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#!/usr/bin/perl -w
use File::Spec::Functions qw ( :ALL );
use File::stat;
use strict;
use warnings;
my $cfgdir = "config";
my $config_h = shift || "config.h";
# Read in a whole file
#
sub read_file {
my $file = shift;
open my $fh, "<$file" or die "Could not open file $file: $!\n";
local $/;
my $data = <$fh>;
close $fh;
return $data;
}
# Write out a whole file
#
sub write_file {
my $file = shift;
my $data = shift;
open my $fh, ">$file" or die "Could not write $file: $!\n";
print $fh $data;
close $fh;
}
# Delete a file
#
sub delete_file {
my $file = shift;
unlink $file or die "Could not delete $file: $!\n";
}
# Get a file modification time
#
sub file_mtime {
my $file = shift;
my $stat = stat ( $file ) or die "Could not stat $file: $!\n";
return $stat->mtime;
}
# Read all the .h files in a directory
#
sub read_dir {
my $dir = shift;
opendir my $dh, $dir or die "Could not open directory $dir: $!\n";
my @entries = grep { /\.h$/ } readdir $dh;
closedir $dh;
return @entries;
}
# Get the current configuration by reading the configuration file
# fragments
#
sub current_config {
my $dir = shift;
my $cfg = {};
foreach my $file ( read_dir ( $dir ) ) {
$cfg->{$file} = read_file ( catfile ( $dir, $file ) );
}
return $cfg;
}
# Calculate guard name for a header file
#
sub guard {
my $name = shift;
$name =~ s/\W/_/g;
return "CONFIG_".( uc $name );
}
# Calculate preamble for a header file
#
sub preamble {
my $name = shift;
my $master = shift;
my $guard = guard ( $name );
my $preamble = <<"EOF";
/*
* This file is automatically generated from $master. Do not edit this
* file; edit $master instead.
*
*/
#ifndef $guard
#define $guard
EOF
return $preamble;
}
# Calculate postamble for a header file
#
sub postamble {
my $name = shift;
my $guard = guard ( $name );
return "\n#endif /* $guard */\n";
}
# Get the new configuration by splitting config.h file using the
# @BEGIN/@END tags
#
sub new_config {
my $file = shift;
my $cfg = {};
my $cursor = "";
open my $fh, "<$file" or die "Could not open $file: $!\n";
while ( <$fh> ) {
if ( ( my $newcursor, my $suffix ) = /\@BEGIN\s+(\w+\.h)(.*)$/ ) {
die "Missing \"\@END $cursor\" before \"\@BEGIN $1\""
." at $file line $.\n" if $cursor;
$cursor = $newcursor;
$cfg->{$cursor} = preamble ( $cursor, $file )
unless exists $cfg->{$cursor};
$cfg->{$cursor} .= "\n/*".$suffix."\n";
} elsif ( ( my $prefix, my $oldcursor ) = /^(.*)\@END\s+(\w+\.h)/ ) {
die "Missing \"\@BEGIN $oldcursor\" before \"\@END $oldcursor\""
." at $file line $.\n" unless $cursor eq $oldcursor;
$cfg->{$cursor} .= $prefix."*/\n";
$cursor = "";
} else {
$cfg->{$cursor} .= $_ if $cursor;
}
}
close $fh;
die "Missing \"\@END $cursor\" in $file\n" if $cursor;
foreach $cursor ( keys %$cfg ) {
$cfg->{$cursor} .= postamble ( $cursor );
}
return $cfg;
}
#############################################################################
#
# Main program
# Read in current config file fragments
#
my $current = current_config ( $cfgdir );
# Read in config.h and split it into fragments
#
my $new = new_config ( $config_h );
# Delete any no-longer-wanted config file fragments
#
foreach my $file ( keys %$current ) {
unlink catfile ( $cfgdir, $file ) unless exists $new->{$file};
}
# Write out any modified fragments, and find the oldest timestamp of
# any unmodified fragments.
#
my $oldest = time ();
foreach my $file ( keys %$new ) {
if ( $current->{$file} && $new->{$file} eq $current->{$file} ) {
# Unmodified
my $time = file_mtime ( catfile ( $cfgdir, $file ) );
$oldest = $time if $time < $oldest;
} else {
write_file ( catfile ( $cfgdir, $file ), $new->{$file} );
}
}
# If we now have fragments that are older than config.h, set the
# timestamp on config.h to match the oldest fragment, to prevent make
# from always attempting to rebuild the fragments.
#
if ( $oldest < file_mtime ( $config_h ) ) {
utime time(), $oldest, $config_h or die "Could not touch $config_h: $!\n";
}
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