MyShell/simpleCommand.cc at master · doudoujay/MyShell · GitHub

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#include <cstdlib>

#include "simpleCommand.hh"

SimpleCommand::SimpleCommand() {
	// Create available space for 5 arguments
	_numOfAvailableArguments = 5;
	_numOfArguments = 0;
	_arguments = (char **) malloc( _numOfAvailableArguments * sizeof( char * ) );
}

char * SimpleCommand::checkExpansion(char * argument) {
	char * arg = strdup(argument);
	char * checkDollar = strchr(arg, '$');
	char * checkBraces = strchr(arg, '{');

	char * replace = (char *) malloc (sizeof(argument) + 50);
	char * temp = replace;

	if (checkDollar && checkBraces) {
		while (*arg != '$') {
			*temp = *arg;
			temp++; arg++;
		}
		*temp = '\0';

		while (checkDollar) {
			if (checkDollar[1] == '{' && checkDollar[2] != '}') {
				char * temporary = checkDollar + 2;
				char * env = (char *) malloc (20);
				char * envtemp = env;

				while (*temporary != '}') {
					*envtemp = *temporary;
					envtemp++; temporary++;
				}
				*envtemp = '\0';

				char * get = getenv(env);

				strcat(replace, get);

				while (*(arg-1) != '}') arg++;

				char * buf = (char *) malloc (20);
				char * tbuf = buf;

				while (*arg != '$' && *arg) {
					*tbuf = *arg;
					tbuf++; arg++;
				}
				*tbuf = '\0';
				strcat(replace, buf);
			}
			checkDollar++;
			checkDollar = strchr(checkDollar, '$');
		}
		argument = strdup(replace);
		return argument;
	}
	return NULL;
}

char * SimpleCommand::tilde(char * argument) {
	if (argument[0] == '~') {

		if (strlen(argument) == 1) {

			argument = strdup(getenv("HOME"));
			return argument;

		} else {

			if (argument[1] == '/') {
				char * dir = strdup(getenv("HOME"));
				argument++;
				argument = strcat(dir, argument);
				return argument;
			}

			char * nArgument = (char *) malloc (strlen(argument) + 20);
			char * uName = (char *) malloc (50);
			char * user = uName;
			char * temp = argument;

			temp++;

			while (*temp != '/' && *temp) *(uName++) = *(temp++);
			*uName = '\0';


			if (*temp) {

				nArgument = strcat(getpwnam(user)->pw_dir, temp);
				argument = strdup(nArgument);
				return argument;

			} else {

				argument = strdup(getpwnam(user)->pw_dir);
				return argument;

			}
		}

	}

	return NULL;
}

void SimpleCommand::insertArgument( char * argument ) {
	if ( _numOfAvailableArguments == _numOfArguments  + 1 ) {
		// Double the available space
		_numOfAvailableArguments *= 2;
		_arguments = (char **) realloc( _arguments,
				  _numOfAvailableArguments * sizeof( char * ) );
	}
	// Variable expansion implementation
	char * exp = checkExpansion(argument);
	if (exp)
		argument = strdup(exp);

	exp = tilde(argument);
	if (exp)
		argument = strdup(exp);

	_arguments[ _numOfArguments ] = argument;

	// Add NULL argument at the end
	_arguments[ _numOfArguments + 1] = NULL;

	_numOfArguments++;
}