* In `nix-store --export', abort if the contents of a path has

  changed.  This prevents corrupt paths from spreading to other
  machines.  Note that checking the hash is cheap because we're
  hashing anyway (because of the --sign feature).

1 files changed, 7 insertions, 0 deletions

diff --git a/src/libutil/hash.cc b/src/libutil/hash.cc
index eef01fe4d..bd7e33a48 100644
--- a/src/libutil/hash.cc
+++ b/src/libutil/hash.cc
@@ -289,6 +289,13 @@ HashSink::HashSink(HashType ht) : ht(ht)
     start(ht, *ctx);
 }
     
+HashSink::HashSink(const HashSink & h)
+{
+    ht = h.ht;
+    ctx = new Ctx;
+    *ctx = *h.ctx;
+}
+    
 HashSink::~HashSink()
 {
     delete ctx;