Merge pull request #2930 from NixOS/eval-cache

Flake evaluation cache

1 files changed, 39 insertions, 0 deletions

diff --git a/src/libexpr/flake/eval-cache.hh b/src/libexpr/flake/eval-cache.hh
new file mode 100644
index 000000000..03aea142e
--- /dev/null
+++ b/src/libexpr/flake/eval-cache.hh
@@ -0,0 +1,39 @@
+#pragma once
+
+#include "sync.hh"
+#include "flake.hh"
+
+namespace nix { struct SQLite; struct SQLiteStmt; }
+
+namespace nix::flake {
+
+class EvalCache
+{
+    struct State;
+
+    std::unique_ptr<Sync<State>> _state;
+
+    EvalCache();
+
+public:
+
+    struct Derivation
+    {
+        Path drvPath;
+        Path outPath;
+        std::string outputName;
+    };
+
+    void addDerivation(
+        const Fingerprint & fingerprint,
+        const std::string & attrPath,
+        const Derivation & drv);
+
+    std::optional<Derivation> getDerivation(
+        const Fingerprint & fingerprint,
+        const std::string & attrPath);
+
+    static EvalCache & singleton();
+};
+
+}