print-multiplexer.h

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// Copyright (c) 2024 anabrid GmbH
// Contact: https://www.anabrid.com/licensing/
// SPDX-License-Identifier: MIT OR GPL-2.0-or-later
 
#pragma once
 
#include <Arduino.h>
 
#ifdef ARDUINO
 
#include <algorithm>
#include <list>
#include <vector>
#include <QNEthernetClient.h>
 
#include "util/PrintUtils.h" // QNEthernet
 
namespace utils {
 
using qindesign::network::EthernetClient;
 
class PrintMultiplexer : public Print {
  bool serial = false; 
  std::list<Print *> print_targets;
  std::list<EthernetClient*> eth_targets;
 
public:
  bool optimistic = false; 
 
  void add(Print *target) { print_targets.push_back(target); }
  void add(EthernetClient *target) { eth_targets.push_back(target); }
  void add_Serial() { serial = true; }
 
  void remove(Print *target) { print_targets.remove(target); }
  void remove(EthernetClient *target) { eth_targets.remove(target); }
 
  size_t size() const { return print_targets.size() + eth_targets.size(); }
 
  virtual size_t write(uint8_t b) override {
    bool success = true;
    if(serial && Serial.availableForWrite())       success &= Serial.write(b) == 1;
    for (auto &target : print_targets) if (target) success &= target->write(b) == 1;
    for (auto &target :   eth_targets) if (target) success &= target->writeFully(b) == 1;
    return success ? 1 : (optimistic ? 1 : 0);
  }
 
  size_t write(const uint8_t *buffer, size_t size) override {
    bool success = true;
    if(serial && Serial.availableForWrite())       success &= Serial.write(buffer,size) == size; // do not use writeFully
    for (auto &target : print_targets) if (target) success &= qindesign::network::util::writeFully(*target, buffer, size) == size;
    for (auto &target :   eth_targets) if (target) success &= target->writeFully(buffer, size) == size;
    // so do all this extra work of print_targets + eth_targets just to exploit that
    // EthernetClient::write_fully internally does a "still connected" check and if
    // not, fails. This way we avoid an endless loop if a client disconnects during printout.
    // Typically, in contrast, print_targets are either Serial or String-Buffers.
    return success ? size : (optimistic ? size : 0);
  }
 
  virtual void flush() override {
    if(serial && Serial) Serial.flush();
    for (auto &target : print_targets) if (target) target->flush();
    for (auto &target :   eth_targets) if (target) target->flush();
  }
};
 
} // namespace utils
 
#endif // ARDUINO