80 lines
2.5 KiB
JavaScript
80 lines
2.5 KiB
JavaScript
//---------------------------------------------------------------------------
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// @syndicate-lang/driver-streams-node, Stream support for Syndicate/js
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// Copyright (C) 2016-2018 Tony Garnock-Jones <tonyg@leastfixedpoint.com>
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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//---------------------------------------------------------------------------
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import { currentFacet, Observe, genUuid, Bytes, List } from "@syndicate-lang/core";
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const S = activate require("./streams");
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message type PacketRequest(size);
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export {
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PacketRequest,
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};
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export function onStartSpawnBufferStream() {
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const id = genUuid('buffer-stream');
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on start _spawnBufferStream(id);
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return id;
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}
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export function spawnBufferStream() {
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const id = genUuid('buffer-stream');
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_spawnBufferStream(id);
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return id;
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}
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function _spawnBufferStream(id) {
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spawn named id {
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stop on retracted Observe(S.Stream(id, S.Duplex()));
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assert S.Stream(id, S.Duplex());
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assert S.Stream(id, S.Info(Symbol.for('Duplex'), null));
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field this.buffer = Bytes();
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field this.queue = List();
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on message S.Stream(id, S.Push($chunk, $ack)) {
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this.buffer = Bytes.concat([this.buffer, chunk]);
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if (ack !== null) send ack;
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}
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stop on message S.Stream(id, S.Close($ack)) {
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if (ack !== false) send ack;
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}
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on message S.Stream(id, PacketRequest($size)) {
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if (size === 0) {
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// Signal to terminate.
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currentFacet().stop(() => { send S.Stream(id, S.Data(this.buffer)); });
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} else {
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this.queue = this.queue.push(size);
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}
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}
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dataflow {
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if (!this.queue.isEmpty()) {
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const expected = this.queue.first();
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if (this.buffer.size >= expected) {
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send S.Stream(id, S.Data(this.buffer.slice(0, expected)));
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this.buffer = this.buffer.slice(expected);
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this.queue = this.queue.shift();
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}
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}
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}
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}
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return id;
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}
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