Merge branch 'jk/pack-objects-optim'

"git pack-objects" has a few options that tell it not to pack
objects found in certain packfiles, which require it to scan .idx
files of all available packs.  The codepaths involved in these
operations have been optimized for a common case of not having any
non-local pack and/or any .kept pack.

* jk/pack-objects-optim:
  pack-objects: compute local/ignore_pack_keep early
  pack-objects: break out of want_object loop early
  find_pack_entry: replace last_found_pack with MRU cache
  add generic most-recently-used list
  sha1_file: drop free_pack_by_name
  t/perf: add tests for many-pack scenarios

1 files changed, 40 insertions, 0 deletions

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 92e2e5f7a8..4a63398960 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -46,6 +46,7 @@ static int keep_unreachable, unpack_unreachable, include_tag;
 static unsigned long unpack_unreachable_expiration;
 static int pack_loose_unreachable;
 static int local;
+static int have_non_local_packs;
 static int incremental;
 static int ignore_packed_keep;
 static int allow_ofs_delta;
@@ -978,6 +979,23 @@ static int want_object_in_pack(const unsigned char *sha1,
 				return 1;
 			if (incremental)
 				return 0;
+
+			/*
+			 * When asked to do --local (do not include an
+			 * object that appears in a pack we borrow
+			 * from elsewhere) or --honor-pack-keep (do not
+			 * include an object that appears in a pack marked
+			 * with .keep), we need to make sure no copy of this
+			 * object come from in _any_ pack that causes us to
+			 * omit it, and need to complete this loop.  When
+			 * neither option is in effect, we know the object
+			 * we just found is going to be packed, so break
+			 * out of the loop to return 1 now.
+			 */
+			if (!ignore_packed_keep &&
+			    (!local || !have_non_local_packs))
+				break;
+
 			if (local && !p->pack_local)
 				return 0;
 			if (ignore_packed_keep && p->pack_local && p->pack_keep)
@@ -2784,6 +2802,28 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 		progress = 2;
 
 	prepare_packed_git();
+	if (ignore_packed_keep) {
+		struct packed_git *p;
+		for (p = packed_git; p; p = p->next)
+			if (p->pack_local && p->pack_keep)
+				break;
+		if (!p) /* no keep-able packs found */
+			ignore_packed_keep = 0;
+	}
+	if (local) {
+		/*
+		 * unlike ignore_packed_keep above, we do not want to
+		 * unset "local" based on looking at packs, as it
+		 * also covers non-local objects
+		 */
+		struct packed_git *p;
+		for (p = packed_git; p; p = p->next) {
+			if (!p->pack_local) {
+				have_non_local_packs = 1;
+				break;
+			}
+		}
+	}
 
 	if (progress)
 		progress_state = start_progress(_("Counting objects"), 0);