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

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

diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 1008897d9ea8de9e62c142902586bcdf2b892edd..be6900766cbf35fc99c42ee258f2e376fe0963bc 100644 (file)
--- 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)))))