1 files changed, 108 insertions, 0 deletions
diff --git a/src/tools/msvc/pgflex.pl b/src/tools/msvc/pgflex.pl
new file mode 100644
index 0000000..0728b85
--- /dev/null
+++ b/src/tools/msvc/pgflex.pl
@@ -0,0 +1,108 @@
+# -*-perl-*- hey - emacs - this is a perl file
+
+# Copyright (c) 2021, PostgreSQL Global Development Group
+
+# src/tools/msvc/pgflex.pl
+
+use strict;
+use warnings;
+
+use File::Basename;
+
+# silence flex bleatings about file path style
+$ENV{CYGWIN} = 'nodosfilewarning';
+
+# assume we are in the postgres source root
+
+do './src/tools/msvc/buildenv.pl' if -e 'src/tools/msvc/buildenv.pl';
+
+my ($flexver) = `flex -V`;    # grab first line
+$flexver = (split(/\s+/, $flexver))[1];
+$flexver =~ s/[^0-9.]//g;
+my @verparts = split(/\./, $flexver);
+unless ($verparts[0] == 2
+	&& ($verparts[1] > 5 || ($verparts[1] == 5 && $verparts[2] >= 31)))
+{
+	print "WARNING! Flex install not found, or unsupported Flex version.\n";
+	print "echo Attempting to build without.\n";
+	exit 0;
+}
+
+my $input = shift;
+if ($input !~ /\.l$/)
+{
+	print "Input must be a .l file\n";
+	exit 1;
+}
+elsif (!-e $input)
+{
+	print "Input file $input not found\n";
+	exit 1;
+}
+
+(my $output = $input) =~ s/\.l$/.c/;
+
+# get flex flags from make file
+my $makefile = dirname($input) . "/Makefile";
+my ($mf, $make);
+open($mf, '<', $makefile);
+local $/ = undef;
+$make = <$mf>;
+close($mf);
+my $basetarg = basename($output);
+my $flexflags = ($make =~ /^$basetarg:\s*FLEXFLAGS\s*=\s*(\S.*)/m ? $1 : '');
+
+system("flex $flexflags -o$output $input");
+if ($? == 0)
+{
+
+	# Check for "%option reentrant" in .l file.
+	my $lfile;
+	open($lfile, '<', $input) || die "opening $input for reading: $!";
+	my $lcode = <$lfile>;
+	close($lfile);
+	if ($lcode =~ /\%option\sreentrant/)
+	{
+
+		# Reentrant scanners usually need a fix to prevent
+		# "unused variable" warnings with older flex versions.
+		system("perl src\\tools\\fix-old-flex-code.pl $output");
+	}
+	else
+	{
+
+		# For non-reentrant scanners we need to fix up the yywrap
+		# macro definition to keep the MS compiler happy.
+		# For reentrant scanners (like the core scanner) we do not
+		# need to (and must not) change the yywrap definition.
+		my $cfile;
+		open($cfile, '<', $output) || die "opening $output for reading: $!";
+		my $ccode = <$cfile>;
+		close($cfile);
+		$ccode =~ s/yywrap\(n\)/yywrap()/;
+		open($cfile, '>', $output) || die "opening $output for writing: $!";
+		print $cfile $ccode;
+		close($cfile);
+	}
+	if ($flexflags =~ /\s-b\s/)
+	{
+		my $lexback = "lex.backup";
+		open($lfile, '<', $lexback) || die "opening $lexback for reading: $!";
+		my $lexbacklines = <$lfile>;
+		close($lfile);
+		my $linecount = $lexbacklines =~ tr /\n/\n/;
+		if ($linecount != 1)
+		{
+			print "Scanner requires backup, see lex.backup.\n";
+			exit 1;
+		}
+		unlink $lexback;
+	}
+
+	exit 0;
+
+}
+else
+{
+	exit $? >> 8;
+}