1 files changed, 116 insertions, 0 deletions
diff --git a/src/libexpr/flake/lockfile.hh b/src/libexpr/flake/lockfile.hh
new file mode 100644
index 000000000..7077db3cd
--- /dev/null
+++ b/src/libexpr/flake/lockfile.hh
@@ -0,0 +1,116 @@
+#pragma once
+
+#include "flakeref.hh"
+
+#include <nlohmann/json.hpp>
+
+namespace nix {
+class Store;
+}
+
+namespace nix::flake {
+
+/* Common lock file information about a flake input, namely the
+   immutable ref and the NAR hash. */
+struct AbstractInput
+{
+    FlakeRef ref;
+    Hash narHash;
+
+    AbstractInput(const FlakeRef & flakeRef, const Hash & narHash)
+        : ref(flakeRef), narHash(narHash)
+    {
+        assert(ref.isImmutable());
+    };
+
+    AbstractInput(const nlohmann::json & json);
+
+    nlohmann::json toJson() const;
+
+    Path computeStorePath(Store & store) const;
+};
+
+/* Lock file information about a non-flake input. */
+struct NonFlakeInput : AbstractInput
+{
+    using AbstractInput::AbstractInput;
+
+    bool operator ==(const NonFlakeInput & other) const
+    {
+        return ref == other.ref && narHash == other.narHash;
+    }
+};
+
+struct FlakeInput;
+
+/* Lock file information about the dependencies of a flake. */
+struct FlakeInputs
+{
+    std::map<FlakeRef, FlakeInput> flakeInputs;
+    std::map<FlakeAlias, NonFlakeInput> nonFlakeInputs;
+
+    FlakeInputs() {};
+    FlakeInputs(const nlohmann::json & json);
+
+    nlohmann::json toJson() const;
+
+    /* A lock file is dirty if it contains a dirty flakeref
+       (i.e. reference to a dirty working tree). */
+    bool isDirty() const;
+};
+
+/* Lock file information about a flake input. */
+struct FlakeInput : FlakeInputs, AbstractInput
+{
+    FlakeId id;
+
+    FlakeInput(const FlakeId & id, const FlakeRef & flakeRef, const Hash & narHash)
+        : AbstractInput(flakeRef, narHash), id(id) {};
+
+    FlakeInput(const nlohmann::json & json);
+
+    bool operator ==(const FlakeInput & other) const
+    {
+        return
+            id == other.id
+            && ref == other.ref
+            && narHash == other.narHash
+            && flakeInputs == other.flakeInputs
+            && nonFlakeInputs == other.nonFlakeInputs;
+    }
+
+    nlohmann::json toJson() 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 : FlakeInputs
+{
+    bool operator ==(const LockFile & other) const
+    {
+        return
+            flakeInputs == other.flakeInputs
+            && nonFlakeInputs == other.nonFlakeInputs;
+    }
+
+    LockFile() {}
+    LockFile(const nlohmann::json & json) : FlakeInputs(json) {}
+    LockFile(FlakeInput && dep)
+    {
+        flakeInputs = std::move(dep.flakeInputs);
+        nonFlakeInputs = std::move(dep.nonFlakeInputs);
+    }
+
+    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);
+
+}
+