`twittering-get-first-status-head' returns nil if no statuses exist.

* twittering-mode.el (twittering-get-first-status-head): return
nil if no statuses are rendered in the current buffer.
(twittering-goto-first-status): go to the beginning of buffer if
no statuses are rendered in the current buffer.
(twittering-render-timeline): render tweets from the beginning of
buffer if no statuses are rendered.

ChangeLog

@@ -1,8 +1,17 @@
+2010-02-16  Tadashi MATSUO  <tad@mymail.twin.jp>
+
+	* twittering-mode.el (twittering-get-first-status-head): return
+	nil if no statuses are rendered in the current buffer.
+	(twittering-goto-first-status): go to the beginning of buffer if
+	no statuses are rendered in the current buffer.
+	(twittering-render-timeline): render tweets from the beginning of
+	buffer if no statuses are rendered.
+
 2010-02-15  Satoshi Yatagawa  <yata_github@y.hauN.org>
 
 	* twittering-mode.el (twittering-http-get-list-index-sentinel):
 	Get a listname from `slug' element which is only in `list' node.
-	
+
 2010-02-15  Tadashi MATSUO  <tad@mymail.twin.jp>
 
 	* twittering-mode.el (twittering-get-and-render-timeline): copy

twittering-mode.el

@@ -2154,6 +2154,7 @@ BUFFER may be a buffer or the name of an existing buffer."
   (with-current-buffer (twittering-buffer)
     (let* ((timeline-data (or timeline-data
 			      (twittering-current-timeline-data)))
+	   (empty (null (twittering-get-first-status-head)))
 	   (window-list (get-buffer-window-list (current-buffer) nil t))
 	   (point-window-list
 	    (mapcar (lambda (window)
@@ -2165,7 +2166,9 @@ BUFFER may be a buffer or the name of an existing buffer."
       (save-excursion
 	(unless additional
 	  (erase-buffer))
-	(let ((pos (twittering-get-first-status-head)))
+	(let ((pos (if empty
+		       (point-min)
+		     (twittering-get-first-status-head))))
 	  (mapc
 	   (lambda (status)
 	     (let* ((id (cdr (assoc 'id status))))
@@ -3153,14 +3156,15 @@ variable `twittering-status-format'."
 (defun twittering-goto-first-status ()
   "Go to the first status."
   (interactive)
-  (goto-char (twittering-get-first-status-head)))
+  (goto-char (or (twittering-get-first-status-head)
+		 (point-min))))
 
 (defun twittering-get-first-status-head ()
+  "Return the head position of the first status in the current buffer.
+Return nil if no statuses are rendered."
   (if (get-text-property (point-min) 'id)
       (point-min)
-    (or (twittering-get-next-status-head (point-min))
-	;; The current buffer is empty.
-	(point-min))))
+    (twittering-get-next-status-head (point-min))))
 
 (defun twittering-goto-next-status ()
   "Go to next status."