sha256: recycle I/O buffer used in stream hash.

* chksum.c (sha256_stream): Use iobuf_get and iobuf_put.

* gc.c (gc): Do not mark the list of recycled buffers; just
consider them to be garbage and clear the list, like we do
with recycled conses via rcyc_empty.

* stream.c (iobuf_free_list): New static variable.
(iobuf_get, iobuf_put, iobuf_list_empty): New functions.

* stream.h (iobuf_get, iobuf_put, iobuf_list_empty): Declared.

1 files changed, 3 insertions, 1 deletions

diff --git a/stream.h b/stream.h
index 2887b305..bc83122c 100644
--- a/stream.h
+++ b/stream.h
@@ -240,5 +240,7 @@ val base_name(val path);
 val dir_name(val path);
 val path_cat(val dir_name, val base_name);
 val make_byte_input_stream(val obj);
-
+val iobuf_get(void);
+void iobuf_put(val buf);
+void iobuf_list_empty(void);
 void stream_init(void);