1 files changed, 166 insertions, 0 deletions
diff --git a/third_party/nix/src/nix-env/user-env.cc b/third_party/nix/src/nix-env/user-env.cc
new file mode 100644
index 000000000000..c8eee4aac09b
--- /dev/null
+++ b/third_party/nix/src/nix-env/user-env.cc
@@ -0,0 +1,166 @@
+#include "user-env.hh"
+
+#include <glog/logging.h>
+
+#include "derivations.hh"
+#include "eval-inline.hh"
+#include "eval.hh"
+#include "globals.hh"
+#include "profiles.hh"
+#include "shared.hh"
+#include "store-api.hh"
+#include "util.hh"
+
+namespace nix {
+
+DrvInfos queryInstalled(EvalState& state, const Path& userEnv) {
+  DrvInfos elems;
+  Path manifestFile = userEnv + "/manifest.nix";
+  if (pathExists(manifestFile)) {
+    Value v;
+    state.evalFile(manifestFile, v);
+    Bindings& bindings(*Bindings::NewGC());
+    getDerivations(state, v, "", bindings, elems, false);
+  }
+  return elems;
+}
+
+bool createUserEnv(EvalState& state, DrvInfos& elems, const Path& profile,
+                   bool keepDerivations, const std::string& lockToken) {
+  /* Build the components in the user environment, if they don't
+     exist already. */
+  PathSet drvsToBuild;
+  for (auto& i : elems) {
+    if (!i.queryDrvPath().empty()) {
+      drvsToBuild.insert(i.queryDrvPath());
+    }
+  }
+
+  DLOG(INFO) << "building user environment dependencies";
+  state.store->buildPaths(drvsToBuild,
+                          state.repair != 0u ? bmRepair : bmNormal);
+
+  /* Construct the whole top level derivation. */
+  PathSet references;
+  Value manifest;
+  state.mkList(manifest, elems.size());
+  unsigned int n = 0;
+  for (auto& i : elems) {
+    /* Create a pseudo-derivation containing the name, system,
+       output paths, and optionally the derivation path, as well
+       as the meta attributes. */
+    Path drvPath = keepDerivations ? i.queryDrvPath() : "";
+
+    Value& v(*state.allocValue());
+    manifest.listElems()[n++] = &v;
+    state.mkAttrs(v, 16);
+
+    mkString(*state.allocAttr(v, state.sType), "derivation");
+    mkString(*state.allocAttr(v, state.sName), i.queryName());
+    auto system = i.querySystem();
+    if (!system.empty()) {
+      mkString(*state.allocAttr(v, state.sSystem), system);
+    }
+    mkString(*state.allocAttr(v, state.sOutPath), i.queryOutPath());
+    if (!drvPath.empty()) {
+      mkString(*state.allocAttr(v, state.sDrvPath), i.queryDrvPath());
+    }
+
+    // Copy each output meant for installation.
+    DrvInfo::Outputs outputs = i.queryOutputs(true);
+    Value& vOutputs = *state.allocAttr(v, state.sOutputs);
+    state.mkList(vOutputs, outputs.size());
+    unsigned int m = 0;
+    for (auto& j : outputs) {
+      mkString(*(vOutputs.listElems()[m++] = state.allocValue()), j.first);
+      Value& vOutputs = *state.allocAttr(v, state.symbols.Create(j.first));
+      state.mkAttrs(vOutputs, 2);
+      mkString(*state.allocAttr(vOutputs, state.sOutPath), j.second);
+
+      /* This is only necessary when installing store paths, e.g.,
+         `nix-env -i /nix/store/abcd...-foo'. */
+      state.store->addTempRoot(j.second);
+      state.store->ensurePath(j.second);
+
+      references.insert(j.second);
+    }
+
+    // Copy the meta attributes.
+    Value& vMeta = *state.allocAttr(v, state.sMeta);
+    state.mkAttrs(vMeta, 16);
+    StringSet metaNames = i.queryMetaNames();
+    for (auto& j : metaNames) {
+      Value* v = i.queryMeta(j);
+      if (v == nullptr) {
+        continue;
+      }
+      vMeta.attrs->push_back(Attr(state.symbols.Create(j), v));
+    }
+
+    if (!drvPath.empty()) {
+      references.insert(drvPath);
+    }
+  }
+
+  /* Also write a copy of the list of user environment elements to
+     the store; we need it for future modifications of the
+     environment. */
+  Path manifestFile = state.store->addTextToStore(
+      "env-manifest.nix", (format("%1%") % manifest).str(), references);
+
+  /* Get the environment builder expression. */
+  Value envBuilder;
+  state.evalFile(state.findFile("nix/buildenv.nix"), envBuilder);
+
+  /* Construct a Nix expression that calls the user environment
+     builder with the manifest as argument. */
+  Value args;
+  Value topLevel;
+  state.mkAttrs(args, 3);
+  mkString(*state.allocAttr(args, state.symbols.Create("manifest")),
+           manifestFile, {manifestFile});
+  args.attrs->push_back(Attr(state.symbols.Create("derivations"), &manifest));
+  mkApp(topLevel, envBuilder, args);
+
+  /* Evaluate it. */
+  DLOG(INFO) << "evaluating user environment builder";
+  state.forceValue(topLevel);
+  PathSet context;
+  Attr& aDrvPath(topLevel.attrs->find(state.sDrvPath)->second);
+  Path topLevelDrv =
+      state.coerceToPath(aDrvPath.pos != nullptr ? *(aDrvPath.pos) : noPos,
+                         *(aDrvPath.value), context);
+  Attr& aOutPath(topLevel.attrs->find(state.sOutPath)->second);
+  Path topLevelOut =
+      state.coerceToPath(aOutPath.pos != nullptr ? *(aOutPath.pos) : noPos,
+                         *(aOutPath.value), context);
+
+  /* Realise the resulting store expression. */
+  DLOG(INFO) << "building user environment";
+  state.store->buildPaths({topLevelDrv},
+                          state.repair != 0u ? bmRepair : bmNormal);
+
+  /* Switch the current user environment to the output path. */
+  auto store2 = state.store.dynamic_pointer_cast<LocalFSStore>();
+
+  if (store2) {
+    PathLocks lock;
+    lockProfile(lock, profile);
+
+    Path lockTokenCur = optimisticLockProfile(profile);
+    if (lockToken != lockTokenCur) {
+      LOG(WARNING) << "profile '" << profile
+                   << "' changed while we were busy; restarting";
+      return false;
+    }
+
+    DLOG(INFO) << "switching to new user environment";
+    Path generation =
+        createGeneration(ref<LocalFSStore>(store2), profile, topLevelOut);
+    switchLink(profile, generation);
+  }
+
+  return true;
+}
+
+}  // namespace nix