make-launcher.rkt

#lang racket/base


;; copy of launcher/launcher since it has a bug in 5.1.1.
;; The bug's fixed in later versions of Racket, but my local machine still
;; has 5.1.1.  As soon as I switch over, this module will lose
;; its meaning.


(require scheme/path
         scheme/file
         scheme/list
         scheme/string

         compiler/embed
         setup/dirs
         setup/variant

         compiler/private/winutf16)


(define current-launcher-variant
  (make-parameter (system-type 'gc)
                  (lambda (v)
                    (unless (memq v '(3m script-3m cgc script-cgc))
                      (raise-type-error
                       'current-launcher-variant
                       "variant symbol"
                       v))
                    v)))

(define (variant-available? kind cased-kind-name variant)
  (cond
   [(or (eq? 'unix (system-type))
        (and (eq? 'macosx (system-type))
             (eq? kind 'mzscheme)))
    (let ([bin-dir (find-console-bin-dir)])
      (and bin-dir
           (file-exists?
            (build-path bin-dir
                        (format "~a~a" 
                                (case kind 
                                  [(mzscheme) 'racket]
                                  [(mred) 'gracket])
                                (variant-suffix variant #f))))))]
   [(eq? 'macosx (system-type))
    ;; kind must be mred, because mzscheme case is caught above
    (directory-exists? (build-path (find-gui-bin-dir)
                                   (format "~a~a.app"
                                           cased-kind-name
                                           (variant-suffix variant #f))))]
   [(eq? 'windows (system-type))
    (file-exists?
     (build-path
      (if (eq? kind 'mzscheme) (find-console-bin-dir) (find-gui-bin-dir))
      (format "~a~a.exe" cased-kind-name (variant-suffix variant #t))))]
   [else (error "unknown system type")]))

(define (available-variants kind)
  (let* ([cased-kind-name (if (eq? kind 'mzscheme)
                              "Racket"
                              "GRacket")]
         [normal-kind (system-type 'gc)]
         [alt-kind (if (eq? '3m normal-kind)
                       'cgc
                       '3m)]
         [normal (if (variant-available? kind cased-kind-name normal-kind)
                     (list normal-kind)
                     null)]
         [alt (if (variant-available? kind cased-kind-name alt-kind)
                  (list alt-kind)
                  null)]
         [script (if (and (eq? 'macosx (system-type))
                          (eq? kind 'mred)
                          (pair? normal))
                     (if (eq? normal-kind '3m)
                         '(script-3m)
                         '(script-cgc))
                     null)]
         [script-alt (if (and (memq alt-kind alt)
                              (pair? script))
                         (if (eq? alt-kind '3m)
                             '(script-3m)
                             '(script-cgc))
                         null)])
    (append normal alt script script-alt)))

(define (available-gracket-variants)
  (available-variants 'mred))
(define (available-mred-variants)
  (available-variants 'mred))

(define (available-racket-variants)
  (available-variants 'mzscheme))
(define (available-mzscheme-variants)
  (available-variants 'mzscheme))

(define (install-template dest kind mz mr)
  (define src (build-path (collection-path "launcher")
                          (if (eq? kind 'mzscheme) mz mr)))
  (when (or (file-exists? dest)
            (directory-exists? dest)
            (link-exists? dest))
    (delete-directory/files dest))
  (copy-file src dest)
  ;; Make sure we can write.
  (file-or-directory-permissions dest
                                 (bitwise-ior
                                  (file-or-directory-permissions dest 'bits)
                                  user-write-bit)))

(define (script-variant? v)
  (memq v '(script-3m script-cgc)))

(define (add-file-suffix path variant mred?)
  (let ([s (variant-suffix
            variant
            (case (system-type)
              [(unix) #f]
              [(windows) #t]
              [(macosx) (and mred? (not (script-variant? variant)))]))])
    (if (string=? "" s)
      path
      (path-replace-suffix
       path
       (string->bytes/utf-8
        (if (and (eq? 'windows (system-type))
                 (regexp-match #rx#"[.]exe$" (path->bytes path)))
          (format "~a.exe" s)
          s))))))

(define (string-append/spaces f flags)
  (string-append* (append-map (lambda (x) (list (f x) " ")) flags)))

(define (str-list->sh-str flags)
  (string-append/spaces
   (lambda (s)
     (string-append "'" (regexp-replace* #rx"'" s "'\"'\"'") "'"))
   flags))

(define (str-list->dos-str flags)
  (define (trans s)
    (if (not (regexp-match? #rx"[ \n\t\r\v\"\\]" s))
      s
      (list->string
       (let loop ([l (string->list s)] [slashes '()])
         (cond [(null? l) '()]
               [(char-whitespace? (car l))
                `(,@slashes #\" ,(car l) #\" ,@(loop (cdr l) '()))]
               [(eq? #\\ (car l))
                `(#\\ ,@(loop (cdr l) (cons #\\ slashes)))]
               [(eq? #\" (car l))
                `(,@slashes #\" #\\ #\" #\" ,@(loop (cdr l) '()))]
               [else `(,(car l) ,@(loop (cdr l) '()))])))))
  (string-append/spaces trans flags))

(define one-arg-x-flags '((xa "-display")
                          (xb "-geometry")
                          (xc "-bg" "-background")
                          (xd "-fg" "-foregound")
                          (xe "-font")
                          (xf "-name")
                          (xg "-selectionTimeout")
                          (xh "-title")
                          (xi "-xnllanguage")
                          (xj "-xrm")))
(define no-arg-x-flags '((xk "-iconic")
                         (xl "-rv" "-reverse")
                         (xm "+rv")
                         (xn "-synchronous")
                         (xo "-singleInstance")))

(define (skip-x-flags flags)
  (let ([xfmem (lambda (flag) (lambda (xf) (member flag (cdr xf))))])
    (let loop ([f flags])
      (cond [(null? f) null]
            [(ormap (xfmem (car f)) one-arg-x-flags)
             (if (null? (cdr f)) null (loop (cddr f)))]
            [(ormap (xfmem (car f)) no-arg-x-flags) (loop (cdr f))]
            [else f]))))

(define (output-x-arg-getter exec args)
  (let ([or-flags (lambda (l) (string-append* (add-between l " | ")))])
    (string-append*
     (append
      (list "# Find X flags and shift them to the front\n"
            "findxend() {\n"
            " oneargflag=''\n"
            " case \"$1\" in\n")
      (map
       (lambda (f)
         (format (string-append
                  "  ~a)\n"
                  "     oneargflag=\"$1\"\n"
                  "     ~a=\"$2\"\n"
                  "   ;;\n")
                 (or-flags (cdr f))
                 (car f)))
       one-arg-x-flags)
      (map
       (lambda (f)
         (format "  ~a)\n    ~a=yes\n  ;;\n" (or-flags (cdr f)) (car f)))
       no-arg-x-flags)
      (list
       (format (string-append
                "  *)\n    ~a~a ~a  ;;\n"
                " esac\n"
                " shift\n"
                " if [ \"$oneargflag\" != '' ] ; then\n"
                "   if [ \"${1+n}\" != 'n' ] ; then echo $0: missing argument for standard X flag $oneargflag ; exit 1 ; fi\n"
                "   shift\n"
                " fi\n"
                " findxend ${1+\"$@\"}\n"
                "}\nfindxend ${1+\"$@\"}\n")
               exec
               (string-append*
                (append
                 (map (lambda (f)
                        (format " ${~a+\"~a\"} ${~a+\"$~a\"}"
                                (car f) (cadr f) (car f) (car f)))
                      one-arg-x-flags)
                 (map (lambda (f)
                        (format " ${~a+\"~a\"}" (car f) (cadr f)))
                      no-arg-x-flags)))
               args))))))

(define (protect-shell-string s)
  (regexp-replace*
   #rx"[\"`'$\\]" (if (path? s) (path->string s) s) "\\\\&"))

(define (normalize+explode-path p)
  (explode-path (normal-case-path (simple-form-path p))))

(define (relativize bindir-explode dest-explode)
  (let loop ([b bindir-explode] [d dest-explode])
    (if (and (pair? b) (equal? (car b) (car d)))
      (loop (cdr b) (cdr d))
      (let ([p (append (map (lambda (x) 'up) (cdr d)) b)])
        (if (null? p) #f (apply build-path p))))))

(define (make-relative-path-header dest bindir)
  ;; rely only on binaries in /usr/bin:/bin
  (define (has-exe? exe)
    (or (file-exists? (build-path "/usr/bin" exe))
        (file-exists? (build-path "/bin" exe))))
  (let* ([has-readlink?  (and (not (eq? 'macosx (system-type)))
                              (has-exe? "readlink"))]
         [dest-explode   (normalize+explode-path dest)]
         [bindir-explode (normalize+explode-path bindir)])
    (if (and (has-exe? "dirname") (has-exe? "basename")
             (or has-readlink? (and (has-exe? "ls") (has-exe? "sed")))
             (equal? (car dest-explode) (car bindir-explode)))
        (string-append
         "# Make this PATH-independent\n"
         "saveP=\"$PATH\"\n"
         "PATH=\"/usr/bin:/bin\"\n"
         "\n"
         (if has-readlink? ""
             (string-append
              "# imitate possibly-missing readlink\n"
              "readlink() {\n"
              "  ls -l -- \"$1\" | sed -e \"s/^.* -> //\"\n"
              "}\n"
              "\n"))
         "# Remember current directory\n"
         "saveD=`pwd`\n"
         "\n"
         "# Find absolute path to this script,\n"
         "# resolving symbolic references to the end\n"
         "# (changes the current directory):\n"
         "D=`dirname \"$0\"`\n"
         "F=`basename \"$0\"`\n"
         "cd \"$D\"\n"
         "while test "
         ;; On solaris, Edward Chrzanowski from Waterloo says that the man
         ;; page says that -L is not supported, but -h is; on other systems
         ;; (eg, freebsd) -h is listed as a compatibility feature
         (if (regexp-match #rx"solaris" (path->string
                                         (system-library-subpath)))
             "-h" "-L")
         " \"$F\"; do\n"
         "  P=`readlink \"$F\"`\n"
         "  D=`dirname \"$P\"`\n"
         "  F=`basename \"$P\"`\n"
         "  cd \"$D\"\n"
         "done\n"
         "D=`pwd`\n"
         "\n"
         "# Restore current directory\n"
         "cd \"$saveD\"\n"
         "\n"
         "bindir=\"$D"
         (let ([s (relativize bindir-explode dest-explode)])
           (if s (string-append "/" (protect-shell-string s)) ""))
         "\"\n"
         "PATH=\"$saveP\"\n")
        ;; fallback to absolute path header
        (make-absolute-path-header bindir))))

(define (make-absolute-path-header bindir)
  (string-append "bindir=\""(protect-shell-string bindir)"\"\n"))

(define (make-unix-launcher kind variant flags dest aux)
  (install-template dest kind "sh" "sh") ; just for something that's executable
  (let* ([alt-exe (let ([m (and (eq? kind 'mred)
                                (script-variant? variant)
                                (assq 'exe-name aux))])
                    (and m
                         (format "~a~a.app/Contents/MacOS/~a~a"
                                 (cdr m) (variant-suffix variant #t)
                                 (cdr m) (variant-suffix variant #t))))]
         [x-flags? (and (eq? kind 'mred)
                        (eq? (system-type) 'unix)
                        (not (script-variant? variant)))]
         [post-flags (cond
                      [x-flags? (skip-x-flags flags)]
                      [alt-exe null]
                      [else flags])]
         [pre-flags (cond
                     [(not x-flags?) null]
                     [else
                      (let loop ([f flags])
                        (if (eq? f post-flags)
                            null
                            (cons (car f) (loop (cdr f)))))])]
         [pre-str (str-list->sh-str pre-flags)]
         [post-str (str-list->sh-str post-flags)]
         [header (string-append
                  "#!/bin/sh\n"
                  "# This script was created by make-"
                  (symbol->string kind)"-launcher\n")]
         [dir-finder
          (let ([bindir (if alt-exe
                            (find-gui-bin-dir)
                            (find-console-bin-dir))])
            (if (let ([a (assq 'relative? aux)])
                  (and a (cdr a)))
                (make-relative-path-header dest bindir)
                (make-absolute-path-header bindir)))]
         [exec (format
                "exec \"${bindir}/~a~a\" ~a"
                (or alt-exe (case kind
                              [(mred) "gracket"]
                              [(mzscheme) "racket"]))
                (if alt-exe "" (variant-suffix variant #f))
                pre-str)]
         [args (format
                "~a~a ${1+\"$@\"}\n"
                (if alt-exe "" "-N \"$0\" ")
                post-str)]
         [assemble-exec (if (and (eq? kind 'mred)
                                 (not (script-variant? variant))
                                 (not (null? post-flags)))
                            output-x-arg-getter
                            string-append)])
    (unless (find-console-bin-dir)
      (error 'make-unix-launcher "unable to locate bin directory"))
    (with-output-to-file dest
      #:exists 'truncate
      (lambda ()
        (display header)
        (newline)
        ;; comments needed to rehack launchers when paths change
        ;; (see setup/unixstyle-install.ss)
        (display "# {{{ bindir\n")
        (display dir-finder)
        (display "# }}} bindir\n")
        (newline)
        (display (assemble-exec exec args))))))

(define (utf-16-regexp b)
  (byte-regexp (bytes-append (bytes->utf-16-bytes b)
                             #"[^>]*"
                             (bytes->utf-16-bytes #">"))))

(define (make-windows-launcher kind variant flags dest aux)
  (if (not (and (let ([m (assq 'independent? aux)])
                  (and m (cdr m)))))
    ;; Normal launcher:
    (make-embedding-executable
     dest (eq? kind 'mred) #f null null null flags aux #t variant)
    ;; Independent launcher (needed for Setup PLT):
    (begin
      (install-template dest kind "mzstart.exe" "mrstart.exe")
      (let ([bstr (bytes->utf-16-bytes
                   (string->bytes/utf-8 (str-list->dos-str flags)))]
            [p (open-input-file dest)]
            [m (utf-16-regexp #"<Command Line: Replace This")]
            [x (utf-16-regexp #"<Executable Directory: Replace This")]
            [v (utf-16-regexp #"<Executable Variant: Replace This")])
        (let* ([exedir (bytes->utf-16-bytes
                        (bytes-append
                         (path->bytes (let ([bin-dir (if (eq? kind 'mred)
                                                       (find-gui-bin-dir)
                                                       (find-console-bin-dir))])
                                        (if (let ([m (assq 'relative? aux)])
                                              (and m (cdr m)))
                                          (or (relativize (normalize+explode-path bin-dir)
                                                          (normalize+explode-path dest))
                                              (build-path 'same))
                                          bin-dir)))
                         ;; null wchar marks end of executable directory
                         #"\0\0"))]
               [find-it ; Find the magic start
                (lambda (magic s)
                  (file-position p 0)
                  (let ([m (regexp-match-positions magic p)])
                    (if m
                      (car m)
                      (begin
                        (close-input-port p)
                        (when (file-exists? dest) (delete-file dest))
                        (error 'make-windows-launcher
                               "Couldn't find ~a position in template" s)))))]
               [exedir-poslen (find-it x "executable path")]
               [command-poslen (find-it m "command-line")]
               [variant-poslen (find-it v "variant")]
               [pos-exedir (car exedir-poslen)]
               [len-exedir (- (cdr exedir-poslen) (car exedir-poslen))]
               [pos-command (car command-poslen)]
               [len-command (- (cdr command-poslen) (car command-poslen))]
               [pos-variant (car variant-poslen)]
               [space (char->integer #\space)]
               [write-magic
                (lambda (p s pos len)
                  (file-position p pos)
                  (display s p)
                  (display (make-bytes (- len (bytes-length s)) space) p))]
               [check-len
                (lambda (len s es)
                  (when (> (bytes-length s) len)
                    (when (file-exists? dest) (delete-file dest))
                    (error
                     (format
                      "~a exceeds limit of ~a characters with ~a characters: ~a"
                      es len (string-length s) s))))])
          (close-input-port p)
          (check-len len-exedir exedir "executable home directory")
          (check-len len-command bstr "collection/file name")
          (let ([p (open-output-file dest #:exists 'update)])
            (write-magic p exedir pos-exedir len-exedir)
            (write-magic p (bytes-append bstr #"\0\0") pos-command len-command)
            (let* ([suffix (variant-suffix (current-launcher-variant) #t)]
                   [suffix-bytes
                    (bytes-append
                     (list->bytes
                      (append-map (lambda (c) (list c 0))
                                  (bytes->list (string->bytes/latin-1 suffix))))
                     #"\0\0")])
              (write-magic p suffix-bytes pos-variant (bytes-length suffix-bytes)))
            (close-output-port p)))))))

;; OS X launcher code:

;; make-macosx-launcher : symbol (listof str) pathname ->
(define (make-macosx-launcher kind variant flags dest aux)
  (if (or (eq? kind 'mzscheme) (script-variant? variant))
      ;; Racket or script launcher is the same as for Unix
      (make-unix-launcher kind variant flags dest aux)
      ;; Gracket "launcher" is a stand-alone executable
      (make-embedding-executable dest (eq? kind 'mred) #f
                                 null null null
                                 flags
                                 aux
                                 #t
                                 variant)))

(define (make-macos-launcher kind variant flags dest aux)
  (install-template dest kind "GoMr" "GoMr")
  (let* ([p (open-input-file dest)]
         [m (regexp-match-positions #rx#"<Insert offset here>" p)])
    ;; fast-forward to the end:
    (let ([s (make-bytes 4096)])
      (let loop ()
        (if (eof-object? (read-bytes! s p)) (file-position p) (loop))))
    (let ([data-fork-size (file-position p)])
      (close-input-port p)
      (let ([p (open-output-file dest #:exists 'update)]
            [str (str-list->sh-str
                  (append (if (eq? kind 'mred) null '("-Z")) flags))])
        (file-position p (caar m))
        (display (integer->integer-bytes (string-length str) 4 #t #t) p)
        (display (integer->integer-bytes data-fork-size 4 #t #t) p)
        (file-position p data-fork-size)
        (display str p)
        (close-output-port p)))))

(define (get-maker)
  (case (system-type)
    [(unix)    make-unix-launcher]
    [(windows) make-windows-launcher]
    [(macos)   make-macos-launcher]
    [(macosx)  make-macosx-launcher]))

(define (make-gracket-launcher flags dest [aux null])
  ((get-maker) 'mred (current-launcher-variant) flags dest aux))
(define (make-mred-launcher flags dest [aux null])
  ((get-maker) 'mred (current-launcher-variant) (list* "-I" "scheme/gui/init" flags) dest aux))

(define (make-racket-launcher flags dest [aux null])
  ((get-maker) 'mzscheme (current-launcher-variant) flags dest aux))
(define (make-mzscheme-launcher flags dest [aux null])
  ((get-maker) 'mzscheme (current-launcher-variant) (list* "-I" "scheme/init" flags) dest aux))

(define (strip-suffix s)
  (path-replace-suffix s #""))

(define (build-aux-from-path aux-root)
  (let ([aux-root (if (string? aux-root) (string->path aux-root) aux-root)])
    (define (try key suffix)
      (let ([p (path-replace-suffix aux-root suffix)])
        (if (file-exists? p) (list (cons key p)) null)))
    (append
     (try 'icns #".icns")
     (try 'ico #".ico")
     (try 'independent? #".lch")
     (let ([l (try 'creator #".creator")])
       (if (null? l)
         l
         (with-handlers ([exn:fail:filesystem? (lambda (x) null)])
           (with-input-from-file (cdar l)
             (lambda ()
               (let ([s (read-string 4)])
                 (if s (list (cons (caar l) s)) null)))))))
     (let ([l (try 'file-types #".filetypes")])
       (if (null? l)
         l
         (with-handlers ([exn:fail:filesystem? (lambda (x) null)])
           (with-input-from-file (cdar l)
             (lambda ()
               (let*-values ([(d) (read)]
                             [(local-dir base dir?) (split-path aux-root)]
                             [(icon-files)
                              (append-map
                               (lambda (spec)
                                 (let ([m (assoc "CFBundleTypeIconFile" spec)])
                                   (if m
                                     (list (build-path
                                            (path->complete-path local-dir)
                                            (format "~a.icns" (cadr m))))
                                     null)))
                               d)])
                 (list (cons 'file-types d)
                       (cons 'resource-files
                             (remove-duplicates icon-files)))))))))
     (let ([l (try 'file-types #".utiexports")])
       (if (null? l)
         l
         (with-handlers ([exn:fail:filesystem? (lambda (x) null)])
           (with-input-from-file (cdar l)
             (lambda ()
               (let ([d (read)])
                 (list (cons 'uti-exports d)))))))))))

(define (make-gracket-program-launcher file collection dest)
  (make-mred-launcher (list "-l-" (string-append collection "/" file))
                      dest
                      (build-aux-from-path
                       (build-path (collection-path collection)
                                   (strip-suffix file)))))
(define (make-mred-program-launcher file collection dest)
  (make-gracket-program-launcher file collection dest))

(define (make-racket-program-launcher file collection dest)
  (make-mzscheme-launcher (list "-l-" (string-append collection "/" file))
                          dest
                          (build-aux-from-path
                           (build-path (collection-path collection)
                                       (strip-suffix file)))))
(define (make-mzscheme-program-launcher file collection dest)
  (make-racket-program-launcher file collection dest))

(define (unix-sfx file mred?)
  (string-downcase (regexp-replace* #px"\\s" file "-")))

(define (sfx file mred?)
  (case (system-type)
    [(unix) (unix-sfx file mred?)]
    [(windows)
     (string-append (if mred? file (unix-sfx file mred?)) ".exe")]
    [else file]))

(define (program-launcher-path name mred?)
  (let* ([variant (current-launcher-variant)]
         [mac-script? (and (eq? (system-type) 'macosx)
                           (script-variant? variant))])
    (let ([p (add-file-suffix
              (build-path
               (if (or mac-script? (not mred?))
                   (find-console-bin-dir)
                   (find-gui-bin-dir))
               ((if mac-script? unix-sfx sfx) name mred?))
              variant
              mred?)])
      (if (and (eq? (system-type) 'macosx)
               (not (script-variant? variant)))
          (path-replace-suffix p #".app")
          p))))

(define (gracket-program-launcher-path name)
  (program-launcher-path name #t))
(define (mred-program-launcher-path name)
  (gracket-program-launcher-path name))

(define (racket-program-launcher-path name)
  (case (system-type)
    [(macosx)
     (add-file-suffix (build-path (find-console-bin-dir) (unix-sfx name #f))
                      (current-launcher-variant)
                      #f)]
    [else (program-launcher-path name #f)]))
(define (mzscheme-program-launcher-path name)
  (racket-program-launcher-path name))

(define (gracket-launcher-is-directory?)
  #f)
(define (racket-launcher-is-directory?)
  #f)
(define (mred-launcher-is-directory?)
  #f)
(define (mzscheme-launcher-is-directory?)
  #f)

(define (gracket-launcher-is-actually-directory?)
  (and (eq? 'macosx (system-type))
       (not (script-variant? (current-launcher-variant)))))
(define (mred-launcher-is-actually-directory?)
  (gracket-launcher-is-actually-directory?))
(define (racket-launcher-is-actually-directory?)
  #f)
(define (mzscheme-launcher-is-actually-directory?)
  #f)

;; Helper:
(define (put-file-extension+style+filters type)
  (case type
    [(windows) (values "exe" null '(("Executable" "*.exe")))]
    [(macosx) (values "app" '(packages) '(("App" "*.app")))]
    [else (values #f null null)]))

(define (gracket-launcher-add-suffix path)
  (embedding-executable-add-suffix path #t))
(define (mred-launcher-add-suffix path)
  (gracket-launcher-add-suffix path))

(define (racket-launcher-add-suffix path)
  (embedding-executable-add-suffix path #f))
(define (mzscheme-launcher-add-suffix path)
  (racket-launcher-add-suffix path))

(define (gracket-launcher-put-file-extension+style+filters)
  (put-file-extension+style+filters
   (if (and (eq? 'macosx (system-type))
            (script-variant? (current-launcher-variant)))
     'unix
     (system-type))))
(define (mred-launcher-put-file-extension+style+filters)
  (gracket-launcher-put-file-extension+style+filters))

(define (racket-launcher-put-file-extension+style+filters)
  (put-file-extension+style+filters
   (if (eq? 'macosx (system-type)) 'unix (system-type))))
(define (mzscheme-launcher-put-file-extension+style+filters)
  (racket-launcher-put-file-extension+style+filters))

(define (gracket-launcher-up-to-date? dest [aux null])
  (racket-launcher-up-to-date? dest aux))
(define (mred-launcher-up-to-date? dest [aux null])
  (racket-launcher-up-to-date? dest aux))
(define (mzscheme-launcher-up-to-date? dest [aux null])
  (racket-launcher-up-to-date? dest aux))

(define (racket-launcher-up-to-date? dest [aux null])
  (cond
    ;; When running Setup PLT under Windows, the
    ;;  launcher process stays running until Racket
    ;;  completes, which means that it cannot be
    ;;  overwritten at that time. So we assume
    ;;  that a Setup-PLT-style independent launcher
    ;;  is always up-to-date.
    [(eq? 'windows (system-type))
     (and (let ([m (assq 'independent? aux)]) (and m (cdr m)))
          (file-exists? dest))]
    ;; For any other setting, we could implement
    ;;  a fancy check, but for now always re-create
    ;;  launchers.
    [else #f]))

(define (install-gracket-program-launcher file collection name)
  (make-gracket-program-launcher file collection
                                 (gracket-program-launcher-path name)))

(define (install-racket-program-launcher file collection name)
  (make-racket-program-launcher file collection
                                (racket-program-launcher-path name)))

(define (install-mred-program-launcher file collection name)
  (make-mred-program-launcher file collection
                              (mred-program-launcher-path name)))

(define (install-mzscheme-program-launcher file collection name)
  (make-mzscheme-program-launcher file collection
                                  (mzscheme-program-launcher-path name)))













;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(require racket/runtime-path)

(define-runtime-path whalesong-path "whalesong.rkt")

(make-racket-launcher (list (path->string whalesong-path))
                      "whalesong"
                      '())