FindReferences.cpp

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/// \file
/// \brief This implements [Find References].
/// [Find References]:
/// https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_references
 
#include "CheckReturn.h"
#include "Convert.h"
#include "Definition.h"
 
#include "nixd/Controller/Controller.h"
 
#include <boost/asio/post.hpp>
#include <lspserver/Protocol.h>
#include <nixf/Sema/ParentMap.h>
#include <nixf/Sema/VariableLookup.h>
 
using namespace lspserver;
using namespace nixd;
using namespace llvm;
using namespace nixf;
 
namespace {
 
std::vector<Location> findReferences(const nixf::Node &Desc,
                                     const ParentMapAnalysis &PMA,
                                     const VariableLookupAnalysis &VLA,
                                     const URIForFile &URI,
                                     llvm::StringRef Src) {
 
  // Two steps.
  //   1. Find some "definition" for this node.
  //   2. Find all "uses", and construct the vector.
 
  // Find "definition"
  auto Def = findDefinition(Desc, PMA, VLA);
  std::vector<Location> Locations;
  // OK, iterate all uses.
  for (const auto *Use : Def.uses()) {
    assert(Use);
    Locations.emplace_back(Location{
        .uri = URI,
        .range = toLSPRange(Src, Use->range()),
    });
  }
  return Locations;
}
 
} // namespace
 
void Controller::onReferences(const TextDocumentPositionParams &Params,
                              Callback<std::vector<Location>> Reply) {
  using CheckTy = std::vector<Location>;
  auto Action = [Reply = std::move(Reply), URI = Params.textDocument.uri,
                 Pos = toNixfPosition(Params.position), this]() mutable {
    std::string File(URI.file());
    return Reply([&]() -> llvm::Expected<CheckTy> {
      const auto TU = CheckDefault(getTU(File));
      const auto AST = CheckDefault(getAST(*TU));
      const auto &Desc = CheckDefault(AST->descend({Pos, Pos}));
      const auto &PM = *TU->parentMap();
      const auto &VLA = *TU->variableLookup();
      try {
        return findReferences(*Desc, PM, VLA, URI, TU->src());
      } catch (std::exception &E) {
        return error("references: {0}", E.what());
      }
    }());
  };
  boost::asio::post(Pool, std::move(Action));
}