clang-tools-extra/unittests/clangd/SyncAPI.cpp

//===--- SyncAPI.cpp - Sync version of ClangdServer's API --------*- C++-*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===---------------------------------------------------------------------===//
#include "SyncAPI.h"

namespace clang {
namespace clangd {

namespace {
/// A helper that waits for async callbacks to fire and exposes their result in
/// the output variable. Intended to be used in the following way:
///    T Result;
///    someAsyncFunc(Param1, Param2, /*Callback=*/capture(Result));
template <typename T> struct CaptureProxy {
  CaptureProxy(llvm::Optional<T> &Target) : Target(&Target) {
    assert(!Target.hasValue());
  }

  CaptureProxy(const CaptureProxy &) = delete;
  CaptureProxy &operator=(const CaptureProxy &) = delete;
  // We need move ctor to return a value from the 'capture' helper.
  CaptureProxy(CaptureProxy &&Other) : Target(Other.Target) {
    Other.Target = nullptr;
  }
  CaptureProxy &operator=(CaptureProxy &&) = delete;

  operator UniqueFunction<void(T)>() && {
    assert(!Future.valid() && "conversion to callback called multiple times");
    Future = Promise.get_future();
    return BindWithForward(
        [](std::promise<std::shared_ptr<T>> Promise, T Value) {
          Promise.set_value(std::make_shared<T>(std::move(Value)));
        },
        std::move(Promise));
  }

  ~CaptureProxy() {
    if (!Target)
      return;
    assert(Future.valid() && "conversion to callback was not called");
    assert(!Target->hasValue());
    Target->emplace(std::move(*Future.get()));
  }

private:
  llvm::Optional<T> *Target;
  // Using shared_ptr to workaround compilation errors with MSVC.
  // MSVC only allows default-construcitble and copyable objects as future<>
  // arguments.
  std::promise<std::shared_ptr<T>> Promise;
  std::future<std::shared_ptr<T>> Future;
};

template <typename T> CaptureProxy<T> capture(llvm::Optional<T> &Target) {
  return CaptureProxy<T>(Target);
}
} // namespace

Tagged<CompletionList>
runCodeComplete(ClangdServer &Server, PathRef File, Position Pos,
                clangd::CodeCompleteOptions Opts,
                llvm::Optional<StringRef> OverridenContents) {
  llvm::Optional<Tagged<CompletionList>> Result;
  Server.codeComplete(File, Pos, Opts, capture(Result), OverridenContents);
  return std::move(*Result);
}

llvm::Expected<Tagged<SignatureHelp>>
runSignatureHelp(ClangdServer &Server, PathRef File, Position Pos,
                 llvm::Optional<StringRef> OverridenContents) {
  llvm::Optional<llvm::Expected<Tagged<SignatureHelp>>> Result;
  Server.signatureHelp(File, Pos, capture(Result), OverridenContents);
  return std::move(*Result);
}

llvm::Expected<Tagged<std::vector<Location>>>
runFindDefinitions(ClangdServer &Server, PathRef File, Position Pos) {
  llvm::Optional<llvm::Expected<Tagged<std::vector<Location>>>> Result;
  Server.findDefinitions(File, Pos, capture(Result));
  return std::move(*Result);
}

llvm::Expected<Tagged<std::vector<DocumentHighlight>>>
runFindDocumentHighlights(ClangdServer &Server, PathRef File, Position Pos) {
  llvm::Optional<llvm::Expected<Tagged<std::vector<DocumentHighlight>>>> Result;
  Server.findDocumentHighlights(File, Pos, capture(Result));
  return std::move(*Result);
}

llvm::Expected<std::vector<tooling::Replacement>>
runRename(ClangdServer &Server, PathRef File, Position Pos, StringRef NewName) {
  llvm::Optional<llvm::Expected<std::vector<tooling::Replacement>>> Result;
  Server.rename(File, Pos, NewName, capture(Result));
  return std::move(*Result);
}

std::string runDumpAST(ClangdServer &Server, PathRef File) {
  llvm::Optional<std::string> Result;
  Server.dumpAST(File, capture(Result));
  return std::move(*Result);
}

} // namespace clangd
} // namespace clang