == head_by_default && next == head_by_default &&
-                   !symmetric) {
-                       /*
-                        * Just ".."?  That is not a range but the
-                        * pathspec for the parent directory.
-                        */
-                       if (!cant_be_filename) {
-                               *dotdot = '.';
-                               return -1;
-                       }
-               }
+                       this = "HEAD";
                if (!get_sha1_committish(this, from_sha1) &&
                    !get_sha1_committish(next, sha1)) {
                        struct object *a_obj, *b_obj;