DocumentHighlight.cpp

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/// \file
/// \brief This implements [Document Highlight].
/// [Document Highlight]:
/// https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_documentHighlight
 
#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>
 
#include <exception>
 
using namespace lspserver;
using namespace nixd;
using namespace llvm;
using namespace nixf;
 
namespace {
 
std::vector<DocumentHighlight> highlight(const nixf::Node &Desc,
                                         const ParentMapAnalysis &PMA,
                                         const VariableLookupAnalysis &VLA,
                                         const URIForFile &URI,
                                         llvm::StringRef Src) {
  // Find "definition"
  auto Def = findDefinition(Desc, PMA, VLA);
 
  std::vector<DocumentHighlight> Highlights;
  // OK, iterate all uses.
  for (const auto *Use : Def.uses()) {
    assert(Use);
    Highlights.emplace_back(DocumentHighlight{
        .range = toLSPRange(Src, Use->range()),
        .kind = DocumentHighlightKind::Read,
    });
  }
  if (Def.syntax()) {
    const Node &Syntax = *Def.syntax();
    Highlights.emplace_back(DocumentHighlight{
        .range = toLSPRange(Src, Syntax.range()),
        .kind = DocumentHighlightKind::Write,
    });
  }
 
  return Highlights;
}
 
} // namespace
 
void Controller::onDocumentHighlight(
    const TextDocumentPositionParams &Params,
    Callback<std::vector<DocumentHighlight>> Reply) {
  using CheckTy = std::vector<DocumentHighlight>;
  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}));
      try {
        const auto &PM = *TU->parentMap();
        const auto &VLA = *TU->variableLookup();
        return highlight(Desc, PM, VLA, URI, TU->src());
      } catch (std::exception &E) {
        elog("textDocument/documentHighlight failed: {0}", E.what());
        return CheckTy{};
      }
    }());
  };
  boost::asio::post(Pool, std::move(Action));
}