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Edit File: Pipe.pm
# IO::Pipe.pm # # Copyright (c) 1996-8 Graham Barr <gbarr@pobox.com>. All rights reserved. # This program is free software; you can redistribute it and/or # modify it under the same terms as Perl itself. package IO::Pipe; use 5.008_001; use IO::Handle; use strict; use Carp; use Symbol; our $VERSION = "1.49"; sub new { my $type = shift; my $class = ref($type) || $type || "IO::Pipe"; @_ == 0 || @_ == 2 or croak "usage: $class->([READFH, WRITEFH])"; my $me = bless gensym(), $class; my($readfh,$writefh) = @_ ? @_ : $me->handles; pipe($readfh, $writefh) or return undef; @{*$me} = ($readfh, $writefh); $me; } sub handles { @_ == 1 or croak 'usage: $pipe->handles()'; (IO::Pipe::End->new(), IO::Pipe::End->new()); } my $do_spawn = $^O eq 'os2' || $^O eq 'MSWin32'; sub _doit { my $me = shift; my $rw = shift; my $pid = $do_spawn ? 0 : fork(); if($pid) { # Parent return $pid; } elsif(defined $pid) { # Child or spawn my $fh; my $io = $rw ? \*STDIN : \*STDOUT; my ($mode, $save) = $rw ? "r" : "w"; if ($do_spawn) { require Fcntl; $save = IO::Handle->new_from_fd($io, $mode); my $handle = shift; # Close in child: unless ($^O eq 'MSWin32') { fcntl($handle, Fcntl::F_SETFD(), 1) or croak "fcntl: $!"; } $fh = $rw ? ${*$me}[0] : ${*$me}[1]; } else { shift; $fh = $rw ? $me->reader() : $me->writer(); # close the other end } bless $io, "IO::Handle"; $io->fdopen($fh, $mode); $fh->close; if ($do_spawn) { $pid = eval { system 1, @_ }; # 1 == P_NOWAIT my $err = $!; $io->fdopen($save, $mode); $save->close or croak "Cannot close $!"; croak "IO::Pipe: Cannot spawn-NOWAIT: $err" if not $pid or $pid < 0; return $pid; } else { exec @_ or croak "IO::Pipe: Cannot exec: $!"; } } else { croak "IO::Pipe: Cannot fork: $!"; } # NOT Reached } sub reader { @_ >= 1 or croak 'usage: $pipe->reader( [SUB_COMMAND_ARGS] )'; my $me = shift; return undef unless(ref($me) || ref($me = $me->new)); my $fh = ${*$me}[0]; my $pid; $pid = $me->_doit(0, $fh, @_) if(@_); close ${*$me}[1]; bless $me, ref($fh); *$me = *$fh; # Alias self to handle $me->fdopen($fh->fileno,"r") unless defined($me->fileno); bless $fh; # Really wan't un-bless here ${*$me}{'io_pipe_pid'} = $pid if defined $pid; $me; } sub writer { @_ >= 1 or croak 'usage: $pipe->writer( [SUB_COMMAND_ARGS] )'; my $me = shift; return undef unless(ref($me) || ref($me = $me->new)); my $fh = ${*$me}[1]; my $pid; $pid = $me->_doit(1, $fh, @_) if(@_); close ${*$me}[0]; bless $me, ref($fh); *$me = *$fh; # Alias self to handle $me->fdopen($fh->fileno,"w") unless defined($me->fileno); bless $fh; # Really wan't un-bless here ${*$me}{'io_pipe_pid'} = $pid if defined $pid; $me; } package IO::Pipe::End; our(@ISA); @ISA = qw(IO::Handle); sub close { my $fh = shift; my $r = $fh->SUPER::close(@_); waitpid(${*$fh}{'io_pipe_pid'},0) if(defined ${*$fh}{'io_pipe_pid'}); $r; } 1; __END__ =head1 NAME IO::Pipe - supply object methods for pipes =head1 SYNOPSIS use IO::Pipe; $pipe = IO::Pipe->new(); if($pid = fork()) { # Parent $pipe->reader(); while(<$pipe>) { ... } } elsif(defined $pid) { # Child $pipe->writer(); print $pipe ... } or $pipe = IO::Pipe->new(); $pipe->reader(qw(ls -l)); while(<$pipe>) { ... } =head1 DESCRIPTION C<IO::Pipe> provides an interface to creating pipes between processes. =head1 CONSTRUCTOR =over 4 =item new ( [READER, WRITER] ) Creates an C<IO::Pipe>, which is a reference to a newly created symbol (see the C<Symbol> package). C<IO::Pipe::new> optionally takes two arguments, which should be objects blessed into C<IO::Handle>, or a subclass thereof. These two objects will be used for the system call to C<pipe>. If no arguments are given then method C<handles> is called on the new C<IO::Pipe> object. These two handles are held in the array part of the GLOB until either C<reader> or C<writer> is called. =back =head1 METHODS =over 4 =item reader ([ARGS]) The object is re-blessed into a sub-class of C<IO::Handle>, and becomes a handle at the reading end of the pipe. If C<ARGS> are given then C<fork> is called and C<ARGS> are passed to exec. =item writer ([ARGS]) The object is re-blessed into a sub-class of C<IO::Handle>, and becomes a handle at the writing end of the pipe. If C<ARGS> are given then C<fork> is called and C<ARGS> are passed to exec. =item handles () This method is called during construction by C<IO::Pipe::new> on the newly created C<IO::Pipe> object. It returns an array of two objects blessed into C<IO::Pipe::End>, or a subclass thereof. =back =head1 SEE ALSO L<IO::Handle> =head1 AUTHOR Graham Barr. Currently maintained by the Perl Porters. Please report all bugs at L<https://github.com/Perl/perl5/issues>. =head1 COPYRIGHT Copyright (c) 1996-8 Graham Barr <gbarr@pobox.com>. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. =cut