Merge pull request #9099 from obsidiansystems/common-proto

Factor out bits of the worker protocol to use elsewhere

(cherry picked from commit 4b1a97338f517f45e6169d3d8845c5caa5724e97)
Change-Id: If93afa0f8b1cf9b0e705b34fa71e6fd708752758

1 files changed, 14 insertions, 46 deletions

diff --git a/src/libstore/worker-protocol.hh b/src/libstore/worker-protocol.hh
index b7f42f24d..c84060103 100644
--- a/src/libstore/worker-protocol.hh
+++ b/src/libstore/worker-protocol.hh
@@ -1,7 +1,7 @@
 #pragma once
 ///@file
 
-#include "serialise.hh"
+#include "common-protocol.hh"
 
 namespace nix {
 
@@ -28,11 +28,7 @@ class Store;
 struct Source;
 
 // items being serialised
-class StorePath;
-struct ContentAddress;
 struct DerivedPath;
-struct DrvOutput;
-struct Realisation;
 struct BuildResult;
 struct KeyedBuildResult;
 enum TrustedFlag : bool;
@@ -193,60 +189,32 @@ inline std::ostream & operator << (std::ostream & s, WorkerProto::Op op)
  * be legal specialization syntax. See below for what that looks like in
  * practice.
  */
-#define MAKE_WORKER_PROTO(T) \
-    struct WorkerProto::Serialise< T > { \
+#define DECLARE_WORKER_SERIALISER(T) \
+    struct WorkerProto::Serialise< T > \
+    { \
         static T read(const Store & store, WorkerProto::ReadConn conn); \
         static void write(const Store & store, WorkerProto::WriteConn conn, const T & t); \
     };
 
 template<>
-MAKE_WORKER_PROTO(std::string);
+DECLARE_WORKER_SERIALISER(DerivedPath);
 template<>
-MAKE_WORKER_PROTO(StorePath);
+DECLARE_WORKER_SERIALISER(BuildResult);
 template<>
-MAKE_WORKER_PROTO(ContentAddress);
+DECLARE_WORKER_SERIALISER(KeyedBuildResult);
 template<>
-MAKE_WORKER_PROTO(DerivedPath);
-template<>
-MAKE_WORKER_PROTO(DrvOutput);
-template<>
-MAKE_WORKER_PROTO(Realisation);
-template<>
-MAKE_WORKER_PROTO(BuildResult);
-template<>
-MAKE_WORKER_PROTO(KeyedBuildResult);
-template<>
-MAKE_WORKER_PROTO(std::optional<TrustedFlag>);
+DECLARE_WORKER_SERIALISER(std::optional<TrustedFlag>);
 
 template<typename T>
-MAKE_WORKER_PROTO(std::vector<T>);
+DECLARE_WORKER_SERIALISER(std::vector<T>);
 template<typename T>
-MAKE_WORKER_PROTO(std::set<T>);
+DECLARE_WORKER_SERIALISER(std::set<T>);
 template<typename... Ts>
-MAKE_WORKER_PROTO(std::tuple<Ts...>);
+DECLARE_WORKER_SERIALISER(std::tuple<Ts...>);
 
+#define COMMA_ ,
 template<typename K, typename V>
-#define X_ std::map<K, V>
-MAKE_WORKER_PROTO(X_);
-#undef X_
-
-/**
- * These use the empty string for the null case, relying on the fact
- * that the underlying types never serialise to the empty string.
- *
- * We do this instead of a generic std::optional<T> instance because
- * ordinal tags (0 or 1, here) are a bit of a compatability hazard. For
- * the same reason, we don't have a std::variant<T..> instances (ordinal
- * tags 0...n).
- *
- * We could the generic instances and then these as specializations for
- * compatability, but that's proven a bit finnicky, and also makes the
- * worker protocol harder to implement in other languages where such
- * specializations may not be allowed.
- */
-template<>
-MAKE_WORKER_PROTO(std::optional<StorePath>);
-template<>
-MAKE_WORKER_PROTO(std::optional<ContentAddress>);
+DECLARE_WORKER_SERIALISER(std::map<K COMMA_ V>);
+#undef COMMA_
 
 }