commit-reach: move can_all_from_reach_with_flags

There are several commit walks in the codebase. Group them together into
a new commit-reach.c file and corresponding header. After we group these
walks into one place, we can reduce duplicate logic by calling
equivalent methods.

The can_all_from_reach_with_flags method is used in a stateful way by
upload-pack.c. The parameters are very flexible, so we will be able to
use its commit walking logic for many other callers.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 69 deletions

diff --git a/upload-pack.c b/upload-pack.c
index 427de46..11c4266 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -24,13 +24,13 @@
 #include "quote.h"
 #include "upload-pack.h"
 #include "serve.h"
+#include "commit-reach.h"
 
 /* Remember to update object flag allocation in object.h */
 #define THEY_HAVE	(1u << 11)
 #define OUR_REF		(1u << 12)
 #define WANTED		(1u << 13)
 #define COMMON_KNOWN	(1u << 14)
-#define REACHABLE	(1u << 15)
 
 #define SHALLOW		(1u << 16)
 #define NOT_SHALLOW	(1u << 17)
@@ -336,74 +336,6 @@ static int got_oid(const char *hex, struct object_id *oid)
 	return 0;
 }
 
-static int reachable(struct commit *from, unsigned int with_flag,
-		     unsigned int assign_flag, time_t min_commit_date)
-{
-	struct prio_queue work = { compare_commits_by_commit_date };
-
-	prio_queue_put(&work, from);
-	while (work.nr) {
-		struct commit_list *list;
-		struct commit *commit = prio_queue_get(&work);
-
-		if (commit->object.flags & with_flag) {
-			from->object.flags |= assign_flag;
-			break;
-		}
-		if (!commit->object.parsed)
-			parse_object(the_repository, &commit->object.oid);
-		if (commit->object.flags & REACHABLE)
-			continue;
-		commit->object.flags |= REACHABLE;
-		if (commit->date < min_commit_date)
-			continue;
-		for (list = commit->parents; list; list = list->next) {
-			struct commit *parent = list->item;
-			if (!(parent->object.flags & REACHABLE))
-				prio_queue_put(&work, parent);
-		}
-	}
-	from->object.flags |= REACHABLE;
-	clear_commit_marks(from, REACHABLE);
-	clear_prio_queue(&work);
-	return (from->object.flags & assign_flag);
-}
-
-/*
- * Determine if every commit in 'from' can reach at least one commit
- * that is marked with 'with_flag'. As we traverse, use 'assign_flag'
- * as a marker for commits that are already visited. Do not walk
- * commits with date below 'min_commit_date'.
- */
-static int can_all_from_reach_with_flag(struct object_array *from,
-					unsigned int with_flag,
-					unsigned int assign_flag,
-					time_t min_commit_date)
-{
-	int i;
-
-	for (i = 0; i < from->nr; i++) {
-		struct object *from_one = from->objects[i].item;
-
-		if (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 (!reachable((struct commit *)from_one, with_flag, assign_flag,
-			       min_commit_date))
-			return 0;
-	}
-	return 1;
-}
-
 static int ok_to_give_up(void)
 {
 	if (!have_obj.nr)