* lisp/gnus/nnmaildir.el: Fix O(n^2) problem when leaving a group

Use lexical-binding.

(nnmaildir-close-group): Use a hash-table rather than a list to keep
track of the files we have seen.

* lisp/gnus/nnheader.el (nnheader-parse-naked-head):
Use make-full-mail-header.

2 files changed, 19 insertions, 13 deletions

diff --git a/lisp/gnus/nnheader.el b/lisp/gnus/nnheader.el
index 199d5241973..fee7a169ff9 100644
--- a/lisp/gnus/nnheader.el
+++ b/lisp/gnus/nnheader.el
@@ -209,7 +209,7 @@ on your system, you could say something like:
         ;; about twice as fast, even though it looks messier.  You
         ;; can't have everything, I guess.  Speed and elegance don't
         ;; always go hand in hand.
-        (vector
+        (make-full-mail-header
          ;; Number.
          (or number 0)
          ;; Subject.
diff --git a/lisp/gnus/nnmaildir.el b/lisp/gnus/nnmaildir.el
index bf1ac31bb3c..9c7b1254413 100644
--- a/lisp/gnus/nnmaildir.el
+++ b/lisp/gnus/nnmaildir.el
@@ -1,4 +1,4 @@
-;;; nnmaildir.el --- maildir backend for Gnus
+;;; nnmaildir.el --- maildir backend for Gnus  -*- lexical-binding:t -*-
 
 ;; This file is in the public domain.
 
@@ -261,7 +261,7 @@ This variable is set by `nnmaildir-request-article'.")
 (defun nnmaildir--param (pgname param)
   (setq param (gnus-group-find-parameter pgname param 'allow-list))
   (if (vectorp param) (setq param (aref param 0)))
-  (eval param))
+  (eval param t))
 
 (defmacro nnmaildir--with-nntp-buffer (&rest body)
   (declare (debug (body)))
@@ -690,7 +690,7 @@ This variable is set by `nnmaildir-request-article'.")
               "You must set \"directory\" in the select method")
         (throw 'return nil))
       (setq dir (cadr dir)
-            dir (eval dir)
+            dir (eval dir t)    ;FIXME: Why `eval'?
             dir (expand-file-name dir)
             dir (file-name-as-directory dir))
       (unless (file-exists-p dir)
@@ -717,13 +717,13 @@ This variable is set by `nnmaildir-request-article'.")
       (if x
           (progn
             (setq x (cadr x)
-                  x (eval x))
+                  x (eval x t)) ;FIXME: Why `eval'?
             (setf (nnmaildir--srv-target-prefix server) x))
         (setq x (assq 'create-directory defs))
         (if x
             (progn
               (setq x (cadr x)
-                    x (eval x)
+                    x (eval x t) ;FIXME: Why `eval'?
                     x (file-name-as-directory x))
               (setf (nnmaildir--srv-target-prefix server) x))
           (setf (nnmaildir--srv-target-prefix server) "")))
@@ -1428,7 +1428,7 @@ This variable is set by `nnmaildir-request-article'.")
       (nnmaildir--with-move-buffer
         (erase-buffer)
         (nnheader-insert-file-contents nnmaildir--file)
-        (setq result (eval accept-form)))
+        (setq result (eval accept-form t)))
       (unless (or (null result) (nnmaildir--param pgname 'read-only))
         (nnmaildir--unlink nnmaildir--file)
         (nnmaildir--expired-article group article))
@@ -1544,7 +1544,7 @@ This variable is set by `nnmaildir-request-article'.")
 (defun nnmaildir-request-expire-articles (ranges &optional gname server force)
   (let ((no-force (not force))
         (group (nnmaildir--prepare server gname))
-        pgname time boundary high low target dir nlist
+        pgname time boundary target dir nlist
         didnt nnmaildir--file nnmaildir-article-file-name
         deactivate-mark)
     (catch 'return
@@ -1720,18 +1720,23 @@ This variable is set by `nnmaildir-request-article'.")
 
 (defun nnmaildir-close-group (gname &optional server)
   (let ((group (nnmaildir--prepare server gname))
-        pgname ls dir msgdir files flist dirs)
+        pgname ls dir msgdir files dirs
+        (fset (make-hash-table :test #'equal)))
     (if (null group)
         (progn
           (setf (nnmaildir--srv-error nnmaildir--cur-server)
                 (concat "No such group: " gname))
           nil)
+      ;; Delete the now obsolete NOV files.
+      ;; FIXME: This can take a somewhat long time, so maybe it's better
+      ;; to do it asynchronously (i.e. in an idle timer).
       (setq pgname (nnmaildir--pgname nnmaildir--cur-server gname)
             ls (nnmaildir--group-ls nnmaildir--cur-server pgname)
             dir (nnmaildir--srv-dir nnmaildir--cur-server)
             dir (nnmaildir--srvgrp-dir dir gname)
             msgdir (if (nnmaildir--param pgname 'read-only)
                        (nnmaildir--new dir) (nnmaildir--cur dir))
+            ;; The dir with the NOV files.
             dir (nnmaildir--nndir dir)
             dirs (cons (nnmaildir--nov-dir dir)
                        (funcall ls (nnmaildir--marks-dir dir) 'full "\\`[^.]"
@@ -1744,14 +1749,15 @@ This variable is set by `nnmaildir-request-article'.")
       (save-match-data
         (dolist (file files)
           (string-match "\\`\\([^:]*\\)\\(:.*\\)?\\'" file)
-          (push (match-string 1 file) flist)))
+          (puthash (match-string 1 file) t fset)))
+      ;; Not sure why, but we specifically avoid deleting the `:' file.
+      (puthash ":" t fset)
       (dolist (dir dirs)
         (setq files (cdr dir)
               dir (file-name-as-directory (car dir)))
         (dolist (file files)
-          (unless (or (member file flist) (string= file ":"))
-            (setq file (concat dir file))
-            (delete-file file))))
+          (unless (gethash file fset)
+            (delete-file (concat dir file)))))
       t)))
 
 (defun nnmaildir-close-server (&optional server _defs)