libstore: turn copyNAR into a generator

Change-Id: Id452f6a03faa1037ff13af0f63e32883966ff40d

2 files changed, 5 insertions, 7 deletions

diff --git a/src/libutil/archive.cc b/src/libutil/archive.cc
index 1b8038649..1c82c3f78 100644
--- a/src/libutil/archive.cc
+++ b/src/libutil/archive.cc
@@ -413,16 +413,14 @@ void restorePath(const Path & path, Source & source)
 }
 
 
-void copyNAR(Source & source, Sink & sink)
+WireFormatGenerator copyNAR(Source & source)
 {
     // FIXME: if 'source' is the output of dumpPath() followed by EOF,
     // we should just forward all data directly without parsing.
 
-    ParseSink parseSink; /* null sink; just parse the NAR */
+    static ParseSink parseSink; /* null sink; just parse the NAR */
 
-    TeeSource wrapper { source, sink };
-
-    parseDump(parseSink, wrapper);
+    return parseAndCopyDump(parseSink, source);
 }
 
 
diff --git a/src/libutil/archive.hh b/src/libutil/archive.hh
index 9b4ad9faf..97d99f2f4 100644
--- a/src/libutil/archive.hh
+++ b/src/libutil/archive.hh
@@ -122,9 +122,9 @@ void parseDump(ParseSink & sink, Source & source);
 void restorePath(const Path & path, Source & source);
 
 /**
- * Read a NAR from 'source' and write it to 'sink'.
+ * Read a NAR from 'source' and return it as a generator.
  */
-void copyNAR(Source & source, Sink & sink);
+WireFormatGenerator copyNAR(Source & source);
 
 
 inline constexpr std::string_view narVersionMagic1 = "nix-archive-1";