X-Git-Url: https://jxself.org/git/?a=blobdiff_plain;f=loopy.scm;h=cb7ee81106d7bace5bfe9841b31684d31cdd0868;hb=0d17f91644ea33444e06155f1e58adb5331fc24d;hp=7172e9b57b3a6d7cefcaad6fe29c00248f3c6bd1;hpb=7ff622de68d583e0dccc400aa887b8f52c7c592e;p=8sync.git

diff --git a/loopy.scm b/loopy.scm
index 7172e9b..cb7ee81 100644
--- a/loopy.scm
+++ b/loopy.scm
@@ -1,31 +1,42 @@
 (define-module (loopy agenda)
+  #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-9)
   #:use-module (srfi srfi-9 gnu)
   #:use-module (ice-9 q)
   #:use-module (ice-9 match)
   #:use-module (ice-9 receive)
-  #:export (make-agenda
-            agenda?
+  #:export (<agenda>
+            make-agenda agenda?
             agenda-queue agenda-prompt-tag
-            agenda-port-pmapping agenda-schedule
+            agenda-read-port-map agenda-write-port-map agenda-except-port-map
+            agenda-schedule
             
             make-async-prompt-tag
 
-            make-time-segment
-            time-segment?
+            <time-segment>
+            make-time-segment time-segment?
             time-segment-time time-segment-queue
 
-            time-< time-= time-<=
+            time-< time-= time-<= time-+
 
-            make-schedule
+            <time-delta>
+            make-time-delta tdelta time-delta?
+            time-delta-sec time-delta-usec
+
+            <schedule>
+            make-schedule schedule?
             schedule-add! schedule-empty?
             schedule-segments
+            schedule-soonest-time
+
+            schedule-segments-split schedule-extract-until!
+            add-segments-contents-to-queue!
 
-            schedule-segments-until schedule-extract-until!
+            <run-request>
+            make-run-request run-request?
+            run-request-proc run-request-when
 
-            make-port-mapping
-            port-mapping-set! port-mapping-remove!
-            port-mapping-empty? port-mapping-non-empty?
+            run wrap run-wrap run-wrap-at
 
             %current-agenda
             start-agenda agenda-run-once))
@@ -52,12 +63,17 @@
 ;;;    and with reasonable separation from functional components?
 
 (define-immutable-record-type <agenda>
-  (make-agenda-intern queue prompt-tag port-mapping schedule)
+  (make-agenda-intern queue prompt-tag
+                      read-port-map write-port-map except-port-map
+                      schedule time)
   agenda?
   (queue agenda-queue)
   (prompt-tag agenda-prompt-tag)
-  (port-mapping agenda-port-mapping)
-  (schedule agenda-schedule))
+  (read-port-map agenda-read-port-map)
+  (write-port-map agenda-write-port-map)
+  (except-port-map agenda-except-port-map)
+  (schedule agenda-schedule)
+  (time agenda-time))
 
 (define (make-async-prompt-tag)
   (make-prompt-tag "prompt"))
@@ -65,9 +81,14 @@
 (define* (make-agenda #:key
                       (queue (make-q))
                       (prompt (make-prompt-tag))
-                      (port-mapping (make-port-mapping))
-                      (schedule (make-schedule)))
-  (make-agenda-intern queue prompt port-mapping schedule))
+                      (read-port-map (make-hash-table))
+                      (write-port-map (make-hash-table))
+                      (except-port-map (make-hash-table))
+                      (schedule (make-schedule))
+                      (time (gettimeofday)))
+  (make-agenda-intern queue prompt
+                      read-port-map write-port-map except-port-map
+                      schedule time))
 
 
 
@@ -76,7 +97,7 @@
 
 ;;; This is where we handle timed events for the future
 
-;; This section totally borrows from SICP
+;; This section totally borrows from the ideas in SICP
 ;; <3 <3 <3
 
 ;; NOTE: time is a cons of (seconds . microseconds)
@@ -117,6 +138,23 @@
   (or (time-< time1 time2)
       (time-= time1 time2)))
 
+
+(define-record-type <time-delta>
+  (make-time-delta-intern sec usec)
+  time-delta?
+  (sec time-delta-sec)
+  (usec time-delta-usec))
+
+(define* (make-time-delta sec #:optional usec)
+  (make-time-delta-intern sec (or usec 0)))
+
+(define tdelta make-time-delta)
+
+(define (time-+ time time-delta)
+  (cons (+ (car time) (time-delta-sec time-delta))
+        (+ (cdr time) (time-delta-usec time-delta))))
+
+
 (define-record-type <schedule>
   (make-schedule-intern segments)
   schedule?
@@ -125,11 +163,18 @@
 (define* (make-schedule #:optional segments)
   (make-schedule-intern (or segments '())))
 
+(define (schedule-soonest-time schedule)
+  "Return a cons of (sec . usec) for next time segement, or #f if none"
+  (let ((segments (schedule-segments schedule)))
+    (if (eq? segments '())
+        #f
+        (time-segment-time (car segments)))))
+
 ;; TODO: This code is reasonably easy to read but it
 ;;   mutates AND is worst case of O(n) in both space and time :(
 ;;   but at least it'll be reasonably easy to refactor to
 ;;   a more functional setup?
-(define (schedule-add! time proc schedule)
+(define (schedule-add! schedule time proc)
   (let ((time (time-segment-right-format time)))
     (define (new-time-segment)
       (let ((new-segment
@@ -169,7 +214,7 @@
 (define (schedule-empty? schedule)
   (eq? (schedule-segments schedule) '()))
 
-(define (schedule-segments-until schedule time)
+(define (schedule-segments-split schedule time)
   "Does a multiple value return of time segments before/at and after TIME"
   (let ((time (time-segment-right-format time)))
     (define (segment-is-now? segment)
@@ -200,10 +245,18 @@
 (define (schedule-extract-until! schedule time)
   "Extract all segments until TIME from SCHEDULE, and pop old segments off"
   (receive (segments-before segments-after)
-      (schedule-split-segments-until schedule time)
+      (schedule-segments-split schedule time)
     (set-schedule-segments! schedule segments-after)
     segments-before))
 
+(define (add-segments-contents-to-queue! segments queue)
+  (for-each
+   (lambda (segment)
+     (let ((seg-queue (time-segment-queue segment)))
+       (while (not (q-empty? seg-queue))
+         (enq! queue (deq! seg-queue)))))
+   segments))
+
 
 
 ;;; Port handling
@@ -235,15 +288,118 @@
   (not (port-mapping-empty? port-mapping)))
 
 
+
+;;; Request to run stuff
+;;; ====================
+
+(define-record-type <run-request>
+  (make-run-request proc when)
+  run-request?
+  (proc run-request-proc)
+  (when run-request-when))
+
+(define* (run proc #:optional when)
+  (make-run-request proc when))
+
+(define-syntax-rule (wrap body ...)
+  (lambda ()
+    body ...))
+
+(define-syntax-rule (run-wrap body ...)
+  (run (wrap body ...)))
+
+(define-syntax-rule (run-wrap-at body ... when)
+  (run (wrap body ...) when))
+
 
 ;;; Execution of agenda, and current agenda
 ;;; =======================================
 
 (define %current-agenda (make-parameter #f))
 
-(define* (start-agenda agenda #:optional stop-condition)
+(define (update-agenda-from-select! agenda)
+  (define (hash-keys selector)
+    (hash-map->list (lambda (k v) k) hash))
+  (define (get-wait-time)
+    ;; TODO: we need to figure this out based on whether there's anything
+    ;;   in the queue, and if not, how long till the next scheduled item
+    (let ((soonest-time (schedule-soonest-time (agenda-schedule agenda))))
+      (cond 
+       ((not (q-empty? (agenda-queue agenda)))
+        (values 0 0))
+       (soonest-time    ; ie, the agenda is non-empty
+        (let* ((current-time (agenda-time agenda)))
+          (if (time-<= soonest-time current-time)
+              ;; Well there's something due so let's select
+              ;; (this avoids a (possible?) race condition chance)
+              (values 0 0)
+              (values
+               (- (car soonest-time) (car current-time))
+               (- (cdr soonest-time) (cdr current-time))))))
+       (else
+        (values #f #f)))))
+  (define (do-select)
+    ;; TODO: support usecond wait time too
+    (receive (sec usec)
+        (get-wait-time)
+      (select (hash-keys (agenda-read-port-map agenda))
+              (hash-keys (agenda-write-port-map agenda))
+              (hash-keys (agenda-except-port-map agenda))
+              sec usec)))
+  (define (get-procs-to-run)
+    (define (ports->procs ports port-map)
+      (lambda (initial-procs)
+        (fold
+         (lambda (port prev)
+           (cons (lambda ()
+                   ((hash-ref port-map port) port))
+                 prev))
+         initial-procs
+         ports)))
+    (match (do-select)
+      ((read-ports write-ports except-ports)
+       ;; @@: Come on, we can do better than append ;P
+       ((compose (ports->procs
+                  read-ports
+                  (agenda-read-port-map agenda))
+                 (ports->procs
+                  write-ports
+                  (agenda-write-port-map agenda))
+                 (ports->procs
+                  except-ports
+                  (agenda-except-port-map agenda)))
+        '()))))
+  (define (update-agenda)
+    (let ((procs-to-run (get-procs-to-run))
+          (q (agenda-queue agenda)))
+      (for-each
+       (lambda (proc)
+         (enq! q proc))
+       procs-to-run))
+    agenda)
+  (define (ports-to-select?)
+    (define (has-items? selector)
+      ;; @@: O(n)
+      ;;    ... we could use hash-for-each and a continuation to jump
+      ;;    out with a #t at first indication of an item
+      (not (= (hash-count (const #t)
+                          (selector agenda))
+              0)))
+    (or (has-items? agenda-read-port-map)
+        (has-items? agenda-write-port-map)
+        (has-items? agenda-except-port-map)))
+
+  (if (ports-to-select?)
+      (update-agenda)
+      agenda))
+
+
+(define* (start-agenda agenda
+                       #:key stop-condition
+                       (get-time gettimeofday)
+                       (handle-ports update-agenda-from-select!))
   (let loop ((agenda agenda))
-    (let ((new-agenda   
+    (let ((agenda   
            ;; @@: Hm, maybe here would be a great place to handle
            ;;   select'ing on ports.
            ;;   We could compose over agenda-run-once and agenda-read-ports
@@ -251,7 +407,19 @@
              (agenda-run-once agenda))))
       (if (and stop-condition (stop-condition agenda))
           'done
-          (loop new-agenda)))))
+          (let* ((new-time (get-time))
+                 (agenda
+                  (handle-ports
+                   ;; Adjust the agenda's time just in time
+                   ;; We do this here rather than in agenda-run-once to make
+                   ;; agenda-run-once's behavior fairly predictable
+                   (set-field agenda (agenda-time) new-time))))
+            ;; Update the agenda's current queue based on
+            ;; currently applicable time segments
+            (add-segments-contents-to-queue!
+             (schedule-extract-until! (agenda-schedule agenda) new-time)
+             (agenda-queue agenda))
+            (loop agenda))))))
 
 (define (agenda-run-once agenda)
   "Run once through the agenda, and produce a new agenda
@@ -270,19 +438,36 @@ based on the results"
       (let* ((proc (q-pop! queue))
              (proc-result (call-proc proc))
              (enqueue
-              (lambda (new-proc)
-                (enq! next-queue new-proc))))
+              (lambda (run-request)
+                (define (schedule-at! time proc)
+                  (schedule-add! (agenda-schedule agenda) time proc))
+                (let ((request-time (run-request-when run-request)))
+                  (match request-time
+                    ((? time-delta? time-delta)
+                     (let ((time (time-+ (agenda-time agenda)
+                                         time-delta)))
+                       (schedule-at! time (run-request-proc run-request))))
+                    ((? integer? sec)
+                     (let ((time (cons sec 0)))
+                       (schedule-at! time (run-request-proc run-request))))
+                    (((? integer? sec) . (? integer? usec))
+                     (schedule-at! request-time (run-request-proc run-request)))
+                    (#f
+                     (enq! next-queue (run-request-proc run-request))))))))
         ;; @@: We might support delay-wrapped procedures here
         (match proc-result
-          ((? procedure? new-proc)
+          ;; TODO: replace procedure with something that indicates
+          ;;   intent to run.  Use a (run foo) procedure
+          ((? run-request? new-proc)
            (enqueue new-proc))
-          (((? procedure? new-procs) ...)
+          (((? run-request? new-procs) ...)
            (for-each
             (lambda (new-proc)
               (enqueue new-proc))
             new-procs))
           ;; do nothing
           (_ #f))))
-    ;; TODO: Selecting on ports would happen here?
+    ;; TODO: Alternately, we could return the next-queue
+    ;;   along with changes to be added to the schedule here?
     ;; Return new agenda, with next queue set
     (set-field agenda (agenda-queue) next-queue)))