tidy PLplot device-reading

lib/PDL/Graphics/Simple/PLplot.pm

@@ -19,6 +19,7 @@ use File::Temp qw/tempfile/;
 use Time::HiRes qw/usleep/;
 use PDL::Options q/iparse/;
 use PDL;
+use IPC::Open2;
 
 our $mod = {
     shortname => 'plplot',
@@ -59,17 +60,7 @@ sub check {
     }
 
     # Module loaded OK, now try to extract valid devices from it.
-    # We would use a pipe, but Microsoft Windows doesn't play nice
-    # with them - so we use a temp file instead.
-    my ($fh1, $gzinta) = tempfile('pgs_gzinta_XXXX');
-    close $fh1;
-    my ($fh2, $gzouta) = tempfile('pgs_gzouta_XXXX');
-    close $fh2;
-
-    open my $fh3, ">", $gzinta or die "Couldn't write to temp file";
-    print $fh3 "1\n"; #Just one line
-    close $fh3;
-
+    my @lines;
     if($^O =~ /MSWin32/i) {
       eval {require Win32::Process};
       die "Win32::Process didn't load: $@"
@@ -79,55 +70,62 @@ sub check {
                             ? "\\Windows\\system32\\cmd.exe"
                             : cmd_location();
 
+      # We would use a pipe, but Microsoft Windows doesn't play nice
+      # with them - so we use a temp file instead.
+      my ($fh1, $gzinta) = tempfile('pgs_gzinta_XXXX');
+      close $fh1;
+      my ($fh2, $gzouta) = tempfile('pgs_gzouta_XXXX');
+      close $fh2;
+
+      open my $fh3, ">", $gzinta or die "Couldn't write to temp file";
+      print $fh3 "1\n"; #Just one line
+      close $fh3;
+
       Win32::Process::Create(
         my $ProcessObj,
         $cmd_location,
-        "cmd /c \"$^X -MPDL -MPDL::Graphics::PLplot -e \"PDL::Graphics::PLplot->new() \" <$gzinta >$gzouta\"",
+        "cmd /c \"$^X -MPDL -MPDL::Graphics::PLplot -e \"PDL::Graphics::PLplot->new(DEV=>'?')\" <$gzinta >$gzouta\"",
         0,
         32, #NORMAL_PRIORITY_CLASS
         ".")|| die ErrorReport();
 
       sleep 1; # Don't read $gzouta before it's written
-    }
-    else {
-      my $pid = fork();
-      unless(defined($pid)) {
-	print STDERR +($mod->{msg} = "Fork failed in PLplot probe -- returning 0"), "\n";
-	return 0;
-      }
 
-      if( $pid==0 ) {   # assignment
+      # Snarf up the file.
+      open my $fh, "<", $gzouta;
+      @lines = <$fh>;
+      close $fh;
 
-	# Daughter: try to create a PLplot window with a bogus device, to stimulate a driver listing
-	open STDOUT,">", $gzouta;
-	open STDERR,">&", STDOUT;
-	open STDIN, "<", $gzinta;
-	PDL::Graphics::PLplot->new(DEV=>'?');
-	exit(0);
+      unlink $gzinta;
+      unlink $gzouta;
+    }
+    else {
+      my $pid;
+      @lines = eval {
+        $pid = open2(my $chld_out, my $chld_in, $^X, qw(-MPDL -MPDL::Graphics::PLplot -e PDL::Graphics::PLplot->new(DEV=>'?')));
+        print $chld_in "1\n";
+        close $chld_in;
+        <$chld_out>;
+      };
+      if ($@) {
+        $mod->{ok} = 0;
+        $mod->{msg} = $@;
+        return 0;
       }
-
       # Parent - snarf up the results from the daughter
       usleep(2e5);          # hang around for 0.2 seconds
       eval {kill 9,$pid;};  # kill it dead, just in case it buzzed or hung (I'm looking at you, Microsoft Windows)
       waitpid($pid,0);      # Clean up.
     }
 
-    # Snarf up the file.
-    open my $fh4, "<", $gzouta;
-    my @lines = <$fh4>;
-    close $fh4;
-
-    unlink $gzinta;
-    unlink $gzouta;
-
     $mod->{devices} = {};
-    for my $l(@lines) {
-	if( $l=~ m/^\s+\<\s*\d+\>\s+(\w+)/ ) {
+    for my $l (@lines) {
+	if ( $l=~ m/^\s+\<\s*\d+\>\s+(\w+)/ ) {
 	    $mod->{devices}->{$1} = 1;
 	}
     }
 
-    if( my ($good_dev) = grep $mod->{devices}{$_}, @DEVICES ) {
+    if ( my ($good_dev) = grep $mod->{devices}{$_}, @DEVICES ) {
 	$mod->{disp_dev} = $good_dev;
     } else {
 	$mod->{ok} = 0;