nixd/Sema: use CompletionBuilder for OptionWorker

nixd/include/nixd/Nix/Value.h

@@ -2,6 +2,7 @@
 
 #include <nix/attr-path.hh>
 #include <nix/eval.hh>
+#include <nix/value.hh>
 
 namespace nixd {
 
@@ -12,6 +13,10 @@ bool isDerivation(nix::EvalState &State, nix::Value &V);
 std::optional<std::string> attrPathStr(nix::EvalState &State, nix::Value &V,
                                        const std::string &AttrPath) noexcept;
 
+/// Select the path given in \p AttrPath, and return the value
+nix::Value selectAttrPath(nix::EvalState &State, nix::Value Set,
+                          const std::vector<std::string> &AttrPath);
+
 extern int PrintDepth;
 
 } // namespace nixd

nixd/include/nixd/Sema/CompletionBuilder.h

@@ -45,6 +45,10 @@ class CompletionBuilder {
   /// builtins.*
   void addStaticEnv(const nix::SymbolTable &STable, const nix::StaticEnv &SEnv);
 
+  /// Complete option items, for Nixpkgs option system.
+  void addOption(nix::EvalState &State, nix::Value &OptionAttrSet,
+                 const std::vector<std::string> &AttrPath);
+
   CompletionResult &getResult() { return Result; }
 
   void setLimit(size_t Limit) { this->Limit = Limit; }

nixd/lib/Nix/Value.cpp

@@ -3,6 +3,8 @@
 #include <nix/eval.hh>
 #include <nix/print.hh>
 
+#include <boost/algorithm/string/join.hpp>
+
 namespace nixd {
 
 bool isOption(nix::EvalState &State, nix::Value &V) {
@@ -41,6 +43,16 @@ std::optional<std::string> attrPathStr(nix::EvalState &State, nix::Value &V,
 
 int PrintDepth;
 
+inline nix::Value selectAttrPath(nix::EvalState &State, nix::Value Set,
+                                 const std::vector<std::string> &AttrPath) {
+  nix::Value V = Set;
+  if (!AttrPath.empty()) {
+    auto AttrPathStr = boost::algorithm::join(AttrPath, ".");
+    auto &Bindings(*State.allocBindings(0));
+    V = *nix::findAlongAttrPath(State, AttrPathStr, Bindings, Set).first;
+  }
+  return V;
+}
 } // namespace nixd
 
 namespace nix {

nixd/lib/Sema/CompletionBuilder.cpp

@@ -1,6 +1,8 @@
 #include "nixd/Sema/CompletionBuilder.h"
 #include "nixd/AST/ParseAST.h"
 #include "nixd/Nix/Eval.h"
+#include "nixd/Nix/Option.h"
+#include "nixd/Nix/Value.h"
 
 #include "lspserver/Protocol.h"
 
@@ -136,4 +138,36 @@ void CompletionBuilder::addStaticEnv(const nix::SymbolTable &STable,
     addStaticEnv(STable, SEnv);
 }
 
+void CompletionBuilder::addOption(nix::EvalState &State, nix::Value &OptionSet,
+                                  const std::vector<std::string> &AttrPath) {
+  using lspserver::MarkupContent;
+  using lspserver::MarkupKind;
+
+  try {
+    nix::Value V = selectAttrPath(State, OptionSet, AttrPath);
+    State.forceValue(V, nix::noPos);
+
+    if (V.type() != nix::ValueType::nAttrs)
+      return;
+
+    if (isOption(State, V))
+      return;
+
+    for (const auto &Attr : *V.attrs) {
+      CompletionItem R;
+      R.label = State.symbols[Attr.name];
+      if (isOption(State, *Attr.value)) {
+        auto Info = optionInfo(State, *Attr.value);
+        R.kind = CompletionItemKind::Constructor;
+        R.detail = Info.Type.value_or("");
+        R.documentation = MarkupContent{MarkupKind::Markdown, Info.mdDoc()};
+      } else {
+        R.kind = CompletionItemKind::Class;
+        R.detail = "{...}";
+      }
+      addItem(std::move(R));
+    }
+  } catch (...) {
+  }
+}
 } // namespace nixd

nixd/lib/Server/OptionWorker.cpp

@@ -2,6 +2,7 @@
 #include "nixd/Nix/Init.h"
 #include "nixd/Nix/Option.h"
 #include "nixd/Nix/Value.h"
+#include "nixd/Sema/CompletionBuilder.h"
 #include "nixd/Server/ConfigSerialization.h"
 #include "nixd/Server/IPCSerialization.h"
 #include "nixd/Support/Diagnostic.h"
@@ -39,29 +40,19 @@ void OptionWorker::onDeclaration(
     return;
 
   try {
-    nix::Value *V = OptionAttrSet;
-    if (!Params.Path.empty()) {
-      auto AttrPath = join(Params.Path, ".");
-      auto &Bindings(*OptionIES->getState()->allocBindings(0));
-      V = nix::findAlongAttrPath(*OptionIES->getState(), AttrPath, Bindings,
-                                 *OptionAttrSet)
-              .first;
-    }
+    auto Path = Params.Path;
+    Path.emplace_back("declarations");
 
     auto &State = *OptionIES->getState();
-    State.forceValue(*V, nix::noPos);
-
-    auto *VDecl = nix::findAlongAttrPath(State, "declarations",
-                                         *State.allocBindings(0), *V)
-                      .first;
 
-    State.forceValue(*VDecl, nix::noPos);
+    auto VDecl = selectAttrPath(State, *OptionAttrSet, Path);
+    State.forceValue(VDecl, nix::noPos);
 
     // declarations should be a list containing file paths
-    if (!VDecl->isList())
+    if (!VDecl.isList())
       return;
 
-    for (auto *VFile : VDecl->listItems()) {
+    for (auto *VFile : VDecl.listItems()) {
       State.forceValue(*VFile, nix::noPos);
       if (VFile->type() == nix::ValueType::nString) {
         auto File = VFile->str();
@@ -116,55 +107,9 @@ void OptionWorker::onCompletion(const ipc::AttrPathParams &Params,
   if (!OptionAttrSet)
     return;
 
-  try {
-    CompletionList List;
-    List.isIncomplete = false;
-    List.items = decltype(CompletionList::items){};
-
-    auto &Items = List.items;
-
-    if (OptionAttrSet->type() == nix::ValueType::nAttrs) {
-      nix::Value *V = OptionAttrSet;
-      if (!Params.Path.empty()) {
-        auto AttrPath = join(Params.Path, ".");
-        auto &Bindings(*OptionIES->getState()->allocBindings(0));
-        V = nix::findAlongAttrPath(*OptionIES->getState(), AttrPath, Bindings,
-                                   *OptionAttrSet)
-                .first;
-      }
-
-      OptionIES->getState()->forceValue(*V, nix::noPos);
-
-      if (V->type() != nix::ValueType::nAttrs)
-        return;
-
-      auto &State = *OptionIES->getState();
-
-      if (isOption(State, *V))
-        return;
-
-      for (auto Attr : *V->attrs) {
-        if (isOption(State, *Attr.value)) {
-          auto OI = optionInfo(State, *Attr.value);
-          Items.emplace_back(CompletionItem{
-              .label = State.symbols[Attr.name],
-              .kind = CompletionItemKind::Constructor,
-              .detail = OI.Type.value_or(""),
-              .documentation =
-                  MarkupContent{MarkupKind::Markdown, OI.mdDoc()}});
-        } else {
-          Items.emplace_back(
-              CompletionItem{.label = OptionIES->getState()->symbols[Attr.name],
-                             .kind = CompletionItemKind::Class,
-                             .detail = "{...}",
-                             .documentation = std::nullopt});
-        }
-      }
-      RR.Response = std::move(List);
-    }
-  } catch (std::exception &E) {
-    RR.Response = error(E.what());
-  }
+  CompletionBuilder Builder;
+  Builder.addOption(*OptionIES->getState(), *OptionAttrSet, Params.Path);
+  RR.Response = Builder.getResult();
 }
 
 } // namespace nixd