JSelectWriter.hh

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#ifndef __JNET__JSELECTWRITER__
#define __JNET__JSELECTWRITER__

#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"


/**
 * \author mdejong
 */

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

namespace JNET {

  using JLANG::JSelectException;
  using JLANG::JFileDescriptorMask;
  using JLANG::JAbstractFile;
  using JLANG::JTimeval;


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


    /**
     * Get writer mask.
     *
     * \return                      mask
     */
    JFileDescriptorMask& getWriterMask()
    {
      return writerMask;
    }


    /**
     * Set writer mask.
     *
     * \param  file                 file
     */
    void setWriterMask(const JAbstractFile& file)
    {
      writerMask.set(file);
    }


    /**
     * Has writer file.
     *
     * \param  file                 file
     * \return                      true if file set; else false
     */
    bool hasWriterMask(const JAbstractFile& file) const
    {
      return writerMask.has(file);
    }


    /**
     * Reset.
     */
    void reset()
    {
      writerMask.reset(true);   // hard reset
    }


    /**
     * Select call.
     *
     * \param  timeout        timeout
     * \return                number of valid file descriptors
     */
    int operator()(JTimeval timeout)
    {
      return this->operator()(&timeout);
    }


    /**
     * Select call.
     *
     * \param  timeout        timeout
     * \return                number of valid file descriptors
     */
    int operator()(timeval* timeout = NULL)
    {
      int nfds = writerMask.getNumberOfFileDescriptors();

      nfds += 1;
      nfds  = ::select(nfds, NULL, &writerMask, NULL, timeout);

      if (nfds != 0) {

        if (nfds < 0) {
          if (errno != EINTR) {
            THROW(JSelectException, "JSelectWriter(..) failed.");
          }
        }

      } else {

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

      return nfds;
    }


  protected:
    JFileDescriptorMask writerMask;
  };
}

#endif