11 files changed, 87 insertions, 63 deletions
diff --git a/src/libstore/build/derivation-goal.cc b/src/libstore/build/derivation-goal.cc
index df7d21e54..e02000c8b 100644
--- a/src/libstore/build/derivation-goal.cc
+++ b/src/libstore/build/derivation-goal.cc
@@ -9,6 +9,7 @@
 #include "archive.hh"
 #include "compression.hh"
 #include "worker-protocol.hh"
+#include "worker-protocol-impl.hh"
 #include "topo-sort.hh"
 #include "callback.hh"
 #include "local-store.hh" // TODO remove, along with remaining downcasts
diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index 7f87cdf55..6e06f6061 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -11,6 +11,7 @@
 #include "compression.hh"
 #include "daemon.hh"
 #include "worker-protocol.hh"
+#include "worker-protocol-impl.hh"
 #include "topo-sort.hh"
 #include "callback.hh"
 #include "json-utils.hh"
diff --git a/src/libstore/daemon.cc b/src/libstore/daemon.cc
index b6dd83684..54b089b30 100644
--- a/src/libstore/daemon.cc
+++ b/src/libstore/daemon.cc
@@ -1,6 +1,7 @@
 #include "daemon.hh"
 #include "monitor-fd.hh"
 #include "worker-protocol.hh"
+#include "worker-protocol-impl.hh"
 #include "build-result.hh"
 #include "store-api.hh"
 #include "store-cast.hh"
diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc
index ccb165d68..4a1f1e99f 100644
--- a/src/libstore/derivations.cc
+++ b/src/libstore/derivations.cc
@@ -5,6 +5,7 @@
 #include "util.hh"
 #include "split.hh"
 #include "worker-protocol.hh"
+#include "worker-protocol-impl.hh"
 #include "fs-accessor.hh"
 #include <boost/container/small_vector.hpp>
 #include <nlohmann/json.hpp>
diff --git a/src/libstore/export-import.cc b/src/libstore/export-import.cc
index 5ea263a86..72ad77124 100644
--- a/src/libstore/export-import.cc
+++ b/src/libstore/export-import.cc
@@ -2,6 +2,7 @@
 #include "store-api.hh"
 #include "archive.hh"
 #include "worker-protocol.hh"
+#include "worker-protocol-impl.hh"
 
 #include <algorithm>
 
diff --git a/src/libstore/legacy-ssh-store.cc b/src/libstore/legacy-ssh-store.cc
index 2b7bebe9d..bff024f96 100644
--- a/src/libstore/legacy-ssh-store.cc
+++ b/src/libstore/legacy-ssh-store.cc
@@ -7,6 +7,7 @@
 #include "store-api.hh"
 #include "path-with-outputs.hh"
 #include "worker-protocol.hh"
+#include "worker-protocol-impl.hh"
 #include "ssh.hh"
 #include "derivations.hh"
 #include "callback.hh"
diff --git a/src/libstore/path-info.cc b/src/libstore/path-info.cc
index 97b72faa3..6b93976fa 100644
--- a/src/libstore/path-info.cc
+++ b/src/libstore/path-info.cc
@@ -1,5 +1,6 @@
 #include "path-info.hh"
 #include "worker-protocol.hh"
+#include "worker-protocol-impl.hh"
 #include "store-api.hh"
 
 namespace nix {
diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index c3dfb5979..f02342d32 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -6,6 +6,7 @@
 #include "build-result.hh"
 #include "remote-store.hh"
 #include "worker-protocol.hh"
+#include "worker-protocol-impl.hh"
 #include "archive.hh"
 #include "globals.hh"
 #include "derivations.hh"
diff --git a/src/libstore/worker-protocol-impl.hh b/src/libstore/worker-protocol-impl.hh
new file mode 100644
index 000000000..509a8a5d0
--- /dev/null
+++ b/src/libstore/worker-protocol-impl.hh
@@ -0,0 +1,78 @@
+#pragma once
+/**
+ * @file
+ *
+ * Template implementations (as opposed to mere declarations).
+ *
+ * This file is an exmample of the "impl.hh" pattern. See the
+ * contributing guide.
+ */
+
+#include "worker-protocol.hh"
+
+namespace nix {
+
+template<typename T>
+std::vector<T> WorkerProto<std::vector<T>>::read(const Store & store, Source & from)
+{
+    std::vector<T> resSet;
+    auto size = readNum<size_t>(from);
+    while (size--) {
+        resSet.push_back(WorkerProto<T>::read(store, from));
+    }
+    return resSet;
+}
+
+template<typename T>
+void WorkerProto<std::vector<T>>::write(const Store & store, Sink & out, const std::vector<T> & resSet)
+{
+    out << resSet.size();
+    for (auto & key : resSet) {
+        WorkerProto<T>::write(store, out, key);
+    }
+}
+
+template<typename T>
+std::set<T> WorkerProto<std::set<T>>::read(const Store & store, Source & from)
+{
+    std::set<T> resSet;
+    auto size = readNum<size_t>(from);
+    while (size--) {
+        resSet.insert(WorkerProto<T>::read(store, from));
+    }
+    return resSet;
+}
+
+template<typename T>
+void WorkerProto<std::set<T>>::write(const Store & store, Sink & out, const std::set<T> & resSet)
+{
+    out << resSet.size();
+    for (auto & key : resSet) {
+        WorkerProto<T>::write(store, out, key);
+    }
+}
+
+template<typename K, typename V>
+std::map<K, V> WorkerProto<std::map<K, V>>::read(const Store & store, Source & from)
+{
+    std::map<K, V> resMap;
+    auto size = readNum<size_t>(from);
+    while (size--) {
+        auto k = WorkerProto<K>::read(store, from);
+        auto v = WorkerProto<V>::read(store, from);
+        resMap.insert_or_assign(std::move(k), std::move(v));
+    }
+    return resMap;
+}
+
+template<typename K, typename V>
+void WorkerProto<std::map<K, V>>::write(const Store & store, Sink & out, const std::map<K, V> & resMap)
+{
+    out << resMap.size();
+    for (auto & i : resMap) {
+        WorkerProto<K>::write(store, out, i.first);
+        WorkerProto<V>::write(store, out, i.second);
+    }
+}
+
+}
diff --git a/src/libstore/worker-protocol.cc b/src/libstore/worker-protocol.cc
index 51bb12026..49708b642 100644
--- a/src/libstore/worker-protocol.cc
+++ b/src/libstore/worker-protocol.cc
@@ -4,6 +4,7 @@
 #include "store-api.hh"
 #include "build-result.hh"
 #include "worker-protocol.hh"
+#include "worker-protocol-impl.hh"
 #include "archive.hh"
 #include "derivations.hh"
 
diff --git a/src/libstore/worker-protocol.hh b/src/libstore/worker-protocol.hh
index f06332d17..18a4e11b2 100644
--- a/src/libstore/worker-protocol.hh
+++ b/src/libstore/worker-protocol.hh
@@ -173,67 +173,4 @@ MAKE_WORKER_PROTO(std::optional<StorePath>);
 template<>
 MAKE_WORKER_PROTO(std::optional<ContentAddress>);
 
-template<typename T>
-std::vector<T> WorkerProto<std::vector<T>>::read(const Store & store, Source & from)
-{
-    std::vector<T> resSet;
-    auto size = readNum<size_t>(from);
-    while (size--) {
-        resSet.push_back(WorkerProto<T>::read(store, from));
-    }
-    return resSet;
-}
-
-template<typename T>
-void WorkerProto<std::vector<T>>::write(const Store & store, Sink & out, const std::vector<T> & resSet)
-{
-    out << resSet.size();
-    for (auto & key : resSet) {
-        WorkerProto<T>::write(store, out, key);
-    }
-}
-
-template<typename T>
-std::set<T> WorkerProto<std::set<T>>::read(const Store & store, Source & from)
-{
-    std::set<T> resSet;
-    auto size = readNum<size_t>(from);
-    while (size--) {
-        resSet.insert(WorkerProto<T>::read(store, from));
-    }
-    return resSet;
-}
-
-template<typename T>
-void WorkerProto<std::set<T>>::write(const Store & store, Sink & out, const std::set<T> & resSet)
-{
-    out << resSet.size();
-    for (auto & key : resSet) {
-        WorkerProto<T>::write(store, out, key);
-    }
-}
-
-template<typename K, typename V>
-std::map<K, V> WorkerProto<std::map<K, V>>::read(const Store & store, Source & from)
-{
-    std::map<K, V> resMap;
-    auto size = readNum<size_t>(from);
-    while (size--) {
-        auto k = WorkerProto<K>::read(store, from);
-        auto v = WorkerProto<V>::read(store, from);
-        resMap.insert_or_assign(std::move(k), std::move(v));
-    }
-    return resMap;
-}
-
-template<typename K, typename V>
-void WorkerProto<std::map<K, V>>::write(const Store & store, Sink & out, const std::map<K, V> & resMap)
-{
-    out << resMap.size();
-    for (auto & i : resMap) {
-        WorkerProto<K>::write(store, out, i.first);
-        WorkerProto<V>::write(store, out, i.second);
-    }
-}
-
 }