forked from clojure/core.async
/
channels.cljs
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/
channels.cljs
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;; 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 cljs.core.async.impl.channels
(:require [cljs.core.async.impl.protocols :as impl]
[cljs.core.async.impl.dispatch :as dispatch]
[cljs.core.async.impl.buffers :as buffers]))
(defn box [val]
(reify cljs.core/IDeref
(-deref [_] val)))
(deftype PutBox [handler val])
(defn put-active? [box]
(impl/active? (.-handler box)))
(def ^:const MAX_DIRTY 64)
(defprotocol MMC
(abort [this]))
(deftype ManyToManyChannel [takes ^:mutable dirty-takes puts ^:mutable dirty-puts ^not-native buf ^:mutable closed add!]
MMC
(abort [this]
(loop []
(let [putter (.pop puts)]
(when-not (nil? putter)
(let [^not-native put-handler (.-handler putter)
val (.-val putter)]
(if ^boolean (impl/active? put-handler)
(let [put-cb (impl/commit put-handler)]
(dispatch/run #(put-cb true)))
(recur))))))
(.cleanup puts (constantly false))
(impl/close! this))
impl/WritePort
(put! [this val ^not-native handler]
(assert (not (nil? val)) "Can't put nil on a channel")
;; bug in CLJS compiler boolean inference - David
(let [^boolean closed closed]
(if (or closed (not ^boolean (impl/active? handler)))
(box (not closed))
(if (and buf (not (impl/full? buf)))
(do
(impl/commit handler)
(let [done? (reduced? (add! buf val))
take-cbs (loop [takers []]
(if (and (pos? (.-length takes)) (pos? (count buf)))
(let [^not-native taker (.pop takes)]
(if ^boolean (impl/active? taker)
(let [ret (impl/commit taker)
val (impl/remove! buf)]
(recur (conj takers (fn [] (ret val)))))
(recur takers)))
takers))]
(when done? (abort this))
(when (seq take-cbs)
(doseq [f take-cbs]
(dispatch/run f)))
(box true)))
(let [taker (loop []
(let [^not-native taker (.pop takes)]
(when taker
(if (impl/active? taker)
taker
(recur)))))]
(if taker
(let [take-cb (impl/commit taker)]
(impl/commit handler)
(dispatch/run (fn [] (take-cb val)))
(box true))
(do
(if (> dirty-puts MAX_DIRTY)
(do (set! dirty-puts 0)
(.cleanup puts put-active?))
(set! dirty-puts (inc dirty-puts)))
(when (impl/blockable? handler)
(assert (< (.-length puts) impl/MAX-QUEUE-SIZE)
(str "No more than " impl/MAX-QUEUE-SIZE
" pending puts are allowed on a single channel."
" Consider using a windowed buffer."))
(.unbounded-unshift puts (PutBox. handler val)))
nil)))))))
impl/ReadPort
(take! [this ^not-native handler]
(if (not ^boolean (impl/active? handler))
nil
(if (and (not (nil? buf)) (pos? (count buf)))
(do
(if-let [take-cb (impl/commit handler)]
(let [val (impl/remove! buf)
[done? cbs] (when (and (not (impl/full? buf)) (pos? (.-length puts)))
(loop [cbs []]
(let [putter (.pop puts)
^not-native put-handler (.-handler putter)
val (.-val putter)
cb (and ^boolean (impl/active? put-handler) (impl/commit put-handler))
cbs (if cb (conj cbs cb) cbs)
done? (when cb (reduced? (add! buf val)))]
(if (and (not done?) (not (impl/full? buf)) (pos? (.-length puts)))
(recur cbs)
[done? cbs]))))]
(when done?
(abort this))
(doseq [cb cbs]
(dispatch/run #(cb true)))
(box val))))
(let [putter (loop []
(let [putter (.pop puts)]
(when putter
(if ^boolean (impl/active? (.-handler putter))
putter
(recur)))))]
(if putter
(let [put-cb (impl/commit (.-handler putter))]
(impl/commit handler)
(dispatch/run #(put-cb true))
(box (.-val putter)))
(if closed
(do
(when buf (add! buf))
(if (and (impl/active? handler) (impl/commit handler))
(let [has-val (and buf (pos? (count buf)))]
(let [val (when has-val (impl/remove! buf))]
(box val)))
nil))
(do
(if (> dirty-takes MAX_DIRTY)
(do (set! dirty-takes 0)
(.cleanup takes impl/active?))
(set! dirty-takes (inc dirty-takes)))
(when (impl/blockable? handler)
(assert (< (.-length takes) impl/MAX-QUEUE-SIZE)
(str "No more than " impl/MAX-QUEUE-SIZE
" pending takes are allowed on a single channel."))
(.unbounded-unshift takes handler))
nil)))))))
impl/Channel
(closed? [_] closed)
(close! [this]
(if ^boolean closed
nil
(do (set! closed true)
(when (and buf (zero? (.-length puts)))
(add! buf))
(loop []
(let [^not-native taker (.pop takes)]
(when-not (nil? taker)
(when ^boolean (impl/active? taker)
(let [take-cb (impl/commit taker)
val (when (and buf (pos? (count buf))) (impl/remove! buf))]
(dispatch/run (fn [] (take-cb val)))))
(recur))))
(when buf (impl/close-buf! buf))
nil))))
(defn- ex-handler [ex]
(.log js/console ex)
nil)
(defn- handle [buf exh t]
(let [else ((or exh ex-handler) t)]
(if (nil? else)
buf
(impl/add! buf else))))
(defn chan
([buf] (chan buf nil))
([buf xform] (chan buf xform nil))
([buf xform exh]
(ManyToManyChannel. (buffers/ring-buffer 32) 0 (buffers/ring-buffer 32)
0 buf false
(let [add! (if xform (xform impl/add!) impl/add!)]
(fn
([buf]
(try
(add! buf)
(catch :default t
(handle buf exh t))))
([buf val]
(try
(add! buf val)
(catch :default t
(handle buf exh t)))))))))