Make rackedit tolerant when there's no GUI available

README.md

@@ -49,5 +49,16 @@ For example, the window title can be changed before the frame becomes visible:
 The standard File menu does not contain the Exit/Quit command, so closing one
 editor window does not imply exiting the application that opened it.
 
+## Headless environments
+
+Requiring `rackedit` does not initialize Racket's GUI subsystem. This means that
+`(require rackedit)` is safe in a headless Racket process, for example a server
+process without access to an X11 or Wayland display.
+
+The GUI implementation is loaded only when `rkdt` is actually called. Calling
+`rkdt` still requires a usable graphical environment. Programs that also support
+a terminal editor can therefore choose that editor before calling `rkdt`, without
+merely requiring `rackedit` causing GTK initialization.
+
 Full API documentation is included as Scribble documentation in
 `scrbl/rkdt.scrbl`.

info.rkt

@@ -1,7 +1,7 @@
 #lang info
 
 (define pkg-authors '(hnmdijkema))
-(define version "0.1.7")
+(define version "0.1.8")
 (define license 'MIT)   ; 
 (define collection "rackedit")
 (define pkg-desc "rackedit exports the rkdt procedure, that can be used to open an editor window with a given file")

main.rkt

@@ -1,101 +1,17 @@
 #lang racket/base
 
-(require framework
+(require racket/runtime-path)
-         racket/gui/base
-         racket/class
-         simple-ini/class
-         )
-
 (provide rkdt)
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;; Internal stuff
+;; Public interface
+;;
+;; Keep the GUI implementation out of this module.  This allows packages to
+;; require rackedit in a headless environment without initializing GTK.
+;; The GUI is loaded only when rkdt is actually called.
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-(define open-editor-counter 0)
+(define-runtime-path rkdt-gui-path "private/gui.rkt")
-(define open-editor-free-list '())
-(define open-editor-use-list '())
-
-(define ini (new ini% [file 'rackedit]))
-
-(define editor-frame%
-  (frame:text-mixin
-   (frame:editor-mixin
-    (frame:standard-menus-mixin
-     (frame:basic-mixin frame%)))))
-
-(define (make-editor-frame% closed close-cb)
-  (class editor-frame%
-
-    (define my-number -1)
-    (define my-x -1)
-    (define my-y -1)
-    (define my-w -1)
-    (define my-h -1)
-
-    (define/override (on-move x y)
-      (set! my-x x)
-      (set! my-y y)
-      (super on-move x y)
-      )
-
-    (define/override (on-size w h) 
-      (set! my-w w)
-      (set! my-h h)
-      (super on-size w h)
-      )
-
-    (define/override (file-menu:create-quit?)
-      #f)
-
-    (define cb (λ args #t))
-    
-    (define/public (set-frame-cb! frame-cb)
-      (set! cb frame-cb)
-      )
-
-    (define/augment (on-close)
-      (close-cb my-number my-x my-y my-w my-h)
-      (set! open-editor-use-list
-            (filter (λ (x)
-                      (when (= x my-number)
-                        (set! open-editor-free-list
-                              (sort (cons x open-editor-free-list) <)))
-                      (not (= x my-number)))
-                    open-editor-use-list))
-      (semaphore-post closed)
-      (cb 'on-close this)
-      (inner (void) on-close))
-
-    (define/public (get-num)
-      my-number)
-
-    (super-new)
-
-    (begin
-      (if (null? open-editor-free-list)
-          (begin
-            (set! open-editor-counter (+ open-editor-counter 1))
-            (set! my-number open-editor-counter))
-          (begin
-            (set! my-number (car open-editor-free-list))
-            (set! open-editor-free-list (cdr open-editor-free-list))))
-      (set! open-editor-use-list (cons my-number open-editor-use-list))
-      )
-
-    ))
-
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;; Goal: start an editor window for a given file
-;; pre : *
-;; post: editor started
-;; result: An editor window that can be used.
-;;
-;; The editor windows are numbered internally and for each editor
-;; number, a window position x, y, w, h is stored.
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
 
 (define (rkdt [filename #f]
               #:wait?    [wait? #f]
@@ -105,62 +21,13 @@
               #:y        [y 100]
               #:frame-cb [frame-cb (λ (call-time frame) #t)])
 
-  (let* ((store-cfg #f)
+  (define gui-rkdt
-         (closed  (make-semaphore 0))
+    (dynamic-require rkdt-gui-path 'rkdt))
-         (frame (new (make-editor-frame% closed
-                                         (λ (num x y w h) (store-cfg num x y w h)))
-                     [filename (if (eq? filename #f)
-                                   #f
-                                   (format "~a" filename))]
-                     [editor% racket:text%]
-                     [width 900]
-                     [height 650]
-                     [x 100]
-                     [y 100]))
-         (editor (send frame get-editor))
-         (my-num -1)
-         )
-
-    (define (get-win-id num)
-      (letrec ((displ (λ (i n)
-                        (if (= i n)
-                            ""
-                            (let-values (((w h) (get-display-size #:monitor i)))
-                              (string-append
-                               (format "-~a-~a-~a" i w h)
-                               (displ (+ i 1) n)))))))
-        (string->symbol
-         (format "win-~a~a" num (displ 0 (get-display-count))))))
-
-    (set! store-cfg (λ (num x y w h)
-                      (let ((win (get-win-id num)))
-                        (send ini set! 'geoms win (list x y w h)))))
-
-    (send editor set-max-undo-history 100)
-
-    (let* ((win-num (send frame get-num))
-           (geom (send ini get 'geoms
-                       (get-win-id win-num)
-                       (list x y width height))))
-
-      (send frame move (car geom) (cadr geom))
-      (send frame resize (caddr geom) (cadddr geom))
-
-      (send frame set-label (format "~a (~a)"
-                                    (send frame get-label)
-                                    win-num))
-
-      (send frame set-frame-cb! frame-cb)
-      (frame-cb 'before-show frame)
-      (send frame show #t)
-      (frame-cb 'after-show frame)
-
-      (when wait?
-        (frame-cb 'wait-for-close frame)
-        (yield closed)
-        )
-
-      (void))))
-
-
 
+  (gui-rkdt filename
+            #:wait? wait?
+            #:width width
+            #:height height
+            #:x x
+            #:y y
+            #:frame-cb frame-cb))

private/gui.rkt

@@ -0,0 +1,166 @@
+#lang racket/base
+
+(require framework
+         racket/gui/base
+         racket/class
+         simple-ini/class
+         )
+
+(provide rkdt)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Internal stuff
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(define open-editor-counter 0)
+(define open-editor-free-list '())
+(define open-editor-use-list '())
+
+(define ini (new ini% [file 'rackedit]))
+
+(define editor-frame%
+  (frame:text-mixin
+   (frame:editor-mixin
+    (frame:standard-menus-mixin
+     (frame:basic-mixin frame%)))))
+
+(define (make-editor-frame% closed close-cb)
+  (class editor-frame%
+
+    (define my-number -1)
+    (define my-x -1)
+    (define my-y -1)
+    (define my-w -1)
+    (define my-h -1)
+
+    (define/override (on-move x y)
+      (set! my-x x)
+      (set! my-y y)
+      (super on-move x y)
+      )
+
+    (define/override (on-size w h) 
+      (set! my-w w)
+      (set! my-h h)
+      (super on-size w h)
+      )
+
+    (define/override (file-menu:create-quit?)
+      #f)
+
+    (define cb (λ args #t))
+    
+    (define/public (set-frame-cb! frame-cb)
+      (set! cb frame-cb)
+      )
+
+    (define/augment (on-close)
+      (close-cb my-number my-x my-y my-w my-h)
+      (set! open-editor-use-list
+            (filter (λ (x)
+                      (when (= x my-number)
+                        (set! open-editor-free-list
+                              (sort (cons x open-editor-free-list) <)))
+                      (not (= x my-number)))
+                    open-editor-use-list))
+      (semaphore-post closed)
+      (cb 'on-close this)
+      (inner (void) on-close))
+
+    (define/public (get-num)
+      my-number)
+
+    (super-new)
+
+    (begin
+      (if (null? open-editor-free-list)
+          (begin
+            (set! open-editor-counter (+ open-editor-counter 1))
+            (set! my-number open-editor-counter))
+          (begin
+            (set! my-number (car open-editor-free-list))
+            (set! open-editor-free-list (cdr open-editor-free-list))))
+      (set! open-editor-use-list (cons my-number open-editor-use-list))
+      )
+
+    ))
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Goal: start an editor window for a given file
+;; pre : *
+;; post: editor started
+;; result: An editor window that can be used.
+;;
+;; The editor windows are numbered internally and for each editor
+;; number, a window position x, y, w, h is stored.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+
+(define (rkdt [filename #f]
+              #:wait?   [wait? #f]
+              #:width   [width 900]
+              #:height  [height 650]
+              #:x       [x 100]
+              #:y       [y 100]
+              #:frame-cb [frame-cb (λ (call-time frame) #t)])
+
+  (let* ((store-cfg #f)
+         (closed  (make-semaphore 0))
+         (frame (new (make-editor-frame% closed
+                                         (λ (num x y w h) (store-cfg num x y w h)))
+                     [filename (if (eq? filename #f)
+                                   #f
+                                   (format "~a" filename))]
+                     [editor% racket:text%]
+                     [width 900]
+                     [height 650]
+                     [x 100]
+                     [y 100]))
+         (editor (send frame get-editor))
+         (my-num -1)
+         )
+
+    (define (get-win-id num)
+      (letrec ((displ (λ (i n)
+                        (if (= i n)
+                            ""
+                            (let-values (((w h) (get-display-size #:monitor i)))
+                              (string-append
+                               (format "-~a-~a-~a" i w h)
+                               (displ (+ i 1) n)))))))
+        (string->symbol
+         (format "win-~a~a" num (displ 0 (get-display-count))))))
+
+    (set! store-cfg (λ (num x y w h)
+                      (let ((win (get-win-id num)))
+                        (send ini set! 'geoms win (list x y w h)))))
+
+    (send editor set-max-undo-history 100)
+
+    (let* ((win-num (send frame get-num))
+           (geom (send ini get 'geoms
+                       (get-win-id win-num)
+                       (list x y width height))))
+
+      (send frame move (car geom) (cadr geom))
+      (send frame resize (caddr geom) (cadddr geom))
+
+      (send frame set-label (format "~a (~a)"
+                                    (send frame get-label)
+                                    win-num))
+
+      (send frame set-frame-cb! frame-cb)
+      (frame-cb 'before-show frame)
+      (send frame show #t)
+      (frame-cb 'after-show frame)
+
+      (when wait?
+        (frame-cb 'wait-for-close frame)
+        (yield closed)
+        )
+
+      (void))))
+
+
+

scrbl/rkdt.scrbl

@@ -64,6 +64,19 @@ The standard File menu does not contain the @onscreen{Exit} or
 @onscreen{Quit} command. Closing an editor window closes only that window.
 }
 
+@section{Headless environments}
+
+Loading @racketmodname[rackedit] does not initialize Racket's GUI subsystem.
+The GUI implementation is loaded dynamically only when @racket[rkdt] is
+actually called. This allows another package to depend on @tt{rackedit} and to
+be loaded in a headless process without immediately attempting to initialize
+GTK or connect to a graphical display.
+
+Calling @racket[rkdt] itself still requires a usable graphical environment. A
+program that supports both graphical and terminal editors can therefore select
+a terminal editor before calling @racket[rkdt], while safely keeping
+@tt{rackedit} as a dependency.
+
 @section{Frame callback lifecycle}
 
 The procedure supplied with @racket[#:frame-cb] is called as