#!/usr/bin/perl -w

use Digest::SHA;
use File::Copy qw(copy);  # Core module
use IO::File;
use strict;

our $Debug;

# We don't use getopt, as want multiple in/outs and stop at first command
my @opt_name;
my @opt_in;  # We allow empty opt_in and opt_out so we can cache --version checks.
my @opt_out;
my @opt_cmd;
my @opt_vercmd;
my $Opt_Gen = "gen";
my $Opt_Verbose;
my $opt_skip_cmd = 0;
my $in_cmd;
my $list = \@opt_in;
while (defined(my $param=shift @ARGV)) {
    if ($in_cmd) { push @opt_cmd, $param; }
    elsif ($param =~ /^-?-debug/) { $Debug=1; }
    elsif ($param =~ /^-?-cmd/) { $in_cmd = 1; }
    elsif ($param =~ /^-?-in/) { $list = \@opt_in; }
    elsif ($param =~ /^-?-name/) { $list = \@opt_name; }
    elsif ($param =~ /^-?-skip-cmd/) { $opt_skip_cmd = shift @ARGV; }
    elsif ($param =~ /^-?-out/) { $list = \@opt_out; }
    elsif ($param =~ /^-?-verbose/) { $Opt_Verbose=1; }
    elsif ($param =~ /^-?-gen/) { $Opt_Gen = shift @ARGV; }
    elsif ($param =~ /^-?-vercmd/) { $list = \@opt_vercmd; }
    elsif ($param =~ /^-/) { die "%Error: Unexpected argument: $param,"; }
    else {
	push @$list, $param;
    }
}
$opt_name[0] ||= $opt_cmd[0];
$opt_vercmd[0] ||= $opt_cmd[0];
$Opt_Verbose = 1 if $Debug;

mkdir $Opt_Gen, 0777;

# Hash of command, including this program args
my $digest = Digest::SHA->new(1);
{
    my $str = 'toolhash_1.0';
    $str .= '----'.join('  ',@opt_in);
    $str .= '----'.join('  ',@opt_out);
    $str .= '----';
    my $i = $opt_skip_cmd;
    foreach (@opt_cmd) { next if ($i-- > 0); $str.='  '.$_; }
    $str .= '----';
    print "toolhash: Hashing $str\n" if $Debug;
    $digest->add($str);
}
foreach my $fn (@opt_in) {
    print "toolhash: Hashing $fn\n" if $Debug;
    my $fh = IO::File->new("<$fn") or die "toolhash: %Error: $! reading $fn\n";
    $digest->addfile($fh);
    $fh->close;
}
my $arcfn = $Opt_Gen."/".$opt_name[0];
my $hash = $digest->b64digest;

# Cache hit?  If so, fill as we go
remove_out();
my $hit = restore($hash, 1);
if ($hit) {
    print "toolhash: Cache hit running $opt_name[0]\n" if $Opt_Verbose;
    exit (0);
} else {
    print "toolhash: Cache miss running $opt_name[0]\n" if $Opt_Verbose;
}
remove_named();
my $out = run_cmd();
encache($hash, $out);

remove_out();
$hit = restore($hash, 0);
exit (0) if $hit;
die "toolhash: %Error: encaching failed, didn't hit second time\n";

#######################################################################

sub restore {
    my $hash = shift;
    my $pass1 = shift;
    if ($pass1 && $ENV{TOOLHASH_RECACHE}) {
	print "toolhash: TOOLHASH_RECACHE set, missing\n" if $Debug;
	return 0;
    }

    # Returns hit
    my $hit = 1;
    my $fh = IO::File->new("<${arcfn}-0");
    if (!$fh) {
	print "toolhash: Cache hash empty $arcfn\n" if $Debug;
	return 0;
    }
    my $line = $fh->getline;
    chomp $line;
    print "toolhash: Cache hash test $arcfn $line ".$hash."\n" if $Debug;
    if ($line ne $hash) {
	print "toolhash: Cache hash miss\n" if $Debug;
	return 0;
    }

    my $n = 1;
    foreach my $fn (@opt_out) {
	my $digout = "${arcfn}-${n}";
	if (-r $digout) {
	    print "toolhash: Cache hit  $digout for $fn\n" if $Debug;
	    # Restore, assuming all hits.
	    copy($digout, $fn) or die "toolhash: %Error: $! on 'cp $digout $fn'\n";
	} else {
	    print "toolhash: Cache miss $digout for $fn\n" if $Debug;
	    $hit = 0; last;
	}
	$n++;
    }

    if ($hit) {
	print "toolhash: Cache hit\n" if $Debug;
	if (my $fh = IO::File->new("<${arcfn}-s")) {  # Dump stdout
	    print join('',$fh->getlines);
	    $fh->close;
	}
    }

    return $hit;
}

sub run_cmd {
    remove_out();
    my $cmd = join(' ',@opt_cmd);
    # We can't use system() as we need the output and fork() isn't portable
    # without pulling in yet another package, so punt on spaces
    foreach (@opt_cmd) {
	if (/ /) { die "%Error: unsupported: spaces in command: '$cmd',"; }
    }
    print "\t$cmd\n" if $Debug||1;
    my $out = `$cmd`;
    my $status = $?;
    print $out;
    if ($status) {
	remove_out();
	# See if bison/gcc/flex --version works
	my $vcmd = "$opt_vercmd[0] --version";
	print "\t$vcmd\n" if $Debug;
	`$vcmd`;
	if ($?) {
	    die "\n%Error: '$opt_cmd[0]' must be installed to build\n";
	}
	exit $status >> 8;
    }
    return $out;
}

sub encache {
    my $hash = shift;
    my $out = shift;

    print "toolhash: Encache ".$hash."\n" if $Debug;

    my $fh = IO::File->new(">${arcfn}-0") or die "toolhash: %Error: $! ${arcfn}-0\n";
    $fh->print($hash);
    $fh->close;

    if ($out ne "") {
	$fh = IO::File->new(">${arcfn}-s") or die "toolhash: %Error: $! ${arcfn}-s\n";
	$fh->print($out);
	$fh->close;
    }

    my $n = 1;
    foreach my $fn (@opt_out) {
	my $digout = "${arcfn}-${n}";
	copy($fn, $digout) or die "toolhash: %Error: $! on 'cp $fn $digout'\n";
	$n++;
    }
}

sub remove_out {
    unlink for (@opt_out);  # Ok if error
}

sub remove_named {
    unlink for (glob $Opt_Gen."/$opt_name[0]-*"); # Ok if error
}

#######################################################################
__END__

=pod

=head1 NAME

toolhash - Generate and hash files to avoid installation of build tools

=head1 SYNOPSIS

  toolhash --in foo.c --out foo.o --cmd gcc -c -o foo.o foo.c

=head1 DESCRIPTION

Toolhash is used to install Verilog-Perl and other tools.  It stores a
hash of generated files (aka the cons make utility) for distribution to
avoid building those files from scratch.

The hash isn't stored as part of the filename, so that the MANIFEST can
remain constant.

=head1 ARGUMENTS

=over 4

=item --cmd command args...

Command and arguments to run.  All further arguments are passed to the command.

=item --gen ARG

Specify location of generated file cache, defaults to "gen".

=item --in filenames...

Input filenames.

=item --name

Prefix for output files, or defaults to first --cmd argument.

=item --verbose

Print hit/miss messages.

=item --skip-cmd <num-args>

Disable hashing first num-arg components of the command.  This is used to
avoid commands like "/usr/bin/perl ...." from hash missing when the Perl
version and thus the path changes.

=item --out filenames...

Output filenames.

=item --vercmd command

Command to run to get --version.

=back

=head1 ENVIRONMENT

=over 4

=item TOOLHASH_RECACHE

Write the cache, but do not read from it.

=back

=head1 DISTRIBUTION

This is part of the L<http://www.veripool.org/> free Verilog EDA software
tool suite.  The latest version is available from CPAN and from
L<http://www.veripool.org/>.

Copyright 2010-2016 by Wilson Snyder.  This package is free software; you
can redistribute it and/or modify it under the terms of either the GNU
Lesser General Public License Version 3 or the Perl Artistic License Version 2.0.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
more details.

=head1 AUTHORS

Wilson Snyder <wsnyder@wsnyder.org>

=head1 SEE ALSO

C<make>

=cut

######################################################################
### Local Variables:
### compile-command: "echo 'void i() {}' > foo.c; ./toolhash toolhash --debug --in foo.c --out foo.o --cmd gcc -c -o foo.o foo.c ; ls -la foo.* gen/* ; rm foo.*"
### End: