JProcess.hh

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#ifndef __JSYSTEM__JPROCESS__
#define __JSYSTEM__JPROCESS__

#include <unistd.h>

#include "JLang/JException.hh"
#include "JLang/JFileStreamBuffer.hh"


/**
 * \author mdejong
 */

namespace JSYSTEM {}
namespace JPP { using namespace JSYSTEM; }

namespace JSYSTEM {

  using JLANG::JPipeOpenException;
  using JLANG::JForkException;
  using JLANG::JSystemException;
  using JLANG::JFileInputStreamBuffer;
  using JLANG::JFileOutputStreamBuffer;


  /**
   * Streaming of input and output from Linux command.
   */
  class JProcess 
  {   
  public:
    /**
     * Default constructor.
     * This constructor starts an interactive shell.
     */
    JProcess() :
      out (-1),
      err (-1),
      in  (-1),
      gOut(NULL),
      gErr(NULL),
      gIn (NULL)
    { 
      execute("/bin/tcsh", "tcsh", "-i", "-f");
    }


    /**
     * Constructor.
     *
     * \param  command         Linux command
     */
    JProcess(const std::string& command) :
      out (-1),
      err (-1),
      in  (-1),
      gOut(NULL),
      gErr(NULL),
      gIn (NULL)
    { 
      execute("/bin/tcsh", "tcsh", "-f", "-c", command.c_str());
    }


    /**
     * Destructor.
     */
    ~JProcess()
    {
      close(err);
      close(out);
      close(in);

      if (gOut != NULL) { delete gOut; }
      if (gErr != NULL) { delete gErr; }
      if (gIn  != NULL) { delete gIn;  }
    }


    /**
     * Get pointer to input stream buffer connected to the normal output stream.
     *
     * \param  size            size of internal buffers
     * \return                 pointer input stream buffer
     */
    JFileInputStreamBuffer* getInputStreamBuffer(const std::size_t size = 65536)
    {
      if (gOut == NULL) {
        gOut = new JFileInputStreamBuffer(out, size);
      }

      return gOut;
    }


    /**
     * Get pointer to input stream buffer connected to the error output stream.
     *
     * \param  size            size of internal buffers
     * \return                 pointer to input stream buffer
     */
    JFileInputStreamBuffer* getErrorStreamBuffer(const std::size_t size = 65536)
    {
      if (gErr == NULL) {
        gErr = new JFileInputStreamBuffer(err, size);
      }

      return gErr;
    }


    /**
     * Get pointer to output stream buffer connected to the normal input stream.
     *
     * \param  size            size of internal buffers
     * \return                 pointer to output stream buffer
     */
    JFileOutputStreamBuffer* getOutputStreamBuffer(const std::size_t size = 65536)
    {
      if (gIn == NULL) {
        gIn = new JFileOutputStreamBuffer(in, size);
      }

      return gIn;
    }

  protected:
    /**
     * Execute command.
     *
     * \param  path            path
     * \param  arg0            comma separted argument list
     * \param  arg1            comma separted argument list
     * \param  arg2            comma separted argument list
     * \param  arg3            comma separted argument list
     * \param  arg4            comma separted argument list
     * \param  arg5            comma separted argument list
     * \param  arg6            comma separted argument list
     * \param  arg7            comma separted argument list
     * \param  arg8            comma separted argument list
     * \param  arg9            comma separted argument list
     */
    void execute(const char* path, 
                 const char* arg0,
                 const char* arg1 = (char*) NULL,
                 const char* arg2 = (char*) NULL,
                 const char* arg3 = (char*) NULL,
                 const char* arg4 = (char*) NULL,
                 const char* arg5 = (char*) NULL,
                 const char* arg6 = (char*) NULL,
                 const char* arg7 = (char*) NULL,
                 const char* arg8 = (char*) NULL,
                 const char* arg9 = (char*) NULL)
    {
      int pipe_stdin [2];
      int pipe_stdout[2];
      int pipe_stderr[2];

      if (pipe(pipe_stdin))  { throw JPipeOpenException("Error at pipe of standard input.");  }
      if (pipe(pipe_stdout)) { throw JPipeOpenException("Error at pipe of standard output."); }
      if (pipe(pipe_stderr)) { throw JPipeOpenException("Error at pipe of standard error.");  }
      
      const pid_t pid = fork();

      if (pid < 0) 

        // error

        throw JForkException("JProcess::fork() failed");

      else if (pid == 0) {

        // child

        close(pipe_stdin [1]);
        if (dup2 (pipe_stdin [0], STDIN_FILENO)  == -1) { JSystemException("dup2-stdin"); }

        close(pipe_stdout[0]);
        if (dup2 (pipe_stdout[1], STDOUT_FILENO) == -1) { JSystemException("dup2-stdout"); }

        close(pipe_stdout[0]);
        if (dup2 (pipe_stdout[1], STDERR_FILENO) == -1) { JSystemException("dup2-stderr"); }

        execl(path, arg0, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, (char*) NULL);

        throw JSystemException(path);

      } else {

        // parent

        in  = pipe_stdin [1];
        out = pipe_stdout[0];
        err = pipe_stderr[0];

        close(pipe_stdin [0]);
        close(pipe_stdout[1]);
        close(pipe_stderr[1]);
      }
    }

    int out;
    int err;
    int in;

  private:
    JFileInputStreamBuffer*  gOut;
    JFileInputStreamBuffer*  gErr;
    JFileOutputStreamBuffer* gIn;
  };  
}

#endif