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'use strict';
const common = require('../common');
// subprocess.send() will return false if the channel has closed or when the
// backlog of unsent messages exceeds a threshold that makes it unwise to send
// more. Otherwise, the method returns true.
const assert = require('assert');
const net = require('net');
const { fork, spawn } = require('child_process');
const fixtures = require('../common/fixtures');
// Just a script that stays alive (does not listen to `process.on('message')`).
const subScript = fixtures.path('child-process-persistent.js');
{
// Test `send` return value on `fork` that opens and IPC by default.
const n = fork(subScript);
// `subprocess.send` should always return `true` for the first send.
const rv = n.send({ h: 'w' }, assert.ifError);
assert.strictEqual(rv, true);
n.kill('SIGKILL');
}
{
// Test `send` return value on `spawn` and saturate backlog with handles.
// Call `spawn` with options that open an IPC channel.
const spawnOptions = { stdio: ['pipe', 'pipe', 'pipe', 'ipc'] };
const s = spawn(process.execPath, [subScript], spawnOptions);
const server = net.createServer(common.mustNotCall()).listen(0, () => {
const handle = server._handle;
// Sending a handle and not giving the tickQueue time to acknowledge should
// create the internal backlog, but leave it empty.
const rv1 = s.send('one', handle, (err) => { if (err) assert.fail(err); });
assert.strictEqual(rv1, true);
// Since the first `send` included a handle (should be unacknowledged),
// we can safely queue up only one more message.
const rv2 = s.send('two', (err) => { if (err) assert.fail(err); });
assert.strictEqual(rv2, true);
// The backlog should now be indicate to backoff.
const rv3 = s.send('three', (err) => { if (err) assert.fail(err); });
assert.strictEqual(rv3, false);
const rv4 = s.send('four', (err) => {
if (err) assert.fail(err);
// `send` queue should have been drained.
const rv5 = s.send('5', handle, (err) => { if (err) assert.fail(err); });
assert.strictEqual(rv5, true);
// End test and cleanup.
s.kill();
handle.close();
server.close();
});
assert.strictEqual(rv4, false);
});
}
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