text: ############################################################################
  # Copyright(c) Open Law Library. All rights reserved.                      #
  # See ThirdPartyNotices.txt in the project root for additional notices.    #
  #                                                                          #
  # Licensed under the Apache License, Version 2.0 (the "License")           #
  # you may not use this file except in compliance with the License.         #
  # You may obtain a copy of the License at                                  #
  #                                                                          #
  #     http: // www.apache.org/licenses/LICENSE-2.0                         #
  #                                                                          #
  # Unless required by applicable law or agreed to in writing, software      #
  # distributed under the License is distributed on an "AS IS" BASIS,        #
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. #
  # See the License for the specific language governing permissions and      #
  # limitations under the License.                                           #
  ############################################################################
  import asyncio
  import logging
  import re
  import sys
  from concurrent.futures import Future, ThreadPoolExecutor
  from multiprocessing.pool import ThreadPool
  from threading import Event
  from typing import Any, Callable, List, Optional, TypeVar
  
  from pygls import IS_WIN
  from pygls.lsp.types import (ApplyWorkspaceEditResponse, ClientCapabilities, ConfigCallbackType,
                               ConfigurationParams, Diagnostic, MessageType, RegistrationParams,
                               ServerCapabilities, TextDocumentSyncKind, UnregistrationParams,
                               WorkspaceEdit)
  from pygls.protocol import LanguageServerProtocol
  from pygls.workspace import Workspace
  
  logger = logging.getLogger(__name__)
  
  F = TypeVar('F', bound=Callable)
  
  
  async def aio_readline(loop, executor, stop_event, rfile, proxy):
      """Reads data from stdin in separate thread (asynchronously)."""
  
      CONTENT_LENGTH_PATTERN = re.compile(rb'^Content-Length: (\d+)\r\n$')
  
      # Initialize message buffer
      message = []
      content_length = 0
  
      while not stop_event.is_set() and not rfile.closed:
          # Read a header line
          header = await loop.run_in_executor(executor, rfile.readline)
          message.append(header)
  
          # Extract content length if possible
          if not content_length:
              match = CONTENT_LENGTH_PATTERN.fullmatch(header)
              if match:
                  content_length = int(match.group(1))
                  logger.debug('Content length: %s', content_length)
  
          # Check if all headers have been read (as indicated by an empty line \r\n)
          if content_length and not header.strip():
  
              # Read body
              body = await loop.run_in_executor(executor, rfile.read, content_length)
              message.append(body)
  
              # Pass message to language server protocol
              proxy(b''.join(message))
  
              # Reset the buffer
              message = []
              content_length = 0
  
  
  class StdOutTransportAdapter:
      """Protocol adapter which overrides write method.
  
      Write method sends data to stdout.
      """
  
      def __init__(self, rfile, wfile):
          self.rfile = rfile
          self.wfile = wfile
  
      def close(self):
          self.rfile.close()
          self.wfile.close()
  
      def write(self, data):
          self.wfile.write(data)
          self.wfile.flush()
  
  
  class Server:
      """Class that represents async server. It can be started using TCP or IO.
  
      Args:
          protocol_cls(Protocol): Protocol implementation that must be derived
                                  from `asyncio.Protocol`
  
          loop(AbstractEventLoop): asyncio event loop
  
          max_workers(int, optional): Number of workers for `ThreadPool` and
                                      `ThreadPoolExecutor`
  
          sync_kind(TextDocumentSyncKind): Text document synchronization option
              - NONE(0): no synchronization
              - FULL(1): replace whole text
              - INCREMENTAL(2): replace text within a given range
  
      Attributes:
          _max_workers(int): Number of workers for thread pool executor
          _server(Server): Server object which can be used to stop the process
          _stop_event(Event): Event used for stopping `aio_readline`
          _thread_pool(ThreadPool): Thread pool for executing methods decorated
                                    with `@ls.thread()` - lazy instantiated
          _thread_pool_executor(ThreadPoolExecutor): Thread pool executor
                                                     passed to `run_in_executor`
                                                      - lazy instantiated
      """
  
      def __init__(self, protocol_cls, loop=None, max_workers=2,
                   sync_kind=TextDocumentSyncKind.INCREMENTAL):
          if not issubclass(protocol_cls, asyncio.Protocol):
              raise TypeError('Protocol class should be subclass of asyncio.Protocol')
  
          self._max_workers = max_workers
          self._server = None
          self._stop_event = None
          self._thread_pool = None
          self._thread_pool_executor = None
          self.sync_kind = sync_kind
  
          if IS_WIN:
              asyncio.set_event_loop(asyncio.ProactorEventLoop())
          else:
              asyncio.set_event_loop(asyncio.SelectorEventLoop())
  
          self.loop = loop or asyncio.get_event_loop()
  
          try:
              asyncio.get_child_watcher().attach_loop(self.loop)
          except NotImplementedError:
              pass
  
          self.lsp = protocol_cls(self)
  
      def shutdown(self):
          """Shutdown server."""
          logger.info('Shutting down the server')
  
          self._stop_event.set()
  
          if self._thread_pool:
              self._thread_pool.terminate()
              self._thread_pool.join()
  
          if self._thread_pool_executor:
              self._thread_pool_executor.shutdown()
  
          if self._server:
              self._server.close()
              self.loop.run_until_complete(self._server.wait_closed())
  
          logger.info('Closing the event loop.')
          self.loop.close()
  
      def start_io(self, stdin=None, stdout=None):
          """Starts IO server."""
          logger.info('Starting IO server')
  
          self._stop_event = Event()
          transport = StdOutTransportAdapter(stdin or sys.stdin.buffer,
                                             stdout or sys.stdout.buffer)
          self.lsp.connection_made(transport)
  
          try:
              self.loop.run_until_complete(
                  aio_readline(self.loop,
                               self.thread_pool_executor,
                               self._stop_event,
                               stdin or sys.stdin.buffer,
                               self.lsp.data_received))
          except (KeyboardInterrupt, SystemExit):
              pass
          finally:
              self.shutdown()
  
      def start_tcp(self, host, port):
          """Starts TCP server."""
          logger.info('Starting server on %s:%s', host, port)
  
          self._stop_event = Event()
          self._server = self.loop.run_until_complete(
              self.loop.create_server(self.lsp, host, port)
          )
          try:
              self.loop.run_forever()
          except (KeyboardInterrupt, SystemExit):
              pass
          finally:
              self.shutdown()
  
      @property
      def thread_pool(self) -> ThreadPool:
          """Returns thread pool instance (lazy initialization)."""
          if not self._thread_pool:
              self._thread_pool = ThreadPool(processes=self._max_workers)
  
          return self._thread_pool
  
      @property
      def thread_pool_executor(self) -> ThreadPoolExecutor:
          """Returns thread pool instance (lazy initialization)."""
          if not self._thread_pool_executor:
              self._thread_pool_executor = \
                  ThreadPoolExecutor(max_workers=self._max_workers)
  
          return self._thread_pool_executor
  
  
  class LanguageServer(Server):
      """A class that represents Language server using Language Server Protocol.
  
      This class can be extended and it can be passed as a first argument to
      registered commands/features.
  
      Args:
          protocol_cls(LanguageServerProtocol): LSP or any subclass of it
          max_workers(int, optional): Number of workers for `ThreadPool` and
                                      `ThreadPoolExecutor`
      """
  
      def __init__(self, loop=None, protocol_cls=LanguageServerProtocol, max_workers: int = 2):
          if not issubclass(protocol_cls, LanguageServerProtocol):
              raise TypeError('Protocol class should be subclass of LanguageServerProtocol')
          super().__init__(protocol_cls, loop, max_workers)
  
      def apply_edit(self, edit: WorkspaceEdit, label: str = None) -> ApplyWorkspaceEditResponse:
          """Sends apply edit request to the client."""
          return self.lsp.apply_edit(edit, label)
  
      def command(self, command_name: str) -> Callable[[F], F]:
          """Decorator used to register custom commands.
  
          Example:
              @ls.command('myCustomCommand')
              def my_cmd(ls, a, b, c):
                  pass
          """
          return self.lsp.fm.command(command_name)
  
      @property
      def client_capabilities(self) -> ClientCapabilities:
          """Return client capabilities."""
          return self.lsp.client_capabilities
  
      def feature(
          self, feature_name: str, options: Optional[Any] = None,
      ) -> Callable[[F], F]:
          """Decorator used to register LSP features.
  
          Example:
              @ls.feature('textDocument/completion', triggerCharacters=['.'])
              def completions(ls, params: CompletionRequest):
                  return CompletionList(False, [CompletionItem("Completion 1")])
          """
          return self.lsp.fm.feature(feature_name, options)
  
      def get_configuration(self, params: ConfigurationParams,
                            callback: ConfigCallbackType = None) -> Future:
          """Gets the configuration settings from the client."""
          return self.lsp.get_configuration(params, callback)
  
      def get_configuration_async(self, params: ConfigurationParams) -> asyncio.Future:
          """Gets the configuration settings from the client. Should be called with `await`"""
          return self.lsp.get_configuration_async(params)
  
      def publish_diagnostics(self, doc_uri: str, diagnostics: List[Diagnostic]):
          """Sends diagnostic notification to the client."""
          self.lsp.publish_diagnostics(doc_uri, diagnostics)
  
      def register_capability(self, params: RegistrationParams, callback):
          """Register a new capability on the client."""
          return self.lsp.register_capability(params, callback)
  
      def register_capability_async(self, params: RegistrationParams):
          """Register a new capability on the client. Should be called with `await`"""
          return self.lsp.register_capability_async(params)
  
      def send_notification(self, method: str, params: object = None) -> None:
          """Sends notification to the client."""
          self.lsp.notify(method, params)
  
      @property
      def server_capabilities(self) -> ServerCapabilities:
          """Return server capabilities."""
          return self.lsp.server_capabilities
  
      def show_message(self, message, msg_type=MessageType.Info) -> None:
          """Sends message to the client to display message."""
          self.lsp.show_message(message, msg_type)
  
      def show_message_log(self, message, msg_type=MessageType.Log) -> None:
          """Sends message to the client's output channel."""
          self.lsp.show_message_log(message, msg_type)
  
      def thread(self) -> Callable[[F], F]:
          """Decorator that mark function to execute it in a thread."""
          return self.lsp.thread()
  
      def unregister_capability(self, params: UnregistrationParams, callback):
          """Unregister a new capability on the client."""
          return self.lsp.unregister_capability(params, callback)
  
      def unregister_capability_async(self, params: UnregistrationParams):
          """Unregister a new capability on the client. Should be called with `await`"""
          return self.lsp.unregister_capability_async(params)
  
      @property
      def workspace(self) -> Workspace:
          """Returns in-memory workspace."""
          return self.lsp.workspace
  