From 7f0f3c3c1ae2eb0e2cf5390586d9a08beca59c68 Mon Sep 17 00:00:00 2001
From: Sascha Matzke <sascha.matzke@didolo.org>
Date: Sun, 30 Aug 2009 17:26:23 +0200
Subject: [PATCH] reworked messaging, now always use an envelope around the
 message to handle expiration correctly in all use-cases

---
 .../messaging/messaging-tests.factor          | 14 ++-
 basis/concurrency/messaging/messaging.factor  | 92 +++++++++++++++----
 2 files changed, 83 insertions(+), 23 deletions(-)

diff --git a/basis/concurrency/messaging/messaging-tests.factor b/basis/concurrency/messaging/messaging-tests.factor
index 7cbe2b21ff..f3e26f9b5d 100644
--- a/basis/concurrency/messaging/messaging-tests.factor
+++ b/basis/concurrency/messaging/messaging-tests.factor
@@ -10,21 +10,24 @@ IN: concurrency.messaging.tests
 
 [ "received" ] [ 
     [
-        receive "received" swap reply-synchronous
+        [ drop "received" ] handle-synchronous
     ] "Synchronous test" spawn
     "sent" swap send-synchronous
 ] unit-test
 
 [ "received" ] [ 
     [
-        receive "received" swap reply-synchronous
+        [ drop "received" ] handle-synchronous
     ] "Synchronous test" spawn
     [ 100 milliseconds "sent" ] dip send-synchronous-timeout
 ] unit-test
 
-[ [ 100 milliseconds sleep
-    receive "received" swap reply-synchronous ] "Synchronous test" spawn
-  [ 50 milliseconds "sent" ] dip send-synchronous-timeout
+[
+    [
+        100 milliseconds sleep
+        [ drop "received" ] handle-synchronous
+    ] "Synchronous test" spawn
+    [ 5 milliseconds "sent" ] dip send-synchronous-timeout
 ] [ wait-timeout? ] must-fail-with
 
 
@@ -77,3 +80,4 @@ SYMBOL: exit
 ! ] "Bad synchronous send" spawn "t" set
 
 ! [ 3 "t" get send-synchronous ] must-fail
+
diff --git a/basis/concurrency/messaging/messaging.factor b/basis/concurrency/messaging/messaging.factor
index 8438f7effe..9046604282 100644
--- a/basis/concurrency/messaging/messaging.factor
+++ b/basis/concurrency/messaging/messaging.factor
@@ -1,32 +1,82 @@
 ! Copyright (C) 2005, 2008 Chris Double, Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: kernel threads concurrency.mailboxes continuations
-namespaces assocs accessors summary fry ;
+namespaces assocs accessors summary fry calendar math sequences ;
 IN: concurrency.messaging
 
+TUPLE: envelope data sender tag expiry ;
+
+<PRIVATE
+
+: new-envelope ( data class -- envelope )
+    new swap >>data self >>sender ;
+
+: <envelope> ( data -- envelope )
+    dup envelope?
+    [ envelope new-envelope ] unless ;
+
+: expired? ( message -- ? )
+    dup envelope?
+    [ expiry>>
+      [ now (time-) 0 < ]
+      [ f ] if*
+    ] [ drop f ] if ; inline
+
+: if-expired ( message quot -- message )
+    [ dup expired? ] dip
+    '[ drop _ call( -- message ) ] [ ] if ; inline
+
+PRIVATE>
+
 GENERIC: send ( message thread -- )
 
+GENERIC: send-timeout ( timeout message thread -- )
+
 : mailbox-of ( thread -- mailbox )
     dup mailbox>> [ ] [
         <mailbox> [ >>mailbox drop ] keep
     ] ?if ;
 
 M: thread send ( message thread -- )
+    [ <envelope> ] dip
     check-registered mailbox-of mailbox-put ;
 
+M: thread send-timeout ( timeout message thread -- )
+    [ <envelope> swap hence >>expiry ] dip send ; 
+
 : my-mailbox ( -- mailbox ) self mailbox-of ;
 
+: (receive) ( -- message )
+    my-mailbox mailbox-get ?linked
+    [ (receive) ] if-expired ;  
+
 : receive ( -- message )
-    my-mailbox mailbox-get ?linked ;
+    (receive) data>> ;
+    
+: (receive-timeout) ( timeout -- message )
+    [ my-mailbox ] dip
+    [ mailbox-get-timeout ?linked ] keep
+    '[ _ (receive-timeout) ] if-expired ; inline
 
 : receive-timeout ( timeout -- message )
-    [ my-mailbox ] dip mailbox-get-timeout ?linked ;
+    (receive-timeout) data>> ;
+
+: (receive-if) ( pred -- message )
+    [ my-mailbox ] dip
+    [ mailbox-get? ?linked ] keep
+    '[ _ (receive-if) ] if-expired ; inline
 
 : receive-if ( pred -- message )
-    [ my-mailbox ] dip mailbox-get? ?linked ; inline
+    [ data>> ] prepend (receive-if) data>> ; inline
+
+: (receive-if-timeout) ( timeout pred -- message )
+    [ my-mailbox ] 2dip
+    [ mailbox-get-timeout? ?linked ] 2keep
+    '[ _ _ (receive-if-timeout) ] if-expired ; inline
 
 : receive-if-timeout ( timeout pred -- message )
-    [ my-mailbox ] 2dip mailbox-get-timeout? ?linked ; inline
+    [ data>> ] prepend 
+    (receive-if-timeout) data>> ; inline
 
 : rethrow-linked ( error process supervisor -- )
     [ <linked-error> ] dip send ;
@@ -34,15 +84,17 @@ M: thread send ( message thread -- )
 : spawn-linked ( quot name -- thread )
     my-mailbox spawn-linked-to ;
 
-TUPLE: synchronous data sender tag ;
+TUPLE: synchronous < envelope ;
 
 : <synchronous> ( data -- sync )
-    self synchronous counter synchronous boa ;
+    synchronous new-envelope 
+    synchronous counter >>tag ;
 
-TUPLE: reply data tag ;
+TUPLE: reply < envelope ;
 
 : <reply> ( data synchronous -- reply )
-    tag>> \ reply boa ;
+    [ reply new-envelope ] dip
+    tag>> >>tag ;
 
 : synchronous-reply? ( response synchronous -- ? )
     over reply? [ [ tag>> ] bi@ = ] [ 2drop f ] if ;
@@ -57,24 +109,28 @@ M: cannot-send-synchronous-to-self summary
         cannot-send-synchronous-to-self
     ] [
         [ <synchronous> dup ] dip send
-        '[ _ synchronous-reply? ] receive-if
-        data>>
-    ] if ;
+        '[ _ synchronous-reply? ] (receive-if) data>>
+    ] if ; 
 
 : send-synchronous-timeout ( timeout message thread -- reply ) 
     dup self eq? [
         cannot-send-synchronous-to-self
     ] [
-        [ <synchronous> dup ] dip send
-        '[ _ synchronous-reply? ] receive-if-timeout
-        data>>
+        [ <synchronous> 2dup ] dip send-timeout
+        '[ _ synchronous-reply? ] (receive-if-timeout) data>>
     ] if ;   
-    
+
+<PRIVATE
+
 : reply-synchronous ( message synchronous -- )
-    [ <reply> ] keep sender>> send ;
+    dup expired?
+    [ 2drop ] 
+    [ [ <reply> ] keep sender>> send ] if ;
+
+PRIVATE>
 
 : handle-synchronous ( quot -- )
-    receive [
+    (receive) [
         data>> swap call
     ] keep reply-synchronous ; inline