lts/lib/internal/js_stream_socket.js
'use strict';
const {
Symbol,
} = primordials;
const { setImmediate } = require('timers');
const assert = require('internal/assert');
const { Socket } = require('net');
const { JSStream } = internalBinding('js_stream');
const uv = internalBinding('uv');
const debug = require('internal/util/debuglog').debuglog('stream_socket');
const { owner_symbol } = require('internal/async_hooks').symbols;
const { ERR_STREAM_WRAP } = require('internal/errors').codes;
const kCurrentWriteRequest = Symbol('kCurrentWriteRequest');
const kCurrentShutdownRequest = Symbol('kCurrentShutdownRequest');
const kPendingShutdownRequest = Symbol('kPendingShutdownRequest');
function isClosing() { return this[owner_symbol].isClosing(); }
function onreadstart() { return this[owner_symbol].readStart(); }
function onreadstop() { return this[owner_symbol].readStop(); }
function onshutdown(req) { return this[owner_symbol].doShutdown(req); }
function onwrite(req, bufs) { return this[owner_symbol].doWrite(req, bufs); }
/* This class serves as a wrapper for when the C++ side of Node wants access
* to a standard JS stream. For example, TLS or HTTP do not operate on network
* resources conceptually, although that is the common case and what we are
* optimizing for; in theory, they are completely composable and can work with
* any stream resource they see.
*
* For the common case, i.e. a TLS socket wrapping around a net.Socket, we
* can skip going through the JS layer and let TLS access the raw C++ handle
* of a net.Socket. The flipside of this is that, to maintain composability,
* we need a way to create "fake" net.Socket instances that call back into a
* "real" JavaScript stream. JSStreamSocket is exactly this.
*/
class JSStreamSocket extends Socket {
constructor(stream) {
const handle = new JSStream();
handle.close = (cb) => {
debug('close');
this.doClose(cb);
};
// Inside of the following functions, `this` refers to the handle
// and `this[owner_symbol]` refers to this JSStreamSocket instance.
handle.isClosing = isClosing;
handle.onreadstart = onreadstart;
handle.onreadstop = onreadstop;
handle.onshutdown = onshutdown;
handle.onwrite = onwrite;
stream.pause();
stream.on('error', (err) => this.emit('error', err));
const ondata = (chunk) => {
if (typeof chunk === 'string' ||
stream.readableObjectMode === true) {
// Make sure that no further `data` events will happen.
stream.pause();
stream.removeListener('data', ondata);
this.emit('error', new ERR_STREAM_WRAP());
return;
}
debug('data', chunk.length);
if (this._handle)
this._handle.readBuffer(chunk);
};
stream.on('data', ondata);
stream.once('end', () => {
debug('end');
if (this._handle)
this._handle.emitEOF();
});
// Some `Stream` don't pass `hasError` parameters when closed.
stream.once('close', () => {
// Errors emitted from `stream` have also been emitted to this instance
// so that we don't pass errors to `destroy()` again.
this.destroy();
});
super({ handle, manualStart: true });
this.stream = stream;
this[kCurrentWriteRequest] = null;
this[kCurrentShutdownRequest] = null;
this[kPendingShutdownRequest] = null;
this.readable = stream.readable;
this.writable = stream.writable;
// Start reading.
this.read(0);
}
// Allow legacy requires in the test suite to keep working:
// const { StreamWrap } = require('internal/js_stream_socket')
static get StreamWrap() {
return JSStreamSocket;
}
isClosing() {
return !this.readable || !this.writable;
}
readStart() {
this.stream.resume();
return 0;
}
readStop() {
this.stream.pause();
return 0;
}
doShutdown(req) {
// TODO(addaleax): It might be nice if we could get into a state where
// DoShutdown() is not called on streams while a write is still pending.
//
// Currently, the only part of the code base where that happens is the
// TLS implementation, which calls both DoWrite() and DoShutdown() on the
// underlying network stream inside of its own DoShutdown() method.
// Working around that on the native side is not quite trivial (yet?),
// so for now that is supported here.
if (this[kCurrentWriteRequest] !== null) {
this[kPendingShutdownRequest] = req;
return 0;
}
assert(this[kCurrentWriteRequest] === null);
assert(this[kCurrentShutdownRequest] === null);
this[kCurrentShutdownRequest] = req;
const handle = this._handle;
setImmediate(() => {
// Ensure that write is dispatched asynchronously.
this.stream.end(() => {
this.finishShutdown(handle, 0);
});
});
return 0;
}
// handle === this._handle except when called from doClose().
finishShutdown(handle, errCode) {
// The shutdown request might already have been cancelled.
if (this[kCurrentShutdownRequest] === null)
return;
const req = this[kCurrentShutdownRequest];
this[kCurrentShutdownRequest] = null;
handle.finishShutdown(req, errCode);
}
doWrite(req, bufs) {
assert(this[kCurrentWriteRequest] === null);
assert(this[kCurrentShutdownRequest] === null);
const handle = this._handle;
const self = this;
let pending = bufs.length;
this.stream.cork();
// Use `var` over `let` for performance optimization.
for (var i = 0; i < bufs.length; ++i)
this.stream.write(bufs[i], done);
this.stream.uncork();
// Only set the request here, because the `write()` calls could throw.
this[kCurrentWriteRequest] = req;
function done(err) {
if (!err && --pending !== 0)
return;
// Ensure that this is called once in case of error
pending = 0;
let errCode = 0;
if (err) {
errCode = uv[`UV_${err.code}`] || uv.UV_EPIPE;
}
// Ensure that write was dispatched
setImmediate(() => {
self.finishWrite(handle, errCode);
});
}
return 0;
}
// handle === this._handle except when called from doClose().
finishWrite(handle, errCode) {
// The write request might already have been cancelled.
if (this[kCurrentWriteRequest] === null)
return;
const req = this[kCurrentWriteRequest];
this[kCurrentWriteRequest] = null;
handle.finishWrite(req, errCode);
if (this[kPendingShutdownRequest]) {
const req = this[kPendingShutdownRequest];
this[kPendingShutdownRequest] = null;
this.doShutdown(req);
}
}
doClose(cb) {
const handle = this._handle;
// When sockets of the "net" module destroyed, they will call
// `this._handle.close()` which will also emit EOF if not emitted before.
// This feature makes sockets on the other side emit "end" and "close"
// even though we haven't called `end()`. As `stream` are likely to be
// instances of `net.Socket`, calling `stream.destroy()` manually will
// avoid issues that don't properly close wrapped connections.
this.stream.destroy();
setImmediate(() => {
// Should be already set by net.js
assert(this._handle === null);
this.finishWrite(handle, uv.UV_ECANCELED);
this.finishShutdown(handle, uv.UV_ECANCELED);
cb();
});
}
}
module.exports = JSStreamSocket;