From: Nicholas Clark <nick@ccl4.org>
Date: Sat, 29 Aug 2009 10:10:00 +0000 (+0100)
Subject: Optimise IPC::Open3 with a compile-time constant, eliminating OS-specific code.
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=ba4c7dd4891fdf4ba3a68fea2323a208aa627586;p=p5sagit%2Fp5-mst-13.2.git

Optimise IPC::Open3 with a compile-time constant, eliminating OS-specific code.

($^O isn't going to change at run time, so why carry a lot of code that is
never going to get called on the platform you're running on.)
---

diff --git a/lib/IPC/Open3.pm b/lib/IPC/Open3.pm
index 815674b..a7365bd 100644
--- a/lib/IPC/Open3.pm
+++ b/lib/IPC/Open3.pm
@@ -9,7 +9,7 @@ require Exporter;
 use Carp;
 use Symbol qw(gensym qualify);
 
-$VERSION	= 1.04;
+$VERSION	= 1.05;
 @ISA		= qw(Exporter);
 @EXPORT		= qw(open3);
 
@@ -181,7 +181,7 @@ sub xfileno {
     return fileno $_[0];
 }
 
-my $do_spawn = $^O eq 'os2' || $^O eq 'MSWin32';
+use constant DO_SPAWN => $^O eq 'os2' || $^O eq 'MSWin32';
 
 sub _open3 {
     local $Me = shift;
@@ -225,7 +225,7 @@ sub _open3 {
     xpipe $dad_rdr, $kid_wtr if !$dup_rdr;
     xpipe $dad_err, $kid_err if !$dup_err && $dad_err ne $dad_rdr;
 
-    $kidpid = $do_spawn ? -1 : xfork;
+    $kidpid = DO_SPAWN ? -1 : xfork;
     if ($kidpid == 0) {		# Kid
 	# A tie in the parent should not be allowed to cause problems.
 	untie *STDIN;
@@ -272,7 +272,7 @@ sub _open3 {
 	    eval { require POSIX; POSIX::_exit(255); };
 	    exit 255;
 	};
-    } elsif ($do_spawn) {
+    } elsif (DO_SPAWN) {
 	# All the bookkeeping of coincidence between handles is
 	# handled in spawn_with_handles.