+ Add code to remove forgotten temporary file.

+ Add note about time of profiling.
+ Don't show profiling pictures anymore. The server can't show them anyway.
Instead provide a link to the pbm file.

scheme/httpd/surflets/web-server/root/surflets/admin-profiling.scm

@@ -50,11 +50,12 @@
 		   (title "Servlet Administration -- Profiling")
 		   (body (h1 "Serlvet Administration")
 			 (h2 "Profiling")
+			 (p "Note: The operations performable via this interface take a while depending on the speed of the machine the server is running. Please be patient.")
 			 (font (@ (color "red")) ,update-text)
 			 (p "Currently, there are " ,(state-counter) " profiles saved.")
 			 (ul
 			  (li (URL ,(new-profile-address new-url)
-				   "Create new profile")
+				   "Create new profile"))
 			  (li (URL ,(result-address new-url)
 				   "Show profile results")
 			      (br)
@@ -64,7 +65,7 @@
 			       (p "This uses " (var "gnuplot") " that is searched at "
 				  ,input-field ,change-button)))
 			  (li (URL ,(reset-address new-url)
-				   "Delete files and reset profile state."))))
+				   "Delete files and reset profile state.")))
 			 (hr)
 			 (URL ,(return-address new-url) 
 			      "Return to administration menu leaving files and state untouched.")
@@ -109,8 +110,8 @@
     (define (result req)
       (let ((results (profile-results (state-file-name)))
 	    (gnuplot-data-file-name (create-temp-file "servlet-profiling.data"))
-	    (picture-file (string-append (create-temp-file 
-					  "../img/servlet-profiling.picture")
+	    (picture-file-name (create-empty-picture-file 
+				"../img/servlet-profiling.picture"
 				".pbm"))
 	    (get-total-bytes (lambda (space-info)
 			       (total-bytes (space-info-total space-info))))
@@ -125,13 +126,14 @@
 set output '~a'
 set size 0.7,0.7
 plot '~a' title 'Servlet Profiling ~a' with lines"
-				 picture-file
+				 picture-file-name
 				 gnuplot-data-file-name
 				 (format-date "~c" (date))
 				 )))))
+
 	  (delete-file gnuplot-data-file-name)
-	  (add-file-name-to-delete! picture-file)
-	  (let* ((req (show-results status picture-file get-total-bytes results 
+	  (add-file-name-to-delete! picture-file-name)
+	  (let* ((req (show-results status picture-file-name get-total-bytes results 
 				    return-address reset-return-address))
 		 (bindings (get-bindings req)))
 	    (cond
@@ -142,6 +144,16 @@ plot '~a' title 'Servlet Profiling ~a' with lines"
 	     (else
 	      (error "unexpected return address")))))))
 
+    (define create-empty-picture-file
+      (let ((lock (make-lock)))
+	(lambda (file-prefix file-suffix)
+	  (obtain-lock lock)
+	  (let* ((tmp-file-name  (create-temp-file  file-prefix))
+		 (picture-file-name (string-append tmp-file-name file-suffix)))
+	    (rename-file tmp-file-name picture-file-name)
+	    (release-lock lock)
+	    picture-file-name))))
+    
     (define (show-results status picture-file get-total-bytes results
 			  return-address reset-return-address)
       (send-html/suspend
@@ -152,8 +164,10 @@ plot '~a' title 'Servlet Profiling ~a' with lines"
 	    (h1 "Servlet-Administration")
 	    (h2 "Profiling Results")
 	    (h3 "Picture")
+	    (p "Note: The picture cannot be shown by your browser, currently. This will be fixed.")
 	    ,(if (zero? status)
-		 `(image (@ (src ,picture-file)))
+;		 `(image (@ (src ,picture-file)))
+		 `(URL ,picture-file "Profiling datagram.")
 		 `(p "An error occured while generating the profiling results picture."
 		     (br)
 		     "Are you sure, you have " (q "gnuplot")