func languageService()

in Sources/SourceKitLSP/SourceKitServer.swift [283:325]
36 lines of code
3 McCabe index (conditional complexity)

  func languageService(
    for toolchain: Toolchain,
    _ language: Language,
    in workspace: Workspace
  ) -> ToolchainLanguageServer? {
    let key = LanguageServiceKey(toolchain: toolchain.identifier, language: language)
    if let service = languageService[key] {
      return service
    }

    // Start a new service.
    return orLog("failed to start language service", level: .error) {
      guard let service = try SourceKitLSP.languageService(
        for: toolchain, language, options: options, client: self, in: workspace, reopenDocuments: { [weak self] in self?.reopenDocuments(for: $0) })
      else {
        return nil
      }

      let pid = Int(ProcessInfo.processInfo.processIdentifier)
      let resp = try service.initializeSync(InitializeRequest(
        processId: pid,
        rootPath: nil,
        rootURI: workspace.rootUri,
        initializationOptions: nil,
        capabilities: workspace.capabilityRegistry.clientCapabilities,
        trace: .off,
        workspaceFolders: nil))
      let languages = languageClass(for: language)
      self.registerCapabilities(
        for: resp.capabilities, languages: languages, registry: workspace.capabilityRegistry)

      // FIXME: store the server capabilities.
      let syncKind = resp.capabilities.textDocumentSync?.change ?? .incremental
      guard syncKind == .incremental else {
        fatalError("non-incremental update not implemented")
      }

      service.clientInitialized(InitializedNotification())

      languageService[key] = service
      return service
    }
  }