From 65f946b63b4786170702097288aa1c84bd8e8fa1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Thu, 6 May 2021 15:58:09 +0200
Subject: Copy only if modified

---
 gen.pl | 84 ++++++++++++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 61 insertions(+), 23 deletions(-)

diff --git a/gen.pl b/gen.pl
index 0b682c2..fe9a786 100644
--- a/gen.pl
+++ b/gen.pl
@@ -2,61 +2,99 @@
 
 # gen.pl -- generate static files for perlisdead.org
 
+package App::PerlIsDead;
+our $VERSION = '0.1';
+
 use strict;
 use warnings;
 use experimental 'switch';
 use File::Copy;
 use FindBin '$Bin';
+use Getopt::Std;
+
+my %opt;
+$Getopt::Std::STANDARD_HELP_VERSION = 1;
+getopts('d', \%opt);
 
 # Change directory to script path
 chdir $Bin;
 
 # Generate index.html
 mkdir 'out' if ! -d 'out';
-open my $f, '<', 'src/index.html' or die "Could not open < src/index.html: $!";
-open my $g, '>', 'out/index.html.tmp' or die "Could not open > out/index.html.tmp: $!";
-for (<$f>) {
+open my $src, '<', 'src/index.html' or die "Could not open < src/index.html: $!";
+open my $out, '>', 'out/index.html.tmp' or die "Could not open > out/index.html.tmp: $!";
+for (<$src>) {
 	when (/^\.inc (.*)/) {
 		open my $h, '<', "inc/$1" or do {
 			warn "Could not open inc/$1: $!";
 			next;
 		};
-		print $g $_ while <$h>;
+		print STDERR "INCLUDE: $_\n" if $opt{d};
+		print $out $_ while <$h>;
 		close $h;
 	}
 	when (/^\.eval (.*)/) {
-		no strict; no warnings; no experimental;
-		local *STDOUT = $g;
-		eval $1;
-		warn $@ if $@;
+		print STDERR "EVAL: $1\n" if $opt{d};
+		{
+			no strict; no warnings; no experimental;
+			select $out;
+			eval $1;
+			select STDOUT;
+			warn $@ if $@;
+		}
 	}
 	when (/^\.run (.*)/) {
 		open my $h, '<', "run/$1" or do {
 			warn "Could not open run/$1: $!";
 			next;
 		};
+		print STDERR "RUN: $1\n" if $opt{d};
 		my $c = do { local $/; <$h> };
 		close $h;
-		local *STDOUT = $g;
-		local $0 = "run/$1";
-		no strict; no warnings; no experimental;
-		eval $c;
-		warn $@ if $@;
+		{
+			no strict; no warnings; no experimental;
+			local $0 = "run/$1";
+			select $out;
+			eval $c;
+			select STDOUT;
+			warn $@ if $@;
+		}
 		# I guess you could just shell out instead...
 	}
 	default {
-		print $g $_;
+		print $out $_;
 	}
 }
-close $g;
-close $f;
-
-# Copy static files
-opendir my $dh, 'src' or die "Could not open directory src: $!";
-while (readdir $dh) {
-	copy "src/$_" => "out/$_" unless /^\./ or /^index\.html$/;
-}
-closedir $dh;
+close $out;
+close $src;
 
 # Rename temporary file
 move 'out/index.html.tmp' => 'out/index.html';
+
+# Copy modified static files
+opendir $src, 'src' or die "Could not open directory src: $!";
+opendir $out, 'out' or die "Could not open directory src: $!";
+my %src = map { ($_, (stat "src/$_")[9]||0) } grep { not /^\./ or /^index\.html$/ } readdir $src;
+my %out = map { ($_, (stat "out/$_")[9]||0) } grep { not /^\./ or /^index\.html$/ } readdir $out;
+for (keys %src) {
+	if ($out{$_} and $src{$_} > $out{$_}) {
+		print STDERR "COPY: src/$_ => out/$_\n" if $opt{d};
+		copy "src/$_" => "out/$_";
+	}
+}
+closedir $out;
+closedir $src;
+
+print STDERR "DONE\n" if $opt{d};
+
+# Definitions
+
+sub main::HELP_MESSAGE {
+	print <<HELP;
+usage: $0 [-d]
+  -d	enable debug messages
+HELP
+}
+sub main::VERSION_MESSAGE {
+	print "App::PerlIsDead version $VERSION\n";
+}
-- 
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