Factor out the unix domain socket-specific code from RemoteStore

src/libstore/local-store.cc

@@ -37,7 +37,8 @@ namespace nix {
 
 
 LocalStore::LocalStore(const Params & params)
-    : LocalFSStore(params)
+    : Store(params)
+    , LocalFSStore(params)
     , realStoreDir(get(params, "real", rootDir != "" ? rootDir + "/nix/store" : storeDir))
     , dbDir(stateDir + "/db")
     , linksDir(realStoreDir + "/.links")

src/libstore/remote-store.cc

@@ -38,9 +38,9 @@ template<class T> T readStorePaths(Store & store, Source & from)
 
 template PathSet readStorePaths(Store & store, Source & from);
 
-
+/* TODO: Separate these store impls into different files, give them better names */
 RemoteStore::RemoteStore(const Params & params, size_t maxConnections)
-    : LocalFSStore(params)
+    : Store(params)
     , connections(make_ref<Pool<Connection>>(
             maxConnections,
             [this]() { return openConnection(); },
@@ -50,13 +50,21 @@ RemoteStore::RemoteStore(const Params & params, size_t maxConnections)
 }
 
 
-std::string RemoteStore::getUri()
+UDSRemoteStore::UDSRemoteStore(const Params & params, size_t maxConnections)
+    : Store(params)
+    , LocalFSStore(params)
+    , RemoteStore(params, maxConnections)
+{
+}
+
+
+std::string UDSRemoteStore::getUri()
 {
     return "daemon";
 }
 
 
-ref<RemoteStore::Connection> RemoteStore::openConnection()
+ref<RemoteStore::Connection> UDSRemoteStore::openConnection()
 {
     auto conn = make_ref<Connection>();
 
@@ -84,46 +92,52 @@ ref<RemoteStore::Connection> RemoteStore::openConnection()
     conn->from.fd = conn->fd.get();
     conn->to.fd = conn->fd.get();
 
-    /* Send the magic greeting, check for the reply. */
-    try {
-        conn->to << WORKER_MAGIC_1;
-        conn->to.flush();
-        unsigned int magic = readInt(conn->from);
-        if (magic != WORKER_MAGIC_2) throw Error("protocol mismatch");
+    initConnection(*conn);
 
-        conn->daemonVersion = readInt(conn->from);
-        if (GET_PROTOCOL_MAJOR(conn->daemonVersion) != GET_PROTOCOL_MAJOR(PROTOCOL_VERSION))
-            throw Error("Nix daemon protocol version not supported");
-        if (GET_PROTOCOL_MINOR(conn->daemonVersion) < 10)
-            throw Error("the Nix daemon version is too old");
-        conn->to << PROTOCOL_VERSION;
-
-        if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 14) {
-            int cpu = settings.lockCPU ? lockToCurrentCPU() : -1;
-            if (cpu != -1)
-                conn->to << 1 << cpu;
-            else
-                conn->to << 0;
+    return conn;
 }
 
-        if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 11)
-            conn->to << false;
 
-        conn->processStderr();
+void RemoteStore::initConnection(Connection & conn)
+{
+    /* Send the magic greeting, check for the reply. */
+    try {
+        conn.to << WORKER_MAGIC_1;
+        conn.to.flush();
+        unsigned int magic = readInt(conn.from);
+        if (magic != WORKER_MAGIC_2) throw Error("protocol mismatch");
+
+        conn.daemonVersion = readInt(conn.from);
+        if (GET_PROTOCOL_MAJOR(conn.daemonVersion) != GET_PROTOCOL_MAJOR(PROTOCOL_VERSION))
+            throw Error("Nix daemon protocol version not supported");
+        if (GET_PROTOCOL_MINOR(conn.daemonVersion) < 10)
+            throw Error("the Nix daemon version is too old");
+        conn.to << PROTOCOL_VERSION;
+
+        if (GET_PROTOCOL_MINOR(conn.daemonVersion) >= 14) {
+            int cpu = settings.lockCPU ? lockToCurrentCPU() : -1;
+            if (cpu != -1)
+                conn.to << 1 << cpu;
+            else
+                conn.to << 0;
+        }
+
+        if (GET_PROTOCOL_MINOR(conn.daemonVersion) >= 11)
+            conn.to << false;
+
+        conn.processStderr();
     }
     catch (Error & e) {
         throw Error(format("cannot start daemon worker: %1%") % e.msg());
     }
 
     setOptions(conn);
-
-    return conn;
 }
 
 
-void RemoteStore::setOptions(ref<Connection> conn)
+void RemoteStore::setOptions(Connection & conn)
 {
-    conn->to << wopSetOptions
+    conn.to << wopSetOptions
        << settings.keepFailed
        << settings.keepGoing
        << settings.tryFallback
@@ -137,16 +151,16 @@ void RemoteStore::setOptions(ref<Connection> conn)
        << settings.buildCores
        << settings.useSubstitutes;
 
-    if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 12) {
+    if (GET_PROTOCOL_MINOR(conn.daemonVersion) >= 12) {
         Settings::SettingsMap overrides = settings.getOverrides();
         if (overrides["ssh-auth-sock"] == "")
             overrides["ssh-auth-sock"] = getEnv("SSH_AUTH_SOCK");
-        conn->to << overrides.size();
+        conn.to << overrides.size();
         for (auto & i : overrides)
-            conn->to << i.first << i.second;
+            conn.to << i.first << i.second;
     }
 
-    conn->processStderr();
+    conn.processStderr();
 }
 
 
@@ -528,7 +542,6 @@ RemoteStore::Connection::~Connection()
 {
     try {
         to.flush();
-        fd = -1;
     } catch (...) {
         ignoreException();
     }

src/libstore/remote-store.hh

@@ -18,7 +18,7 @@ template<typename T> class Pool;
 
 /* FIXME: RemoteStore is a misnomer - should be something like
    DaemonStore. */
-class RemoteStore : public LocalFSStore
+class RemoteStore : public virtual Store
 {
 public:
 
@@ -26,8 +26,6 @@ public:
 
     /* Implementations of abstract store API methods. */
 
-    std::string getUri() override;
-
     bool isValidPathUncached(const Path & path) override;
 
     PathSet queryValidPaths(const PathSet & paths) override;
@@ -84,11 +82,10 @@ public:
 
     void addSignatures(const Path & storePath, const StringSet & sigs) override;
 
-private:
+protected:
 
     struct Connection
     {
-        AutoCloseFD fd;
         FdSink to;
         FdSource from;
         unsigned int daemonVersion;
@@ -98,11 +95,33 @@ private:
         void processStderr(Sink * sink = 0, Source * source = 0);
     };
 
+    virtual ref<Connection> openConnection() = 0;
+
+    void setOptions(Connection & conn);
+
+    void initConnection(Connection & conn);
+
+private:
+
     ref<Pool<Connection>> connections;
+};
 
-    ref<Connection> openConnection();
+class UDSRemoteStore : public LocalFSStore, public RemoteStore
+{
+public:
 
-    void setOptions(ref<Connection> conn);
+    UDSRemoteStore(const Params & params, size_t maxConnections = std::numeric_limits<size_t>::max());
+
+    std::string getUri() override;
+
+private:
+
+    struct Connection : RemoteStore::Connection
+    {
+        AutoCloseFD fd;
+    };
+
+    ref<RemoteStore::Connection> openConnection() override;
 };
 
 

src/libstore/store-api.cc

@@ -554,7 +554,7 @@ static RegisterStoreImplementation regStore([](
 {
     switch (getStoreType(uri, get(params, "state", settings.nixStateDir))) {
         case tDaemon:
-            return std::shared_ptr<Store>(std::make_shared<RemoteStore>(params));
+            return std::shared_ptr<Store>(std::make_shared<UDSRemoteStore>(params));
         case tLocal:
             return std::shared_ptr<Store>(std::make_shared<LocalStore>(params));
         default:

src/libstore/store-api.hh

@@ -526,7 +526,7 @@ protected:
 };
 
 
-class LocalFSStore : public Store
+class LocalFSStore : public virtual Store
 {
 public:
     const Path rootDir;