master d737e49: * lisp/gnus/nnmaildir.el: Fix O(n^2) problem when leaving a group

[Stefan Monnier]

branch: master
commit d737e497a82431b2ca4debb7a68c5422cb5a7929
Author: Stefan Monnier <address@hidden>
Commit: Stefan Monnier <address@hidden>

    * 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.
---
 lisp/gnus/nnheader.el  |  2 +-
 lisp/gnus/nnmaildir.el | 30 ++++++++++++++++++------------
 2 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/lisp/gnus/nnheader.el b/lisp/gnus/nnheader.el
index 199d524..fee7a16 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 bf1ac31..9c7b125 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)