Add 'third_party/nix/' from commit 'be66c7a6b24e3c3c6157fd37b86c7203d14acf10'

git-subtree-dir: third_party/nix
git-subtree-mainline: cf8cd640c1
git-subtree-split: be66c7a6b24e3c3c6157fd37b86c7203d14acf10

third_party/nix/src/libstore/nar-info-disk-cache.hh

@@ -0,0 +1,31 @@
+#pragma once
+
+#include "ref.hh"
+#include "nar-info.hh"
+
+namespace nix {
+
+class NarInfoDiskCache
+{
+public:
+    typedef enum { oValid, oInvalid, oUnknown } Outcome;
+
+    virtual void createCache(const std::string & uri, const Path & storeDir,
+        bool wantMassQuery, int priority) = 0;
+
+    virtual bool cacheExists(const std::string & uri,
+        bool & wantMassQuery, int & priority) = 0;
+
+    virtual std::pair<Outcome, std::shared_ptr<NarInfo>> lookupNarInfo(
+        const std::string & uri, const std::string & hashPart) = 0;
+
+    virtual void upsertNarInfo(
+        const std::string & uri, const std::string & hashPart,
+        std::shared_ptr<ValidPathInfo> info) = 0;
+};
+
+/* Return a singleton cache object that can be used concurrently by
+   multiple threads. */
+ref<NarInfoDiskCache> getNarInfoDiskCache();
+
+}