avoid unnecessarily changing timestamp on perly.h

Make regen_perly.pl use rename_if_different() to avoid overwriting files
that aren't actually changing.

1 files changed, 17 insertions, 10 deletions

diff --git a/regen_perly.pl b/regen_perly.pl
index a988a631f6..e9e1be90cb 100644
--- a/regen_perly.pl
+++ b/regen_perly.pl
@@ -34,6 +34,8 @@ sub usage { die "usage: $0 [ -b bison_executable ] [ file.y ]\n" }
 use warnings;
 use strict;
 
+BEGIN { require 'regen_lib.pl'; }
+
 my $bison = 'bison';
 
 if (@ARGV >= 2 and $ARGV[0] eq '-b') {
@@ -50,6 +52,9 @@ usage unless @ARGV==0 && $y_file =~ /\.y$/;
 (my $tab_file  = $y_file) =~ s/\.y$/.tab/;
 (my $tmpc_file = $y_file) =~ s/\.y$/tmp.c/;
 (my $tmph_file = $y_file) =~ s/\.y$/tmp.h/;
+my $new_h_file = "$h_file-new";
+my $new_act_file = "$act_file-new";
+my $new_tab_file = "$tab_file-new";
 
 # the yytranslate[] table generated by bison is ASCII/EBCDIC sensitive
 
@@ -94,17 +99,17 @@ my ($actlines, $tablines) = extract($clines);
 
 $tablines .= make_type_tab($y_file, $tablines);
 
-chmod 0644, $act_file;
-open ACTFILE, ">$act_file" or die "can't open $act_file: $!\n";
+chmod 0644, $new_act_file;
+open ACTFILE, ">$new_act_file" or die "can't open $new_act_file: $!\n";
 print ACTFILE $actlines;
 close ACTFILE;
-chmod 0444, $act_file;
+chmod 0444, $new_act_file;
 
-chmod 0644, $tab_file;
-open TABFILE, ">$tab_file" or die "can't open $tab_file: $!\n";
+chmod 0644, $new_tab_file;
+open TABFILE, ">$new_tab_file" or die "can't open $new_tab_file: $!\n";
 print TABFILE $tablines;
 close TABFILE;
-chmod 0444, $tab_file;
+chmod 0444, $new_tab_file;
 
 unlink $tmpc_file;
 
@@ -113,8 +118,8 @@ unlink $tmpc_file;
 # C<#line 188 "perlytmp.h"> gets picked up by make depend, so remove them.
 
 open TMPH_FILE, $tmph_file or die "Can't open $tmph_file: $!\n";
-chmod 0644, $h_file;
-open H_FILE, ">$h_file" or die "Can't open $h_file: $!\n";
+chmod 0644, $new_h_file;
+open H_FILE, ">$new_h_file" or die "Can't open $new_h_file: $!\n";
 my $endcore_done = 0;
 # Token macros need to be generated manually on bison 2.4
 my $gather_tokens = ($version =~ /\b2\.4\b/ ? undef : 0);
@@ -143,10 +148,12 @@ while (<TMPH_FILE>) {
 }
 close TMPH_FILE;
 close H_FILE;
-chmod 0444, $h_file;
+chmod 0444, $new_h_file;
 unlink $tmph_file;
 
-print "rebuilt:  $h_file $tab_file $act_file\n";
+rename_if_different($new_h_file, $h_file);
+rename_if_different($new_tab_file, $tab_file);
+rename_if_different($new_act_file, $act_file);
 
 exit 0;