JSelect.hh

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#ifndef __JNET__JSELECT__
#define __JNET__JSELECT__

#include <algorithm>
#include <sys/select.h>
#include <limits>
#include <errno.h>

#include "JLang/JException.hh"
#include "JLang/JFileDescriptorMask.hh"
#include "JLang/JAbstractFile.hh"
#include "JLang/JTimeval.hh"

#include "JNet/JSelectReader.hh"
#include "JNet/JSelectWriter.hh"


/**
 * \author mdejong
 */

namespace JNET {}
namespace JPP { using namespace JNET; }

namespace JNET {

  using JLANG::JTimeval;
  using JLANG::JSelectException;


  /**
   * Wrapper class for select call.
   */
  class JSelect :
    public JSelectReader,
    public JSelectWriter
  {
  public:
    /**
     * Default constructor.
     */
    JSelect() :
      JSelectReader(),
      JSelectWriter()
    {}


    /**
     * Reset.
     */
    void reset()
    {
      static_cast<JSelectReader&>(*this).reset();
      static_cast<JSelectWriter&>(*this).reset();
    }


    /**
     * Infinite wait select call.
     *
     * \return                true if data can be read or written; else false
     */

    bool operator ()()
    {
      return this->operator ()(0);
    }


    /**
     * Select call.
     *
     * \param  timeout        timeout
     * \return                true if data can be read or written; else false
     */
    bool operator()(JTimeval timeout)
    {
      return this->operator ()(static_cast<JTimeval*>(static_cast<void*>(&timeout)));
    }


    /**
     * Select call.
     *
     * \return                number of valid file descriptors
     */
    int operator()(JTimeval* timeout)
    {
      int nfds = std::max(readerMask.getNumberOfFileDescriptors(),
                          writerMask.getNumberOfFileDescriptors());

      nfds += 1;
      nfds  = ::select(nfds, &readerMask, &writerMask, NULL, timeout->get());

      if (nfds != 0) {

        if (nfds < 0) {

          readerMask.reset(true);   // hard reset
          writerMask.reset(true);   // hard reset

          if (errno != EINTR) {
            THROW(JSelectException, "select(..) failed " << nfds << "; errno = " << errno);
          }
        }

      } else {

        readerMask.reset(false);    // soft reset
        writerMask.reset(false);    // soft reset
      }

      return nfds;
    }
  };
}

#endif