DirectoryWatcher::Collector

Create a new StatCollector from the given Configuration, and an optional
Scan.

configuration - The Collector uses from Configuration:
  collection_queue   - The Queue to read items from the Scanner on
  notification_queue - The Queue to submit the Events to the Notifier on
  stable             - The number of times we see a file hasn't changed before
                       emitting a stable event
  sort_by            - the method used to sort events during on_scan results
  order_by           - The method used to order events from call to on_scan

pre_load_scan - A Scan to use to load our internal state from before. No
                events will be emitted for the FileStat's in this scan.

def initialize( notification_queue, collection_queue, options = {} )

# File lib/directory_watcher/collector.rb, line 23
def initialize( config )
  @stats = Hash.new
  @stable_counts = Hash.new
  @config = config
  on_scan( DirectoryWatcher::Scan.new( config.glob ), false ) if config.pre_load?
  self.interval = 0.01 # yes this is a fast loop
end

The queue from which to read items from the scanners. See Configuration.

# File lib/directory_watcher/collector.rb, line 51
def collection_queue
  @config.collection_queue
end

Write the current stats to the given IO object as a YAML document.

io - The IO object to write the document to.

Returns nothing.

# File lib/directory_watcher/collector.rb, line 122
def dump_stats( io )
  YAML.dump(@stats, io)
end

Read the current stats from the given IO object. Any existing stats in the Collector will be overwritten

io - The IO object from which to read the document.

Returns nothing.

# File lib/directory_watcher/collector.rb, line 132
def load_stats( io )
  @stats = YAML.load(io)
end

The queue to write Events for the Notifier. See Configuration.

# File lib/directory_watcher/collector.rb, line 57
def notification_queue
  @config.notification_queue
end

Given the scan, update the set of stats with the results from the Scan and emit events to the notification queue as appropriate.

scan - The Scan containing all the new FileStat items emit_events - Should events be emitted for the events in the scan

(default: true)

There is one odd thing that happens here. Scanners that are EventableScanners use on_stat to emit removed events, and the standard threaded Scanner only uses Scans. So we make sure and only emit removed events in this method if the scanner that gave us the scan was the basic threaded Scanner.

TODO: Possibly fix this through another abstraction in the Scanners. No idea about what that would be yet.

Returns nothing.

# File lib/directory_watcher/collector.rb, line 78
def on_scan( scan, emit_events = true )
  seen_paths = Set.new
  logger.debug "Sorting by #{sort_by} #{order_by}"
  sorted_stats( scan.run ).each do |stat|
    on_stat(stat, emit_events)
    seen_paths << stat.path
  end
  emit_removed_events(seen_paths) if @config.scanner.nil?
end

Process a single stat and emit an event if necessary.

stat - The new FileStat to process and see if an event should

be emitted

emit_event - Whether or not an event should be emitted.

Returns nothing

# File lib/directory_watcher/collector.rb, line 95
def on_stat( stat, emit_event = true )
  orig_stat = update_stat( stat )
  logger.debug "Emitting event for on_stat #{stat}"
  emit_event_for( orig_stat, stat ) if emit_event
end

How to order Scan results. See Configuration.

# File lib/directory_watcher/collector.rb, line 45
def order_by
  @config.order_by
end

Remove one item from the collection queue and process it.

This method is required by the Threaded API

Returns nothing

# File lib/directory_watcher/collector.rb, line 106
def run
  case thing = collection_queue.deq
  when ::DirectoryWatcher::Scan
    on_scan(thing)
  when ::DirectoryWatcher::FileStat
    on_stat(thing)
  else
    raise "Unknown item in the queue: #{thing}"
  end
end

How to sort Scan results. See Configuration.

# File lib/directory_watcher/collector.rb, line 39
def sort_by
  @config.sort_by
end

The number of times we see a file hasn't changed before emitting a stable count. See Configuration#stable

# File lib/directory_watcher/collector.rb, line 33
def stable_threshold
  @config.stable
end