refactor(sterni/mblog): move REDIRECT-STREAM into mime4cl

Eventually, we'll want to replace dump-stream-binary with something more
efficient—given that we have flexi-streams we can use something that
only does matching element types no problem. REDIRECT-STREAM is much
more efficient thanks to using an internal buffer.

streams.lisp gets a new section at the beginning for grouping utilities
that don't have any real (internal) dependencies.

Change-Id: I141cd36440d532131f389be2768fdaa54e7c7218
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8583
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI

users/sterni/mblog/mblog.lisp

@@ -26,14 +26,6 @@
                            :if-does-not-exist :create)
      ,@body))
 
-(defun redirect-stream (in out)
-  "Consume input stream IN and write all its content to output stream OUT.
-  The streams' element types need to match."
-  (let ((buf (make-array config:*general-buffer-size* :element-type (stream-element-type in))))
-    (loop for pos = (read-sequence buf in)
-          while (> pos 0)
-          do (write-sequence buf out :end pos))))
-
 ;; CSS
 
 (defvar *style* "
@@ -98,7 +90,8 @@ a:link, a:visited {
         (with-overwrite-file (attachment-out attachment-dst
                               :element-type
                               (stream-element-type attachment-in))
-          (redirect-stream attachment-in attachment-out)))))
+          (redirect-stream attachment-in attachment-out
+                           :buffer-size *general-buffer-size*)))))
 
   (values))
 

users/sterni/mblog/packages.lisp

@@ -50,6 +50,7 @@
    :config)
   (:export :build-mblog)
   (:import-from :local-time :universal-to-timestamp)
+  (:import-from :mime4cl :redirect-stream)
   (:shadowing-import-from :common-lisp :list))
 
 (defpackage :cli