Merge branch 'mh/mmap-packed-refs'

Operations that do not touch (majority of) packed refs have been
optimized by making accesses to packed-refs file lazy; we no longer
pre-parse everything, and an access to a single ref in the
packed-refs does not touch majority of irrelevant refs, either.

* mh/mmap-packed-refs: (21 commits)
  packed-backend.c: rename a bunch of things and update comments
  mmapped_ref_iterator: inline into `packed_ref_iterator`
  ref_cache: remove support for storing peeled values
  packed_ref_store: get rid of the `ref_cache` entirely
  ref_store: implement `refs_peel_ref()` generically
  packed_read_raw_ref(): read the reference from the mmapped buffer
  packed_ref_iterator_begin(): iterate using `mmapped_ref_iterator`
  read_packed_refs(): ensure that references are ordered when read
  packed_ref_cache: keep the `packed-refs` file mmapped if possible
  packed-backend.c: reorder some definitions
  mmapped_ref_iterator_advance(): no peeled value for broken refs
  mmapped_ref_iterator: add iterator over a packed-refs file
  packed_ref_cache: remember the file-wide peeling state
  read_packed_refs(): read references with minimal copying
  read_packed_refs(): make parsing of the header line more robust
  read_packed_refs(): only check for a header at the top of the file
  read_packed_refs(): use mmap to read the `packed-refs` file
  die_unterminated_line(), die_invalid_line(): new functions
  packed_ref_cache: add a backlink to the associated `packed_ref_store`
  prefix_ref_iterator: break when we leave the prefix
  ...

1 files changed, 2 insertions, 42 deletions

diff --git a/refs/ref-cache.c b/refs/ref-cache.c
index 76bb723c86..4f850e1b5c 100644
--- a/refs/ref-cache.c
+++ b/refs/ref-cache.c
@@ -38,7 +38,6 @@ struct ref_entry *create_ref_entry(const char *refname,
 
 	FLEX_ALLOC_STR(ref, name, refname);
 	oidcpy(&ref->u.value.oid, oid);
-	oidclr(&ref->u.value.peeled);
 	ref->flag = flag;
 	return ref;
 }
@@ -491,49 +490,10 @@ static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator)
 	}
 }
 
-enum peel_status peel_entry(struct ref_entry *entry, int repeel)
-{
-	enum peel_status status;
-
-	if (entry->flag & REF_KNOWS_PEELED) {
-		if (repeel) {
-			entry->flag &= ~REF_KNOWS_PEELED;
-			oidclr(&entry->u.value.peeled);
-		} else {
-			return is_null_oid(&entry->u.value.peeled) ?
-				PEEL_NON_TAG : PEEL_PEELED;
-		}
-	}
-	if (entry->flag & REF_ISBROKEN)
-		return PEEL_BROKEN;
-	if (entry->flag & REF_ISSYMREF)
-		return PEEL_IS_SYMREF;
-
-	status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
-	if (status == PEEL_PEELED || status == PEEL_NON_TAG)
-		entry->flag |= REF_KNOWS_PEELED;
-	return status;
-}
-
 static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator,
 				   struct object_id *peeled)
 {
-	struct cache_ref_iterator *iter =
-		(struct cache_ref_iterator *)ref_iterator;
-	struct cache_ref_iterator_level *level;
-	struct ref_entry *entry;
-
-	level = &iter->levels[iter->levels_nr - 1];
-
-	if (level->index == -1)
-		die("BUG: peel called before advance for cache iterator");
-
-	entry = level->dir->entries[level->index];
-
-	if (peel_entry(entry, 0))
-		return -1;
-	oidcpy(peeled, &entry->u.value.peeled);
-	return 0;
+	return peel_object(ref_iterator->oid->hash, peeled->hash);
 }
 
 static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator)
@@ -574,7 +534,7 @@ struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache,
 
 	iter = xcalloc(1, sizeof(*iter));
 	ref_iterator = &iter->base;
-	base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable);
+	base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable, 1);
 	ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
 
 	iter->levels_nr = 1;