text: /*
   * Copyright 2007-2021 CM4all GmbH
   * All rights reserved.
   *
   * author: Max Kellermann <mk@cm4all.com>
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * - Redistributions of source code must retain the above copyright
   * notice, this list of conditions and the following disclaimer.
   *
   * - Redistributions in binary form must reproduce the above copyright
   * notice, this list of conditions and the following disclaimer in the
   * documentation and/or other materials provided with the
   * distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
   * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #pragma once
  
  #include "io/MultiWriteBuffer.hxx"
  #include "net/djb/NetstringInput.hxx"
  #include "net/djb/NetstringGenerator.hxx"
  #include "event/SocketEvent.hxx"
  #include "event/CoarseTimerEvent.hxx"
  
  #include <exception>
  #include <cstddef>
  
  class UniqueSocketDescriptor;
  
  /**
   * A server that receives netstrings
   * (http://cr.yp.to/proto/netstrings.txt) from its clients and
   * responds with another netstring.
   */
  class NetstringServer {
  	SocketEvent event;
  	CoarseTimerEvent timeout_event;
  
  	NetstringInput input;
  	NetstringGenerator generator;
  	MultiWriteBuffer write;
  
  public:
  	NetstringServer(EventLoop &event_loop,
  			UniqueSocketDescriptor _fd,
  			size_t max_size=16*1024*1024) noexcept;
  	~NetstringServer() noexcept;
  
  protected:
  	SocketDescriptor GetSocket() const noexcept {
  		return event.GetSocket();
  	}
  
  	bool SendResponse(const void *data, size_t size) noexcept;
  	bool SendResponse(const char *data) noexcept;
  
  	/**
  	 * A netstring has been received.
  	 *
  	 * @param payload the netstring value; for the implementation's
  	 * convenience, the netstring is writable
  	 */
  	virtual void OnRequest(AllocatedArray<uint8_t> &&payload) = 0;
  	virtual void OnError(std::exception_ptr ep) noexcept = 0;
  	virtual void OnDisconnect() noexcept = 0;
  
  private:
  	void OnEvent(unsigned events) noexcept;
  	void OnTimeout() noexcept;
  };
  