#!/home/ben/software/install/bin/perl
use warnings;
use strict;
use Carp;
use C::Tokenize '0.18', '$include';
use File::Temp 'tempfile';
use IPC::Run3;
use Cwd;
use File::Slurper qw!read_text write_text!;

sub minimize_headers
{
    my ($file, %options) = @_;
    my $verbose = $options{verbose};
    if ($file !~ /\.c$/) {
	croak "'$file' doesn't look like a C file";
    }
    my $ofile = $file;
    $ofile =~ s/\.c$/\.o/;
    my $dir = getcwd ();
    if ($ofile =~ m!^(.*)/([^/]+)$!) {
	$dir = $1;
	$ofile = $2;
    }
    my $make = $options{make};
    if (! $make) {
	$make = 'make';
    }
    if (-f $ofile) {
	unlink $ofile or die "unlink $ofile failed: $!";
    }
    my $command = "$make -C $dir $ofile";
    my $status = run3 ($command, undef, \my $output, \my $errors);
    if (-f $ofile) {
	unlink $ofile or die "unlink $ofile failed: $!";
    }
    if ($errors) {
	warn "$command failed, fix that and run again";
	return;
    }
    my (undef, $tempfile) = tempfile ("$file.XXXXX");
    if (! rename $file, $tempfile) {
	croak "Could not rename $file to $tempfile: $!";
    }
    my $ctext = read_text ($tempfile);
    my @includes;
    while ($ctext =~ /$include/g) {
	my $include = $1;
	chomp ($include);
	push @includes, $include;
    }
    if (-f $file) {
	unlink ($file) or die "Could not remove $file: $!";
    }
    my %uniques;
    for my $include (@includes) {
	if ($include !~ /#include\s*[<"](.*)[>"]/) {
	    warn "Strange include '$include'";
	}
	else {
	    my $ifile = $1;
	    if ($uniques{$ifile}) {
		warn "File '$ifile' seems to be included more than once.\n";
	    }
	    else {
		$uniques{$ifile} = 1;
	    }
	}
    }
    for my $include (@includes) {
	my $newtext = $ctext;
	$newtext =~ s!\Q$include!// C:MinimizeHeaders removed this: $include!g;
	write_text ($file, $newtext);
	run3 ("$make -C $dir $ofile", undef, \my $output, \my $errors);
	if (! $errors) {
	    print "$file: '$include' may be unnecessary since it compiles without this.\n";
	}
	else {
	    if ($verbose) {
		print "$file: '$include' seems to be necessary.\n";
		print "The make errors were as follows:\n$errors";
	    }
	}
	if (! unlink ($file)) {
	    croak "Could not remove $file: $!";
	}
	if (-f $ofile) {
	    unlink $ofile or die "unlink $ofile failed: $!";
	}
    }
    if (! rename $tempfile, $file) {
	croak "Could not rename $tempfile to $file: $!";
    }
    return;
}

for my $file (@ARGV) {
    eval {
	minimize_headers ($file);
    };
    if ($@) {
	print "Minimize failed for '$file': $@";
    }
}
exit;

# Local variables:
# mode: perl
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