Fixed massive bug introduced by new caching system.

Since the old caching system associated with nodes rather than
addresses, it was never possible to encounter cached pages generated
by other parts of the hierarchy.  With the new cached content being
associated with _addresses_, this became possible.  Since any nodes
referenced by that content already had parents pointing to that other
part of the hierarchy, this led to confusing behaviour when navigating
to parent nodes - these would be the "old" parents, not the new ones!

To address this, node parents are now set every time they are
visited (unless they are visited from below).

diff --git a/elpher.el b/elpher.el
index 4b08a50..56ab5e8 100644 (file)
--- a/elpher.el
+++ b/elpher.el
@@ -225,27 +225,35 @@ special address types, such as 'start for the start page."
 
 ;; Node
 
-(defun elpher-make-node (display-string parent address)
+(defun elpher-make-node (display-string address &optional parent)
   "Create a node in the gopher page hierarchy.
 
 DISPLAY-STRING records the display string used for the page.
 
-PARENT specifies the parent of the node, and ADDRESS specifies the
-address of the gopher page."
-  (list display-string parent address))
+ADDRESS specifies the address of the gopher page.
+
+The optional PARENT specifies the parent node in the hierarchy.
+This is set every time the node is visited, so while it forms
+an important part of the node data there is no need to set it
+initially."
+  (list display-string address parent))
 
 (defun elpher-node-display-string (node)
   "Retrieve the display string of NODE."
   (elt node 0))
 
-(defun elpher-node-parent (node)
-  "Retrieve the parent node of NODE."
-  (elt node 1))
-
 (defun elpher-node-address (node)
   "Retrieve the address of NODE."
+  (elt node 1))
+
+(defun elpher-node-parent (node)
+  "Retrieve the parent node of NODE."
   (elt node 2))
 
+(defun elpher-set-node-parent (node parent)
+  "Set the parent node of NODE to be PARENT."
+  (setcar (cdr (cdr node)) parent))
+
 ;; Cache
 
 (defvar elpher-content-cache (make-hash-table :test 'equal))
@@ -275,6 +283,8 @@ address of the gopher page."
   "Visit NODE using its own getter or GETTER, if non-nil."
   (elpher-save-pos)
   (elpher-process-cleanup)
+  (unless (eq node (elpher-node-parent elpher-current-node))
+      (elpher-set-node-parent node elpher-current-node))
   (setq elpher-current-node node)
   (if getter
       (funcall getter)
@@ -382,7 +392,7 @@ and PORT."
     (if type-map-entry
         (let* ((margin-code (elt type-map-entry 1))
                (face (elt type-map-entry 2))
-               (node (elpher-make-node display-string elpher-current-node address)))
+               (node (elpher-make-node display-string address)))
           (elpher-insert-margin margin-code)
           (insert-text-button display-string
                               'face face
@@ -471,11 +481,9 @@ The result is stored as a string in the variable ‘elpher-selector-string’."
   "\\([a-zA-Z]+\\)://\\([a-zA-Z0-9.\-]+\\)\\(?3::[0-9]+\\)?\\(?4:/[^ \r\n\t(),]*\\)?"
   "Regexp used to locate and buttinofy URLs in text files loaded by elpher.")
 
-(defun elpher-make-node-from-matched-url (parent &optional string)
+(defun elpher-make-node-from-matched-url (&optional string)
   "Convert most recent `elpher-url-regex' match to a node.
 
-PARENT defines the node to set as the parent to the new node.
-
 If STRING is non-nil, this is given as an argument to all `match-string'
 calls, as is necessary if the match is performed by `string-match'."
   (let ((url (match-string 0 string))
@@ -493,14 +501,14 @@ calls, as is necessary if the match is performed by `string-match'."
                              (substring type-and-selector 2)
                            ""))
                (address (elpher-make-address type selector host port)))
-          (elpher-make-node url elpher-current-node address))
+          (elpher-make-node url address))
       (let* ((host (match-string 2 string))
              (port (if (> (length (match-string 3 string)) 1)
                        (string-to-number (substring (match-string 3 string) 1))
                      70))
              (selector (concat "URL:" url))
              (address (elpher-make-address ?h selector host port)))
-        (elpher-make-node url elpher-current-node address)))))
+        (elpher-make-node url address)))))
 
 
 (defun elpher-buttonify-urls (string)
@@ -509,7 +517,7 @@ calls, as is necessary if the match is performed by `string-match'."
     (insert string)
     (goto-char (point-min))
     (while (re-search-forward elpher-url-regex nil t)
-        (let ((node (elpher-make-node-from-matched-url elpher-current-node)))
+        (let ((node (elpher-make-node-from-matched-url)))
           (make-text-button (match-beginning 0)
                             (match-end 0)
                             'elpher-node  node
@@ -820,14 +828,12 @@ host, selector and port."
   (let ((node
          (let ((host-or-url (read-string "Gopher host or URL: ")))
            (if (string-match elpher-url-regex host-or-url)
-               (elpher-make-node-from-matched-url elpher-current-node
-                                                  host-or-url)
+               (elpher-make-node-from-matched-url host-or-url)
              (let ((selector (read-string "Selector (default none): " nil nil ""))
                    (port-string (read-string "Port (default 70): " nil nil "70")))
                (elpher-make-node (concat "gopher://" host-or-url
                                          ":" port-string
                                          "/1" selector)
-                                 elpher-current-node
                                  (elpher-make-address ?1 selector host-or-url
                                                       (string-to-number port-string))))))))
     (switch-to-buffer "*elpher*")
@@ -913,7 +919,6 @@ host, selector and port."
                  (elpher-make-node (concat "gopher://" host
                                            ":" (number-to-string port)
                                            "/1/")
-                                   elpher-current-node
                                    root-address)))
             (error "Already at root directory of current server")))
       (error "Command invalid for this page"))))
@@ -974,9 +979,7 @@ host, selector and port."
   (interactive)
   (switch-to-buffer "*elpher*")
   (elpher-visit-node
-   (elpher-make-node "Bookmarks"
-                     elpher-current-node
-                     (elpher-make-address 'bookmarks))))
+   (elpher-make-node "Bookmarks" (elpher-make-address 'bookmarks))))
 
 (defun elpher-info-node (node)
   "Display information on NODE."
@@ -1101,7 +1104,8 @@ host, selector and port."
       (switch-to-buffer "*elpher*")
     (switch-to-buffer "*elpher*")
     (setq elpher-current-node nil)
-    (let ((start-node (elpher-make-node "Elpher Start Page" nil (elpher-make-address 'start))))
+    (let ((start-node (elpher-make-node "Elpher Start Page"
+                                        (elpher-make-address 'start))))
       (elpher-visit-node start-node)))
   "Started Elpher.") ; Otherwise (elpher) evaluates to start page string.