bug#51699: 29.0.50; [PATCH] Improve performance of 'file-name-case-insensitive-p' for Tramp files

[Jim Porter <jporterbugs@gmail.com>]

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On 11/10/2021 4:17 AM, Michael Albinus wrote:
> `tramp-find-foreign-file-name-handler' loops through
> `tramp-register-foreign-file-name-handler'. Only operations registered
> there need to support a VEC-OR-FILENAME argument.
> `tramp-archive-file-name-p' and `tramp-crypt-file-name-p' are not
> registered, so no change is needed.

Ah ha. I didn't realize they weren't included (I thought I just had to 
configure something to add them in 
`tramp-foreign-file-name-handler-alist'). In that case, it definitely 
makes sense eliminate the `accepts-vec' bits from my patch.

> We could (and should) inform the authors of both packages, that the
> signature for the `tramp-FOO-file-name-p' functions will change with
> Tramp 2.6. As I can see, there's no problem to adapt
> `magit-tramp-file-name-p' and `tramp-jumper-file-name-p'. And yes, an
> entry in etc/NEWS should be added as well.

Sounds good to me. I've added a NEWS entry that hopefully explains the 
change fairly clearly. Just to be extra-certain, I re-ran my performance 
tests from before and the results are the same.

> A  little bit more friendly for debugging:
> 
> --8<---------------cut here---------------start------------->8---
> 	;; The signature of `tramp-FOO-file-name-p' has changed, it
> 	;; expects a VEC here.
>          (when (with-demoted-errors "Error: %S" (funcall (car elt) vec))
> --8<---------------cut here---------------end--------------->8---

I went with this since it should make it easier for third parties to 
notice the issue and make the appropriate update to their code. Thanks 
for the pointer.

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From 2aec8e21a3e37728a990c4f116f60c8b12bb2110 Mon Sep 17 00:00:00 2001
From: Jim Porter <jporterbugs@gmail.com>
Date: Wed, 10 Nov 2021 16:41:00 -0800
Subject: [PATCH] Improve performance of 'tramp-find-foreign-file-name-handler'

Previously, each function in 'tramp-foreign-file-name-handler-alist'
would call 'tramp-dissect-file-name', resulting in it being called
several times whenever 'tramp-find-foreign-file-name-handler' was
called.  Now, functions take the dissected file name to avoid this
duplicated effort.

* lisp/net/tramp.el (tramp-ensure-dissected-file-name): New function.
(tramp-find-foreign-file-name-handler): Pass dissected file name to
functions.
(tramp-connectable-p): Use 'tramp-ensure-dissected-file-name'.

* lisp/net/tramp-adb.el (tramp-adb-file-name-p):
* lisp/net/tramp-ftp.el (tramp-ftp-file-name-p):
* lisp/net/tramp-gvfs.el (tramp-gvfs-file-name-p):
* lisp/net/tramp-rclone.el (tramp-rclone-file-name-p):
* lisp/net/tramp-smb.el (tramp-smb-file-name-p):
* lisp/net/tramp-sshfs.el (tramp-sshfs-file-name-p):
* lisp/net/tramp-sudoedit.el (tramp-sudoedit-file-name-p):
Accept dissected file names.

* etc/NEWS: Announce this change.
---
 etc/NEWS                   |  6 ++++++
 lisp/net/tramp-adb.el      |  9 ++++-----
 lisp/net/tramp-ftp.el      |  9 ++++-----
 lisp/net/tramp-gvfs.el     | 11 +++++------
 lisp/net/tramp-rclone.el   |  9 ++++-----
 lisp/net/tramp-smb.el      |  9 ++++-----
 lisp/net/tramp-sshfs.el    |  9 ++++-----
 lisp/net/tramp-sudoedit.el |  9 ++++-----
 lisp/net/tramp.el          | 26 ++++++++++++++++++--------
 9 files changed, 53 insertions(+), 44 deletions(-)

diff --git a/etc/NEWS b/etc/NEWS
index 807f31fa33..9f3a773a5b 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -571,6 +571,12 @@ get proper locale-dependent downcasing, the string has to be converted
 to multibyte first.  (This goes for the other case-changing functions,
 too.)
 
+---
+** Functions in 'tramp-foreign-file-name-handler-alist' have changed.
+Functions to determine which Tramp file name handler to use are now
+passed a file name in dissected form (via 'tramp-dissect-file-name')
+instead of in string form.
+
 ---
 ** 'def' indentation changes.
 In 'emacs-lisp-mode', forms with a symbol with a name that start with
diff --git a/lisp/net/tramp-adb.el b/lisp/net/tramp-adb.el
index 362a258f43..e7fe07e417 100644
--- a/lisp/net/tramp-adb.el
+++ b/lisp/net/tramp-adb.el
@@ -191,11 +191,10 @@ tramp-adb-file-name-handler-alist
 ;; It must be a `defsubst' in order to push the whole code into
 ;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
 ;;;###tramp-autoload
-(defsubst tramp-adb-file-name-p (filename)
-  "Check if it's a FILENAME for ADB."
-  (and (tramp-tramp-file-p filename)
-       (string= (tramp-file-name-method (tramp-dissect-file-name filename))
-		tramp-adb-method)))
+(defsubst tramp-adb-file-name-p (vec-or-filename)
+  "Check if it's a VEC-OR-FILENAME for ADB."
+  (when-let* ((vec (tramp-ensure-dissected-file-name vec-or-filename)))
+    (string= (tramp-file-name-method vec) tramp-adb-method)))
 
 ;;;###tramp-autoload
 (defun tramp-adb-file-name-handler (operation &rest args)
diff --git a/lisp/net/tramp-ftp.el b/lisp/net/tramp-ftp.el
index 11ccdc8a4c..f78c08ec41 100644
--- a/lisp/net/tramp-ftp.el
+++ b/lisp/net/tramp-ftp.el
@@ -175,11 +175,10 @@ tramp-ftp-file-name-handler
 ;; It must be a `defsubst' in order to push the whole code into
 ;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
 ;;;###tramp-autoload
-(defsubst tramp-ftp-file-name-p (filename)
-  "Check if it's a FILENAME that should be forwarded to Ange-FTP."
-  (and (tramp-tramp-file-p filename)
-       (string= (tramp-file-name-method (tramp-dissect-file-name filename))
-		tramp-ftp-method)))
+(defsubst tramp-ftp-file-name-p (vec-or-filename)
+  "Check if it's a VEC-OR-FILENAME that should be forwarded to Ange-FTP."
+  (when-let* ((vec (tramp-ensure-dissected-file-name vec-or-filename)))
+    (string= (tramp-file-name-method vec) tramp-ftp-method)))
 
 ;;;###tramp-autoload
 (tramp--with-startup
diff --git a/lisp/net/tramp-gvfs.el b/lisp/net/tramp-gvfs.el
index cab912bd93..1f9d9d9415 100644
--- a/lisp/net/tramp-gvfs.el
+++ b/lisp/net/tramp-gvfs.el
@@ -834,12 +834,11 @@ tramp-gvfs-file-name-handler-alist
 ;; It must be a `defsubst' in order to push the whole code into
 ;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
 ;;;###tramp-autoload
-(defsubst tramp-gvfs-file-name-p (filename)
-  "Check if it's a FILENAME handled by the GVFS daemon."
-  (and (tramp-tramp-file-p filename)
-       (let ((method
-	      (tramp-file-name-method (tramp-dissect-file-name filename))))
-	 (and (stringp method) (member method tramp-gvfs-methods)))))
+(defsubst tramp-gvfs-file-name-p (vec-or-filename)
+  "Check if it's a VEC-OR-FILENAME handled by the GVFS daemon."
+  (when-let* ((vec (tramp-ensure-dissected-file-name vec-or-filename)))
+    (let ((method (tramp-file-name-method vec)))
+      (and (stringp method) (member method tramp-gvfs-methods)))))
 
 ;;;###tramp-autoload
 (defun tramp-gvfs-file-name-handler (operation &rest args)
diff --git a/lisp/net/tramp-rclone.el b/lisp/net/tramp-rclone.el
index 812e06f3f1..64b0176d08 100644
--- a/lisp/net/tramp-rclone.el
+++ b/lisp/net/tramp-rclone.el
@@ -156,11 +156,10 @@ tramp-rclone-file-name-handler-alist
 ;; It must be a `defsubst' in order to push the whole code into
 ;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
 ;;;###tramp-autoload
-(defsubst tramp-rclone-file-name-p (filename)
-  "Check if it's a FILENAME for rclone."
-  (and (tramp-tramp-file-p filename)
-       (string= (tramp-file-name-method (tramp-dissect-file-name filename))
-		tramp-rclone-method)))
+(defsubst tramp-rclone-file-name-p (vec-or-filename)
+  "Check if it's a VEC-OR-FILENAME for rclone."
+  (when-let* ((vec (tramp-ensure-dissected-file-name vec-or-filename)))
+    (string= (tramp-file-name-method vec) tramp-rclone-method)))
 
 ;;;###tramp-autoload
 (defun tramp-rclone-file-name-handler (operation &rest args)
diff --git a/lisp/net/tramp-smb.el b/lisp/net/tramp-smb.el
index 49f049d3f3..aeabc69246 100644
--- a/lisp/net/tramp-smb.el
+++ b/lisp/net/tramp-smb.el
@@ -330,11 +330,10 @@ tramp-smb-winexe-shell-command-switch
 ;; It must be a `defsubst' in order to push the whole code into
 ;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
 ;;;###tramp-autoload
-(defsubst tramp-smb-file-name-p (filename)
-  "Check if it's a FILENAME for SMB servers."
-  (and (tramp-tramp-file-p filename)
-       (string= (tramp-file-name-method (tramp-dissect-file-name filename))
-		tramp-smb-method)))
+(defsubst tramp-smb-file-name-p (vec-or-filename)
+  "Check if it's a VEC-OR-FILENAME for SMB servers."
+  (when-let* ((vec (tramp-ensure-dissected-file-name vec-or-filename)))
+    (string= (tramp-file-name-method vec) tramp-smb-method)))
 
 ;;;###tramp-autoload
 (defun tramp-smb-file-name-handler (operation &rest args)
diff --git a/lisp/net/tramp-sshfs.el b/lisp/net/tramp-sshfs.el
index a100786345..4bc804571e 100644
--- a/lisp/net/tramp-sshfs.el
+++ b/lisp/net/tramp-sshfs.el
@@ -156,11 +156,10 @@ tramp-sshfs-file-name-handler-alist
 ;; It must be a `defsubst' in order to push the whole code into
 ;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
 ;;;###tramp-autoload
-(defsubst tramp-sshfs-file-name-p (filename)
-  "Check if it's a FILENAME for sshfs."
-  (and (tramp-tramp-file-p filename)
-       (string= (tramp-file-name-method (tramp-dissect-file-name filename))
-	        tramp-sshfs-method)))
+(defsubst tramp-sshfs-file-name-p (vec-or-filename)
+  "Check if it's a VEC-OR-FILENAME for sshfs."
+  (when-let* ((vec (tramp-ensure-dissected-file-name vec-or-filename)))
+    (string= (tramp-file-name-method vec) tramp-sshfs-method)))
 
 ;;;###tramp-autoload
 (defun tramp-sshfs-file-name-handler (operation &rest args)
diff --git a/lisp/net/tramp-sudoedit.el b/lisp/net/tramp-sudoedit.el
index 845f31d09b..48c81a5988 100644
--- a/lisp/net/tramp-sudoedit.el
+++ b/lisp/net/tramp-sudoedit.el
@@ -148,11 +148,10 @@ tramp-sudoedit-file-name-handler-alist
 ;; It must be a `defsubst' in order to push the whole code into
 ;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
 ;;;###tramp-autoload
-(defsubst tramp-sudoedit-file-name-p (filename)
-  "Check if it's a FILENAME for SUDOEDIT."
-  (and (tramp-tramp-file-p filename)
-       (string= (tramp-file-name-method (tramp-dissect-file-name filename))
-		tramp-sudoedit-method)))
+(defsubst tramp-sudoedit-file-name-p (vec-or-filename)
+  "Check if it's a VEC-OR-FILENAME for SUDOEDIT."
+  (when-let* ((vec (tramp-ensure-dissected-file-name vec-or-filename)))
+    (string= (tramp-file-name-method vec) tramp-sudoedit-method)))
 
 ;;;###tramp-autoload
 (defun tramp-sudoedit-file-name-handler (operation &rest args)
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index a8972ce69e..85effe1a04 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -1669,6 +1669,16 @@ tramp-dissect-file-name
 
 (put #'tramp-dissect-file-name 'tramp-suppress-trace t)
 
+(defun tramp-ensure-dissected-file-name (vec-or-filename)
+  "Return a `tramp-file-name' structure for VEC-OR-FILENAME.
+
+VEC-OR-FILENAME may be either a string or a `tramp-file-name'.
+If it's not a Tramp filename, return nil."
+  (cond
+   ((tramp-file-name-p vec-or-filename) vec-or-filename)
+   ((tramp-tramp-file-p vec-or-filename)
+    (tramp-dissect-file-name vec-or-filename))))
+
 (defun tramp-dissect-hop-name (name &optional nodefault)
   "Return a `tramp-file-name' structure of `hop' part of NAME.
 See `tramp-dissect-file-name' for details."
@@ -2552,11 +2562,14 @@ tramp-find-foreign-file-name-handler
   "Return foreign file name handler if exists."
   (when (tramp-tramp-file-p filename)
     (let ((handler tramp-foreign-file-name-handler-alist)
+          (vec (tramp-dissect-file-name filename))
 	  elt res)
       (while handler
 	(setq elt (car handler)
 	      handler (cdr handler))
-	(when (funcall (car elt) filename)
+        ;; Previously, this function was called with FILENAME, but now
+        ;; it's called with the VEC.
+        (when (with-demoted-errors "Error: %S" (funcall (car elt) vec))
 	  (setq handler nil
 		res (cdr elt))))
       res)))
@@ -2755,8 +2768,9 @@ tramp-register-file-name-handlers
 (defun tramp-register-foreign-file-name-handler
     (func handler &optional append)
   "Register (FUNC . HANDLER) in `tramp-foreign-file-name-handler-alist'.
-FUNC is the function, which determines whether HANDLER is to be called.
-Add operations defined in `HANDLER-alist' to `tramp-file-name-handler'."
+FUNC is the function, which takes a dissected filename and determines
+whether HANDLER is to be called.  Add operations defined in
+`HANDLER-alist' to `tramp-file-name-handler'."
   (add-to-list
    'tramp-foreign-file-name-handler-alist `(,func . ,handler) append)
   ;; Mark `operations' the handler is responsible for.
@@ -2814,11 +2828,7 @@ tramp-connectable-p
 This is true, if either the remote host is already connected, or if we are
 not in completion mode."
   (let ((tramp-verbose 0)
-	(vec
-	 (cond
-	  ((tramp-file-name-p vec-or-filename) vec-or-filename)
-	  ((tramp-tramp-file-p vec-or-filename)
-	   (tramp-dissect-file-name vec-or-filename)))))
+	(vec (tramp-ensure-dissected-file-name vec-or-filename)))
     (or ;; We check this for the process related to
 	;; `tramp-buffer-name'; otherwise `start-file-process'
 	;; wouldn't run ever when `non-essential' is non-nil.
-- 
2.25.1