shell/Sequence.cc at master · nvelthorst/shell · GitHub

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/** @file Sequence.cc
 * Implementation of class Sequence.
 */
#include <iostream>
#include <sys/wait.h>		// for: wait(), WIF...(status)
#include <cstring>			// for: strsignal()
#include "asserts.h"
#include "unix_error.h"
#include "Sequence.h"
using namespace std;


void  Sequence::addPipeline(Pipeline *pp)
{
	require(pp != 0);
	commands.push_back(pp);
}


Sequence::~Sequence()
{
	for (vector<Pipeline*>::iterator  i = commands.begin() ; i != commands.end() ; ++i)
		delete  *i;
}


bool	Sequence::isEmpty()	const
{
	return commands.empty();
}


// TODO:	Lookout somewhere for special commands such as 'exit',
//			'logout', 'cd', etc, which may have to be
//			done by the shell itself.


// Execute the pipelines in this sequence one by one
void	Sequence::execute()
{
	//cerr << "Sequence::execute\n";//DEBUG

	// Execute each pipeline in turn.
	// Also see: fork(2), nice(2), wait(2), WIF...(2), strsignal(3)
	size_t  j = commands.size();			// for count-down
	for (vector<Pipeline*>::iterator  i = commands.begin() ; i != commands.end() ; ++i, --j)
	{
		Pipeline  *pp = *i;
		if (!pp->isEmpty())
		{
			if (j == commands.size()) {//DEBUG
				cerr << "Sequence::FIRST PIPELINE\n";//DEBUG
			}//DEBUG
			// if (pp->isBuiltin()) ...
			pp->execute();
			// TODO
			if (j == 1) {//DEBUG
				cerr << "Sequence::LAST PIPELINE\n";//DEBUG
			} else {//DEBUG
				cerr << "Sequence::WAIT FOR PIPELINE\n";//DEBUG
			}//DEBUG
		}
		// else ignore empty pipeline
	}
}


// vim:ai:aw:ts=4:sw=4: