From 8aa29810bb77611cc20b7a384897ff6703783ea1 Mon Sep 17 00:00:00 2001 From: Chris Dyer Date: Sun, 18 Nov 2012 13:35:42 -0500 Subject: major restructure of the training code --- training/dpmert/line_mediator.pl | 116 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) create mode 100755 training/dpmert/line_mediator.pl (limited to 'training/dpmert/line_mediator.pl') diff --git a/training/dpmert/line_mediator.pl b/training/dpmert/line_mediator.pl new file mode 100755 index 00000000..bc2bb24c --- /dev/null +++ b/training/dpmert/line_mediator.pl @@ -0,0 +1,116 @@ +#!/usr/bin/perl -w +#hooks up two processes, 2nd of which has one line of output per line of input, expected by the first, which starts off the communication + +# if you don't know how to fork/exec in a C program, this could be helpful under limited cirmustances (would be ok to liaise with sentserver) + +#WARNING: because it waits for the result from command 2 after sending every line, and especially if command 1 does the same, using sentserver as command 2 won't actually buy you any real parallelism. + +use strict; +use IPC::Open2; +use POSIX qw(pipe dup2 STDIN_FILENO STDOUT_FILENO); + +my $quiet=!$ENV{DEBUG}; +$quiet=1 if $ENV{QUIET}; +sub info { + local $,=' '; + print STDERR @_ unless $quiet; +} + +my $mode='CROSS'; +my $ser='DIRECT'; +$mode='PIPE' if $ENV{PIPE}; +$mode='SNAKE' if $ENV{SNAKE}; +$mode='CROSS' if $ENV{CROSS}; +$ser='SERIAL' if $ENV{SERIAL}; +$ser='DIRECT' if $ENV{DIRECT}; +$ser='SERIAL' if $mode eq 'SNAKE'; +info("mode: $mode\n"); +info("connection: $ser\n"); + + +my @c1; +if (scalar @ARGV) { + do { + push @c1,shift + } while scalar @ARGV && $c1[$#c1] ne '--'; +} +pop @c1; +my @c2=@ARGV; +@ARGV=(); +(scalar @c1 && scalar @c2) || die qq{ +usage: $0 cmd1 args -- cmd2 args +all options are environment variables. +DEBUG=1 env var enables debugging output. +CROSS=1 hooks up two processes, 2nd of which has one line of output per line of input, expected by the first, which starts off the communication. crosses stdin/stderr of cmd1 and cmd2 line by line (both must flush on newline and output. cmd1 initiates the conversation (sends the first line). default: attempts to cross stdin/stdout of c1 and c2 directly (via two unidirectional posix pipes created before fork). +SERIAL=1: (no parallelism possible) but lines exchanged are logged if DEBUG. +if SNAKE then stdin -> c1 -> c2 -> c1 -> stdout. +if PIPE then stdin -> c1 -> c2 -> stdout (same as shell c1|c2, but with SERIAL you can see the intermediate in real time; you could do similar with c1 | tee /dev/fd/2 |c2. +DIRECT=1 (default) will override SERIAL=1. +CROSS=1 (default) will override SNAKE or PIPE. +}; + +info("1 cmd:",@c1,"\n"); +info("2 cmd:",@c2,"\n"); + +sub lineto { + select $_[0]; + $|=1; + shift; + print @_; +} + +if ($ser eq 'SERIAL') { + my ($R1,$W1,$R2,$W2); + my $c1p=open2($R1,$W1,@c1); # Open2 R W backward from Open3. + my $c2p=open2($R2,$W2,@c2); + if ($mode eq 'CROSS') { + while(<$R1>) { + info("1:",$_); + lineto($W2,$_); + last unless defined ($_=<$R2>); + info("1|2:",$_); + lineto($W1,$_); + } + } else { + my $snake=$mode eq 'SNAKE'; + while() { + info("IN:",$_); + lineto($W1,$_); + last unless defined ($_=<$R1>); + info("IN|1:",$_); + lineto($W2,$_); + last unless defined ($_=<$R2>); + info("IN|1|2:",$_); + if ($snake) { + lineto($W1,$_); + last unless defined ($_=<$R1>); + info("IN|1|2|1:",$_); + } + lineto(*STDOUT,$_); + } + } +} else { + info("DIRECT mode\n"); + my @rw1=POSIX::pipe(); + my @rw2=POSIX::pipe(); + my $pid=undef; + $SIG{CHLD} = sub { wait }; + while (not defined ($pid=fork())) { + sleep 1; + } + my $pipe = $mode eq 'PIPE'; + unless ($pipe) { + POSIX::close(STDOUT_FILENO); + POSIX::close(STDIN_FILENO); + } + if ($pid) { + POSIX::dup2($rw1[1],STDOUT_FILENO); + POSIX::dup2($rw2[0],STDIN_FILENO) unless $pipe; + exec @c1; + } else { + POSIX::dup2($rw2[1],STDOUT_FILENO) unless $pipe; + POSIX::dup2($rw1[0],STDIN_FILENO); + exec @c2; + } + while (wait()!=-1) {} +} -- cgit v1.2.3