subtree: performance improvement for finding unexpected parent commits

diff --git a/commit-reach.c b/commit-reach.c
index c9965240323633fa1e6145290cc56596cfb1c3bb..00e5ceee6fc8c33dad6071862ee7fe7923f3aa33 100644 (file)
--- a/commit-reach.c
+++ b/commit-reach.c
@@ -4,7 +4,7 @@
 #include "decorate.h"
 #include "prio-queue.h"
 #include "tree.h"
-#include "ref-filter.c"
+#include "ref-filter.h"
 #include "revision.h"
 #include "tag.h"
 #include "commit-reach.h"
@@ -39,6 +39,9 @@ static struct commit_list *paint_down_to_common(struct commit *one, int n,
        int i;
        uint32_t last_gen = GENERATION_NUMBER_INFINITY;
 
+       if (!min_generation)
+               queue.compare = compare_commits_by_commit_date;
+
        one->object.flags |= PARENT1;
        if (!n) {
                commit_list_append(one, &result);
@@ -56,7 +59,7 @@ static struct commit_list *paint_down_to_common(struct commit *one, int n,
                struct commit_list *parents;
                int flags;
 
-               if (commit->generation > last_gen)
+               if (min_generation && commit->generation > last_gen)
                        BUG("bad generation skip %8x > %8x at %s",
                            commit->generation, last_gen,
                            oid_to_hex(&commit->object.oid));
@@ -544,20 +547,42 @@ int can_all_from_reach_with_flag(struct object_array *from,
 {
        struct commit **list = NULL;
        int i;
+       int nr_commits;
        int result = 1;
 
        ALLOC_ARRAY(list, from->nr);
+       nr_commits = 0;
        for (i = 0; i < from->nr; i++) {
-               list[i] = (struct commit *)from->objects[i].item;
+               struct object *from_one = from->objects[i].item;
+
+               if (!from_one || from_one->flags & assign_flag)
+                       continue;
+
+               from_one = deref_tag(the_repository, from_one,
+                                    "a from object", 0);
+               if (!from_one || from_one->type != OBJ_COMMIT) {
+                       /* no way to tell if this is reachable by
+                        * looking at the ancestry chain alone, so
+                        * leave a note to ourselves not to worry about
+                        * this object anymore.
+                        */
+                       from->objects[i].item->flags |= assign_flag;
+                       continue;
+               }
 
-               if (parse_commit(list[i]) ||
-                   list[i]->generation < min_generation)
-                       return 0;
+               list[nr_commits] = (struct commit *)from_one;
+               if (parse_commit(list[nr_commits]) ||
+                   list[nr_commits]->generation < min_generation) {
+                       result = 0;
+                       goto cleanup;
+               }
+
+               nr_commits++;
        }
 
-       QSORT(list, from->nr, compare_commits_by_gen);
+       QSORT(list, nr_commits, compare_commits_by_gen);
 
-       for (i = 0; i < from->nr; i++) {
+       for (i = 0; i < nr_commits; i++) {
                /* DFS from list[i] */
                struct commit_list *stack = NULL;
 
@@ -600,10 +625,15 @@ int can_all_from_reach_with_flag(struct object_array *from,
        }
 
 cleanup:
-       for (i = 0; i < from->nr; i++) {
+       for (i = 0; i < nr_commits; i++) {
                clear_commit_marks(list[i], RESULT);
                clear_commit_marks(list[i], assign_flag);
        }
+       free(list);
+
+       for (i = 0; i < from->nr; i++)
+               from->objects[i].item->flags &= ~assign_flag;
+
        return result;
 }