Add protocols.clj

Author: dmiller

src/main/clojure/clojure/core/async/impl/protocols.clj

@@ -0,0 +1,47 @@
+;;   Copyright (c) Rich Hickey and contributors. All rights reserved.
+;;   The use and distribution terms for this software are covered by the
+;;   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
+;;   which can be found in the file epl-v10.html at the root of this distribution.
+;;   By using this software in any fashion, you are agreeing to be bound by
+;;   the terms of this license.
+;;   You must not remove this notice, or any other, from this software.
+
+(ns ^{:skip-wiki true}
+  clojure.core.async.impl.protocols)
+
+
+(def ^:const ^{:tag 'int} MAX-QUEUE-SIZE 1024)
+
+(defprotocol ReadPort
+  (take! [port fn1-handler] "derefable val if taken, nil if take was enqueued"))
+
+(defprotocol WritePort
+  (put! [port val fn1-handler] "derefable boolean (false iff already closed) if handled, nil if put was enqueued. Must throw on nil val."))
+
+(defprotocol Channel
+  (close! [chan])
+  (closed? [chan]))
+
+(defprotocol Handler
+  (active? [h] "returns true if has callback. Must work w/o lock")
+  (blockable? [h] "returns true if this handler may be blocked, otherwise it must not block")
+  (lock-id [h] "a unique id for lock acquisition order, 0 if no lock")
+  (commit [h] "commit to fulfilling its end of the transfer, returns cb. Must be called within lock"))
+
+(defprotocol ABuffer                                                                               ;;; Rename Buffer because of conflict with System.Buffer
+  (full? [b] "returns true if buffer cannot accept put")
+  (remove! [b] "remove and return next item from buffer, called under chan mutex")
+  (add!* [b itm] "if room, add item to the buffer, returns b, called under chan mutex")
+  (close-buf! [b] "called on chan closed under chan mutex, return ignored"))
+
+(defn add!
+  ([b] b)
+  ([b itm]
+     (assert (not (nil? itm)))
+     (add!* b itm)))
+
+(defprotocol Executor
+  (exec [e runnable] "execute runnable asynchronously"))
+
+;; Defines a buffer that will never block (return true to full?)
+(defprotocol UnblockingBuffer)