3 files changed, 18 insertions, 1 deletions
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 06cadcb0ff0e..3c1f2ecacdcb 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -1255,7 +1255,7 @@ Path LocalStore::importPath(bool requireSignature, Source & source)
     bool haveSignature = readInt(hashAndReadSource) == 1;
 
     if (requireSignature && !haveSignature)
-        throw Error("imported archive lacks a signature");
+        throw Error(format("imported archive of `%1%' lacks a signature") % dstPath);
     
     if (haveSignature) {
         string signature = readString(hashAndReadSource);
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index d67ff2c77299..36ade2170876 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -298,6 +298,17 @@ string showPaths(const PathSet & paths)
 }
 
 
+void exportPaths(StoreAPI & store, const Paths & paths,
+    bool sign, Sink & sink)
+{
+    foreach (Paths::const_iterator, i, paths) {
+        writeInt(1, sink);
+        store.exportPath(*i, sign, sink);
+    }
+    writeInt(0, sink);
+}
+
+
 }
 
 
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index b3e67436c6c3..8bfb09880edd 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -342,6 +342,12 @@ ValidPathInfo decodeValidPathInfo(std::istream & str,
     bool hashGiven = false);
 
 
+/* Export multiple paths in the format expected by ‘nix-store
+   --import’. */
+void exportPaths(StoreAPI & store, const Paths & paths,
+    bool sign, Sink & sink);
+
+
 }