* Add a NarSize field to Hydra manifests. This allows nix-env

to predict how much disk space a package will require.
* Compute the output / closure size using the info stored in the
  Nix database (rather than doing a slow "du").

src/lib/Hydra/Helper/Nix.pm

@@ -9,7 +9,7 @@ use Hydra::Helper::CatalystUtils;
 
 our @ISA = qw(Exporter);
 our @EXPORT = qw(
-    isValidPath queryPathInfo
+    isValidPath
     getHydraPath getHydraDBPath openHydraDB txn_do
     registerRoot getGCRootsDir gcRootFor
     getPrimaryBuildsForView 
@@ -23,17 +23,6 @@ sub isValidPath {
 }
 
 
-sub queryPathInfo {
-    my $path = shift;
-
-    my $hash = Nix::queryPathHash($path);
-    my $deriver = Nix::queryDeriver($path);
-    my @refs = Nix::queryReferences($path);
-
-    return ($hash, $deriver, \@refs);
-}
-
-
 sub getHydraPath {
     my $dir = $ENV{"HYDRA_DATA"};
     die "The HYDRA_DATA environment variable is not set!\n" unless defined $dir;