1 files changed, 101 insertions, 0 deletions
diff --git a/src/libexpr/flake/lockfile.hh b/src/libexpr/flake/lockfile.hh
new file mode 100644
index 000000000..82cbffd19
--- /dev/null
+++ b/src/libexpr/flake/lockfile.hh
@@ -0,0 +1,101 @@
+#pragma once
+
+#include "flakeref.hh"
+
+#include <nlohmann/json_fwd.hpp>
+
+namespace nix {
+class Store;
+struct StorePath;
+}
+
+namespace nix::flake {
+
+using namespace fetchers;
+
+typedef std::vector<FlakeId> InputPath;
+
+struct LockedInput;
+
+/* Lock file information about the dependencies of a flake. */
+struct LockedInputs
+{
+    std::map<FlakeId, LockedInput> inputs;
+
+    LockedInputs() {};
+    LockedInputs(const nlohmann::json & json);
+
+    nlohmann::json toJson() const;
+
+    std::string to_string() const;
+
+    bool isImmutable() const;
+
+    std::optional<LockedInput *> findInput(const InputPath & path);
+
+    void removeInput(const InputPath & path);
+};
+
+/* Lock file information about a flake input. */
+struct LockedInput : LockedInputs
+{
+    FlakeRef lockedRef, originalRef;
+    TreeInfo info;
+    bool isFlake = true;
+
+    LockedInput(
+        const FlakeRef & lockedRef,
+        const FlakeRef & originalRef,
+        const TreeInfo & info,
+        bool isFlake = true)
+        : lockedRef(lockedRef), originalRef(originalRef), info(info), isFlake(isFlake)
+    { }
+
+    LockedInput(const nlohmann::json & json);
+
+    bool operator ==(const LockedInput & other) const
+    {
+        return
+            lockedRef == other.lockedRef
+            && originalRef == other.originalRef
+            && info == other.info
+            && inputs == other.inputs
+            && isFlake == other.isFlake;
+    }
+
+    nlohmann::json toJson() const;
+
+    StorePath computeStorePath(Store & store) const;
+};
+
+/* An entire lock file. Note that this cannot be a FlakeInput for the
+   top-level flake, because then the lock file would need to contain
+   the hash of the top-level flake, but committing the lock file
+   would invalidate that hash. */
+struct LockFile : LockedInputs
+{
+    bool operator ==(const LockFile & other) const
+    {
+        return inputs == other.inputs;
+    }
+
+    LockFile() {}
+    LockFile(const nlohmann::json & json) : LockedInputs(json) {}
+    LockFile(LockedInput && dep)
+    {
+        inputs = std::move(dep.inputs);
+    }
+
+    nlohmann::json toJson() const;
+
+    static LockFile read(const Path & path);
+
+    void write(const Path & path) const;
+};
+
+std::ostream & operator <<(std::ostream & stream, const LockFile & lockFile);
+
+InputPath parseInputPath(std::string_view s);
+
+}
+