Class: RBWatch::Watcher

Inherits:
Object
  • Object
show all
Defined in:
lib/rbwatch/watcher.rb

Defined Under Namespace

Classes: Event

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(scanner:, delay:, poll_interval: 0.1, clock: -> { Process.clock_gettime(Process::CLOCK_MONOTONIC) }) ⇒ Watcher

Returns a new instance of Watcher.



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# File 'lib/rbwatch/watcher.rb', line 9

def initialize(scanner:, delay:, poll_interval: 0.1, clock: -> { Process.clock_gettime(Process::CLOCK_MONOTONIC) })
  @scanner = scanner
  @delay = delay.to_f
  @poll_interval = poll_interval.to_f
  @clock = clock
  @baseline_snapshot = {}
  @last_observed_snapshot = {}
  @pending_change = nil
  @stopped = false
end

Instance Attribute Details

#baseline_snapshot ⇒ Object (readonly)

Returns the value of attribute baseline_snapshot.



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# File 'lib/rbwatch/watcher.rb', line 7

def baseline_snapshot
  @baseline_snapshot
end

#delay ⇒ Object (readonly)

Returns the value of attribute delay.



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# File 'lib/rbwatch/watcher.rb', line 7

def delay
  @delay
end

#poll_interval ⇒ Object (readonly)

Returns the value of attribute poll_interval.



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# File 'lib/rbwatch/watcher.rb', line 7

def poll_interval
  @poll_interval
end

Instance Method Details

#reset(snapshot = @scanner.scan) ⇒ Object 



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# File 'lib/rbwatch/watcher.rb', line 20

def reset(snapshot = @scanner.scan)
  @baseline_snapshot = snapshot.dup
  @last_observed_snapshot = snapshot.dup
  @pending_change = nil
  self
end

#run ⇒ Object 



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# File 'lib/rbwatch/watcher.rb', line 81

def run
  return enum_for(:run) unless block_given?

  until stopped?
    if (event = step)
      yield event
    end
    sleep poll_interval
  end
end

#step ⇒ Object 



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# File 'lib/rbwatch/watcher.rb', line 35

def step
  current_snapshot = @scanner.scan
  now = @clock.call
  poll_diff = @scanner.diff(@last_observed_snapshot, current_snapshot)

  if poll_diff.changed?
    if current_snapshot == @baseline_snapshot
      @pending_change = nil
    else
      @pending_change ||= { first_seen_at: now }
      @pending_change[:change_set] = @scanner.diff(@baseline_snapshot, current_snapshot)
      @pending_change[:snapshot] = current_snapshot
      @pending_change[:last_change_at] = now
    end
  elsif @pending_change && now - @pending_change[:last_change_at] >= delay_seconds
    event = Event.new(
      change_set: @pending_change[:change_set],
      snapshot: @pending_change[:snapshot],
      first_seen_at: @pending_change[:first_seen_at],
      delivered_at: now
    )

    @baseline_snapshot = @pending_change[:snapshot].dup
    @last_observed_snapshot = current_snapshot.dup
    @pending_change = nil
    return event
  end

  @last_observed_snapshot = current_snapshot.dup

  if @pending_change && now - @pending_change[:last_change_at] >= delay_seconds
    event = Event.new(
      change_set: @pending_change[:change_set],
      snapshot: @pending_change[:snapshot],
      first_seen_at: @pending_change[:first_seen_at],
      delivered_at: now
    )

    @baseline_snapshot = @pending_change[:snapshot].dup
    @pending_change = nil
    event
  else
    nil
  end
end

#stop ⇒ Object 



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# File 'lib/rbwatch/watcher.rb', line 27

def stop
  @stopped = true
end

#stopped? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rbwatch/watcher.rb', line 31

def stopped?
  @stopped
end