Function shouldOpenInExistingInstance

src/node/cli.ts:846–893

(
  args: UserProvidedArgs,
  sessionSocket: string,
)

 * explicitly passed on the command line, *NOT DEFAULTS* or the configuration.
 */
export const shouldOpenInExistingInstance = async (
  args: UserProvidedArgs,
  sessionSocket: string,
): Promise<string | undefined> => {
  // Always use the existing instance if we're running from VS Code's terminal.
  if (process.env.VSCODE_IPC_HOOK_CLI) {
    logger.debug("Found VSCODE_IPC_HOOK_CLI")
    return process.env.VSCODE_IPC_HOOK_CLI
  }

  const paths = getResolvedPathsFromArgs(args)
  const client = new EditorSessionManagerClient(sessionSocket)

  // If these flags are set then assume the user is trying to open in an
  // existing instance since these flags have no effect otherwise.  That means
  // if there is no existing instance we should error rather than falling back
  // to spawning code-server normally.
  const openInFlagCount = ["reuse-window", "new-window"].reduce((prev, cur) => {
    return args[cur as keyof UserProvidedArgs] ? prev + 1 : prev
  }, 0)
  if (openInFlagCount > 0) {
    logger.debug("Found --reuse-window or --new-window")
    const socketPath = await client.getConnectedSocketPath(paths[0])
    if (!socketPath) {
      throw new Error(`No opened code-server instances found to handle ${paths[0]}`)
    }
    return socketPath
  }

  // It's possible the user is trying to spawn another instance of code-server.
  // 1. Check if any unrelated flags are set (this should only run when
  //    code-server is invoked exactly like this: `code-server my-file`).
  // 2. That a file or directory was passed.
  // 3. That the socket is active.
  // 4. That an instance exists to handle the path (implied by #3).
  if (Object.keys(args).length === 1 && typeof args._ !== "undefined" && args._.length > 0) {
    if (!(await client.canConnect())) {
      return undefined
    }
    const socketPath = await client.getConnectedSocketPath(paths[0])
    if (socketPath) {
      logger.debug("Found existing code-server socket")
      return socketPath
    }
  }

  return undefined
}

/**
 * Arguments for running Code's server.