1 files changed, 36 insertions, 0 deletions
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 93fcb068f..cfdfb5269 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -627,6 +627,42 @@ string Store::makeValidityRegistration(const StorePathSet & paths,
 }
 
 
+StorePathSet Store::exportReferences(const StorePathSet & storePaths, const StorePathSet & inputPaths)
+{
+    StorePathSet paths;
+
+    for (auto & storePath : storePaths) {
+        if (!inputPaths.count(storePath))
+            throw BuildError("cannot export references of path '%s' because it is not in the input closure of the derivation", printStorePath(storePath));
+
+        computeFSClosure({storePath}, paths);
+    }
+
+    /* If there are derivations in the graph, then include their
+       outputs as well.  This is useful if you want to do things
+       like passing all build-time dependencies of some path to a
+       derivation that builds a NixOS DVD image. */
+    auto paths2 = paths;
+
+    for (auto & j : paths2) {
+        if (j.isDerivation()) {
+            Derivation drv = derivationFromPath(j);
+            for (auto & k : drv.outputsAndOptPaths(*this)) {
+                if (!k.second.second)
+                    /* FIXME: I am confused why we are calling
+                       `computeFSClosure` on the output path, rather than
+                       derivation itself. That doesn't seem right to me, so I
+                       won't try to implemented this for CA derivations. */
+                    throw UnimplementedError("exportReferences on CA derivations is not yet implemented");
+                computeFSClosure(*k.second.second, paths);
+            }
+        }
+    }
+
+    return paths;
+}
+
+
 void Store::pathInfoToJSON(JSONPlaceholder & jsonOut, const StorePathSet & storePaths,
     bool includeImpureInfo, bool showClosureSize,
     Base hashBase,