Sketched out simple chat multi-user chat client.

[sam.git] / sam.scm

diff --git a/sam.scm b/sam.scm
index 5c5ec88..8e8a730 100644 (file)
--- a/sam.scm
+++ b/sam.scm
@@ -5,36 +5,46 @@
 
 (import (chicken io)
         (chicken string)
+        (chicken port)
         matchable
         srfi-18 ; threads
-        srfi-69 ; hashtable
+        srfi-69 ; hash-table
+        uuid ; ids for actors
+        uri-generic
         udp
         fifo)
 
 ;; Actors
 
-(define (make-machine host port)
-  (cons host port))
-(define (machine-host m) (car m))
-(define (machine-port m) (cdr m))
+(define this-host "localhost")
+(define this-port 8000)
 
-(define this-machine (make-machine "localhost" 1234))
+(define (make-address host port id)
+  (make-uri #:scheme "actor"
+            #:host host
+            #:port port
+            #:path (list '/ id)))
 
-(define next-actor-id 1)
-
-(define (address-id address) (car address))
-(define (address-machine address) (cdr address))
+(define (make-local-address . args)
+  (make-address this-host
+                this-port
+                (if (null? args)
+                    (uuid)
+                    (car args))))
+                
+(define (address-id address) (cadr (uri-path address)))
 
 (define (address-local? address)
-  (equal? (address-machine address)
-          this-machine))
+  (and (equal? (uri-host address) this-host)
+       (equal? (uri-port address) this-port)))
 
 (define actor-table (make-hash-table))
 
 (define (make-actor beh)
-  (let* ((id next-actor-id))
-    (hash-table-put! id beh)
-    (cons id this-machine)))
+  (let* ((address (make-local-address))
+         (id (address-id address)))
+    (hash-table-set! actor-table id beh)
+    address))
   
 (define (deliver-message address . message)
   (let ((id (address-id address)))
@@ -42,9 +52,9 @@
       (if (null? behaviour)
           (print "Warning: discarded message" message " to unknown actor " address)
           (match (apply (hash-table-ref actor-table id) (cons address message))
-            ('done (hash-table-delete! actor-table actor))
+            ('done (hash-table-delete! actor-table id))
             ('sleep 'do-nothing)
-            (new-beh (hash-table-put! actor new-beh)))))))
+            (new-beh (hash-table-set! actor-table id new-beh)))))))
 
 ;; Scheduler
 
@@ -57,7 +67,7 @@
   (apply (if (address-local? address)
              send-local-message
              send-network-message)
-         message))
+         (cons address message)))
 
 (define (send-local-message address . message)
   (mutex-lock! local-queue-mutex)
@@ -77,20 +87,105 @@
 
 (define (next-local-message)
   (let ((res #f))
-    (mutex-lock! message-available-mutex)
+    (mutex-lock! message-available-mutex #f #f)
     (mutex-lock! local-queue-mutex)
     (set! res (fifo-pop local-queue))
-    (mutex-unlock! message-available-mutex)
+    (if (not (fifo-empty? local-queue))
+      (mutex-unlock! message-available-mutex))
     (mutex-unlock! local-queue-mutex)
     res))
 
-(define scheduler-thread
-  (make-thread
+(define (start-scheduler)
+  (thread-start!
    (lambda ()
-     (let loop ((next-addressed-message (next-local-message)))
-       (apply deliver-message next-addressed-message)
-       (loop (next-local-message))))))
+     (let loop ()
+       (apply deliver-message (next-local-message))
+       (loop)))))
+
+;; Console
+
+(define reader-queue-mutex (make-mutex "reader queue"))
+(define reader-available-mutex (make-mutex "reader available"))
+(mutex-lock! reader-available-mutex #f #f)
+(define reader-queue (make-fifo))
+
+(define console
+  (make-actor (lambda (self . message)
+                (mutex-lock! reader-queue-mutex)
+                (fifo-push reader-queue (car message))
+                (mutex-unlock! reader-available-mutex)
+                (mutex-unlock! reader-queue-mutex)
+                'sleep)))
+
+(define (next-reader)
+  (let ((res #f))
+    (mutex-lock! reader-available-mutex #f #f)
+    (mutex-lock! reader-queue-mutex)
+    (set! res (fifo-pop reader-queue))
+    (if (not (fifo-empty? reader-queue))
+        (mutex-unlock! reader-available-mutex))
+    (mutex-unlock! reader-queue-mutex)
+    res))
 
-(thread-start! scheduler-thread)
+(define (start-console)
+  (let loop ()
+    (let ((reader (next-reader)))
+      (##sys#thread-block-for-i/o! (current-thread) 0 #t)
+      (thread-yield!)
+      (send-message reader (read-line)))
+    (loop)))
 
-(thread-join! scheduler-thread)
+
+;; Network
+
+(define (start-network-listener)
+  (thread-start!
+   (lambda ()
+     (let ((s (udp-open-socket*)))
+       (udp-bind! s #f this-port)
+       (let loop ()
+         (let-values (((n str) (udp-recv s 1024)))
+           (print "Received " n " bytes over network: " str)
+           (match (with-input-from-string str read)
+             ((uri-str message ...)
+              (apply send-message (cons (uri-reference uri-str) message)))
+             (else
+              (print "Warning: received badly formatted message string '" str "'"))))
+         (loop))))))
+
+;; System interface
+
+(define system
+  (make-actor (lambda (self . message)
+                (match message
+                  (('shutdown)
+                   (print "## System actor received shutdown message.")
+                   (exit 0)
+                   'done)
+                  (('println strings ...)
+                   (apply print strings)
+                   'sleep)))))
+
+;; Testing
+
+
+(send-message system 'println "Hello, what is your name?")
+(send-message console
+              (make-actor (lambda (self . message)
+                            (match message
+                              ((name)
+                               (send-message system 'println "Hello, " name "!")
+                               'done)))))
+
+(thread-start!
+ (lambda ()
+   (thread-sleep! 120)
+   (send-message system 'shutdown)))
+
+(print (uri->string system))
+
+(start-scheduler)
+(start-network-listener)
+(start-console)
+
+;; (thread-join! scheduler-thread)