Make 'nix copy' to file:// binary caches run in constant memory

2 files changed, 15 insertions, 2 deletions

diff --git a/src/libutil/archive.hh b/src/libutil/archive.hh
index 768fe2536..795e9ce02 100644
--- a/src/libutil/archive.hh
+++ b/src/libutil/archive.hh
@@ -63,11 +63,11 @@ struct ParseSink
     virtual void createSymlink(const Path & path, const string & target) { };
 };
 
-struct TeeSink : ParseSink
+struct TeeParseSink : ParseSink
 {
     TeeSource source;
 
-    TeeSink(Source & source) : source(source) { }
+    TeeParseSink(Source & source) : source(source) { }
 };
 
 void parseDump(ParseSink & sink, Source & source);
diff --git a/src/libutil/serialise.hh b/src/libutil/serialise.hh
index a04118512..bd651fb7d 100644
--- a/src/libutil/serialise.hh
+++ b/src/libutil/serialise.hh
@@ -166,6 +166,19 @@ struct StringSource : Source
 };
 
 
+/* A sink that writes all incoming data to two other sinks. */
+struct TeeSink : Sink
+{
+    Sink & sink1, & sink2;
+    TeeSink(Sink & sink1, Sink & sink2) : sink1(sink1), sink2(sink2) { }
+    virtual void operator () (const unsigned char * data, size_t len)
+    {
+        sink1(data, len);
+        sink2(data, len);
+    }
+};
+
+
 /* Adapter class of a Source that saves all data read to `s'. */
 struct TeeSource : Source
 {