sha1-file: add function to update existing loose object cache

Create a function to add a new object to the loose object cache
after the existing odb/xx/ directory was scanned.

This will be used in a later commit to keep the loose object
cache fresh after dynamically fetching an individual object
and without requiring the odb/xx/ directory to be rescanned.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>

Author: jeffhostetler

object-file.c

@@ -1859,6 +1859,13 @@ struct oidtree *odb_source_loose_cache(struct odb_source *source,
 	return source->loose->cache;
 }
 
+void odb_source_loose_cache_add_new_oid(struct odb_source *source,
+					const struct object_id *oid)
+{
+	struct oidtree *cache = odb_source_loose_cache(source, oid);
+	append_loose_object(oid, NULL, cache);
+}
+
 static void odb_source_loose_clear_cache(struct odb_source_loose *loose)
 {
 	oidtree_clear(loose->cache);

object-file.h

@@ -81,6 +81,14 @@ int odb_source_loose_write_stream(struct odb_source *source,
 struct oidtree *odb_source_loose_cache(struct odb_source *source,
 				       const struct object_id *oid);
 
+/*
+ * Add a new object to the loose object cache (possibly after the
+ * cache was populated).  This might be used after dynamically
+ * fetching a missing object.
+ */
+void odb_source_loose_cache_add_new_oid(struct odb_source *source,
+				 const struct object_id *oid);
+
 /*
  * Put in `buf` the name of the file in the local object database that
  * would be used to store a loose object with the specified oid.