battletank/arduino/libraries/Firmata/utility/EthernetClientStream.h

/*
  EthernetClientStream.h
  An Arduino-Stream that wraps an instance of Client reconnecting to
  the remote-ip in a transparent way. A disconnected client may be
  recognized by the returnvalues -1 from calls to peek or read and
  a 0 from calls to write.

  Copyright (C) 2013 Norbert Truchsess. All rights reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  See file LICENSE.txt for further informations on licensing terms.

  Last updated June 18th, 2016
 */

#ifndef ETHERNETCLIENTSTREAM_H
#define ETHERNETCLIENTSTREAM_H

#include <inttypes.h>
#include <Stream.h>

//#define SERIAL_DEBUG
#include "firmataDebug.h"

#define MILLIS_RECONNECT 5000

class EthernetClientStream : public Stream
{
  public:
    EthernetClientStream(Client &client, IPAddress localip, IPAddress ip, const char* host, uint16_t port);
    int available();
    int read();
    int peek();
    void flush();
    size_t write(uint8_t);
    void maintain(IPAddress localip);

  private:
    Client &client;
    IPAddress localip;
    IPAddress ip;
    const char* host;
    uint16_t port;
    bool connected;
    uint32_t time_connect;
    bool maintain();
    void stop();
};


/*
 * EthernetClientStream.cpp
 * Copied here as a hack to linker issues with 3rd party board packages that don't properly
 * implement the Arduino network APIs.
 */
EthernetClientStream::EthernetClientStream(Client &client, IPAddress localip, IPAddress ip, const char* host, uint16_t port)
  : client(client),
    localip(localip),
    ip(ip),
    host(host),
    port(port),
    connected(false)
{
}

int
EthernetClientStream::available()
{
  return maintain() ? client.available() : 0;
}

int
EthernetClientStream::read()
{
  return maintain() ? client.read() : -1;
}

int
EthernetClientStream::peek()
{
  return maintain() ? client.peek() : -1;
}

void EthernetClientStream::flush()
{
  if (maintain())
    client.flush();
}

size_t
EthernetClientStream::write(uint8_t c)
{
  return maintain() ? client.write(c) : 0;
}

void
EthernetClientStream::maintain(IPAddress localip)
{
  // ensure the local IP is updated in the case that it is changed by the DHCP server
  if (this->localip != localip) {
    this->localip = localip;
    if (connected)
      stop();
  }
}

void
EthernetClientStream::stop()
{
  client.stop();
  connected = false;
  time_connect = millis();
}

bool
EthernetClientStream::maintain()
{
  if (client && client.connected())
    return true;

  if (connected) {
    stop();
  }
  // if the client is disconnected, attempt to reconnect every 5 seconds
  else if (millis() - time_connect >= MILLIS_RECONNECT) {
    connected = host ? client.connect(host, port) : client.connect(ip, port);
    if (!connected) {
      time_connect = millis();
      DEBUG_PRINTLN("Connection failed. Attempting to reconnect...");
    } else {
      DEBUG_PRINTLN("Connected");
    }
  }
  return connected;
}

#endif /* ETHERNETCLIENTSTREAM_H */