configure

#!/usr/bin/env perl

use strict;
use warnings;
use File::Temp qw(tempfile);
use Getopt::Long;

my $verbose = "";
my $CFLAGS;
my $LDFLAGS;
my $CC;
my %defines = ();
my $define_prefix = "EXCOM_";
my $header_file = "inc/excom/config.h";

if(!defined $ENV{CC}) {
  $CC = "cc";
} else {
  $CC = $ENV{CC};
}

if(!defined $ENV{CFLAGS}) {
  $CFLAGS = "";
} else {
  $CFLAGS = "$ENV{CFLAGS} ";
}

if(!defined $ENV{LDFLAGS}) {
  $LDFLAGS = "";
} else {
  $LDFLAGS = "$ENV{LDFLAGS} ";
}


GetOptions(
  "verbose" => \$verbose,
  "define-prefix=s" => \$define_prefix,
  "header-file=s" => \$header_file
  )
or die();


sub compile {
  my $body = shift;
  my $flags = shift || "";

  my ($fh, $filename) = tempfile(SUFFIX => '.c');
  my $out = $filename;
  $out =~ s/\.c$/.out/;
  print $fh $body;
  close $fh;
  my $command = "$CC $CFLAGS $LDFLAGS $flags -o $out $filename 2>&1";
  print "$command\n" if $verbose;
  my $output = `$command`;
  print "$output\n" if $verbose;
  return $? << 8 == 0;
}

sub check_command {
  my $command = shift;

  print "$command\n" if $verbose;
  my $output = `$command`;
  print "$output\n" if $verbose;
  return $? << 8 == 0;
}

sub command {
  my $command = shift;
  my $arguments = shift || "";
  my $fail = shift || 1;

  print "Checking for $command... ";

  if (!check_command("$command $arguments")) {
    print "no\n";
    if($fail)
    {
      exit 1;
    }
  } else {
    printf "yes\n";
  }
}

sub define_header {
  my $header_name = shift;

  my $define = uc $header_name;
  $define =~ s/(\/|\.)/_/g;
  $define = "${define_prefix}HAVE_$define";

  $defines{$define} = "";
}

sub check_header {
  my $header = shift;
  my $flags = shift;
  my $body = shift || "";
  print "Checking for $header... ";
  my $src = <<C
  #include <stdlib.h>
  $body
  #include <$header>
  int main(){ return 0; }
C
  ;

  if(compile($src, $flags)) {
    print "yes\n";
    define_header $header;
    return 1;
  } else {
    print "no\n";
    return "";
  }
}

sub write_header {
  my $fh;
  open($fh, ">", $header_file) or die("Cannot open $header_file: $!");
  my $define_data = "";

  foreach my $key (keys %defines) {
    $define_data .= "#define $key $defines{$key}\n";
  }

  print $fh <<CONFIG
#ifndef _${define_prefix}CONFIG_H
#define _${define_prefix}CONFIG_H

$define_data
#endif
CONFIG
;
  close($fh) or die("Could not close file: $!");
}

check_header "sys/epoll.h";
check_header "sys/event.h", "", "#include <sys/types.h>";
check_header "poll.h";

command "ragel", "--version";
command "valgrind", "--version";

write_header;