net-lib/net/sendurl.rkt: use same executable filtering on all systems

Use “cmd.exe” on Windows. This enables us to have a list (of length one on
macOS and Windows) of launcher executables on all platforms, and use
send-url/unix, now renamed to send-url/simple, to launch all URLs without a
query or fragment.

pkgs/net-lib/net/sendurl.rkt

@@ -7,7 +7,9 @@
          racket/contract racket/promise json)
 
 (provide send-url send-url/file send-url/contents
-         unix-browser-list browser-preference? external-browser
+         browser-list external-browser
+         ;; Obsolete definitions
+         unix-browser-list browser-preference?
          (contract-out
           [send-url/mac
            (->* (string?) (#:browser string?)
@@ -19,7 +21,7 @@
 
 ;; all possible unix browsers, filtered later to just existing executables
 ;; order matters: the default will be the first of these that is found
-(define all-unix-browsers
+(define all-browsers/unix
   '(;; general purpose launchers
     xdg-open
     ;; default browser launchers
@@ -27,11 +29,44 @@
     ;; common browsers
     firefox chromium-browser google-chrome opera seamonkey epiphany
     ))
+(define all-browsers/win '(cmd.exe)) ; proxy for a basic functioning Windows system
+(define all-browsers/mac '(open))
+
+;; by-need filtering of found executables
+(define existing-browsers->exes
+  (delay/sync
+    (filter values
+            (map (lambda (b)
+                   (let ([exe (find-executable-path (symbol->string b) #f)])
+                     (and exe (cons b exe))))
+                 (case (system-type)
+                   [(macosx)  all-browsers/mac]
+                   [(windows) all-browsers/win]
+                   [(unix)    all-browsers/unix]
+                   [else (error 'send-url
+                                "don't know how to open URL on platform: ~s" (system-type))])))))
+
+(define existing-browsers
+  (delay/sync (map car (force existing-browsers->exes))))
+(define-syntax browser-list
+  (syntax-id-rules (set!)
+    [(_ . xs) ((force existing-browsers) . xs)]
+    [(set! _ . xs) (error 'browser-list "cannot be mutated")]
+    [_ (force existing-browsers)]))
+
+
+;; Backwards compatibility
+
+(define unix-browser-list browser-list)
 
 ;; : any -> bool
 (define (custom-browser? x)
   (and (pair? x) (string? (car x)) (string? (cdr x))))
 
+;; : any -> bool
+(define (browser-preference? x)
+  (or (not x) (memq x browser-list) (custom-browser? x) (procedure? x)))
+
 (define external-browser
   (make-parameter
    #f ; #f means "consult the preferences file"
@@ -40,25 +75,12 @@
        x
        (error 'external-browser "~e is not a valid browser preference" x)))))
 
-;; by-need filtering of found unix executables
-(define existing-unix-browsers->exes
-  (delay/sync
-    (filter values
-            (map (lambda (b)
-                   (let ([exe (find-executable-path (symbol->string b) #f)])
-                     (and exe (cons b exe))))
-                 all-unix-browsers))))
-(define existing-unix-browsers
-  (delay/sync (map car (force existing-unix-browsers->exes))))
-(define-syntax unix-browser-list
-  (syntax-id-rules (set!)
-    [(_ . xs) ((force existing-unix-browsers) . xs)]
-    [(set! _ . xs) (error 'unix-browser-list "cannot be mutated")]
-    [_ (force existing-unix-browsers)]))
+(define (send-url/mac url #:browser [browser #f])
+  (let ([browser-command (car browser-list)])
+    (if browser
+        (browser-run browser-command "-a" browser url)
+        (browser-run browser-command url))))
 
-;; : any -> bool
-(define (browser-preference? x)
-  (or (not x) (memq x unix-browser-list) (custom-browser? x) (procedure? x)))
 
 (define (%escape str)
   (apply string-append
@@ -82,12 +104,7 @@
       ((external-browser) url-str)
       (if (regexp-match? #rx"[#?]" url-str)
           (send-url/trampoline url-str separate-window?)
-          (case (system-type)
-            [(macosx)  (send-url/mac url-str)]
-            [(windows) (send-url/win url-str)]
-            [(unix)    (send-url/unix url-str separate-window?)]
-            [else (error 'send-url
-                         "don't know how to open URL on platform: ~s" (system-type))]))))
+          (send-url/simple url-str separate-window?))))
   (void))
 
 (define (send-url/file path [separate-window? separate-by-default?]
@@ -140,30 +157,20 @@
     (when delete-at (thread (lambda () (sleep delete-at) (delete-file temp))))
     (send-url/file temp)))
 
-(define open-program (delay/sync (find-executable-path "open" #f)))
-(define (send-url/mac url #:browser [browser #f])
-  (let ([browser-command (force open-program)])
-    (if browser
-        (browser-run browser-command "-a" browser url)
-        (browser-run browser-command url))))
-
-(define (send-url/win url)
-  (shell-execute #f url "" (current-directory) 'SW_SHOWNORMAL))
-
-(define (send-url/unix url [separate-window? separate-by-default?])
+(define (send-url/simple url [separate-window? separate-by-default?])
   ;; in cases where a browser was uninstalled, we might get a preference that
   ;; is no longer valid, this will turn it back to #f
   (define (try pref)
     (if (symbol? pref)
-      (if (memq pref unix-browser-list) pref #f)
+      (if (memq pref browser-list) pref #f)
       pref))
   (define browser
     (or (try (external-browser))
         (try (get-preference 'external-browser))
         ;; no preference -- chose the first one from the filtered list
-        (and (pair? unix-browser-list) (car unix-browser-list))))
+        (and (pair? browser-list) (car browser-list))))
   (define exe
-    (cond [(assq browser (force existing-unix-browsers->exes)) => cdr]
+    (cond [(assq browser (force existing-browsers->exes)) => cdr]
           [else #f]))
   (define (simple) (browser-run exe url))
   (define (w/arg a) (browser-run exe a url))
@@ -171,6 +178,8 @@
     (or (browser-run exe "-remote" (format "openURL(~a~a)" url
                                            (if separate-window? ",new-window" "")))
         (simple)))
+  (define (windows-start)
+    (shell-execute #f url "" (current-directory) 'SW_SHOWNORMAL))
   (cond
     [(not browser)
      (error 'send-url "Couldn't find a browser to open URL: ~e" url)]
@@ -185,8 +194,10 @@
     ;; finally, deal with the actual browser process
     [else
      (case browser
-       [(xdg-open sensible-browser x-www-browser firefox konqueror google-chrome chromium-browser)
+       [(open xdg-open
+         sensible-browser x-www-browser firefox konqueror google-chrome chromium-browser)
         (simple)]
+       [(cmd.exe) (windows-start)]
        ;; don't really know how to run these
        [(epiphany) (if separate-window? (w/arg "--new-window") (simple))]
        [(seamonkey opera) (try-remote)]