* Add an API function exportPaths() that provides the functionality of

  ‘nix-store --export’.
* Add a Perl module that provides the functionality of
  ‘nix-copy-closure --to’.  This is used by build-remote.pl so it no
  longer needs to start a separate nix-copy-closure process.  Also, it
  uses the Perl API to do the export, so it doesn't need to start a
  separate nix-store process either.  As a result, nix-copy-closure
  and build-remote.pl should no longer fail on very large closures due
  to an "Argument list too long" error.  (Note that having very many
  dependencies in a single derivation can still fail because the
  environment can become too large.  Can't be helped though.)

2 files changed, 10 insertions, 30 deletions

diff --git a/scripts/build-remote.pl.in b/scripts/build-remote.pl.in
index 110c95f223..72d09565bc 100755
--- a/scripts/build-remote.pl.in
+++ b/scripts/build-remote.pl.in
@@ -5,6 +5,7 @@ use English '-no_match_vars';
 use IO::Handle;
 use Nix::Config;
 use Nix::SSH qw/sshOpts openSSHConnection/;
+use Nix::CopyClosure;
 no warnings('once');
 
 
@@ -225,8 +226,7 @@ sub removeRoots {
 
 
 # Copy the derivation and its dependencies to the build machine.
-system("NIX_SSHOPTS=\"@sshOpts\" @bindir@/nix-copy-closure $hostName $maybeSign $drvPath @inputs") == 0
-    or die "cannot copy inputs to $hostName: $?";
+Nix::CopyClosure::copyTo($hostName, [ @sshOpts ], [ $drvPath, @inputs ], "", "", 0, 0, $maybeSign ne "");
 
 
 # Perform the build.
diff --git a/scripts/nix-copy-closure.in b/scripts/nix-copy-closure.in
index 172acd9e7d..2eac56e3f2 100755
--- a/scripts/nix-copy-closure.in
+++ b/scripts/nix-copy-closure.in
@@ -3,6 +3,7 @@
 use Nix::SSH;
 use Nix::Config;
 use Nix::Store;
+use Nix::CopyClosure;
 
 
 if (scalar @ARGV < 1) {
@@ -39,8 +40,8 @@ while (@ARGV) {
         $sign = 1;
     }
     elsif ($arg eq "--gzip") {
-        $compressor = "| gzip";
-        $decompressor = "gunzip |";
+        $compressor = "gzip";
+        $decompressor = "gunzip";
     }
     elsif ($arg eq "--from") {
         $toMode = 0;
@@ -67,30 +68,7 @@ openSSHConnection $sshHost or die "$0: unable to start SSH\n";
 
 
 if ($toMode) { # Copy TO the remote machine.
-
-    # Get the closure of this path.
-    my @allStorePaths = reverse(topoSortPaths(computeFSClosure(0, $includeOutputs, map { followLinksToStorePath $_ } @storePaths)));
-
-    # Ask the remote host which paths are invalid.
-    open(READ, "set -f; ssh $sshHost @sshOpts nix-store --check-validity --print-invalid @allStorePaths|");
-    my @missing = ();
-    while (<READ>) {
-        chomp;
-        push @missing, $_;
-    }
-    close READ or die;
-
-    # Export the store paths and import them on the remote machine.
-    if (scalar @missing > 0) {
-        print STDERR "copying these missing paths:\n";
-        print STDERR "  $_\n" foreach @missing;
-        unless ($dryRun) {
-            my $extraOpts = $sign ? "--sign" : "";
-            system("set -f; nix-store --export $extraOpts @missing $compressor | ssh $sshHost @sshOpts '$decompressor nix-store --import'") == 0
-                or die "copying store paths to remote machine `$sshHost' failed: $?";
-        }
-    }
-
+    Nix::CopyClosure::copyTo($sshHost, [ @sshOpts ], [ @storePaths ], $compressor, $decompressor, $includeOutputs, $dryRun, $sign);
 }
 
 else { # Copy FROM the remote machine.
@@ -112,8 +90,10 @@ else { # Copy FROM the remote machine.
 
     # Export the store paths on the remote machine and import them on locally.
     if (scalar @missing > 0) {
-        print STDERR "copying these missing paths:\n";
-        print STDERR "  $_\n" foreach @missing;
+        print STDERR "copying ", scalar @missing, " missing paths from ‘$sshHost’...\n";
+        #print STDERR "  $_\n" foreach @missing;
+        $compressor = "| $compressor" if $compressor ne "";
+        $decompressor = "$decompressor |" if $decompressor ne "";
         unless ($dryRun) {
             my $extraOpts = $sign ? "--sign" : "";
             system("set -f; ssh $sshHost @sshOpts 'nix-store --export $extraOpts @missing $compressor' | $decompressor $Nix::Config::binDir/nix-store --import") == 0