From c9e3deffab6e9de3a214a3b7f7a5921018fc1a9d Mon Sep 17 00:00:00 2001
From: Lars Magne Ingebrigtsen <larsi@gnus.org>
Date: Wed, 10 Dec 2014 05:38:23 +0100
Subject: [PATCH] Speed up directory-files-recursively

* files.el (directory-files-recursively): Use
`file-name-all-completions' instead of `directory-files' for
greater speed.
---
 lisp/ChangeLog |  4 ++++
 lisp/files.el  | 27 +++++++++++++++------------
 2 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 20461a654fe..445a4618714 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,5 +1,9 @@
 2014-12-10  Lars Magne Ingebrigtsen  <larsi@gnus.org>
 
+	* files.el (directory-files-recursively): Use
+	`file-name-all-completions' instead of `directory-files' for
+	greater speed.
+
 	* net/shr.el (shr-tag-object): Don't bug out on text elements in
 	<object>.
 
diff --git a/lisp/files.el b/lisp/files.el
index 5127519732d..e948c745b3c 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -769,18 +769,21 @@ and alphabetical order.
 If INCLUDE-DIRECTORIES, also include directories that have matching names."
   (let ((result nil)
 	(files nil))
-    (dolist (file (directory-files dir t))
-      (let ((leaf (file-name-nondirectory file)))
-	(unless (member leaf '("." ".."))
-	  (if (file-directory-p file)
-	      (progn
-		(when (and include-directories
-			   (string-match match leaf))
-		  (push file files))
-		(setq result (nconc result (directory-files-recursively
-					    file match include-directories))))
-	    (when (string-match match leaf)
-	      (push file files))))))
+    (dolist (file (sort (file-name-all-completions "" dir)
+			'string<))
+      (unless (member file '("./" "../"))
+	(if (= (aref file (1- (length file))) ?/)
+	    (progn
+	      (setq result (nconc result (directory-files-recursively
+					  (expand-file-name file dir)
+					  match include-directories)))
+	      (when (and include-directories
+			 (string-match match
+				       (substring file 0 (1- (length file)))))
+		(setq result (nconc result (list
+					    (expand-file-name file dir))))))
+	  (when (string-match match file)
+	    (push (expand-file-name file dir) files)))))
     (nconc result (nreverse files))))
 
 (defun load-file (file)
-- 
2.39.2