* net/tramp-cache.el (tramp-cache-data-changed): New defvar.

(tramp-set-connection-property, tramp-flush-connection-property)
(tramp-dump-connection-properties): Use it.

2 files changed, 47 insertions, 34 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index e22d1d8c475..efb33f53d3f 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2008-12-01  Michael Albinus  <michael.albinus@gmx.de>
+
+        * net/tramp-cache.el (tramp-cache-data-changed): New defvar.
+        (tramp-set-connection-property, tramp-flush-connection-property)
+        (tramp-dump-connection-properties): Use it.
+
 2008-11-30  Chong Yidong  <cyd@stupidchicken.com>
 
         * wdired.el (wdired-finish-edit): If displaying a single file,
diff --git a/lisp/net/tramp-cache.el b/lisp/net/tramp-cache.el
index e4218808574..466cd7f5a41 100644
--- a/lisp/net/tramp-cache.el
+++ b/lisp/net/tramp-cache.el
@@ -89,6 +89,9 @@
   :group 'tramp
   :type 'file)
 
+(defvar tramp-cache-data-changed nil
+  "Whether persistent cache data have been changed.")
+
 (defun tramp-get-file-property (vec file property default)
   "Get the PROPERTY of FILE from the cache context of VEC.
 Returns DEFAULT if not set."
@@ -195,6 +198,7 @@ PROPERTY is set persistent when KEY is a vector."
                   (puthash key (make-hash-table :test 'equal)
                             tramp-cache-data))))
     (puthash property value hash)
+    (setq tramp-cache-data-changed t)
     ;; This function is called also during initialization of
     ;; tramp-cache.el.  `tramp-message´ is not defined yet at this
     ;; time, so we ignore the corresponding error.
@@ -211,6 +215,7 @@ KEY identifies the connection, it is either a process or a vector."
   (when (vectorp key)
     (setq key (copy-sequence key))
     (aset key 3 nil))
+  (setq tramp-cache-data-changed t)
   (remhash key tramp-cache-data))
 
 (defun tramp-cache-print (table)
@@ -246,39 +251,40 @@ KEY identifies the connection, it is either a process or a vector."
 (defun tramp-dump-connection-properties ()
   "Write persistent connection properties into file `tramp-persistency-file-name'."
   ;; We shouldn't fail, otherwise (X)Emacs might not be able to be closed.
-  (condition-case nil
-      (when (and (hash-table-p tramp-cache-data)
-                 (not (zerop (hash-table-count tramp-cache-data)))
-                 (stringp tramp-persistency-file-name))
-        (let ((cache (copy-hash-table tramp-cache-data)))
-          ;; Remove temporary data.
-          (maphash
-           '(lambda (key value)
-              (if (and (vectorp key) (not (tramp-file-name-localname key)))
-                  (progn
-                    (remhash "process-name" value)
-                    (remhash "process-buffer" value))
-                (remhash key cache)))
-           cache)
-          ;; Dump it.
-          (with-temp-buffer
-            (insert
-             ";; -*- emacs-lisp -*-"
-             ;; `time-stamp-string' might not exist in all (X)Emacs flavors.
-             (condition-case nil
-                 (progn
-                   (format
-                    " <%s %s>\n"
-                    (time-stamp-string "%02y/%02m/%02d %02H:%02M:%02S")
-                    tramp-persistency-file-name))
-               (error "\n"))
-             ";; Tramp connection history.  Don't change this file.\n"
-             ";; You can delete it, forcing Tramp to reapply the checks.\n\n"
-             (with-output-to-string
-               (pp (read (format "(%s)" (tramp-cache-print cache))))))
-            (write-region
-             (point-min) (point-max) tramp-persistency-file-name))))
-    (error nil)))
+  (when tramp-cache-data-changed
+    (condition-case nil
+        (when (and (hash-table-p tramp-cache-data)
+                   (not (zerop (hash-table-count tramp-cache-data)))
+                   (stringp tramp-persistency-file-name))
+          (let ((cache (copy-hash-table tramp-cache-data)))
+            ;; Remove temporary data.
+            (maphash
+             '(lambda (key value)
+                (if (and (vectorp key) (not (tramp-file-name-localname key)))
+                    (progn
+                      (remhash "process-name" value)
+                      (remhash "process-buffer" value))
+                  (remhash key cache)))
+             cache)
+            ;; Dump it.
+            (with-temp-buffer
+              (insert
+               ";; -*- emacs-lisp -*-"
+               ;; `time-stamp-string' might not exist in all (X)Emacs flavors.
+               (condition-case nil
+                   (progn
+                     (format
+                      " <%s %s>\n"
+                      (time-stamp-string "%02y/%02m/%02d %02H:%02M:%02S")
+                      tramp-persistency-file-name))
+                 (error "\n"))
+               ";; Tramp connection history.  Don't change this file.\n"
+               ";; You can delete it, forcing Tramp to reapply the checks.\n\n"
+               (with-output-to-string
+                 (pp (read (format "(%s)" (tramp-cache-print cache))))))
+              (write-region
+               (point-min) (point-max) tramp-persistency-file-name))))
+      (error nil))))
 
 (add-hook 'kill-emacs-hook 'tramp-dump-connection-properties)
 (add-hook 'tramp-cache-unload-hook
@@ -313,7 +319,8 @@ for all methods.  Resulting data are derived from connection history."
           (while (setq element (pop list))
             (setq key (pop element))
             (while (setq item (pop element))
-              (tramp-set-connection-property key (pop item) (car item))))))
+              (tramp-set-connection-property key (pop item) (car item)))))
+        (setq tramp-cache-data-changed nil))
     (file-error
      ;; Most likely because the file doesn't exist yet.  No message.
      (clrhash tramp-cache-data))