3 files changed, 53 insertions, 18 deletions

diff --git a/src/libstore/legacy-ssh-store.cc b/src/libstore/legacy-ssh-store.cc
index 7e119ce49..890c8a149 100644
--- a/src/libstore/legacy-ssh-store.cc
+++ b/src/libstore/legacy-ssh-store.cc
@@ -172,24 +172,12 @@ struct LegacySSHStore : public virtual LegacySSHStoreConfig, public virtual Stor
             if (p.empty()) return callback(nullptr);
             auto path2 = parseStorePath(p);
             assert(path == path2);
-            /* Hash will be set below. FIXME construct ValidPathInfo at end. */
-            auto info = std::make_shared<ValidPathInfo>(path, Hash::dummy);
-
-            auto deriver = readString(conn->from);
-            if (deriver != "")
-                info->deriver = parseStorePath(deriver);
-            info->references = ServeProto::Serialise<StorePathSet>::read(*this, *conn);
-            readLongLong(conn->from); // download size
-            info->narSize = readLongLong(conn->from);
-
-            {
-                auto s = readString(conn->from);
-                if (s == "")
-                    throw Error("NAR hash is now mandatory");
-                info->narHash = Hash::parseAnyPrefixed(s);
-            }
-            info->ca = ContentAddress::parseOpt(readString(conn->from));
-            info->sigs = readStrings<StringSet>(conn->from);
+            auto info = std::make_shared<ValidPathInfo>(
+                path,
+                ServeProto::Serialise<UnkeyedValidPathInfo>::read(*this, *conn));
+
+            if (info->narHash == Hash::dummy)
+                throw Error("NAR hash is now mandatory");
 
             auto s = readString(conn->from);
             assert(s == "");
diff --git a/src/libstore/serve-protocol.cc b/src/libstore/serve-protocol.cc
index 97a0ddf0e..2e15d28d5 100644
--- a/src/libstore/serve-protocol.cc
+++ b/src/libstore/serve-protocol.cc
@@ -6,6 +6,7 @@
 #include "serve-protocol.hh"
 #include "serve-protocol-impl.hh"
 #include "archive.hh"
+#include "path-info.hh"
 
 #include <nlohmann/json.hpp>
 
@@ -55,4 +56,47 @@ void ServeProto::Serialise<BuildResult>::write(const Store & store, ServeProto::
     }
 }
 
+
+UnkeyedValidPathInfo ServeProto::Serialise<UnkeyedValidPathInfo>::read(const Store & store, ReadConn conn)
+{
+    /* Hash should be set below unless very old `nix-store --serve`.
+       Caller should assert that it did set it. */
+    UnkeyedValidPathInfo info { Hash::dummy };
+
+    auto deriver = readString(conn.from);
+    if (deriver != "")
+        info.deriver = store.parseStorePath(deriver);
+    info.references = ServeProto::Serialise<StorePathSet>::read(store, conn);
+
+    readLongLong(conn.from); // download size, unused
+    info.narSize = readLongLong(conn.from);
+
+    if (GET_PROTOCOL_MINOR(conn.version) >= 4) {
+        auto s = readString(conn.from);
+        if (!s.empty())
+            info.narHash = Hash::parseAnyPrefixed(s);
+        info.ca = ContentAddress::parseOpt(readString(conn.from));
+        info.sigs = readStrings<StringSet>(conn.from);
+    }
+
+    return info;
+}
+
+void ServeProto::Serialise<UnkeyedValidPathInfo>::write(const Store & store, WriteConn conn, const UnkeyedValidPathInfo & info)
+{
+    conn.to
+        << (info.deriver ? store.printStorePath(*info.deriver) : "");
+
+    ServeProto::write(store, conn, info.references);
+    // !!! Maybe we want compression?
+    conn.to
+        << info.narSize // downloadSize, lie a little
+        << info.narSize;
+    if (GET_PROTOCOL_MINOR(conn.version) >= 4)
+        conn.to
+            << info.narHash.to_string(Base32, true)
+            << renderContentAddress(info.ca)
+            << info.sigs;
+}
+
 }
diff --git a/src/libstore/serve-protocol.hh b/src/libstore/serve-protocol.hh
index ba159f6e9..3f82c8177 100644
--- a/src/libstore/serve-protocol.hh
+++ b/src/libstore/serve-protocol.hh
@@ -18,6 +18,7 @@ struct Source;
 
 // items being serialised
 struct BuildResult;
+struct UnkeyedValidPathInfo;
 
 
 /**
@@ -141,6 +142,8 @@ inline std::ostream & operator << (std::ostream & s, ServeProto::Command op)
 
 template<>
 DECLARE_SERVE_SERIALISER(BuildResult);
+template<>
+DECLARE_SERVE_SERIALISER(UnkeyedValidPathInfo);
 
 template<typename T>
 DECLARE_SERVE_SERIALISER(std::vector<T>);