Move flake-related stuff to src/libexpr/flake

src/libexpr/flake/lockfile.cc

@@ -0,0 +1,102 @@
+#include "lockfile.hh"
+#include "store-api.hh"
+
+namespace nix::flake {
+
+AbstractInput::AbstractInput(const nlohmann::json & json)
+    : ref(json["uri"])
+    , narHash(Hash((std::string) json["narHash"]))
+{
+    if (!ref.isImmutable())
+        throw Error("lockfile contains mutable flakeref '%s'", ref);
+}
+
+nlohmann::json AbstractInput::toJson() const
+{
+    nlohmann::json json;
+    json["uri"] = ref.to_string();
+    json["narHash"] = narHash.to_string(SRI);
+    return json;
+}
+
+Path AbstractInput::computeStorePath(Store & store) const
+{
+    return store.makeFixedOutputPath(true, narHash, "source");
+}
+
+FlakeInput::FlakeInput(const nlohmann::json & json)
+    : FlakeInputs(json)
+    , AbstractInput(json)
+    , id(json["id"])
+{
+}
+
+nlohmann::json FlakeInput::toJson() const
+{
+    auto json = FlakeInputs::toJson();
+    json.update(AbstractInput::toJson());
+    json["id"] = id;
+    return json;
+}
+
+FlakeInputs::FlakeInputs(const nlohmann::json & json)
+{
+    for (auto & i : json["nonFlakeInputs"].items())
+        nonFlakeInputs.insert_or_assign(i.key(), NonFlakeInput(i.value()));
+
+    for (auto & i : json["inputs"].items())
+        flakeInputs.insert_or_assign(i.key(), FlakeInput(i.value()));
+}
+
+nlohmann::json FlakeInputs::toJson() const
+{
+    nlohmann::json json;
+    {
+        auto j = nlohmann::json::object();
+        for (auto & i : nonFlakeInputs)
+            j[i.first] = i.second.toJson();
+        json["nonFlakeInputs"] = std::move(j);
+    }
+    {
+        auto j = nlohmann::json::object();
+        for (auto & i : flakeInputs)
+            j[i.first.to_string()] = i.second.toJson();
+        json["inputs"] = std::move(j);
+    }
+    return json;
+}
+
+nlohmann::json LockFile::toJson() const
+{
+    auto json = FlakeInputs::toJson();
+    json["version"] = 2;
+    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 != 2)
+            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));
+}
+
+}