Optimize host name completion in Tramp

* lisp/net/tramp-adb.el (tramp-adb-maybe-open-connection):
* lisp/net/tramp-gvfs.el (tramp-gvfs-maybe-open-connection):
* lisp/net/tramp-rclone.el (tramp-rclone-maybe-open-connection):
* lisp/net/tramp-sh.el (tramp-maybe-open-connection):
* lisp/net/tramp-smb.el (tramp-smb-maybe-open-connection):
* lisp/net/tramp-sudoedit.el (tramp-sudoedit-maybe-open-connection):
Throw `non-essential' at the beginning of the function.

* lisp/net/tramp.el (tramp-handle-file-exists-p):
* lisp/net/tramp-sh.el (tramp-sh-handle-file-exists-p):
* lisp/net/tramp-sudoedit.el (tramp-sudoedit-handle-file-exists-p):
Run only when host is connectable.  This is due to host name
completion, which shall be optimized.

* lisp/net/tramp-smb.el (tramp-smb-do-file-attributes-with-stat)
(tramp-smb-get-file-entries): Access connection buffer only after
sending the command.

* lisp/net/tramp.el (tramp-get-buffer, tramp-get-connection-buffer):
New argument DONT-CREATE.
(tramp-message): Use it.
(tramp-get-mutex): Check, whether host is connectable.
(tramp-file-name-handler): Set thread only when host is connectable.
(tramp-connectable-p): Allow also VEC as argument.
(tramp-completion-handle-file-name-completion): Do not expand directory.

7 files changed, 120 insertions, 120 deletions

diff --git a/lisp/net/tramp-adb.el b/lisp/net/tramp-adb.el
index df4778c9c96..982522bdaf4 100644
--- a/lisp/net/tramp-adb.el
+++ b/lisp/net/tramp-adb.el
@@ -1191,6 +1191,10 @@ FMT and ARGS are passed to `error'."
   "Maybe open a connection VEC.
 Does not do anything if a connection is already open, but re-opens the
 connection if a previous connection has died for some reason."
+  ;; During completion, don't reopen a new connection.
+  (unless (tramp-connectable-p vec)
+    (throw 'non-essential 'non-essential))
+
   (let* ((buf (tramp-get-connection-buffer vec))
          (p (get-buffer-process buf))
          (host (tramp-file-name-host vec))
@@ -1204,14 +1208,6 @@ connection if a previous connection has died for some reason."
       (tramp-error vec 'file-error "Cannot switch to user `%s'" user))
 
     (unless (process-live-p p)
-      ;; During completion, don't reopen a new connection.  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.
-      (when (and (tramp-completion-mode-p)
-                 (null (get-process (tramp-buffer-name vec))))
-        (throw 'non-essential 'non-essential))
-
       (save-match-data
         (when (and p (processp p)) (delete-process p))
         (if (zerop (length device))
diff --git a/lisp/net/tramp-gvfs.el b/lisp/net/tramp-gvfs.el
index b9b6b4b6d18..1036865e4ec 100644
--- a/lisp/net/tramp-gvfs.el
+++ b/lisp/net/tramp-gvfs.el
@@ -1787,6 +1787,10 @@ This is relevant for GNOME Online Accounts."
   "Maybe open a connection VEC.
 Does not do anything if a connection is already open, but re-opens the
 connection if a previous connection has died for some reason."
+  ;; During completion, don't reopen a new connection.
+  (unless (tramp-connectable-p vec)
+    (throw 'non-essential 'non-essential))
+
   ;; We set the file name, in case there are incoming D-Bus signals or
   ;; D-Bus errors.
   (setq tramp-gvfs-dbus-event-vector vec)
diff --git a/lisp/net/tramp-rclone.el b/lisp/net/tramp-rclone.el
index 866e7791bf8..1f0c7eadbc5 100644
--- a/lisp/net/tramp-rclone.el
+++ b/lisp/net/tramp-rclone.el
@@ -520,19 +520,14 @@ file names."
   "Maybe open a connection VEC.
 Does not do anything if a connection is already open, but re-opens the
 connection if a previous connection has died for some reason."
+  ;; During completion, don't reopen a new connection.
+  (unless (tramp-connectable-p vec)
+    (throw 'non-essential 'non-essential))
+
   (let ((host (tramp-file-name-host vec)))
     (when (rassoc `(,host) (tramp-rclone-parse-device-names nil))
       (if (zerop (length host))
           (tramp-error vec 'file-error "Storage %s not connected" host))
-
-      ;; During completion, don't reopen a new connection.  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.
-      (when (and (tramp-completion-mode-p)
-                 (null (get-process (tramp-buffer-name vec))))
-        (throw 'non-essential 'non-essential))
-
       ;; We need a process bound to the connection buffer.  Therefore,
       ;; we create a dummy process.  Maybe there is a better solution?
       (unless (get-buffer-process (tramp-get-connection-buffer vec))
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index bcfac78ee65..4bc37f01694 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -1198,18 +1198,22 @@ component is used as the target of the symlink."
 
 (defun tramp-sh-handle-file-exists-p (filename)
   "Like `file-exists-p' for Tramp files."
-  (with-parsed-tramp-file-name filename nil
-    (with-tramp-file-property v localname "file-exists-p"
-      (or (not (null (tramp-get-file-property
-                      v localname "file-attributes-integer" nil)))
-          (not (null (tramp-get-file-property
-                      v localname "file-attributes-string" nil)))
-          (tramp-send-command-and-check
-           v
-           (format
-            "%s %s"
-            (tramp-get-file-exists-command v)
-            (tramp-shell-quote-argument localname)))))))
+  ;; `file-exists-p' is used as predicate in file name completion.
+  ;; We don't want to run it when `non-essential' is t, or there is
+  ;; no connection process yet.
+  (when (tramp-connectable-p filename)
+    (with-parsed-tramp-file-name filename nil
+      (with-tramp-file-property v localname "file-exists-p"
+        (or (not (null (tramp-get-file-property
+                        v localname "file-attributes-integer" nil)))
+            (not (null (tramp-get-file-property
+                        v localname "file-attributes-string" nil)))
+            (tramp-send-command-and-check
+             v
+             (format
+              "%s %s"
+              (tramp-get-file-exists-command v)
+              (tramp-shell-quote-argument localname))))))))
 
 (defun tramp-sh-handle-file-attributes (filename &optional id-format)
   "Like `file-attributes' for Tramp files."
@@ -4762,6 +4766,10 @@ If there is just some editing, retry it after 5 seconds."
   "Maybe open a connection VEC.
 Does not do anything if a connection is already open, but re-opens the
 connection if a previous connection has died for some reason."
+  ;; During completion, don't reopen a new connection.
+  (unless (tramp-connectable-p vec)
+    (throw 'non-essential 'non-essential))
+
   (let ((p (tramp-get-connection-process vec))
         (process-name (tramp-get-connection-property vec "process-name" nil))
         (process-environment (copy-sequence process-environment))
@@ -4806,15 +4814,6 @@ connection if a previous connection has died for some reason."
     ;; New connection must be opened.
     (condition-case err
         (unless (process-live-p p)
-
-          ;; During completion, don't reopen a new connection.  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.
-          (when (and (tramp-completion-mode-p)
-                     (null (get-process (tramp-buffer-name vec))))
-            (throw 'non-essential 'non-essential))
-
           (with-tramp-progress-reporter
               vec 3
               (if (zerop (length (tramp-file-name-user vec)))
diff --git a/lisp/net/tramp-smb.el b/lisp/net/tramp-smb.el
index 5df26a1e33e..b008e6b25eb 100644
--- a/lisp/net/tramp-smb.el
+++ b/lisp/net/tramp-smb.el
@@ -832,12 +832,12 @@ PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are completely ignored."
   "Implement `file-attributes' for Tramp files using stat command."
   (tramp-message
    vec 5 "file attributes with stat: %s" (tramp-file-name-localname vec))
-  (with-current-buffer (tramp-get-connection-buffer vec)
-    (let* (size id link uid gid atime mtime ctime mode inode)
-      (when (tramp-smb-send-command
-             vec (format "stat \"%s\"" (tramp-smb-get-localname vec)))
+  (let* (size id link uid gid atime mtime ctime mode inode)
+    (when (tramp-smb-send-command
+           vec (format "stat \"%s\"" (tramp-smb-get-localname vec)))
 
-        ;; Loop the listing.
+      ;; Loop the listing.
+      (with-current-buffer (tramp-get-connection-buffer vec)
         (goto-char (point-min))
         (unless (re-search-forward tramp-smb-errors nil t)
           (while (not (eobp))
@@ -1628,40 +1628,40 @@ Result is a list of (LOCALNAME MODE SIZE MONTH DAY TIME YEAR)."
   (with-parsed-tramp-file-name (file-name-as-directory directory) nil
     (setq localname (or localname "/"))
     (with-tramp-file-property v localname "file-entries"
-      (with-current-buffer (tramp-get-connection-buffer v)
-        (let* ((share (tramp-smb-get-share v))
-               (cache (tramp-get-connection-property v "share-cache" nil))
-               res entry)
-
-          (if (and (not share) cache)
-              ;; Return cached shares.
-              (setq res cache)
-
-            ;; Read entries.
-            (if share
-                (tramp-smb-send-command
-                 v (format "dir \"%s*\"" (tramp-smb-get-localname v)))
-              ;; `tramp-smb-maybe-open-connection' lists also the share names.
-              (tramp-smb-maybe-open-connection v))
-
-            ;; Loop the listing.
+      (let* ((share (tramp-smb-get-share v))
+             (cache (tramp-get-connection-property v "share-cache" nil))
+             res entry)
+
+        (if (and (not share) cache)
+            ;; Return cached shares.
+            (setq res cache)
+
+          ;; Read entries.
+          (if share
+              (tramp-smb-send-command
+               v (format "dir \"%s*\"" (tramp-smb-get-localname v)))
+            ;; `tramp-smb-maybe-open-connection' lists also the share names.
+            (tramp-smb-maybe-open-connection v))
+
+          ;; Loop the listing.
+          (with-current-buffer (tramp-get-connection-buffer v)
             (goto-char (point-min))
             (if (re-search-forward tramp-smb-errors nil t)
                 (tramp-error v 'file-error "%s `%s'" (match-string 0) directory)
               (while (not (eobp))
                 (setq entry (tramp-smb-read-file-entry share))
                 (forward-line)
-                (when entry (push entry res))))
+                (when entry (push entry res)))))
 
-            ;; Cache share entries.
-            (unless share
-              (tramp-set-connection-property v "share-cache" res)))
+          ;; Cache share entries.
+          (unless share
+            (tramp-set-connection-property v "share-cache" res)))
 
-          ;; Add directory itself.
-          (push '("" "drwxrwxrwx" 0 (0 0)) res)
+        ;; Add directory itself.
+        (push '("" "drwxrwxrwx" 0 (0 0)) res)
 
-          ;; Return entries.
-          (delq nil res))))))
+        ;; Return entries.
+        (delq nil res)))))
 
 ;; Return either a share name (if SHARE is nil), or a file name.
 ;;
@@ -1855,6 +1855,10 @@ Does not do anything if a connection is already open, but re-opens the
 connection if a previous connection has died for some reason.
 If ARGUMENT is non-nil, use it as argument for
 `tramp-smb-winexe-program', and suppress any checks."
+  ;; During completion, don't reopen a new connection.
+  (unless (tramp-connectable-p vec)
+    (throw 'non-essential 'non-essential))
+
   (let* ((share (tramp-smb-get-share vec))
          (buf (tramp-get-connection-buffer vec))
          (p (get-buffer-process buf)))
@@ -1909,15 +1913,6 @@ If ARGUMENT is non-nil, use it as argument for
                      (string-equal
                       share
                       (tramp-get-connection-property p "smb-share" ""))))
-
-      ;; During completion, don't reopen a new connection.  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.
-      (when (and (tramp-completion-mode-p)
-                 (null (get-process (tramp-buffer-name vec))))
-        (throw 'non-essential 'non-essential))
-
       (save-match-data
         ;; There might be unread output from checking for share names.
         (when buf (with-current-buffer buf (erase-buffer)))
diff --git a/lisp/net/tramp-sudoedit.el b/lisp/net/tramp-sudoedit.el
index 80ce8f78747..bfc9b3bdc3a 100644
--- a/lisp/net/tramp-sudoedit.el
+++ b/lisp/net/tramp-sudoedit.el
@@ -424,10 +424,14 @@ the result will be a local, non-Tramp, file name."
 
 (defun tramp-sudoedit-handle-file-exists-p (filename)
   "Like `file-exists-p' for Tramp files."
-  (with-parsed-tramp-file-name filename nil
-    (with-tramp-file-property v localname "file-exists-p"
-      (tramp-sudoedit-send-command
-       v "test" "-e" (tramp-compat-file-name-unquote localname)))))
+  ;; `file-exists-p' is used as predicate in file name completion.
+  ;; We don't want to run it when `non-essential' is t, or there is
+  ;; no connection process yet.
+  (when (tramp-connectable-p filename)
+    (with-parsed-tramp-file-name filename nil
+      (with-tramp-file-property v localname "file-exists-p"
+        (tramp-sudoedit-send-command
+         v "test" "-e" (tramp-compat-file-name-unquote localname))))))
 
 (defun tramp-sudoedit-handle-file-name-all-completions (filename directory)
   "Like `file-name-all-completions' for Tramp files."
@@ -760,18 +764,13 @@ Remove unneeded output."
   "Maybe open a connection VEC.
 Does not do anything if a connection is already open, but re-opens the
 connection if a previous connection has died for some reason."
+  ;; During completion, don't reopen a new connection.
+  (unless (tramp-connectable-p vec)
+    (throw 'non-essential 'non-essential))
+
   ;; We need a process bound to the connection buffer.  Therefore, we
   ;; create a dummy process.  Maybe there is a better solution?
   (unless (tramp-get-connection-process vec)
-
-    ;; During completion, don't reopen a new connection.  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.
-    (when (and (tramp-completion-mode-p)
-               (null (get-process (tramp-buffer-name vec))))
-      (throw 'non-essential 'non-essential))
-
     (let ((p (make-network-process
               :name (tramp-get-connection-name vec)
               :buffer (tramp-get-connection-buffer vec)
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index ed0f1def181..8903d38d20f 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -1566,25 +1566,27 @@ necessary only.  This function will be used in file name completion."
              tramp-postfix-host-format))
           (when localname localname)))
 
-(defun tramp-get-buffer (vec)
+(defun tramp-get-buffer (vec &optional dont-create)
   "Get the connection buffer to be used for VEC."
   (or (get-buffer (tramp-buffer-name vec))
-      (with-current-buffer (get-buffer-create (tramp-buffer-name vec))
-        ;; We use the existence of connection property "process-buffer"
-        ;; as indication, whether a connection is active.
-        (tramp-set-connection-property
-         vec "process-buffer"
-         (tramp-get-connection-property vec "process-buffer" nil))
-        (setq buffer-undo-list t
-              default-directory (tramp-make-tramp-file-name vec 'noloc 'nohop))
-        (current-buffer))))
-
-(defun tramp-get-connection-buffer (vec)
+      (unless dont-create
+        (with-current-buffer (get-buffer-create (tramp-buffer-name vec))
+          ;; We use the existence of connection property "process-buffer"
+          ;; as indication, whether a connection is active.
+          (tramp-set-connection-property
+           vec "process-buffer"
+           (tramp-get-connection-property vec "process-buffer" nil))
+          (setq buffer-undo-list t
+                default-directory
+                (tramp-make-tramp-file-name vec 'noloc 'nohop))
+          (current-buffer)))))
+
+(defun tramp-get-connection-buffer (vec &optional dont-create)
   "Get the connection buffer to be used for VEC.
 In case a second asynchronous communication has been started, it is different
 from `tramp-get-buffer'."
   (or (tramp-get-connection-property vec "process-buffer" nil)
-      (tramp-get-buffer vec)))
+      (tramp-get-buffer vec dont-create)))
 
 (defun tramp-get-connection-name (vec)
   "Get the connection name to be used for VEC.
@@ -1770,14 +1772,15 @@ applicable)."
       ;; Log only when there is a minimum level.
       (when (>= tramp-verbose 4)
         (let ((tramp-verbose 0))
-          ;; Append connection buffer for error messages.
+          ;; Append connection buffer for error messages, if exists.
           (when (= level 1)
-            (with-current-buffer
-                (if (processp vec-or-proc)
-                    (process-buffer vec-or-proc)
-                  (tramp-get-connection-buffer vec-or-proc))
-              (setq fmt-string (concat fmt-string "\n%s")
-                    arguments (append arguments (list (buffer-string))))))
+            (ignore-errors
+              (with-current-buffer
+                  (if (processp vec-or-proc)
+                      (process-buffer vec-or-proc)
+                    (tramp-get-connection-buffer vec-or-proc 'dont-create))
+                (setq fmt-string (concat fmt-string "\n%s")
+                      arguments (append arguments (list (buffer-string)))))))
           ;; Translate proc to vec.
           (when (processp vec-or-proc)
             (setq vec-or-proc (process-get vec-or-proc 'vector))))
@@ -2517,16 +2520,22 @@ Add operations defined in `HANDLER-alist' to `tramp-file-name-handler'."
    ;; This variable has been obsoleted in Emacs 26.
    tramp-completion-mode))
 
-(defun tramp-connectable-p (filename)
+(defun tramp-connectable-p (vec-or-filename)
   "Check, whether it is possible to connect the remote host w/o side-effects.
 This is true, if either the remote host is already connected, or if we are
 not in completion mode."
-  (let (tramp-verbose)
-    (and (tramp-tramp-file-p filename)
-         (or (not (tramp-completion-mode-p))
-             (process-live-p
-              (tramp-get-connection-process
-               (tramp-dissect-file-name filename)))))))
+  (let (tramp-verbose
+        (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)))))
+    (when vec
+      (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.
+          (process-live-p (get-process (tramp-buffer-name vec)))
+          (not (tramp-completion-mode-p))))))
 
 ;; Method, host name and user name completion.
 ;; `tramp-completion-dissect-file-name' returns a list of
@@ -2606,8 +2615,7 @@ not in completion mode."
   (try-completion
    filename
    (mapcar #'list (file-name-all-completions filename directory))
-   (when (and predicate
-              (tramp-connectable-p (expand-file-name filename directory)))
+   (when (and predicate (tramp-connectable-p directory))
      (lambda (x) (funcall predicate (expand-file-name (car x) directory))))))
 
 ;; I misuse a little bit the `tramp-file-name' structure in order to
@@ -3096,7 +3104,11 @@ User is always nil."
 
 (defun tramp-handle-file-exists-p (filename)
   "Like `file-exists-p' for Tramp files."
-  (not (null (file-attributes filename))))
+  ;; `file-exists-p' is used as predicate in file name completion.
+  ;; We don't want to run it when `non-essential' is t, or there is
+  ;; no connection process yet.
+  (when (tramp-connectable-p filename)
+    (not (null (file-attributes filename)))))
 
 (defun tramp-handle-file-in-directory-p (filename directory)
   "Like `file-in-directory-p' for Tramp files."