FIFOConnection.cpp

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// DUNE DAQ modification notice:
// This file has been modified from the original ATLAS system source for the DUNE DAQ project.
// Fork baseline commit: system-00-00-20 (2020-09-25).
// Renamed since fork: yes (from src/FIFOConnection.cxx to src/FIFOConnection.cpp).
 
/*
 *  FIFOConnection.cxx
 *  OksSystem
 *
 *  Created by Matthias Wiesmann on 07.04.05.
 *  Copyright 2005 CERN. All rights reserved.
 *
 */
 
#include <fcntl.h>
 
#include "ers/ers.hpp"
 
#include "okssystem/FIFOConnection.hpp"
#include "okssystem/exceptions.hpp"
 
const unsigned int OksSystem::FIFOConnection::MAX_MESSAGE_LEN = 512;

 
OksSystem::FIFOConnection::FIFOConnection(const std::string &name) : OksSystem::File(name) {
  m_fifo_fd = 0;
  m_is_blocking = true;
} 

 
OksSystem::FIFOConnection::FIFOConnection(const File &file) : OksSystem::File(file) {
  m_fifo_fd = 0;
  m_is_blocking = true;
} 
 
OksSystem::FIFOConnection::~FIFOConnection() {
  delete m_fifo_fd;
}
 
void OksSystem::FIFOConnection::make(mode_t perm) const {
    File::make_fifo(perm); 
} // make

 
std::string OksSystem::FIFOConnection::read_message() const {
    ERS_ASSERT_MSG(exists(),"FIFO "<< c_full_name() << " does not exist."); 
    if (! is_fifo()) {
    ers::warning(OksSystem::Exception(ERS_HERE, std::string(c_full_name()) + std::string(" is not a FIFO"))); 
    } // should probably be FIFO
    OksSystem::Descriptor connection_fd(this,O_RDONLY,0); 
    char buffer[MAX_MESSAGE_LEN];
    while(true) {
    const int status = connection_fd.read(buffer,sizeof(buffer)-1);
    if (status>0) {
        ERS_ASSERT(status<(int) sizeof(buffer)); 
        buffer[status] = '\0';// we make sure we have a C-string
        return std::string(buffer); 
    } // if 
    usleep(100000);
    } // while 
} // read_message
 
void OksSystem::FIFOConnection::send_message(const std::string &message) const {
    ERS_ASSERT_MSG(exists(),"FIFO "<< c_full_name() << " does not exist. Cannot put "<< message << " into FIFO.");
    if (! is_fifo()) {
    ers::warning(OksSystem::Exception(ERS_HERE, std::string(c_full_name()) + std::string(" is not a FIFO"))); 
    } // should probably be FIFO 
    const unsigned int l = message.size();
    ERS_RANGE_CHECK(1,l,MAX_MESSAGE_LEN); 
    OksSystem::Descriptor connection_fd(this,O_WRONLY,0);
    connection_fd.write(message.data(),l); 
} // send_message 

 
void OksSystem::FIFOConnection::send(const std::string &message) const {
    ERS_ASSERT(m_fifo_fd);
    const unsigned int l = message.size();
    ERS_RANGE_CHECK(1,l,MAX_MESSAGE_LEN); 
    m_fifo_fd->write(message.data(),l); 
} // send

 
std::string OksSystem::FIFOConnection::read() const {
    ERS_ASSERT(m_fifo_fd);    
    char buffer[MAX_MESSAGE_LEN];
    while(true) {
      const int status = m_fifo_fd->read(buffer,sizeof(buffer)-1);
      if (status>0) {
    ERS_ASSERT(status<(int) sizeof(buffer)); 
    buffer[status] = '\0';// we make sure we have a C-string
    return std::string(buffer); 
      } // if 
      if (m_is_blocking == false && status == 0) return std::string("");
      usleep(100000); // Slow down the loop 
    } // while 
} // read

 
OksSystem::Descriptor* OksSystem::FIFOConnection::open_r(bool block) {
 
  ERS_ASSERT(!m_fifo_fd);
 
  int flags = O_RDONLY; 
  
  if(block == false) {
    flags = O_RDONLY|O_NONBLOCK;
    m_is_blocking = false;
  }
 
  try {
    m_fifo_fd = new OksSystem::Descriptor(this,flags,0);
  }
  catch(OksSystem::OpenFileIssue &ex) {
    delete m_fifo_fd;
    m_fifo_fd = 0;
    throw;
  }
 
  return m_fifo_fd;
  
}

 
 
OksSystem::Descriptor* OksSystem::FIFOConnection::open_w(bool block) {
  
  ERS_ASSERT(!m_fifo_fd);
 
  int flags = O_WRONLY;
  
  if(block == false) {
    flags = O_WRONLY|O_NONBLOCK;
    m_is_blocking = false;
  }
 
  try {
    m_fifo_fd = new OksSystem::Descriptor(this,flags,0);
  }
  catch(OksSystem::OpenFileIssue &ex) {
    delete m_fifo_fd;
    m_fifo_fd = 0;
    throw;
  }
 
  return m_fifo_fd;
 
}

 
OksSystem::Descriptor* OksSystem::FIFOConnection::open_rw(bool block) {
  
  ERS_ASSERT(!m_fifo_fd);
 
  int flags = O_RDWR;
  
  if(block == false) {
    flags = O_RDWR|O_NONBLOCK;
    m_is_blocking = false;
  }
 
  try {
    m_fifo_fd = new OksSystem::Descriptor(this,flags,0);
  }
  catch(OksSystem::OpenFileIssue &ex) {
    delete m_fifo_fd;
    m_fifo_fd = 0;
    throw;
  }
  
  return m_fifo_fd;
  
}

 
void OksSystem::FIFOConnection::close() {
 
  delete m_fifo_fd;
  m_fifo_fd = 0;
 
}

 
int OksSystem::FIFOConnection::fd() const {
 
  ERS_ASSERT(m_fifo_fd);
  return m_fifo_fd->fd();
 
}