get_revision(): do not dig deeper when we know we are at the end.

This resurrects the special casing for "rev-list -n 1" which
avoided reading parents unnecessarily.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/revision.c b/revision.c
index a3df810..2a33637 100644 (file)
--- a/revision.c
+++ b/revision.c
@@ -684,13 +684,11 @@ static void rewrite_parents(struct commit *commit)
 struct commit *get_revision(struct rev_info *revs)
 {
        struct commit_list *list = revs->commits;
-       struct commit *commit;
 
        if (!list)
                return NULL;
 
        /* Check the max_count ... */
-       commit = list->item;
        switch (revs->max_count) {
        case -1:
                break;
@@ -701,22 +699,28 @@ struct commit *get_revision(struct rev_info *revs)
        }
 
        do {
-               commit = pop_most_recent_commit(&revs->commits, SEEN);
+               struct commit *commit = revs->commits->item;
+
                if (commit->object.flags & (UNINTERESTING|SHOWN))
-                       continue;
+                       goto next;
                if (revs->min_age != -1 && (commit->date > revs->min_age))
-                       continue;
+                       goto next;
                if (revs->max_age != -1 && (commit->date < revs->max_age))
                        return NULL;
                if (revs->no_merges && commit->parents && commit->parents->next)
-                       continue;
+                       goto next;
                if (revs->paths && revs->dense) {
                        if (!(commit->object.flags & TREECHANGE))
-                               continue;
+                               goto next;
                        rewrite_parents(commit);
                }
+               /* More to go? */
+               if (revs->max_count)
+                       pop_most_recent_commit(&revs->commits, SEEN);
                commit->object.flags |= SHOWN;
                return commit;
+next:
+               pop_most_recent_commit(&revs->commits, SEEN);
        } while (revs->commits);
        return NULL;
 }