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, 39 insertions, 37 deletions

diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index 9253ce09e..1e2104e1f 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -5,6 +5,7 @@
 #include "remote-fs-accessor.hh"
 #include "build-result.hh"
 #include "remote-store.hh"
+#include "remote-store-connection.hh"
 #include "worker-protocol.hh"
 #include "worker-protocol-impl.hh"
 #include "archive.hh"
@@ -101,7 +102,7 @@ void RemoteStore::initConnection(Connection & conn)
         }
 
         if (GET_PROTOCOL_MINOR(conn.daemonVersion) >= 35) {
-            conn.remoteTrustsUs = WorkerProto::Serialise<std::optional<TrustedFlag>>::read(*this, conn.from);
+            conn.remoteTrustsUs = WorkerProto::Serialise<std::optional<TrustedFlag>>::read(*this, conn);
         } else {
             // We don't know the answer; protocol to old.
             conn.remoteTrustsUs = std::nullopt;
@@ -185,6 +186,7 @@ struct ConnectionHandle
     }
 
     RemoteStore::Connection * operator -> () { return &*handle; }
+    RemoteStore::Connection & operator * () { return *handle; }
 
     void processStderr(Sink * sink = 0, Source * source = 0, bool flush = true)
     {
@@ -228,12 +230,12 @@ StorePathSet RemoteStore::queryValidPaths(const StorePathSet & paths, Substitute
         return res;
     } else {
         conn->to << WorkerProto::Op::QueryValidPaths;
-        WorkerProto::write(*this, conn->to, paths);
+        WorkerProto::write(*this, *conn, paths);
         if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 27) {
             conn->to << (settings.buildersUseSubstitutes ? 1 : 0);
         }
         conn.processStderr();
-        return WorkerProto::Serialise<StorePathSet>::read(*this, conn->from);
+        return WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
     }
 }
 
@@ -243,7 +245,7 @@ StorePathSet RemoteStore::queryAllValidPaths()
     auto conn(getConnection());
     conn->to << WorkerProto::Op::QueryAllValidPaths;
     conn.processStderr();
-    return WorkerProto::Serialise<StorePathSet>::read(*this, conn->from);
+    return WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
 }
 
 
@@ -260,9 +262,9 @@ StorePathSet RemoteStore::querySubstitutablePaths(const StorePathSet & paths)
         return res;
     } else {
         conn->to << WorkerProto::Op::QuerySubstitutablePaths;
-        WorkerProto::write(*this, conn->to, paths);
+        WorkerProto::write(*this, *conn, paths);
         conn.processStderr();
-        return WorkerProto::Serialise<StorePathSet>::read(*this, conn->from);
+        return WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
     }
 }
 
@@ -284,7 +286,7 @@ void RemoteStore::querySubstitutablePathInfos(const StorePathCAMap & pathsMap, S
             auto deriver = readString(conn->from);
             if (deriver != "")
                 info.deriver = parseStorePath(deriver);
-            info.references = WorkerProto::Serialise<StorePathSet>::read(*this, conn->from);
+            info.references = WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
             info.downloadSize = readLongLong(conn->from);
             info.narSize = readLongLong(conn->from);
             infos.insert_or_assign(i.first, std::move(info));
@@ -297,9 +299,9 @@ void RemoteStore::querySubstitutablePathInfos(const StorePathCAMap & pathsMap, S
             StorePathSet paths;
             for (auto & path : pathsMap)
                 paths.insert(path.first);
-            WorkerProto::write(*this, conn->to, paths);
+            WorkerProto::write(*this, *conn, paths);
         } else
-            WorkerProto::write(*this, conn->to, pathsMap);
+            WorkerProto::write(*this, *conn, pathsMap);
         conn.processStderr();
         size_t count = readNum<size_t>(conn->from);
         for (size_t n = 0; n < count; n++) {
@@ -307,7 +309,7 @@ void RemoteStore::querySubstitutablePathInfos(const StorePathCAMap & pathsMap, S
             auto deriver = readString(conn->from);
             if (deriver != "")
                 info.deriver = parseStorePath(deriver);
-            info.references = WorkerProto::Serialise<StorePathSet>::read(*this, conn->from);
+            info.references = WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
             info.downloadSize = readLongLong(conn->from);
             info.narSize = readLongLong(conn->from);
         }
@@ -350,7 +352,7 @@ void RemoteStore::queryReferrers(const StorePath & path,
     auto conn(getConnection());
     conn->to << WorkerProto::Op::QueryReferrers << printStorePath(path);
     conn.processStderr();
-    for (auto & i : WorkerProto::Serialise<StorePathSet>::read(*this, conn->from))
+    for (auto & i : WorkerProto::Serialise<StorePathSet>::read(*this, *conn))
         referrers.insert(i);
 }
 
@@ -360,7 +362,7 @@ StorePathSet RemoteStore::queryValidDerivers(const StorePath & path)
     auto conn(getConnection());
     conn->to << WorkerProto::Op::QueryValidDerivers << printStorePath(path);
     conn.processStderr();
-    return WorkerProto::Serialise<StorePathSet>::read(*this, conn->from);
+    return WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
 }
 
 
@@ -372,7 +374,7 @@ StorePathSet RemoteStore::queryDerivationOutputs(const StorePath & path)
     auto conn(getConnection());
     conn->to << WorkerProto::Op::QueryDerivationOutputs << printStorePath(path);
     conn.processStderr();
-    return WorkerProto::Serialise<StorePathSet>::read(*this, conn->from);
+    return WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
 }
 
 
@@ -382,7 +384,7 @@ std::map<std::string, std::optional<StorePath>> RemoteStore::queryPartialDerivat
         auto conn(getConnection());
         conn->to << WorkerProto::Op::QueryDerivationOutputMap << printStorePath(path);
         conn.processStderr();
-        return WorkerProto::Serialise<std::map<std::string, std::optional<StorePath>>>::read(*this, conn->from);
+        return WorkerProto::Serialise<std::map<std::string, std::optional<StorePath>>>::read(*this, *conn);
     } else {
         // Fallback for old daemon versions.
         // For floating-CA derivations (and their co-dependencies) this is an
@@ -428,7 +430,7 @@ ref<const ValidPathInfo> RemoteStore::addCAToStore(
             << WorkerProto::Op::AddToStore
             << name
             << caMethod.render(hashType);
-        WorkerProto::write(*this, conn->to, references);
+        WorkerProto::write(*this, *conn, references);
         conn->to << repair;
 
         // The dump source may invoke the store, so we need to make some room.
@@ -453,7 +455,7 @@ ref<const ValidPathInfo> RemoteStore::addCAToStore(
                         name, printHashType(hashType));
                 std::string s = dump.drain();
                 conn->to << WorkerProto::Op::AddTextToStore << name << s;
-                WorkerProto::write(*this, conn->to, references);
+                WorkerProto::write(*this, *conn, references);
                 conn.processStderr();
             },
             [&](const FileIngestionMethod & fim) -> void {
@@ -519,7 +521,7 @@ void RemoteStore::addToStore(const ValidPathInfo & info, Source & source,
             sink
                 << exportMagic
                 << printStorePath(info.path);
-            WorkerProto::write(*this, sink, info.references);
+            WorkerProto::write(*this, *conn, info.references);
             sink
                 << (info.deriver ? printStorePath(*info.deriver) : "")
                 << 0 // == no legacy signature
@@ -529,7 +531,7 @@ void RemoteStore::addToStore(const ValidPathInfo & info, Source & source,
 
         conn.processStderr(0, source2.get());
 
-        auto importedPaths = WorkerProto::Serialise<StorePathSet>::read(*this, conn->from);
+        auto importedPaths = WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
         assert(importedPaths.size() <= 1);
     }
 
@@ -538,7 +540,7 @@ void RemoteStore::addToStore(const ValidPathInfo & info, Source & source,
                  << printStorePath(info.path)
                  << (info.deriver ? printStorePath(*info.deriver) : "")
                  << info.narHash.to_string(Base16, false);
-        WorkerProto::write(*this, conn->to, info.references);
+        WorkerProto::write(*this, *conn, info.references);
         conn->to << info.registrationTime << info.narSize
                  << info.ultimate << info.sigs << renderContentAddress(info.ca)
                  << repair << !checkSigs;
@@ -611,7 +613,7 @@ void RemoteStore::registerDrvOutput(const Realisation & info)
         conn->to << info.id.to_string();
         conn->to << std::string(info.outPath.to_string());
     } else {
-        WorkerProto::write(*this, conn->to, info);
+        WorkerProto::write(*this, *conn, info);
     }
     conn.processStderr();
 }
@@ -634,13 +636,13 @@ void RemoteStore::queryRealisationUncached(const DrvOutput & id,
         auto real = [&]() -> std::shared_ptr<const Realisation> {
             if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 31) {
                 auto outPaths = WorkerProto::Serialise<std::set<StorePath>>::read(
-                    *this, conn->from);
+                    *this, *conn);
                 if (outPaths.empty())
                     return nullptr;
                 return std::make_shared<const Realisation>(Realisation { .id = id, .outPath = *outPaths.begin() });
             } else {
                 auto realisations = WorkerProto::Serialise<std::set<Realisation>>::read(
-                    *this, conn->from);
+                    *this, *conn);
                 if (realisations.empty())
                     return nullptr;
                 return std::make_shared<const Realisation>(*realisations.begin());
@@ -651,10 +653,10 @@ void RemoteStore::queryRealisationUncached(const DrvOutput & id,
     } catch (...) { return callback.rethrow(); }
 }
 
-static void writeDerivedPaths(RemoteStore & store, ConnectionHandle & conn, const std::vector<DerivedPath> & reqs)
+static void writeDerivedPaths(RemoteStore & store, RemoteStore::Connection & conn, const std::vector<DerivedPath> & reqs)
 {
-    if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 30) {
-        WorkerProto::write(store, conn->to, reqs);
+    if (GET_PROTOCOL_MINOR(conn.daemonVersion) >= 30) {
+        WorkerProto::write(store, conn, reqs);
     } else {
         Strings ss;
         for (auto & p : reqs) {
@@ -666,12 +668,12 @@ static void writeDerivedPaths(RemoteStore & store, ConnectionHandle & conn, cons
                 [&](const StorePath & drvPath) {
                     throw Error("trying to request '%s', but daemon protocol %d.%d is too old (< 1.29) to request a derivation file",
                         store.printStorePath(drvPath),
-                        GET_PROTOCOL_MAJOR(conn->daemonVersion),
-                        GET_PROTOCOL_MINOR(conn->daemonVersion));
+                        GET_PROTOCOL_MAJOR(conn.daemonVersion),
+                        GET_PROTOCOL_MINOR(conn.daemonVersion));
                 },
             }, sOrDrvPath);
         }
-        conn->to << ss;
+        conn.to << ss;
     }
 }
 
@@ -697,7 +699,7 @@ void RemoteStore::buildPaths(const std::vector<DerivedPath> & drvPaths, BuildMod
     auto conn(getConnection());
     conn->to << WorkerProto::Op::BuildPaths;
     assert(GET_PROTOCOL_MINOR(conn->daemonVersion) >= 13);
-    writeDerivedPaths(*this, conn, drvPaths);
+    writeDerivedPaths(*this, *conn, drvPaths);
     if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 15)
         conn->to << buildMode;
     else
@@ -721,10 +723,10 @@ std::vector<KeyedBuildResult> RemoteStore::buildPathsWithResults(
 
     if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 34) {
         conn->to << WorkerProto::Op::BuildPathsWithResults;
-        writeDerivedPaths(*this, conn, paths);
+        writeDerivedPaths(*this, *conn, paths);
         conn->to << buildMode;
         conn.processStderr();
-        return WorkerProto::Serialise<std::vector<KeyedBuildResult>>::read(*this, conn->from);
+        return WorkerProto::Serialise<std::vector<KeyedBuildResult>>::read(*this, *conn);
     } else {
         // Avoid deadlock.
         conn_.reset();
@@ -807,7 +809,7 @@ BuildResult RemoteStore::buildDerivation(const StorePath & drvPath, const BasicD
         conn->from >> res.timesBuilt >> res.isNonDeterministic >> res.startTime >> res.stopTime;
     }
     if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 28) {
-        auto builtOutputs = WorkerProto::Serialise<DrvOutputs>::read(*this, conn->from);
+        auto builtOutputs = WorkerProto::Serialise<DrvOutputs>::read(*this, *conn);
         for (auto && [output, realisation] : builtOutputs)
             res.builtOutputs.insert_or_assign(
                 std::move(output.outputName),
@@ -866,7 +868,7 @@ void RemoteStore::collectGarbage(const GCOptions & options, GCResults & results)
 
     conn->to
         << WorkerProto::Op::CollectGarbage << options.action;
-    WorkerProto::write(*this, conn->to, options.pathsToDelete);
+    WorkerProto::write(*this, *conn, options.pathsToDelete);
     conn->to << options.ignoreLiveness
         << options.maxFreed
         /* removed options */
@@ -923,11 +925,11 @@ void RemoteStore::queryMissing(const std::vector<DerivedPath> & targets,
             // to prevent a deadlock.
             goto fallback;
         conn->to << WorkerProto::Op::QueryMissing;
-        writeDerivedPaths(*this, conn, targets);
+        writeDerivedPaths(*this, *conn, targets);
         conn.processStderr();
-        willBuild = WorkerProto::Serialise<StorePathSet>::read(*this, conn->from);
-        willSubstitute = WorkerProto::Serialise<StorePathSet>::read(*this, conn->from);
-        unknown = WorkerProto::Serialise<StorePathSet>::read(*this, conn->from);
+        willBuild = WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
+        willSubstitute = WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
+        unknown = WorkerProto::Serialise<StorePathSet>::read(*this, *conn);
         conn->from >> downloadSize >> narSize;
         return;
     }