1 files changed, 91 insertions, 0 deletions
diff --git a/src/libexpr/flake/lockfile.cc b/src/libexpr/flake/lockfile.cc
new file mode 100644
index 000000000..5693e57dc
--- /dev/null
+++ b/src/libexpr/flake/lockfile.cc
@@ -0,0 +1,91 @@
+#include "lockfile.hh"
+#include "store-api.hh"
+
+#include <nlohmann/json.hpp>
+
+namespace nix::flake {
+
+LockedInput::LockedInput(const nlohmann::json & json)
+    : LockedInputs(json)
+    , ref(json.value("url", json.value("uri", "")))
+    , originalRef(json.value("originalUrl", json.value("originalUri", "")))
+    , narHash(Hash((std::string) json["narHash"]))
+{
+    if (!ref.isImmutable())
+        throw Error("lockfile contains mutable flakeref '%s'", ref);
+}
+
+nlohmann::json LockedInput::toJson() const
+{
+    auto json = LockedInputs::toJson();
+    json["url"] = ref.to_string();
+    json["originalUrl"] = originalRef.to_string();
+    json["narHash"] = narHash.to_string(SRI);
+    return json;
+}
+
+Path LockedInput::computeStorePath(Store & store) const
+{
+    return store.makeFixedOutputPath(true, narHash, "source");
+}
+
+LockedInputs::LockedInputs(const nlohmann::json & json)
+{
+    for (auto & i : json["inputs"].items())
+        inputs.insert_or_assign(i.key(), LockedInput(i.value()));
+}
+
+nlohmann::json LockedInputs::toJson() const
+{
+    nlohmann::json json;
+    {
+        auto j = nlohmann::json::object();
+        for (auto & i : inputs)
+            j[i.first] = i.second.toJson();
+        json["inputs"] = std::move(j);
+    }
+    return json;
+}
+
+bool LockedInputs::isDirty() const
+{
+    for (auto & i : inputs)
+        if (i.second.ref.isDirty() || i.second.isDirty()) return true;
+
+    return false;
+}
+
+nlohmann::json LockFile::toJson() const
+{
+    auto json = LockedInputs::toJson();
+    json["version"] = 3;
+    return json;
+}
+
+LockFile LockFile::read(const Path & path)
+{
+    if (pathExists(path)) {
+        auto json = nlohmann::json::parse(readFile(path));
+
+        auto version = json.value("version", 0);
+        if (version != 3)
+            throw Error("lock file '%s' has unsupported version %d", path, version);
+
+        return LockFile(json);
+    } else
+        return LockFile();
+}
+
+std::ostream & operator <<(std::ostream & stream, const LockFile & lockFile)
+{
+    stream << lockFile.toJson().dump(4); // '4' = indentation in json file
+    return stream;
+}
+
+void LockFile::write(const Path & path) const
+{
+    createDirs(dirOf(path));
+    writeFile(path, fmt("%s\n", *this));
+}
+
+}