File Coverage

blib/lib/IO/Pipe/Producer.pm

Criterion	Covered	Total	%
statement	56	71	78.8
branch	23	28	82.1
condition	3	6	50.0
subroutine	9	9	100.0
pod	1	3	33.3
total	92	117	78.6

package IO::Pipe::Producer;

use 5.012003;
use strict;
use warnings;
use Carp;

our @ISA = qw(IO::Pipe);
use base qw(IO::Pipe);

our $VERSION = '2.0';

#NOTICE
#
#This software and ancillary information (herein called "SOFTWARE") called
#Producer.pm is made available under the terms described here.  The
#SOFTWARE has been approved for release with associated LA-CC number
#LA-CC-05-060.
#
#Unless otherwise indicated, this software has been authored by an employee or
#employees of the University of California, operator of the Los Alamos National
#Laboratory under Contract No. W-7405-ENG-36 with the U.S. Department of
#Energy.  The U.S. government has rights to use, reproduce, and distribute this
#SOFTWARE.  The public may copy, distribute, prepare derivative works and
#publicly display this SOFTWARE without charge, provided that this notice and
#any statement of authorship are reproduced on all copies.  Neither the
#government nor the university makes any warranty, express or implied, or
#assumes any liability or responsibility for the use of this SOFTWARE.
#
#If SOFTWARE is modified to produce derivative works, such modified SOFTWARE
#should be clearly marked, so as not to confuse it with the version available
#from LANL.


#Constructor

sub new
  {
    #Get the class name
    my $class = shift(@_);
    #Instantiate an instance of the super class
    my $self = $class->SUPER::new();
    #Bless the instantiation into this class so we can call our own methods
    bless($self,$class);
    #If a subroutine call was supplied
    if(scalar(@_))
      {
	#Declare file handles for STDOUT and STDERR
	my($fh,$eh);
	#If new was called in list context
	if(wantarray)
	  {
	    #Fill the handles with the outputs from the subroutine
	    ($fh,$eh) = $self->getSubroutineProducer(@_);
	    #Return blessed referents to the file handles
	    return(bless($fh,$class),bless($eh,$class));
	  }
	#Fill the STDOUT handle with the output from the subroutine
	$fh = $self->getSubroutineProducer(@_);
	#Return blessed referent to the STDOUT handle
	return(bless($fh,$class));
      }
    #Return a blessed referent of the object hash
    if(wantarray)
      {return($self,bless($class->SUPER::new(),$class))}
    return($self);
  }



#This method is also a constructor
sub getSubroutineProducer
  {
    #Read in subroutine reference
    my $self         = shift;
    my $producer_sub = shift;
    my @params       = @_;
    my($pid,$error);

    if(!defined($producer_sub) || ref($producer_sub) ne 'CODE')
      {
	$error = "ERROR:Producer.pm:getSubroutineProducer:A referenced " .
	  "subroutine is required as the first argument to " .
	    "getSubroutineProducer.";
	$Producer::errstr = $error;
	carp($error);
	return(undef);
      }

    #Create a pipe
    my $stdout_pipe = $self->SUPER::new();
    my($stderr_pipe);
    $stderr_pipe = $self->SUPER::new() if(wantarray);

    #Fork off the Producer
    if(defined($pid = fork()))
      {
	if($pid)
	  {
	    ##
	    ## Parent
	    ##

	    #Create a read file handle
	    $stdout_pipe->reader();
	    $stderr_pipe->reader() if(wantarray);

	    #Return the read file handle to the consumer
	    if(wantarray)
	      {return(bless($stdout_pipe,ref($self)),
		      bless($stderr_pipe,ref($self)))}
	    return(bless($stdout_pipe,ref($self)));
	  }
	else
	  {
	    ##
	    ## Child
	    ##

	    #Create a write file handle for the Producer
	    $stdout_pipe->writer();
	    $stdout_pipe->autoflush;
	    $stderr_pipe->writer()  if(defined($stderr_pipe));
	    $stderr_pipe->autoflush if(defined($stderr_pipe));

	    #Redirect standard outputs to the pipes or kill the child
	    if(!open(STDOUT,">&",\${$stdout_pipe}))
	      {
		$error = "ERROR:Producer.pm:getSubroutineProducer:Can't " .
		  "redirect stdout to pipe: [" .
		    select($stdout_pipe) .
		      "]. $!";
		$Producer::errstr = $error;
		croak($error);
	      }
	    elsif(defined($stderr_pipe) && !open(STDERR,">&",\${$stderr_pipe}))
	      {
		$error = "ERROR:Producer.pm:getSubroutineProducer:Can't " .
		  "redirect stderr to pipe: [" .
		    select($stderr_pipe) .
		      "]. $!";
		$Producer::errstr = $error;
		croak($error);
	      }

	    #Call the subroutine passed in (ignore it's return value)
	    $producer_sub->(@params);

	    #Close the writer pipes
	    close($stdout_pipe);
	    close($stderr_pipe) if(defined($stderr_pipe));

	    #Successfully exiting the child process
	    exit(0);
	  }
      }
    else
      {
	$error = "ERROR:Producer.pm:getSubroutineProducer:fork() didn't work!";
	$Producer::errstr = $error;
	carp($error);
	return(undef);
      }
  }


sub getSystemProducer
  {
    my $self = shift;
    return($self->getSubroutineProducer(sub {system(@_)},@_));
  }


1;
__END__