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// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
$262.agent = (function () {
var workers = [];
var i32a = null;
var pendingReports = [];
// Agents call Atomics.wait on this location to sleep.
var SLEEP_LOC = 0;
// 1 if the started worker is ready, 0 otherwise.
var START_LOC = 1;
// The number of workers that have received the broadcast.
var BROADCAST_LOC = 2;
// Each worker has a count of outstanding reports; worker N uses memory
// location [WORKER_REPORT_LOC + N].
var WORKER_REPORT_LOC = 3;
function workerScript(script) {
return `
var index;
var i32a = null;
var broadcasts = [];
var pendingReceiver = null;
function handleBroadcast() {
if (pendingReceiver && broadcasts.length > 0) {
pendingReceiver.apply(null, broadcasts.shift());
pendingReceiver = null;
}
};
var onmessage = function(msg) {
switch (msg.kind) {
case 'start':
i32a = msg.i32a;
index = msg.index;
(0, eval)(\`${script}\`);
break;
case 'broadcast':
Atomics.add(i32a, ${BROADCAST_LOC}, 1);
broadcasts.push([msg.sab, msg.id]);
handleBroadcast();
break;
}
};
var $262 = {
agent: {
receiveBroadcast(receiver) {
pendingReceiver = receiver;
handleBroadcast();
},
report(msg) {
postMessage(String(msg));
Atomics.add(i32a, ${WORKER_REPORT_LOC} + index, 1);
},
sleep(s) { Atomics.wait(i32a, ${SLEEP_LOC}, 0, s); },
leaving() {},
monotonicNow() {
return performance.now();
}
}
};`;
}
var agent = {
start(script) {
if (i32a === null) {
i32a = new Int32Array(new SharedArrayBuffer(256));
}
var w = new Worker(workerScript(script), {type: 'string'});
w.index = workers.length;
w.postMessage({kind: 'start', i32a: i32a, index: w.index});
workers.push(w);
},
broadcast(sab, id) {
if (!(sab instanceof SharedArrayBuffer)) {
throw new TypeError('sab must be a SharedArrayBuffer.');
}
Atomics.store(i32a, BROADCAST_LOC, 0);
for (var w of workers) {
w.postMessage({kind: 'broadcast', sab: sab, id: id|0});
}
while (Atomics.load(i32a, BROADCAST_LOC) != workers.length) {}
},
getReport() {
for (var w of workers) {
while (Atomics.load(i32a, WORKER_REPORT_LOC + w.index) > 0) {
pendingReports.push(w.getMessage());
Atomics.sub(i32a, WORKER_REPORT_LOC + w.index, 1);
}
}
return pendingReports.shift() || null;
},
sleep(s) { Atomics.wait(i32a, SLEEP_LOC, 0, s); },
monotonicNow() {
return performance.now();
}
};
return agent;
})();
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