Add preliminary binary substituter.

* guix/scripts/substitute-binary.scm: New file.
* Makefile.am (MODULES): Add it.
* nix/scripts/substitute-binary.in: New file.
* config-daemon.ac: Produce nix/scripts/substitute-binary.
* daemon.am (nodist_pkglibexec_SCRIPTS): Add
  nix/scripts/substitute-binary.
* guix/store.scm (substitutable-path-info): Use the
  `query-substitutable-path-infos' RPC.
* nix/nix-daemon/guix-daemon.cc (main): Honor `NIX_SUBSTITUTERS'.
* pre-inst-env.in: Set `NIX_SUBSTITUTERS'.
* test-env.in: Leave `NIX_SUBSTITUTERS' unchanged.  Set
  `GUIX_BINARY_SUBSTITUTE_URL, and create
  $NIX_STATE_DIR/substituter-data.
  Run `guix-daemon' within `./pre-inst-env'.
* tests/store.scm ("substitute query"): New test.

1 files changed, 10 insertions, 2 deletions

diff --git a/nix/nix-daemon/guix-daemon.cc b/nix/nix-daemon/guix-daemon.cc
index 1611840bd4..0e2f36150b 100644
--- a/nix/nix-daemon/guix-daemon.cc
+++ b/nix/nix-daemon/guix-daemon.cc
@@ -200,9 +200,17 @@ main (int argc, char *argv[])
     {
       settings.processEnvironment ();
 
-      /* FIXME: Disable substitutes until we have something that works.  */
-      settings.useSubstitutes = false;
+      /* Use our substituter by default.  */
       settings.substituters.clear ();
+      string subs = getEnv ("NIX_SUBSTITUTERS", "default");
+      if (subs == "default")
+	/* XXX: No substituters until we have something that works.  */
+	settings.substituters.clear ();
+	// settings.substituters.push_back (settings.nixLibexecDir
+	// 				 + "/guix/substitute-binary");
+      else
+	settings.substituters = tokenizeString<Strings> (subs, ":");
+
 
       argp_parse (&argp, argc, argv, 0, 0, 0);