From: unbewusst <yvon.thoraval@...>
Date: 2007-09-05T02:35:11+09:00
Subject: [C ext to Ruby] returning a pipe ???

i'm writting a RubyCocoa application for synchronizing folders of a
computer to folders of an usb key.

to let the user not bored, because it could takes time, i have a log
window where i print the messages coming from rsync.

on another side, i need the call to rsync to have root privileges,
then i'm writing a tinu ruby module in C to get the root privileges
for rsync.

the way it is done, for the time being :

C side:
+-----+

if ( myStatus != errAuthorizationSuccess ) break;
{
	FILE *myCommunicationsPipe = NULL;
	char myReadBuffer[ LINE_MAX ];

	myFlags = kAuthorizationFlagDefaults;

	myStatus = AuthorizationExecuteWithPrivileges(	myAuthorizationRef,
													myToolPath, myFlags,
													myArguments,
													&myCommunicationsPipe );
	if ( bufferOut != NULL )
	{
		if ( myStatus == errAuthorizationSuccess )
		{
			int i = 0;
			int len;
			while ( fgets( myReadBuffer, LINE_MAX, myCommunicationsPipe ) )
			{
				bufferOut[ i ] = strdup( myReadBuffer );
				len = strlen( bufferOut[ i ] );
				bufferOut[ i ] += len - 1;
				*bufferOut[ i ] = 0;			// ~= chomp
				bufferOut[ i ] -= len - 1;
				i++;
			}
			bufferOut[ i ] = NULL;
		}
	}
}

C ext to Ruby side:
+-----------------+

VALUE ary = rb_ary_new2( LINES_MAX );
i = 0;
while( bufferOut[ i ] != NULL)
{
	rb_ary_push( ary, (VALUE) rb_str_new2( bufferOut[ i ] ) );
	i++;
}

return ary;


obviously, it works but i'm not satisfied of the returned result
because the user gets an array of it's whole at a time, where i would
prefer continously outputting the values (string in this case)


then i wonder if there is a way somehow to return the
"myCommunicationsPipe" above directly (more directly) from C to ruby.

something like IO.popen...

BUT, i've tried IO.popen in my RubyCocoa app it doesn't work as
expected, i get the whole result at a time intead of having the
results in a line by nline basis...


some light about that ?