From 77007e55bdf10e498912701f590f33d49efa4c09 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Mon, 17 Feb 2014 14:13:25 -0500
Subject: Revert "Make agendas thread-safe."

This reverts commit 38f9696fed2b55e6f5484433298b7c34141da243.
---
 2d/agenda.scm | 69 +++++++++++++++++++++++++++--------------------------------
 1 file changed, 32 insertions(+), 37 deletions(-)

diff --git a/2d/agenda.scm b/2d/agenda.scm
index 5154f06..2b28a54 100644
--- a/2d/agenda.scm
+++ b/2d/agenda.scm
@@ -23,7 +23,6 @@
 
 (define-module (2d agenda)
   #:use-module (ice-9 q)
-  #:use-module (ice-9 threads)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-9)
   #:use-module (srfi srfi-26)
@@ -68,15 +67,14 @@ list CALLBACKS."
 ;;;
 
 (define-record-type <agenda>
-  (%make-agenda time mutex segments)
+  (%make-agenda time segments)
   agenda?
   (time agenda-time set-agenda-time!)
-  (mutex agenda-mutex)
   (segments agenda-segments set-agenda-segments!))
 
 (define (make-agenda)
   "Create a new, empty agenda."
-  (%make-agenda 0 (make-mutex 'recursive) '()))
+  (%make-agenda 0 '()))
 
 (define (agenda-empty? agenda)
   "Return #t if AGENDA has no scheduled procedures."
@@ -121,46 +119,43 @@ and enqueue CALLBACK."
 
 (define (tick-agenda! agenda)
   "Move AGENDA forward in time and run scheduled procedures."
-  (with-mutex (agenda-mutex agenda)
-    (set-agenda-time! agenda (1+ (agenda-time agenda)))
-    (let next-segment ()
-      (unless (agenda-empty? agenda)
-        (let ((segment (first-segment agenda)))
-          ;; Process time segment if it is scheduled before or at the
-          ;; current agenda time.
-          (when (>= (agenda-time agenda) (segment-time segment))
-            (flush-queue! (segment-queue segment))
-            (set-agenda-segments! agenda (rest-segments agenda))
-            (next-segment)))))))
+  (set-agenda-time! agenda (1+ (agenda-time agenda)))
+  (let next-segment ()
+    (unless (agenda-empty? agenda)
+      (let ((segment (first-segment agenda)))
+        ;; Process time segment if it is scheduled before or at the
+        ;; current agenda time.
+        (when (>= (agenda-time agenda) (segment-time segment))
+          (flush-queue! (segment-queue segment))
+          (set-agenda-segments! agenda (rest-segments agenda))
+          (next-segment))))))
 
 (define (clear-agenda! agenda)
   "Remove all scheduled procedures from AGENDA."
-  (with-mutex (agenda-mutex agenda)
-    (set-agenda-segments! agenda '())))
+  (set-agenda-segments! agenda '()))
 
 (define* (schedule agenda thunk #:optional (delay 1))
   "Schedule the procedure THUNK in AGENDA to be run DELAY ticks from
 now.  DELAY defaults to 1 if not specified."
-  (with-mutex (agenda-mutex agenda)
-    (let ((time (agenda-time-delay agenda delay)))
-      (define (belongs-before? segments)
-        (or (null? segments)
-            (< time (segment-time (car segments)))))
-
-      (define (add-to-segments segments)
-        ;; Add to existing time segment if the times match
-        (if (= (segment-time (car segments)) time)
-            (segment-enq (car segments) thunk)
-            ;; Continue searching
-            (if (belongs-before? (cdr segments))
-                ;; Create new time segment and insert it where it belongs
-                (insert-segment segments time thunk)
-                ;; Continue searching
-                (add-to-segments (cdr segments)))))
-
-      (if (belongs-before? (agenda-segments agenda))
-          (agenda-add-segment agenda time thunk)
-          (add-to-segments (agenda-segments agenda))))))
+  (let ((time (agenda-time-delay agenda delay)))
+    (define (belongs-before? segments)
+      (or (null? segments)
+          (< time (segment-time (car segments)))))
+
+    (define (add-to-segments segments)
+      ;; Add to existing time segment if the times match
+      (if (= (segment-time (car segments)) time)
+          (segment-enq (car segments) thunk)
+          ;; Continue searching
+          (if (belongs-before? (cdr segments))
+              ;; Create new time segment and insert it where it belongs
+              (insert-segment segments time thunk)
+              ;; Continue searching
+              (add-to-segments (cdr segments)))))
+
+    (if (belongs-before? (agenda-segments agenda))
+        (agenda-add-segment agenda time thunk)
+        (add-to-segments (agenda-segments agenda)))))
 
 (define (schedule-interval agenda thunk delay)
   "Schedule THUNK within AGENDA to be applied every DELAY ticks."
-- 
cgit v1.2.3