diff --git a/streaming.c b/streaming.c
index 807a6e03a8..0635b7c12e 100644
--- a/streaming.c
+++ b/streaming.c
@@ -12,19 +12,8 @@
 #include "replace-object.h"
 #include "packfile.h"
 
-typedef int (*close_istream_fn)(struct odb_read_stream *);
-typedef ssize_t (*read_istream_fn)(struct odb_read_stream *, char *, size_t);
-
 #define FILTER_BUFFER (1024*16)
 
-struct odb_read_stream {
-	close_istream_fn close;
-	read_istream_fn read;
-
-	enum object_type type;
-	unsigned long size; /* inflated size of full object */
-};
-
 /*****************************************************************
  *
  * Filtered stream
diff --git a/streaming.h b/streaming.h
index 148f6b3069..acfdef1598 100644
--- a/streaming.h
+++ b/streaming.h
@@ -7,10 +7,23 @@
 #include "object.h"
 
 struct object_database;
-/* opaque */
 struct odb_read_stream;
 struct stream_filter;
 
+typedef int (*odb_read_stream_close_fn)(struct odb_read_stream *);
+typedef ssize_t (*odb_read_stream_read_fn)(struct odb_read_stream *, char *, size_t);
+
+/*
+ * A stream that can be used to read an object from the object database without
+ * loading all of it into memory.
+ */
+struct odb_read_stream {
+	odb_read_stream_close_fn close;
+	odb_read_stream_read_fn read;
+	enum object_type type;
+	unsigned long size; /* inflated size of full object */
+};
+
 struct odb_read_stream *open_istream(struct repository *, const struct object_id *,
 				     enum object_type *, unsigned long *,
 				     struct stream_filter *);