Merge branch 'read-only-local-store' into overlayfs-store

src/libstore/local-store.hh

@@ -46,6 +46,22 @@ struct LocalStoreConfig : virtual LocalFSStoreConfig
         "require-sigs",
         "Whether store paths copied into this store should have a trusted signature."};
 
+    Setting<bool> readOnly{(StoreConfig*) this,
+        false,
+        "read-only",
+        R"(
+          Allow this store to be opened when its database is on a read-only filesystem.
+
+          Normally Nix will attempt to open the store database in read-write mode, even
+          for querying (when write access is not needed). This causes it to fail if the
+          database is on a read-only filesystem.
+
+          Enable read-only mode to disable locking and open the SQLite database with the
+          **immutable** parameter set. Do not use this unless the filesystem is read-only.
+          Using it when the filesystem is writable can cause incorrect query results or
+          corruption errors if the database is changed by another process.
+        )"};
+
     const std::string name() override { return "Local Store"; }
 
     std::string doc() override;
@@ -240,8 +256,6 @@ public:
 
     void vacuumDB();
 
-    void repairPath(const StorePath & path) override;
-
     void addSignatures(const StorePath & storePath, const StringSet & sigs) override;
 
     /**