xAOD::TSocket Class Reference

Very simple wrapper around POSIX sockets. More...

#include <TSocket.h>

Collaboration diagram for xAOD::TSocket:

Public Member Functions
	TSocket ()
	Constructor with an address and a port.
	~TSocket ()
	Destructor.
	TSocket (const TSocket &)=delete
	Do not allow object copying.
TSocket &	operator= (const TSocket &)=delete
	Do not allow assignment.
StatusCode	connect (const TInetAddress &address, int port)
	Function connecting to the specified address.
StatusCode	close ()
	Close the current connection.
bool	isConnected () const
	Check if the socket is connected to some address at the moment.
StatusCode	send (const TString &payload)
	Function sending a message to the connected address.
StatusCode	receive (std::size_t maxSize, TString &response)
	Function receiving a message from the connected address.

Private Attributes
int	m_socket
	The underlying socket.

Detailed Description

Very simple wrapper around POSIX sockets.

Since ROOT's TSocket is not fit to be used in TFileAccessTracer's destructor (as some ROOT infrastructure may not be available by the time the destructor is called), we need our own simple implementation instead.

Most of the implementation is simply a copy of the code from TUnixSystem. Slightly simplified in some cases where we don't need the flexibility of the ROOT implementation.

Author

Attila Krasznahorkay Attil.nosp@m.a.Kr.nosp@m.aszna.nosp@m.hork.nosp@m.ay@ce.nosp@m.rn.c.nosp@m.h

Definition at line 32 of file TSocket.h.

Constructor & Destructor Documentation

TSocket() [1/2]

xAOD::TSocket::TSocket

(

)

Constructor with an address and a port.

Definition at line 26 of file TSocket.cxx.

: m_socket(-1) {}

~TSocket()

xAOD::TSocket::~TSocket

(

)

Destructor.

Definition at line 28 of file TSocket.cxx.

                  {
 
  // Close the socket if it's open:
  if (isConnected()) {
    close().ignore();
  }
}

TSocket() [2/2]

xAOD::TSocket::TSocket ( const TSocket & )

delete

Do not allow object copying.

Member Function Documentation

close()

StatusCode xAOD::TSocket::close

(

)

Close the current connection.

Definition at line 91 of file TSocket.cxx.

                          {
 
  // Check if anything needs to be done:
  if (!isConnected()) {
    return StatusCode::RECOVERABLE;
  }
 
  // Close the socket:
  if (::close(m_socket) != 0) {
    return StatusCode::FAILURE;
  }
 
  // Return gracefully:
  m_socket = -1;
  return StatusCode::SUCCESS;
}

connect()

StatusCode xAOD::TSocket::connect	(	const TInetAddress &	address,
		int	port )

Function connecting to the specified address.

It turns out that translating a string address name into an integer address that the connect(...) function understands, is no easy feat.

So instead we leave that up to ROOT. This translation just needs to be done "early enough" in the job when ROOT can still do it.

Parameters

address	The address to connect to
port	The port number to connect to

Returns

The usual return codes...

Definition at line 45 of file TSocket.cxx.

                                                                 {
 
  // If the address is invalid, give up now:
  if (!address.IsValid()) {
    return StatusCode::FAILURE;
  }
 
  // If not, translate it to a network address:
  const UInt_t adr = htonl(address.GetAddress());
 
  // "Translate" the port number:
  short sport = 0;
  struct servent sp_buf;
  struct servent* sp;
  char buf[1024];  // needs to be large enough for all strings in servent
  getservbyport_r(htons(port), "tcp", &sp_buf, buf, sizeof(buf), &sp);
  if (sp) {
    sport = sp->s_port;
  } else {
    sport = htons(port);
  }
 
  // Create a socket:
  m_socket = ::socket(AF_INET, SOCK_STREAM, 0);
  if (m_socket < 0) {
    return StatusCode::FAILURE;
  }
 
  // Create the address that we want to connect to:
  struct sockaddr_in server;
  memset(&server, 0, sizeof(server));
  memcpy(&server.sin_addr, &adr, sizeof(adr));
  server.sin_family = address.GetFamily();
  server.sin_port = sport;
 
  // Connect to the address:
  if (::connect(m_socket, reinterpret_cast<const sockaddr*>(&server),
                sizeof(server)) < 0) {
    m_socket = -1;
    return StatusCode::FAILURE;
  }
 
  // Return gracefully:
  return StatusCode::SUCCESS;
}

isConnected()

bool xAOD::TSocket::isConnected

(

)

const

Check if the socket is connected to some address at the moment.

Definition at line 108 of file TSocket.cxx.

                                {
 
  return (m_socket != -1);
}

operator=()

TSocket & xAOD::TSocket::operator= ( const TSocket & )

delete

Do not allow assignment.

receive()

StatusCode xAOD::TSocket::receive	(	std::size_t	maxSize,
		TString &	response )

Function receiving a message from the connected address.

Definition at line 147 of file TSocket.cxx.

                                                                {
 
  // Check if we're connected.
  if (!isConnected()) {
    return StatusCode::FAILURE;
  }
 
  // Buffer to receive the message into.
  auto buffer = std::make_unique<char[]>(maxSize);
 
  // Try to receive a message.
  const auto n = ::recv(m_socket, buffer.get(), maxSize, 0);
  if (n <= 0) {
    return StatusCode::FAILURE;
  }
 
  // Return the message as a TString.
  response = TString(buffer.get(), static_cast<Ssiz_t>(n));
  return StatusCode::SUCCESS;
}

send()

StatusCode xAOD::TSocket::send

(

const TString &

payload

)

Function sending a message to the connected address.

This function is custom made for our use case.

It sends HTML style information to the connected server.

Parameters

payload

The HTML style payload to send to the server

Returns

The usual return codes...

Definition at line 119 of file TSocket.cxx.

                                               {
 
  // Check if we're connected:
  if (!isConnected()) {
    return StatusCode::FAILURE;
  }
 
  // The buffer we are sending from:
  const char* buffer = payload.Data();
  // The total length of the message:
  const auto length = payload.Length();
  // Number of bytes already sent:
  int sent = 0;
 
  // Keep sending the message until everything is through:
  for (int i = 0; i < length; i += sent) {
    sent = ::send(m_socket, buffer + i, length - i, 0);
    if (sent < 0) {
      return StatusCode::FAILURE;
    } else if (sent == 0) {
      break;
    }
  }
 
  // Return gracefully:
  return StatusCode::SUCCESS;
}

Member Data Documentation

m_socket

int xAOD::TSocket::m_socket

private

The underlying socket.

Definition at line 61 of file TSocket.h.

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The documentation for this class was generated from the following files:

• TSocket.h
• TSocket.cxx