* net/tramp.el (tramp-mode): New defcustom.

(tramp-file-name-handler, tramp-completion-file-name-handler): Use
it.
(tramp-replace-environment-variables): Handle "$$".

1 files changed, 42 insertions, 27 deletions

diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 1008897d9ea..be6900766cb 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -150,6 +150,14 @@
   :group 'files
   :version "22.1")
 
+;; Maybe we need once a real Tramp mode, with key bindings etc.
+;;;###autoload
+(defcustom tramp-mode t
+  "*Whether Tramp is enabled.
+If it is set to nil, all remote file names are used literally."
+  :group 'tramp
+  :type 'boolean)
+
 (defcustom tramp-verbose 3
   "*Verbosity level for Tramp.
 Any level x includes messages for all levels 1 .. x-1.  The levels are
@@ -3574,12 +3582,15 @@ the result will be a local, non-Tramp, filename."
 (defun tramp-replace-environment-variables (filename)
   "Replace environment variables in FILENAME.
 Return the string with the replaced variables."
-  (when (string-match "$\\w+" filename)
-    (setq filename
-          (replace-match
-           (substitute-in-file-name (match-string 0 filename))
-           t nil filename)))
-  filename)
+  (save-match-data
+    (let ((idx (string-match "$\\w+" filename)))
+      ;; `$' is coded as `$$'.
+      (when (and idx (or (zerop idx) (not (eq ?$ (aref filename (1- idx))))))
+        (setq filename
+              (replace-match
+               (substitute-in-file-name (match-string 0 filename))
+               t nil filename)))
+      filename)))
 
 (defun tramp-handle-substitute-in-file-name (filename)
   "Like `substitute-in-file-name' for Tramp files.
@@ -4486,26 +4497,29 @@ ARGS are the arguments OPERATION has been called with."
 (defun tramp-file-name-handler (operation &rest args)
   "Invoke Tramp file name handler.
 Falls back to normal file name handler if no Tramp file name handler exists."
-  (save-match-data
-    (let* ((filename
-            (tramp-replace-environment-variables
-             (apply 'tramp-file-name-for-operation operation args)))
-           (completion (tramp-completion-mode-p))
-           (foreign (tramp-find-foreign-file-name-handler filename)))
-      (with-parsed-tramp-file-name filename nil
-        (cond
-         ;; When we are in completion mode, some operations shouldn't be
-         ;; handled by backend.
-         ((and completion (zerop (length localname))
-               (memq operation '(file-exists-p file-directory-p)))
-          t)
-         ((and completion (zerop (length localname))
-               (memq operation '(file-name-as-directory)))
-          filename)
-         ;; Call the backend function.
-         (foreign (apply foreign operation args))
-         ;; Nothing to do for us.
-         (t (tramp-run-real-handler operation args)))))))
+  (if tramp-mode
+      (save-match-data
+        (let* ((filename
+                (tramp-replace-environment-variables
+                 (apply 'tramp-file-name-for-operation operation args)))
+               (completion (tramp-completion-mode-p))
+               (foreign (tramp-find-foreign-file-name-handler filename)))
+          (with-parsed-tramp-file-name filename nil
+            (cond
+             ;; When we are in completion mode, some operations
+             ;; shouldn't be handled by backend.
+             ((and completion (zerop (length localname))
+                   (memq operation '(file-exists-p file-directory-p)))
+              t)
+             ((and completion (zerop (length localname))
+                   (memq operation '(file-name-as-directory)))
+              filename)
+             ;; Call the backend function.
+             (foreign (apply foreign operation args))
+             ;; Nothing to do for us.
+             (t (tramp-run-real-handler operation args))))))
+    ;; When `tramp-mode' is not enabled, we don't do anything.
+    (tramp-run-real-handler operation args)))
 
 ;; In Emacs, there is some concurrency due to timers.  If a timer
 ;; interrupts Tramp and wishes to use the same connection buffer as
@@ -4559,7 +4573,8 @@ Falls back to normal file name handler if no Tramp file name handler exists."
   ;; would otherwise use backslash.
   (let ((directory-sep-char ?/)
         (fn (assoc operation tramp-completion-file-name-handler-alist)))
-    (if fn
+    ;; When `tramp-mode' is not enabled, we don't do anything.
+    (if (and fn tramp-mode)
         (save-match-data (apply (cdr fn) args))
       (tramp-completion-run-real-handler operation args)))))