/home/mhx/git/github/libmoost/include/moost/process/pidfile.hpp

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/* vim:set ts=3 sw=3 sts=3 et: */
#ifndef MOOST_PROCESS_PIDFILE_HPP__
#define MOOST_PROCESS_PIDFILE_HPP__

#include <boost/filesystem.hpp>

#include <string>
#include <fstream>

namespace moost { namespace process {

class pidfile
{
public:
   pidfile(
      pid_t const pid,
      std::string const & process_name,
      boost::filesystem::path const & rundir
      )
      : pid_(pid), filepath_((rundir.empty() ? get_default_rundir() : rundir) / (process_name + ".pid"))
   {
      if(!create())
      {
         throw std::runtime_error("failed to create pid file");
      }
   }

   explicit pidfile(
      std::string const & process_name,
      boost::filesystem::path const & rundir
      )
      : pid_(-1), filepath_((rundir.empty() ? get_default_rundir() : rundir) / (process_name + ".pid"))
   {
   }

   pidfile(
      pid_t const pid,
      boost::filesystem::path const & filepath
      )
      : pid_(pid), filepath_(filepath)
   {
      if(!create())
      {
         throw std::runtime_error("failed to create pid file");
      }
   }

   explicit pidfile(
      boost::filesystem::path const & filepath
      )
      : pid_(-1), filepath_(filepath)
   {
   }

   ~pidfile()
   {
      try
      {
         remove();
      }
      catch(...) {}
   }

   bool create() const
   {
      if(pid_ == -1)
      {
         throw std::runtime_error("Cannot create a pid file until the pid is set.");
      }

      remove(); // just in case there is a rogue file

      std::ofstream out(filepath_.string().c_str());
      out << pid_;
      return out.good();
   }

   bool create(pid_t const pid)
   {
      pid_ = pid;
      return create();
   }

   bool remove() const
   {
      return boost::filesystem::remove(filepath_);
   }


   static boost::filesystem::path get_default_rundir()
   {
      return "/var/run";
   }


private:
   pid_t pid_;
   boost::filesystem::path filepath_;
};

}}


#endif // MOOST_PROCESS_PIDFILE_HPP__