// -*- c++ -*-
//------------------------------------------------------------------------------
// $Id: Pipe.cpp,v 1.5 2006/07/20 02:30:54 vlg Exp $
//------------------------------------------------------------------------------
//                            Pipe.cpp
//------------------------------------------------------------------------------
//  Copyright (c) 1997-2002,2005 by Vladislav Grinchenko
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Library General Public
//  License as published by the Free Software Foundation; either
//  version 2 of the License, or (at your option) any later version.
//------------------------------------------------------------------------------
//
// Pipe class is based on ./unixsysdevel-734/homework3/src/bin/pipe/pipe.c
// code I wrote for UNIX system development class of JohnsHopking 
// part time engineering school in November 1997. 
// The class implementation is a rip off of Stevens' popen ()/ pclose()
// function, p. 438.
//
//------------------------------------------------------------------------------

#include <errno.h>
#include <sys/types.h>			// kill (2)
#include <signal.h>				// kill (2)
#include <unistd.h>				// pipe (2)

#include "assa/Pipe.h"
#include "assa/Fork.h"

using namespace ASSA;

Pipe::
Pipe ()
	: m_fp (NULL), 
	  m_child_pid (0)
 {
	trace_with_mask("Pipe::Pipe", PIPE);
	/* no-op */
}

Pipe::
~Pipe ()
{
	trace_with_mask("Pipe::~Pipe", PIPE);
	close ();
}

FILE*
Pipe::
open (const string& cmd_, const string& type_)
{
	trace_with_mask("Pipe::open", PIPE);

#if !defined(WIN32)       // not yet implemented

	if (type_ != "r" && type_ != "w") {
		EL((ASSAERR,"Wrong type \"%s\"\n", type_.c_str ()));
		errno = EINVAL;
		return NULL;
	}
	
	int fd [2];	
	if (pipe (fd) < 0) {
		EL((ASSAERR,"failed: pipe(2)\n"));
		return NULL;
	}
	Fork f (Fork::KILL_ON_EXIT, Fork::IGNORE_STATUS);

	if (f.isChild ()) {
		if (type_ == "r") {
			::close (fd [0]);
			if (fd [1] != STDOUT_FILENO) {
				dup2 (fd [1], STDOUT_FILENO);
				::close (fd [1]);
			}
		}
		else {					// 'w'
			::close (fd [1]);
			if (fd [0] != STDIN_FILENO) {
				dup2 (fd [0], STDIN_FILENO);
				::close (fd [0]);
			}
		}

		DL((PIPE,"Executing cmd: \"%s\"\n", cmd_.c_str ()));
		execl ("/bin/sh", "sh", "-c", cmd_.c_str (), (char* ) 0);
		EL((ASSAERR,"failed: execl(2)\n"));
		_exit (127);
	}
	/* parent */
	if (type_ == "r") {
		::close (fd [1]);
		if ((m_fp = fdopen (fd [0], type_.c_str ())) == NULL) {
			EL((ASSAERR,"failed: fdopen ()\n"));
			return NULL;
		}
	}
	else {					// 'w'
		::close (fd [0]);
		if ((m_fp = fdopen (fd [1], type_.c_str ())) == NULL) {
			EL((ASSAERR,"failed: fdopen ()\n"));
			return NULL;
		}
	}
	m_child_pid = f.getChildPID ();
	DL((PIPE,"m_child_pid = %d\n",m_child_pid));
	return m_fp;
	
#else
     DL((ASSAERR|PIPE,"Not implemented for win32!\n"));
     return NULL;
#endif
}

int 
Pipe::
kill ()
{
	trace_with_mask("Pipe::kill", PIPE);

#if !defined(WIN32)
	if (m_child_pid == 0) return -1;

	int ret = ::kill (m_child_pid, SIGTERM);
	close ();
	return ret;
#else
     DL((ASSAERR|PIPE,"Not implemented for win32!\n"));
     return -1;
#endif
}

int 
Pipe::
close ()
{
	trace_with_mask("Pipe::close", PIPE);

	int ret = 0;
	if (m_child_pid == 0) {
		ret = EOF;
	}

	if (m_fp) {
		ret = fclose (m_fp);
	}
	m_fp = NULL;
	m_child_pid = 0;
	return ret == EOF ? -1 : 0;
}