nodejs http2 pre-read connection stream wrapper

SocketProxy.js

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _stream = require("stream");

const kWait = Symbol("wait");
const kNread = Symbol("nread");
const kSocket = Symbol("socket");
const kBuffer = Symbol("buffer");

class SocketProxy extends _stream.Duplex {

  constructor(socket, buffer) {
    super({
      allowHalfOpen: true,
      decodeStrings: false
    });
    this[kWait] = true;
    this[kNread] = -1;
    this[kSocket] = socket;
    this[kBuffer] = buffer;
    const handleError = () => this.destroy();
    const handleData = chunk => this._checkSocket() && this.addChunk(chunk);
    socket.addListener("error", handleError);
    socket.addListener("data", handleData);
    socket.once("close", err => this.emit("close", err));
    socket.once("end", () => {
      this[kWait] = false;
      this.tryRead();
      this.emit("end");
      this.destroy();
    });
  }

  _checkSocket() {
    const socket = this[kSocket];
    if (socket && !socket.destroyed) {
      return true;
    } else if (socket) {
      this[kWait] = false;
      delete this[kSocket];
      delete this[kBuffer];
    }
    return false;
  }

  _write(data, encoding, cb) {
    if (this._checkSocket()) {
      try {
        this[kSocket].write(data, encoding);
        cb();
      } catch (err) {
        cb(err);
      }
    } else {
      cb();
    }
  }

  _destroy(e, cb) {
    if (this[kSocket]) {
      this[kWait] = false;
      this[kNread] = -1;
      if (!this[kSocket].destroyed) {
        this[kSocket].destroy();
      }
      delete this[kSocket];
      delete this[kBuffer];
    }
    cb();
  }

  _read(nread) {
    if (this._checkSocket()) {
      if (this[kBuffer] && this[kBuffer].length > 0) {
        const data = this[kBuffer].slice(0, nread);
        this[kBuffer] = this[kBuffer].slice(nread);
        return this.push(data);
      } else if (this[kWait]) {
        this[kNread] = nread;
      } else {
        return this.push(null);
      }
    }
  }

  addChunk(chunk) {
    this[kBuffer] = Buffer.concat([this[kBuffer], chunk]);
    this.tryRead();
  }

  tryRead() {
    const nread = this[kNread];
    if (nread !== -1) {
      this[kNread] = -1;
      this._read(nread);
    }
  }

  get remoteAddress() {
    return this._checkSocket() && this[kSocket].remoteAddress;
  }

  get remotePort() {
    return this._checkSocket() && this[kSocket].remotePort;
  }

  setTimeout(timeout, callback) {
    return this._checkSocket() && this[kSocket].setTimeout(timeout, callback);
  }
}