From b87639b7a40400ffcc6553949e1f48021783e389 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonygarnockjones@gmail.com>
Date: Wed, 7 Dec 2016 09:47:53 +1300
Subject: [PATCH] Split out reloader-mixin and reloader-mixin*

---
 racket/syndicate/reload.rkt | 87 ++++++++++++++++++++++---------------
 1 file changed, 53 insertions(+), 34 deletions(-)

diff --git a/racket/syndicate/reload.rkt b/racket/syndicate/reload.rkt
index 3e7ab4f..f68bd90 100644
--- a/racket/syndicate/reload.rkt
+++ b/racket/syndicate/reload.rkt
@@ -7,7 +7,9 @@
 
          stop-when-reloaded
          spawn-reloader
-         spawn-reloader*)
+         spawn-reloader*
+         reloader-mixin
+         reloader-mixin*)
 
 (define-logger syndicate/reload)
 
@@ -36,13 +38,32 @@
   (spawn-reloader* 'module-path))
 
 (define (spawn-reloader* module-path)
+  (match (module-path->path-string module-path)
+    [#f #f]
+    [pathstr
+     (supervise #:name (list 'reloader-supervisor pathstr)
+                (actor #:name 'reloader
+                       (reloader-mixin** module-path pathstr)))
+     #t]))
+
+(define-syntax-rule (reloader-mixin module-path)
+  (reloader-mixin* 'module-path))
+
+(define (reloader-mixin* module-path)
+  (define pathstr (module-path->path-string module-path))
+  (when (not pathstr)
+    (error 'reloader-mixin "Cannot deduce source path from module-path ~v" module-path))
+  (reloader-mixin** module-path pathstr))
+
+(define (module-path->path-string module-path)
   (define mpi (module-path-index-join module-path #f))
   (define rpath (module-path-index-resolve mpi))
   (define path (let ((p (resolved-module-path-name rpath)))
                  (if (pair? p) (car p) p)))
   (if (path? path)
-      (spawn-reloader** module-path (path->string path))
-      (log-syndicate/reload-error "Could not process module-path ~v" module-path)))
+      (path->string path)
+      (begin (log-syndicate/reload-error "Could not process module-path ~v" module-path)
+             #f)))
 
 (define counter
   (let ((count 0))
@@ -50,35 +71,33 @@
       (begin0 count
         (set! count (+ count 1))))))
 
-(define (spawn-reloader** module-path pathstr)
-  (supervise #:name (list 'reloader-supervisor pathstr)
-   (actor #:name 'reloader
-          (field [reloading? #f])
-          (define (reload!)
-            (when (not (reloading?))
-              (reloading? #t)
-              (react (field [obstacles-cleared? #f])
-                     (define/query-value obstacles-exist? #f (observe (reload-pending pathstr)) #t
-                       #:on-add (log-syndicate/reload-info "waiting to reload ~v" pathstr)
-                       #:on-remove (obstacles-cleared? #t))
-                     (assert #:when (obstacles-exist?) (reload-pending pathstr))
-                     (on-start (flush!)
-                               (obstacles-cleared? (not (obstacles-exist?))))
-                     (stop-when (rising-edge (obstacles-cleared?))
-                                (flush!) ;; Wait one turn for effects of newly-cleared obstacles
-                                (log-syndicate/reload-info "(re)loading ~v" pathstr)
-                                (dynamic-rerequire module-path)
-                                (schedule-actions!
-                                 ((dynamic-require `(submod ,module-path syndicate-main)
-                                                   'activate!)))
-                                (reloading? #f)))))
+(define (reloader-mixin** module-path pathstr)
+  (field [reloading? #f])
+  (define (reload!)
+    (when (not (reloading?))
+      (reloading? #t)
+      (react (field [obstacles-cleared? #f])
+             (define/query-value obstacles-exist? #f (observe (reload-pending pathstr)) #t
+               #:on-add (log-syndicate/reload-info "waiting to reload ~v" pathstr)
+               #:on-remove (obstacles-cleared? #t))
+             (assert #:when (obstacles-exist?) (reload-pending pathstr))
+             (on-start (flush!)
+                       (obstacles-cleared? (not (obstacles-exist?))))
+             (stop-when (rising-edge (obstacles-cleared?))
+                        (flush!) ;; Wait one turn for effects of newly-cleared obstacles
+                        (log-syndicate/reload-info "(re)loading ~v" pathstr)
+                        (dynamic-rerequire module-path)
+                        (schedule-actions!
+                         ((dynamic-require `(submod ,module-path syndicate-main)
+                                           'activate!)))
+                        (reloading? #f)))))
 
-          (field [previous-version #f])
-          (define/query-value latest-version 'unknown (file-content pathstr counter $p) p)
-          (begin/dataflow
-            (when (and (not (eq? (latest-version) 'unknown))
-                       (not (equal? (latest-version) (previous-version))))
-              (if (latest-version)
-                  (reload!)
-                  (log-syndicate/reload-warning "Module ~v does not exist" pathstr))
-              (previous-version (latest-version)))))))
+  (field [previous-version #f])
+  (define/query-value latest-version 'unknown (file-content pathstr counter $p) p)
+  (begin/dataflow
+    (when (and (not (eq? (latest-version) 'unknown))
+               (not (equal? (latest-version) (previous-version))))
+      (if (latest-version)
+          (reload!)
+          (log-syndicate/reload-warning "Module ~v does not exist" pathstr))
+      (previous-version (latest-version)))))