nix/scripts/nix-unpack-closure.in

#! @perl@ -w

# This tool unpacks the closures created by "nix-pack-closure" and
# adds them to the Nix store.

# TODO: make this program "streamy", i.e., don't use a temporary
# directory.

use strict;
use File::Temp qw(tempdir);

my $binDir = $ENV{"NIX_BIN_DIR"};
$binDir = "@bindir@" unless defined $binDir;

my $tmpDir = tempdir("nix-unpack-closure.XXXXXX", CLEANUP => 1, TMPDIR => 1)
    or die "cannot create a temporary directory";


# Unpack the NAR archive on standard input.
system("nix-store --restore '$tmpDir/unpacked'") == 0
    or die "nix-store --restore failed";


open VALID, ">$tmpDir/validity" or die;


# For each path in the closure that is not yet valid, add it to the
# store.  TODO: use proper locking.  Or even better, let nix-store do
# this.
opendir(DIR, "$tmpDir/unpacked/contents") or die "cannot open directory: $!";

foreach my $name (sort(readdir DIR)) {
    next if $name eq "." or $name eq "..";

    my $storePath = "@storedir@/$name"; # !!!

    # !!! this really isn't a good validity check!
    system "$binDir/nix-store --check-validity '$storePath' 2> /dev/null";
    if ($? != 0) {
        print STDERR "unpacking `$storePath'...\n";

        # !!! race
        system("@coreutils@/rm -rf '$storePath'") == 0
            or die "cannot remove `$storePath': $?";

        system("$binDir/nix-store --restore '$storePath' < '$tmpDir/unpacked/contents/$name'") == 0
            or die "nix-store --dump failed on `$storePath': $?";
        
        print VALID "$storePath\n";

        open DRV, "<$tmpDir/unpacked/derivers/$name" or die;
        my $deriver = <DRV>;
        chomp $deriver;
        $deriver = "" if $deriver eq "unknown-deriver";
        close DRV;

        my @refs;
        open REFS, "<$tmpDir/unpacked/references/$name" or die;
        while (<REFS>) {
            chomp;
            push @refs, $_;
        }
        close REFS;

        print VALID "$deriver\n";
        
        print VALID (scalar @refs), "\n";
        foreach my $ref (@refs) {
            print VALID "$ref\n";
        }
    }
}

closedir(DIR) or die;


# Register the invalid paths as valid.
system("nix-store --register-validity <'$tmpDir/validity'") == 0
    or die "nix-store --register-validity failed";