Create `worker_proto::{Read,Write}Conn`

Pass this around instead of `Source &` and `Sink &` directly. This will
give us something to put the protocol version on once the time comes.

To do this ergonomically, we need to expose `RemoteStore::Connection`,
so do that too. Give it some more API docs while we are at it.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc
index 2295ff9e8..6f63685d4 100644
--- a/src/libstore/derivations.cc
+++ b/src/libstore/derivations.cc
@@ -750,7 +750,8 @@ Source & readDerivation(Source & in, const Store & store, BasicDerivation & drv,
         drv.outputs.emplace(std::move(name), std::move(output));
     }
 
-    drv.inputSrcs = WorkerProto::Serialise<StorePathSet>::read(store, in);
+    drv.inputSrcs = WorkerProto::Serialise<StorePathSet>::read(store,
+        WorkerProto::ReadConn { .from = in });
     in >> drv.platform >> drv.builder;
     drv.args = readStrings<Strings>(in);
 
@@ -798,7 +799,9 @@ void writeDerivation(Sink & out, const Store & store, const BasicDerivation & dr
             },
         }, i.second.raw());
     }
-    WorkerProto::write(store, out, drv.inputSrcs);
+    WorkerProto::write(store,
+        WorkerProto::WriteConn { .to = out },
+        drv.inputSrcs);
     out << drv.platform << drv.builder << drv.args;
     out << drv.env.size();
     for (auto & i : drv.env)