1 files changed, 114 insertions, 0 deletions
diff --git a/src/libexpr/flake/flake.hh b/src/libexpr/flake/flake.hh
new file mode 100644
index 000000000..63d848889
--- /dev/null
+++ b/src/libexpr/flake/flake.hh
@@ -0,0 +1,114 @@
+#pragma once
+
+#include "types.hh"
+#include "flakeref.hh"
+#include "lockfile.hh"
+
+namespace nix {
+
+struct Value;
+class EvalState;
+
+namespace flake {
+
+static const size_t FLAG_REGISTRY = 0;
+static const size_t USER_REGISTRY = 1;
+static const size_t GLOBAL_REGISTRY = 2;
+
+struct FlakeRegistry
+{
+    std::map<FlakeRef, FlakeRef> entries;
+};
+
+typedef std::vector<std::shared_ptr<FlakeRegistry>> Registries;
+
+std::shared_ptr<FlakeRegistry> readRegistry(const Path &);
+
+void writeRegistry(const FlakeRegistry &, const Path &);
+
+Path getUserRegistryPath();
+
+enum HandleLockFile : unsigned int
+    { AllPure // Everything is handled 100% purely
+    , TopRefUsesRegistries // The top FlakeRef uses the registries, apart from that, everything happens 100% purely
+    , UpdateLockFile // Update the existing lockfile and write it to file
+    , UseUpdatedLockFile // `UpdateLockFile` without writing to file
+    , RecreateLockFile // Recreate the lockfile from scratch and write it to file
+    , UseNewLockFile // `RecreateLockFile` without writing to file
+    };
+
+struct SourceInfo
+{
+    // Immutable flakeref that this source tree was obtained from.
+    FlakeRef resolvedRef;
+
+    Path storePath;
+
+    // Number of ancestors of the most recent commit.
+    std::optional<uint64_t> revCount;
+
+    // NAR hash of the store path.
+    Hash narHash;
+
+    // A stable timestamp of this source tree. For Git and GitHub
+    // flakes, the commit date (not author date!) of the most recent
+    // commit.
+    std::optional<time_t> lastModified;
+
+    SourceInfo(const FlakeRef & resolvRef) : resolvedRef(resolvRef) {};
+};
+
+struct FlakeInput
+{
+    FlakeRef ref;
+    bool isFlake = true;
+    FlakeInput(const FlakeRef & ref) : ref(ref) {};
+};
+
+struct Flake
+{
+    FlakeRef originalRef;
+    std::string description;
+    SourceInfo sourceInfo;
+    std::map<FlakeId, FlakeInput> inputs;
+    Value * vOutputs; // FIXME: gc
+    unsigned int edition;
+
+    Flake(const FlakeRef & origRef, const SourceInfo & sourceInfo)
+        : originalRef(origRef), sourceInfo(sourceInfo) {};
+};
+
+Flake getFlake(EvalState & state, const FlakeRef & flakeRef, bool allowLookup);
+
+/* Fingerprint of a locked flake; used as a cache key. */
+typedef Hash Fingerprint;
+
+struct ResolvedFlake
+{
+    Flake flake;
+    LockFile lockFile;
+
+    ResolvedFlake(Flake && flake, LockFile && lockFile)
+        : flake(flake), lockFile(lockFile) {}
+
+    Fingerprint getFingerprint() const;
+};
+
+ResolvedFlake resolveFlake(EvalState &, const FlakeRef &, HandleLockFile);
+
+void callFlake(EvalState & state,
+    const Flake & flake,
+    const LockedInputs & inputs,
+    Value & v);
+
+void callFlake(EvalState & state,
+    const ResolvedFlake & resFlake,
+    Value & v);
+
+void updateLockFile(EvalState &, const FlakeRef & flakeRef, bool recreateLockFile);
+
+void gitCloneFlake(FlakeRef flakeRef, EvalState &, Registries, const Path & destDir);
+
+}
+
+}