Add a `nix realisation` command for working on realisations

Currently only has `nix realisation info`, more to come probably

1 files changed, 78 insertions, 0 deletions

diff --git a/src/nix/realisation.cc b/src/nix/realisation.cc
new file mode 100644
index 000000000..9ee9ccb91
--- /dev/null
+++ b/src/nix/realisation.cc
@@ -0,0 +1,78 @@
+#include "command.hh"
+#include "common-args.hh"
+
+#include <nlohmann/json.hpp>
+
+using namespace nix;
+
+struct CmdRealisation : virtual NixMultiCommand
+{
+    CmdRealisation() : MultiCommand(RegisterCommand::getCommandsFor({"realisation"}))
+    { }
+
+    std::string description() override
+    {
+        return "manipulate a Nix realisation";
+    }
+
+    Category category() override { return catUtility; }
+
+    void run() override
+    {
+        if (!command)
+            throw UsageError("'nix realisation' requires a sub-command.");
+        command->second->prepare();
+        command->second->run();
+    }
+};
+
+static auto rCmdRealisation = registerCommand<CmdRealisation>("realisation");
+
+struct CmdRealisationInfo : RealisedPathsCommand, MixJSON
+{
+    std::string description() override
+    {
+        return "query information about one or several realisations";
+    }
+
+    std::string doc() override
+    {
+        return
+            #include "realisation/info.md"
+            ;
+    }
+
+    Category category() override { return catSecondary; }
+
+    void run(ref<Store> store, std::vector<RealisedPath> paths) override
+    {
+        settings.requireExperimentalFeature("ca-derivations");
+        if (json) {
+            nlohmann::json res = nlohmann::json::array();
+            for (auto & path : paths) {
+                nlohmann::json currentPath;
+                if (auto realisation = std::get_if<Realisation>(&path.raw))
+                    currentPath = realisation->toJSON();
+                else
+                    currentPath["opaquePath"] = store->printStorePath(path.path());
+
+                res.push_back(currentPath);
+            }
+            std::cout << res.dump();
+        }
+        else {
+            for (auto & path : paths) {
+                if (auto realisation = std::get_if<Realisation>(&path.raw)) {
+                    std::cout <<
+                        realisation->id.to_string() << " " <<
+                        store->printStorePath(realisation->outPath);
+                } else
+                    std::cout << store->printStorePath(path.path());
+
+                std::cout << std::endl;
+            }
+        }
+    }
+};
+
+static auto rCmdRealisationInfo = registerCommand2<CmdRealisationInfo>({"realisation", "info"});