refs: drop infrastructure to peel via iterators

Now that the peeled object ID gets propagated via the `struct reference`
there is no need anymore to call into the reference iterator itself to
dereference an object. Remove this infrastructure.

Most of the changes are straight-forward deletions of code. There is one
exception though in `refs/packed-backend.c::write_with_updates()`. Here
we stop peeling the iterator and instead just pass the peeled object ID
of that iterator directly.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

refs.h

@@ -1289,10 +1289,6 @@ int repo_migrate_ref_storage_format(struct repository *repo,
  * to the next entry, ref_iterator_advance() aborts the iteration,
  * frees the ref_iterator, and returns ITER_ERROR.
  *
- * The reference currently being looked at can be peeled by calling
- * ref_iterator_peel(). This function is often faster than peel_ref(),
- * so it should be preferred when iterating over references.
- *
  * Putting it all together, a typical iteration looks like this:
  *
  *     int ok;
@@ -1307,9 +1303,6 @@ int repo_migrate_ref_storage_format(struct repository *repo,
  *             // Access information about the current reference:
  *             if (!(iter->flags & REF_ISSYMREF))
  *                     printf("%s is %s\n", iter->refname, oid_to_hex(iter->oid));
- *
- *             // If you need to peel the reference:
- *             ref_iterator_peel(iter, &oid);
  *     }
  *
  *     if (ok != ITER_DONE)
@@ -1400,13 +1393,6 @@ enum ref_iterator_seek_flag {
 int ref_iterator_seek(struct ref_iterator *ref_iterator, const char *refname,
 		      unsigned int flags);
 
-/*
- * If possible, peel the reference currently being viewed by the
- * iterator. Return 0 on success.
- */
-int ref_iterator_peel(struct ref_iterator *ref_iterator,
-		      struct object_id *peeled);
-
 /* Free the reference iterator and any associated resources. */
 void ref_iterator_free(struct ref_iterator *ref_iterator);
 

refs/debug.c

@@ -178,16 +178,6 @@ static int debug_ref_iterator_seek(struct ref_iterator *ref_iterator,
 	return res;
 }
 
-static int debug_ref_iterator_peel(struct ref_iterator *ref_iterator,
-				   struct object_id *peeled)
-{
-	struct debug_ref_iterator *diter =
-		(struct debug_ref_iterator *)ref_iterator;
-	int res = diter->iter->vtable->peel(diter->iter, peeled);
-	trace_printf_key(&trace_refs, "iterator_peel: %s: %d\n", diter->iter->ref.name, res);
-	return res;
-}
-
 static void debug_ref_iterator_release(struct ref_iterator *ref_iterator)
 {
 	struct debug_ref_iterator *diter =
@@ -199,7 +189,6 @@ static void debug_ref_iterator_release(struct ref_iterator *ref_iterator)
 static struct ref_iterator_vtable debug_ref_iterator_vtable = {
 	.advance = debug_ref_iterator_advance,
 	.seek = debug_ref_iterator_seek,
-	.peel = debug_ref_iterator_peel,
 	.release = debug_ref_iterator_release,
 };
 

refs/files-backend.c

@@ -994,15 +994,6 @@ static int files_ref_iterator_seek(struct ref_iterator *ref_iterator,
 	return ref_iterator_seek(iter->iter0, refname, flags);
 }
 
-static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
-				   struct object_id *peeled)
-{
-	struct files_ref_iterator *iter =
-		(struct files_ref_iterator *)ref_iterator;
-
-	return ref_iterator_peel(iter->iter0, peeled);
-}
-
 static void files_ref_iterator_release(struct ref_iterator *ref_iterator)
 {
 	struct files_ref_iterator *iter =
@@ -1013,7 +1004,6 @@ static void files_ref_iterator_release(struct ref_iterator *ref_iterator)
 static struct ref_iterator_vtable files_ref_iterator_vtable = {
 	.advance = files_ref_iterator_advance,
 	.seek = files_ref_iterator_seek,
-	.peel = files_ref_iterator_peel,
 	.release = files_ref_iterator_release,
 };
 
@@ -2389,12 +2379,6 @@ static int files_reflog_iterator_seek(struct ref_iterator *ref_iterator UNUSED,
 	BUG("ref_iterator_seek() called for reflog_iterator");
 }
 
-static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator UNUSED,
-				      struct object_id *peeled UNUSED)
-{
-	BUG("ref_iterator_peel() called for reflog_iterator");
-}
-
 static void files_reflog_iterator_release(struct ref_iterator *ref_iterator)
 {
 	struct files_reflog_iterator *iter =
@@ -2405,7 +2389,6 @@ static void files_reflog_iterator_release(struct ref_iterator *ref_iterator)
 static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 	.advance = files_reflog_iterator_advance,
 	.seek = files_reflog_iterator_seek,
-	.peel = files_reflog_iterator_peel,
 	.release = files_reflog_iterator_release,
 };
 

refs/iterator.c

@@ -21,12 +21,6 @@ int ref_iterator_seek(struct ref_iterator *ref_iterator, const char *refname,
 	return ref_iterator->vtable->seek(ref_iterator, refname, flags);
 }
 
-int ref_iterator_peel(struct ref_iterator *ref_iterator,
-		      struct object_id *peeled)
-{
-	return ref_iterator->vtable->peel(ref_iterator, peeled);
-}
-
 void ref_iterator_free(struct ref_iterator *ref_iterator)
 {
 	if (ref_iterator) {
@@ -60,20 +54,13 @@ static int empty_ref_iterator_seek(struct ref_iterator *ref_iterator UNUSED,
 	return 0;
 }
 
-static int empty_ref_iterator_peel(struct ref_iterator *ref_iterator UNUSED,
-				   struct object_id *peeled UNUSED)
-{
-	BUG("peel called for empty iterator");
-}
-
 static void empty_ref_iterator_release(struct ref_iterator *ref_iterator UNUSED)
 {
 }
 
 static struct ref_iterator_vtable empty_ref_iterator_vtable = {
 	.advance = empty_ref_iterator_advance,
 	.seek = empty_ref_iterator_seek,
-	.peel = empty_ref_iterator_peel,
 	.release = empty_ref_iterator_release,
 };
 
@@ -240,18 +227,6 @@ static int merge_ref_iterator_seek(struct ref_iterator *ref_iterator,
 	return 0;
 }
 
-static int merge_ref_iterator_peel(struct ref_iterator *ref_iterator,
-				   struct object_id *peeled)
-{
-	struct merge_ref_iterator *iter =
-		(struct merge_ref_iterator *)ref_iterator;
-
-	if (!iter->current) {
-		BUG("peel called before advance for merge iterator");
-	}
-	return ref_iterator_peel(*iter->current, peeled);
-}
-
 static void merge_ref_iterator_release(struct ref_iterator *ref_iterator)
 {
 	struct merge_ref_iterator *iter =
@@ -263,7 +238,6 @@ static void merge_ref_iterator_release(struct ref_iterator *ref_iterator)
 static struct ref_iterator_vtable merge_ref_iterator_vtable = {
 	.advance = merge_ref_iterator_advance,
 	.seek = merge_ref_iterator_seek,
-	.peel = merge_ref_iterator_peel,
 	.release = merge_ref_iterator_release,
 };
 
@@ -412,15 +386,6 @@ static int prefix_ref_iterator_seek(struct ref_iterator *ref_iterator,
 	return ref_iterator_seek(iter->iter0, refname, flags);
 }
 
-static int prefix_ref_iterator_peel(struct ref_iterator *ref_iterator,
-				    struct object_id *peeled)
-{
-	struct prefix_ref_iterator *iter =
-		(struct prefix_ref_iterator *)ref_iterator;
-
-	return ref_iterator_peel(iter->iter0, peeled);
-}
-
 static void prefix_ref_iterator_release(struct ref_iterator *ref_iterator)
 {
 	struct prefix_ref_iterator *iter =
@@ -432,7 +397,6 @@ static void prefix_ref_iterator_release(struct ref_iterator *ref_iterator)
 static struct ref_iterator_vtable prefix_ref_iterator_vtable = {
 	.advance = prefix_ref_iterator_advance,
 	.seek = prefix_ref_iterator_seek,
-	.peel = prefix_ref_iterator_peel,
 	.release = prefix_ref_iterator_release,
 };
 

refs/packed-backend.c

@@ -1030,22 +1030,6 @@ static int packed_ref_iterator_seek(struct ref_iterator *ref_iterator,
 	return 0;
 }
 
-static int packed_ref_iterator_peel(struct ref_iterator *ref_iterator,
-				   struct object_id *peeled)
-{
-	struct packed_ref_iterator *iter =
-		(struct packed_ref_iterator *)ref_iterator;
-
-	if ((iter->base.ref.flags & REF_KNOWS_PEELED)) {
-		oidcpy(peeled, &iter->peeled);
-		return is_null_oid(&iter->peeled) ? -1 : 0;
-	} else if ((iter->base.ref.flags & (REF_ISBROKEN | REF_ISSYMREF))) {
-		return -1;
-	} else {
-		return peel_object(iter->repo, &iter->oid, peeled) ? -1 : 0;
-	}
-}
-
 static void packed_ref_iterator_release(struct ref_iterator *ref_iterator)
 {
 	struct packed_ref_iterator *iter =
@@ -1059,7 +1043,6 @@ static void packed_ref_iterator_release(struct ref_iterator *ref_iterator)
 static struct ref_iterator_vtable packed_ref_iterator_vtable = {
 	.advance = packed_ref_iterator_advance,
 	.seek = packed_ref_iterator_seek,
-	.peel = packed_ref_iterator_peel,
 	.release = packed_ref_iterator_release,
 };
 
@@ -1526,13 +1509,8 @@ static enum ref_transaction_error write_with_updates(struct packed_ref_store *re
 
 		if (cmp < 0) {
 			/* Pass the old reference through. */
-
-			struct object_id peeled;
-			int peel_error = ref_iterator_peel(iter, &peeled);
-
 			if (write_packed_entry(out, iter->ref.name,
-					       iter->ref.oid,
-					       peel_error ? NULL : &peeled))
+					       iter->ref.oid, iter->ref.peeled_oid))
 				goto write_error;
 
 			if ((ok = ref_iterator_advance(iter)) != ITER_OK) {

refs/ref-cache.c

@@ -546,14 +546,6 @@ static int cache_ref_iterator_seek(struct ref_iterator *ref_iterator,
 	return 0;
 }
 
-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;
-	return peel_object(iter->repo, ref_iterator->ref.oid, peeled) ? -1 : 0;
-}
-
 static void cache_ref_iterator_release(struct ref_iterator *ref_iterator)
 {
 	struct cache_ref_iterator *iter =
@@ -565,7 +557,6 @@ static void cache_ref_iterator_release(struct ref_iterator *ref_iterator)
 static struct ref_iterator_vtable cache_ref_iterator_vtable = {
 	.advance = cache_ref_iterator_advance,
 	.seek = cache_ref_iterator_seek,
-	.peel = cache_ref_iterator_peel,
 	.release = cache_ref_iterator_release,
 };
 

refs/refs-internal.h

@@ -357,12 +357,6 @@ typedef int ref_iterator_advance_fn(struct ref_iterator *ref_iterator);
 typedef int ref_iterator_seek_fn(struct ref_iterator *ref_iterator,
 				 const char *refname, unsigned int flags);
 
-/*
- * Peels the current ref, returning 0 for success or -1 for failure.
- */
-typedef int ref_iterator_peel_fn(struct ref_iterator *ref_iterator,
-				 struct object_id *peeled);
-
 /*
  * Implementations of this function should free any resources specific
  * to the derived class.
@@ -372,7 +366,6 @@ typedef void ref_iterator_release_fn(struct ref_iterator *ref_iterator);
 struct ref_iterator_vtable {
 	ref_iterator_advance_fn *advance;
 	ref_iterator_seek_fn *seek;
-	ref_iterator_peel_fn *peel;
 	ref_iterator_release_fn *release;
 };
 

refs/reftable-backend.c

@@ -744,21 +744,6 @@ static int reftable_ref_iterator_seek(struct ref_iterator *ref_iterator,
 	return iter->err;
 }
 
-static int reftable_ref_iterator_peel(struct ref_iterator *ref_iterator,
-				      struct object_id *peeled)
-{
-	struct reftable_ref_iterator *iter =
-		(struct reftable_ref_iterator *)ref_iterator;
-
-	if (iter->ref.value_type == REFTABLE_REF_VAL2) {
-		oidread(peeled, iter->ref.value.val2.target_value,
-			iter->refs->base.repo->hash_algo);
-		return 0;
-	}
-
-	return -1;
-}
-
 static void reftable_ref_iterator_release(struct ref_iterator *ref_iterator)
 {
 	struct reftable_ref_iterator *iter =
@@ -776,7 +761,6 @@ static void reftable_ref_iterator_release(struct ref_iterator *ref_iterator)
 static struct ref_iterator_vtable reftable_ref_iterator_vtable = {
 	.advance = reftable_ref_iterator_advance,
 	.seek = reftable_ref_iterator_seek,
-	.peel = reftable_ref_iterator_peel,
 	.release = reftable_ref_iterator_release,
 };
 
@@ -2098,13 +2082,6 @@ static int reftable_reflog_iterator_seek(struct ref_iterator *ref_iterator UNUSE
 	return -1;
 }
 
-static int reftable_reflog_iterator_peel(struct ref_iterator *ref_iterator UNUSED,
-					 struct object_id *peeled UNUSED)
-{
-	BUG("reftable reflog iterator cannot be peeled");
-	return -1;
-}
-
 static void reftable_reflog_iterator_release(struct ref_iterator *ref_iterator)
 {
 	struct reftable_reflog_iterator *iter =
@@ -2117,7 +2094,6 @@ static void reftable_reflog_iterator_release(struct ref_iterator *ref_iterator)
 static struct ref_iterator_vtable reftable_reflog_iterator_vtable = {
 	.advance = reftable_reflog_iterator_advance,
 	.seek = reftable_reflog_iterator_seek,
-	.peel = reftable_reflog_iterator_peel,
 	.release = reftable_reflog_iterator_release,
 };