1 files changed, 68 insertions, 0 deletions
diff --git a/third_party/nix/src/nix/build.cc b/third_party/nix/src/nix/build.cc
new file mode 100644
index 000000000000..9ab2d27e0fc9
--- /dev/null
+++ b/third_party/nix/src/nix/build.cc
@@ -0,0 +1,68 @@
+#include "command.hh"
+#include "common-args.hh"
+#include "shared.hh"
+#include "store-api.hh"
+
+using namespace nix;
+
+struct CmdBuild : MixDryRun, InstallablesCommand {
+  Path outLink = "result";
+
+  CmdBuild() {
+    mkFlag()
+        .longName("out-link")
+        .shortName('o')
+        .description("path of the symlink to the build result")
+        .labels({"path"})
+        .dest(&outLink);
+
+    mkFlag()
+        .longName("no-link")
+        .description("do not create a symlink to the build result")
+        .set(&outLink, Path(""));
+  }
+
+  std::string name() override { return "build"; }
+
+  std::string description() override {
+    return "build a derivation or fetch a store path";
+  }
+
+  Examples examples() override {
+    return {
+        Example{"To build and run GNU Hello from NixOS 17.03:",
+                "nix build -f channel:nixos-17.03 hello; ./result/bin/hello"},
+        Example{"To build the build.x86_64-linux attribute from release.nix:",
+                "nix build -f release.nix build.x86_64-linux"},
+    };
+  }
+
+  void run(ref<Store> store) override {
+    auto buildables = build(store, dryRun ? DryRun : Build, installables);
+
+    if (dryRun) {
+      return;
+    }
+
+    for (size_t i = 0; i < buildables.size(); ++i) {
+      auto& b(buildables[i]);
+
+      if (!outLink.empty()) {
+        for (auto& output : b.outputs) {
+          if (auto store2 = store.dynamic_pointer_cast<LocalFSStore>()) {
+            std::string symlink = outLink;
+            if (i != 0u) {
+              symlink += fmt("-%d", i);
+            }
+            if (output.first != "out") {
+              symlink += fmt("-%s", output.first);
+            }
+            store2->addPermRoot(output.second, absPath(symlink), true);
+          }
+        }
+      }
+    }
+  }
+};
+
+static RegisterCommand r1(make_ref<CmdBuild>());