racket/gui: add `application-start-empty-handler'

collects/mred/mred-sig.rkt

@@ -10,6 +10,7 @@ application-about-handler
 application-file-handler
 application-preferences-handler
 application-quit-handler
+application-start-empty-handler
 area-container-window<%>
 area-container<%>
 area<%>

collects/mred/private/app.rkt

@@ -10,6 +10,7 @@
            application-about-handler
            application-quit-handler
            application-file-handler
+           application-start-empty-handler
            current-eventspace-has-standard-menus?
            current-eventspace-has-menu-root?
            eventspace-handler-thread)
@@ -150,6 +151,17 @@
 			values
                         requeue-saved-files))]))
 
+  (define application-start-empty-handler
+    (case-lambda
+     [() (or (and (wx:main-eventspace? (wx:current-eventspace))
+		  (app-handler-orig (wx:application-start-empty-handler)))
+	     void)]
+     [(proc)
+      (set-handler! 'application-start-empty-handler proc
+		    wx:application-start-empty-handler
+		    0
+		    values
+                    void)]))
 
   (define (current-eventspace-has-standard-menus?)
     (and (eq? 'macosx (system-type))

collects/mred/private/kernel.rkt

@@ -38,4 +38,5 @@
          application-file-handler
          application-quit-handler
          application-about-handler
-         application-pref-handler)
+         application-pref-handler
+         application-start-empty-handler)

collects/mred/private/mred.rkt

@@ -272,6 +272,7 @@
 	   application-preferences-handler
 	   application-quit-handler
 	   application-file-handler
+	   application-start-empty-handler
 	   current-eventspace-has-standard-menus?
 	   current-eventspace-has-menu-root?
 	   eventspace-handler-thread

collects/mred/private/wx/cocoa/queue.rkt

@@ -47,6 +47,8 @@
 
 (define app (tell NSApplication sharedApplication))
 
+(define got-file? #f)
+
 (define-objc-class MyApplicationDelegate NSObject #:protocols (NSApplicationDelegate)
   []
   [-a _NSUInteger (applicationShouldTerminate: [_id app])
@@ -72,7 +74,11 @@
           (queue-about-event))
       #t]
   [-a _BOOL (application: [_id theApplication] openFile: [_NSString filename])
+      (set! got-file? #t)
       (queue-file-event (string->path filename))]
+  [-a _void (applicationDidFinishLaunching: [_id notification])
+      (unless got-file?
+        (queue-start-empty-event))]
   [-a _BOOL (applicationShouldHandleReopen: [_id app] hasVisibleWindows: [_BOOL has-visible?])
       ;; If we have any visible windows, return #t to do the default thing.
       ;; Otherwise return #f, because we don't want any invisible windows resurrected.

collects/mred/private/wx/common/handlers.rkt

@@ -2,6 +2,7 @@
 
 (provide
  (protect-out application-file-handler
+              application-start-empty-handler
               application-quit-handler
               application-about-handler
               application-pref-handler
@@ -10,8 +11,15 @@
               nothing-application-about-handler))
 
 (define saved-files null)
-(define afh (lambda (f)
+(define orig-afh (lambda (f)
-              (set! saved-files (cons f saved-files))))
+                   (if (eq? afh orig-afh)
+                       (set! saved-files (cons f saved-files))
+                       ;; handler has changed between time a call here
+                       ;;  was queued and the call happened
+                       (let ([sf (cons f saved-files)])
+                         (set! saved-files null)
+                         (for-each afh (reverse sf))))))
+(define afh orig-afh)
 (define application-file-handler
   (case-lambda
    [(proc) 
@@ -21,6 +29,21 @@
       (for-each proc (reverse sf)))]
    [() afh]))
 
+(define started-empty? #f)
+(define orig-aseh (lambda ()
+                    (if (eq? aseh orig-aseh)
+                        (set! started-empty? #t)
+                        (aseh))))
+(define aseh orig-aseh)
+(define application-start-empty-handler
+  (case-lambda
+   [(proc) 
+    (set! aseh proc)
+    (when started-empty?
+      (set! started-empty? #f)
+      (proc))]
+   [() aseh]))
+
 (define aqh void)
 (define application-quit-handler
   (case-lambda

collects/mred/private/wx/common/queue.rkt

@@ -56,6 +56,7 @@
               queue-prefs-event
               queue-about-event
               queue-file-event
+              queue-start-empty-event
 
               begin-busy-cursor
               end-busy-cursor
@@ -582,6 +583,11 @@
                                  ((application-file-handler) file))
                'med))
 
+(define (queue-start-empty-event)
+  ;; called in event-pump thread
+  (queue-event main-eventspace (application-start-empty-handler)
+               'med))
+
 (define (begin-busy-cursor) 
   (let ([e (current-eventspace)])
     (atomically 

collects/scribblings/gui/system-menu-funcs.scrbl

@@ -53,6 +53,39 @@ or has no effect (when called with a handler).
 
 }
 
+
+@defproc*[([(application-file-handler)
+            (path? . -> . any)]
+           [(application-file-handler [handler-proc (path? . -> . any)])
+            void?])]{
+When the current eventspace is the initial eventspace, this procedure
+ retrieves or installs a procedure that is called on Mac OS X
+ and Windows when the application is running and user double-clicks an
+ application-handled file or drags a file onto the application's
+ icon. The procedure is always called in the initial eventspace's
+ handler thread (as a callback), and the argument is a filename.
+
+The default handler queues a callback to the
+@method[window<%> on-drop-file] method of the most-recently activated frame in the main eventspace (see
+@racket[get-top-level-edit-target-window]), if
+ drag-and-drop is enabled for that frame. Otherwise, it saves
+ the filename and re-queues the handler event when the application
+ file handler is later changed.
+
+On Windows, when the application is @italic{not} running and user double-clicks an
+ application-handled file or drags a file onto the application's icon,
+ the filename is provided as a command-line argument to the
+ application.
+
+On Mac OS X, if an application is started @emph{without} files, then
+ the @racket[application-start-empty-handler] procedure is called.
+
+If the current eventspace is not the initial eventspace, this
+procedure returns @racket[void] (when called with zero arguments)
+or has no effect (when called with a handler).
+}
+
+
 @defproc*[([(application-preferences-handler)
             (or/c (-> any) false/c)]
            [(application-preferences-handler [handler-thunk (or/c (-> any) false/c)])
@@ -99,28 +132,22 @@ procedure returns @racket[void] (when called with zero arguments)
 or has no effect (when called with a handler).
 }
 
-@defproc*[([(application-file-handler)
+
-            (path? . -> . any)]
+@defproc*[([(application-start-empty-handler)
-           [(application-file-handler [handler-proc (path? . -> . any)])
+            (-> any)]
+           [(application-start-empty-handler [handler-thunk (-> any)])
             void?])]{
 When the current eventspace is the initial eventspace, this procedure
- retrieves or installs a procedure that is called on Mac OS X
+ retrieves or installs a thunk that is called when the user starts
- and Windows when the application is running and user double-clicks an
+ the application on Mac OS X without supplying any initial files (e.g.,
- application-handled file or drags a file onto the application's
+ by double-clicking the application icon instead of double-clicking
- icon. The procedure is always called in the initial eventspace's
+ files that are handled by the application).
- handler thread (as a callback), and the argument is a filename.
 
-The default handler queues a callback to the
+The default handler re-queues the handler event when the application
-@method[window<%> on-drop-file] method of the most-recently activated frame in the main eventspace (see
+ start-empty handler is later changed. As a result, if an application
-@racket[get-top-level-edit-target-window]), if
+ sets both @racket[application-start-empty-handler] and
- drag-and-drop is enabled for that frame. Otherwise, it saves
+ @racket[application-file-handler], then one or the other is
- the filename and re-queues the handler event when the application
+ eventually called.
- file handler is later changed.
-
-When the application is @italic{not} running and user double-clicks an
- application-handled file or drags a file onto the application's icon,
- the filename is provided as a command-line argument to the
- application.
 
 If the current eventspace is not the initial eventspace, this
 procedure returns @racket[void] (when called with zero arguments)