unpack-trees: refactor prefetching code

Refactor the prefetching code in unpack-trees.c into its own function,
because it will be used elsewhere in a subsequent commit.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/read-cache.c b/read-cache.c
index ba2b012a6c..4e396bf17f 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -27,6 +27,7 @@
 #include "progress.h"
 #include "sparse-index.h"
 #include "csum-file.h"
+#include "promisor-remote.h"
 
 /* Mask for the name length in ce_flags in the on-disk index */
 
@@ -3657,3 +3658,25 @@ static void write_ieot_extension(struct strbuf *sb, struct index_entry_offset_ta
 		strbuf_add(sb, &buffer, sizeof(uint32_t));
 	}
 }
+
+void prefetch_cache_entries(const struct index_state *istate,
+			    must_prefetch_predicate must_prefetch)
+{
+	int i;
+	struct oid_array to_fetch = OID_ARRAY_INIT;
+
+	for (i = 0; i < istate->cache_nr; i++) {
+		struct cache_entry *ce = istate->cache[i];
+
+		if (S_ISGITLINK(ce->ce_mode) || !must_prefetch(ce))
+			continue;
+		if (!oid_object_info_extended(the_repository, &ce->oid,
+					      NULL,
+					      OBJECT_INFO_FOR_PREFETCH))
+			continue;
+		oid_array_append(&to_fetch, &ce->oid);
+	}
+	promisor_remote_get_direct(the_repository,
+				   to_fetch.oid, to_fetch.nr);
+	oid_array_clear(&to_fetch);
+}