Allow gnus backends to return a list of headers

* lisp/gnus/nnselect.el (nnselect-add-novitem): New macro.

  (nnselect-retrieve-headers): Allow backends to return headers as a
  list. Return this list rather than re-populating the server buffer
  with 'nov format headers.

* lisp/gnus/gnus-sum.el (gnus-fetch-headers): Allow backends to return
  headers as a list. Make sure the dependencies structure is updated.

diff --git a/lisp/gnus/nnselect.el b/lisp/gnus/nnselect.el
index fc2d98bca213a1726e54fe729a19ce5f42efdc54..7d57ddc9a562214cff0aac24eb501cbf9f0dc3b2 100644 (file)
--- a/lisp/gnus/nnselect.el
+++ b/lisp/gnus/nnselect.el
@@ -328,12 +328,11 @@ If this variable is nil, or if the provided function returns nil,
                (_ (error "Unknown header type %s while requesting articles \
                     of group %s" gnus-headers-retrieved-by artgroup)))))
          (setq headers
-               (sort headers
-                     (lambda (x y)
-                       (< (mail-header-number x) (mail-header-number y)))))
-         (erase-buffer)
-         (mapc 'nnheader-insert-nov headers)
-         'nov)))))
+               (sort
+                headers
+                (lambda (x y)
+                  (< (mail-header-number x) (mail-header-number y))))))))))
+
 
 (deffoo nnselect-request-article (article &optional _group server to-buffer)
   (let* ((gnus-override-method nil)