gzip bzip2 lzma gnutar unzip git

        gzip bzip2 lzma gnutar unzip git mercurial

        cp ${"${nixpkgs}/pkgs/build-support/fetchhg/nix-prefetch-hg"} $out/bin/nix-prefetch-hg

use Digest::SHA qw(sha256_hex);
use File::Path;

sub scmPath {
    return getHydraPath . "/scm" ;
}

sub fetchInputCVS {

sub fetchInputHg {

    
    (my $uri, my $branch) = split ' ', $value;
    $branch = defined $branch ? $branch : "default";
    # init local hg clone
    my $stdout; my $stderr;
    my $clonePath;
    mkpath(scmPath);
    $clonePath = scmPath . "/" . sha256_hex($uri);
    if (! -d $clonePath) {
        (my $res, $stdout, $stderr) = captureStdoutStderr(600,
            ("hg", "clone", $uri, $clonePath));
        die "Error cloning mercurial repo at `$uri':\n$stderr" unless $res;
    }
    # hg pull + check rev
    chdir $clonePath or die $!;
    (my $res, $stdout, $stderr) = captureStdoutStderr(600,
        ("hg", "pull"));
    die "Error pulling latest change mercurial repo at `$uri':\n$stderr" unless $res;
    (my $res1, $stdout, $stderr) = captureStdoutStderr(600,
        ("hg", "heads", $branch));
    die "Error getting head of $branch from `$uri':\n$stderr" unless $res;
    $stdout =~ m/[0-9]+:([0-9A-Fa-f]{12})/;
    my $revision = $1;
    die "Could not determine head revision of branch $branch" unless $revision;
    
    my $storePath;
    my $sha256;
    (my $cachedInput) = $db->resultset('CachedHgInputs')->search(
        {uri => $uri, branch => $branch, revision => $revision});
    if (defined $cachedInput && isValidPath($cachedInput->storepath)) {
        $storePath = $cachedInput->storepath;
        $sha256 = $cachedInput->sha256hash;
    } else {
        print STDERR "checking out Mercurial input from $uri $branch revision $revision\n";
        $ENV{"NIX_HASH_ALGO"} = "sha256";
        $ENV{"PRINT_PATH"} = "1";
        
        (my $res, $stdout, $stderr) = captureStdoutStderr(600,
            ("nix-prefetch-hg", $uri, $revision));
        die "Cannot check out Mercurial repository `$uri':\n$stderr" unless $res;
        ($sha256, $storePath) = split ' ', $stdout;
        txn_do($db, sub {
            $db->resultset('CachedHgInputs')->create(
                { uri => $uri
                , branch => $branch
                , revision => $revision
                , sha256hash => $sha256
                , storepath => $storePath
                });
            });
    }
    return 
        { type => $type
        , uri => $uri
        , branch => $branch
        , storePath => $storePath
        , sha256hash => $sha256
        , revision => $revision
        };
    

                when (["svn", "svn-checkout", "path", "build", "git", "cvs", "sysbuild"]) {

                when (["svn", "svn-checkout", "path", "build", "git", "hg", "sysbuild"]) {

    , "hg" = "Mercurial checkout"

    sha256hash    text not null,
    storePath     text not null,
    primary key   (uri, branch, revision)
);
create table CachedHgInputs (
    uri           text not null,
    branch        text not null,
    revision      text not null,

create index IndexCachedHgInputsOnHash on CachedHgInputs(uri, branch, sha256hash);