1 files changed, 39 insertions, 0 deletions
diff --git a/third_party/nix/corepkgs/unpack-channel.nix b/third_party/nix/corepkgs/unpack-channel.nix
new file mode 100644
index 0000000000..d39a206378
--- /dev/null
+++ b/third_party/nix/corepkgs/unpack-channel.nix
@@ -0,0 +1,39 @@
+with import <nix/config.nix>;
+
+let
+
+  builder = builtins.toFile "unpack-channel.sh"
+    ''
+      mkdir $out
+      cd $out
+      xzpat="\.xz\$"
+      gzpat="\.gz\$"
+      if [[ "$src" =~ $xzpat ]]; then
+        ${xz} -d < $src | ${tar} xf - ${tarFlags}
+      elif [[ "$src" =~ $gzpat ]]; then
+        ${gzip} -d < $src | ${tar} xf - ${tarFlags}
+      else
+        ${bzip2} -d < $src | ${tar} xf - ${tarFlags}
+      fi
+      if [ * != $channelName ]; then
+        mv * $out/$channelName
+      fi
+    '';
+
+in
+
+{ name, channelName, src }:
+
+derivation {
+  system = builtins.currentSystem;
+  builder = shell;
+  args = [ "-e" builder ];
+  inherit name channelName src;
+
+  PATH = "${nixBinDir}:${coreutils}";
+
+  # No point in doing this remotely.
+  preferLocalBuild = true;
+
+  inherit chrootDeps;
+}