Module: Mbeditor::FileWatcher

Defined in:
lib/mbeditor/file_watcher.rb

Overview

Watches the workspace for changes made outside the editor — a terminal git checkout, a rebase, another editor, a generator — and broadcasts the same files_changed payload the mutation endpoints send. Clients refresh the file tree, git line-number tinting and cached globals from it.

The listen gem is an optional host dependency. Without it the editor behaves exactly as before: only changes made through mbeditor announce themselves. Nothing warns loudly about the missing gem — it is opt-in.

Only one watcher runs per process. It is deliberately not started in test or in non-server processes (rake, console, the Rails runner), where a background listener thread is pure overhead.

Constant Summary collapse

DEBOUNCE_SECONDS =

Coalesce bursts: a branch switch touches hundreds of files, and each one would otherwise be its own broadcast.

0.3

Class Method Summary collapse

Class Method Details

.available? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/mbeditor/file_watcher.rb', line 22

def available?
  return @available if defined?(@available)

  @available = begin
    require "listen"
    true
  rescue LoadError
    false
  end
end

.running? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/mbeditor/file_watcher.rb', line 33

def running?
  !@listener.nil?
end

.start(root) ⇒ Object

Returns true when a watcher was started, false for every reason not to (gem absent, already running, no workspace, disabled by config).



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# File 'lib/mbeditor/file_watcher.rb', line 53

def start(root)
  return false unless available?
  return false if running?

  root = root.to_s
  return false if root.empty? || !File.directory?(root)

  ignores = ignore_patterns(root)
  @listener = ::Listen.to(root, ignore: ignores, latency: DEBOUNCE_SECONDS) do |modified, added, removed|
    broadcast(root, modified + added + removed)
  end
  @listener.start
  Rails.logger.info("[mbeditor] watching #{root} for external changes")
  true
rescue StandardError => e
  # A watcher that cannot start must never take the host app down with it:
  # inotify limits on Linux, permission issues, an unreadable root.
  Rails.logger.warn("[mbeditor] file watcher failed to start: #{e.class}: #{e.message}")
  @listener = nil
  false
end

.start_if_enabled ⇒ Object

Boot entry point. Confined to the environments the editor is allowed in and to processes that actually serve requests — a rake task or console has no client to broadcast to, and a listener thread there would only burn file handles. MBEDITOR_FORCE_WATCH overrides the process check for unusual servers and for tests.



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# File 'lib/mbeditor/file_watcher.rb', line 42

def start_if_enabled
  cfg = Mbeditor.configuration
  return false if cfg.watch_files == false
  return false unless cfg.allowed_environments.map(&:to_s).include?(Rails.env.to_s)
  return false unless serving_requests?

  start(cfg.workspace_root.presence || Rails.root.to_s)
end

.stop ⇒ Object 



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# File 'lib/mbeditor/file_watcher.rb', line 75

def stop
  @listener&.stop
rescue StandardError
  nil
ensure
  @listener = nil
end