Merge 4e926b4 into ba5059c

lib/listen/adapter/base.rb

@@ -87,10 +87,7 @@ def start
 
       def stop
         _stop
-      end
-
-      def self.usable?
-        const_get('OS_REGEXP') =~ RbConfig::CONFIG['target_os']
+        config.queue.close # this causes queue.pop to return `nil` to the front-end
       end
 
       private
@@ -130,6 +127,10 @@ def _log_exception(msg, caller_stack)
       end
 
       class << self
+        def usable?
+          const_get('OS_REGEXP') =~ RbConfig::CONFIG['target_os']
+        end
+
         private
 
         def _log(*args, &block)

lib/listen/event/config.rb

@@ -1,6 +1,10 @@
 module Listen
   module Event
     class Config
+      attr_reader :listener
+      attr_reader :event_queue
+      attr_reader :min_delay_between_events
+
       def initialize(
         listener,
         event_queue,
@@ -15,8 +19,8 @@ def initialize(
         @block = block
       end
 
-      def sleep(*args)
-        Kernel.sleep(*args)
+      def sleep(seconds)
+        Kernel.sleep(seconds)
       end
 
       def call(*args)
@@ -27,29 +31,13 @@ def timestamp
         Time.now.to_f
       end
 
-      attr_reader :event_queue
-
       def callable?
         @block
       end
 
       def optimize_changes(changes)
         @queue_optimizer.smoosh_changes(changes)
       end
-
-      attr_reader :min_delay_between_events
-
-      def stopped?
-        listener.state == :stopped
-      end
-
-      def paused?
-        listener.state == :paused
-      end
-
-      private
-
-      attr_reader :listener
     end
   end
 end

lib/listen/event/loop.rb

@@ -6,97 +6,86 @@
 module Listen
   module Event
     class Loop
+      include Listen::FSM
+
       class Error < RuntimeError
-        class NotStarted < Error
-        end
+        class ThreadFailedToStart < Error; end
+        class AlreadyStarted < Error; end
       end
 
+      start_state :pre_start
+      state :pre_start
+      state :starting
+      state :started
+      state :stopped
+
       def initialize(config)
         @config = config
         @wait_thread = nil
-        @state = :paused
         @reasons = ::Queue.new
+        super()
       end
 
       def wakeup_on_event
-        return if stopped?
-        return unless processing?
-        return unless wait_thread.alive?
-        _wakeup(:event)
+        if started? && @wait_thread&.alive?
+          _wakeup(:event)
+        end
       end
 
-      def paused?
-        wait_thread && state == :paused
+      def started?
+        state == :started
       end
 
-      def processing?
-        return false if stopped?
-        return false if paused?
-        state == :processing
-      end
+      MAX_STARTUP_SECONDS = 5.0
+
+      def start
+        transition! :starting do
+          state == :pre_start or raise Error::AlreadyStarted
+        end
 
-      def setup
-        # TODO: use a Fiber instead?
-        q = ::Queue.new
         @wait_thread = Internals::ThreadPool.add do
-          _wait_for_changes(q, config)
+          _process_changes
         end
 
-        Listen::Logger.debug('Waiting for processing to start...')
-        Timeout.timeout(5) { q.pop }
-      end
+        Listen::Logger.debug("Waiting for processing to start...")
+
+        wait_for_state(:started, MAX_STARTUP_SECONDS) or raise Error::ThreadFailedToStart, "thread didn't start in #{MAX_STARTUP_SECONDS} seconds (in state: #{state.inspect})"
 
-      def resume
-        fail Error::NotStarted if stopped?
-        return unless wait_thread
-        _wakeup(:resume)
+        Listen::Logger.debug('Processing started.')
       end
 
       def pause
         # TODO: works?
         # fail NotImplementedError
       end
 
-      def teardown
-        return unless wait_thread
-        if wait_thread.alive?
-          _wakeup(:teardown)
-          wait_thread.join
+      def stop
+        return if stopped?
+        transition! :stopped
+
+        if @wait_thread.alive?
+          @wait_thread.join
         end
         @wait_thread = nil
       end
 
       def stopped?
-        !wait_thread
+        state == :stopped
       end
 
       private
 
-      attr_reader :config
-      attr_reader :wait_thread
+      def _process_changes
+        processor = Event::Processor.new(@config, @reasons)
 
-      attr_accessor :state
+        transition! :started
 
-      def _wait_for_changes(ready_queue, config)
-        processor = Event::Processor.new(config, @reasons)
+        processor.loop_for(@config.min_delay_between_events)
 
-        _wait_until_resumed(ready_queue)
-        processor.loop_for(config.min_delay_between_events)
       rescue StandardError => ex
         _nice_error(ex)
       end
 
-      def _sleep(*args)
-        Kernel.sleep(*args)
-      end
-
-      def _wait_until_resumed(ready_queue)
-        self.state = :paused
-        ready_queue << :ready
-        sleep
-        self.state = :processing
-      end
-
       def _nice_error(ex)
         indent = "\n -- "
         msg = format(
@@ -110,7 +99,7 @@ def _nice_error(ex)
 
       def _wakeup(reason)
         @reasons << reason
-        wait_thread.wakeup
+        @wait_thread.wakeup
       end
     end
   end

lib/listen/event/processor.rb

@@ -3,6 +3,7 @@ module Event
     class Processor
       def initialize(config, reasons)
         @config = config
+        @listener = config.listener
         @reasons = reasons
         _reset_no_unprocessed_events
       end
@@ -13,10 +14,11 @@ def loop_for(latency)
         @latency = latency
 
         loop do
-          _wait_until_events
+          event = _wait_until_events
+          _check_stopped
           _wait_until_events_calm_down
           _wait_until_no_longer_paused
-          _process_changes
+          _process_changes(event)
         end
       rescue Stopped
         Listen::Logger.debug('Processing stopped')
@@ -38,33 +40,31 @@ def _wait_until_events_calm_down
 
           # give events a bit of time to accumulate so they can be
           # compressed/optimized
-          _sleep(:waiting_until_latency, diff)
+          _sleep(diff)
         end
       end
 
       def _wait_until_no_longer_paused
-        # TODO: may not be a good idea?
-        _sleep(:waiting_for_unpause) while config.paused?
+        @listener.wait_for_state(*(Listener.states.keys - [:paused]))
       end
 
       def _check_stopped
-        return unless config.stopped?
+        return unless @listener.stopped?
 
         _flush_wakeup_reasons
         raise Stopped
       end
 
-      def _sleep(_local_reason, *args)
+      def _sleep(seconds)
         _check_stopped
-        sleep_duration = config.sleep(*args)
+        config.sleep(seconds)
         _check_stopped
 
         _flush_wakeup_reasons do |reason|
-          next unless reason == :event
-          _remember_time_of_first_unprocessed_event unless config.paused?
+          if reason == :event && !@listener.paused?
+            _remember_time_of_first_unprocessed_event
+          end
         end
-
-        sleep_duration
       end
 
       def _remember_time_of_first_unprocessed_event
@@ -79,16 +79,17 @@ def _deadline
         @first_unprocessed_event_time + @latency
       end
 
+      # blocks until event is popped
+      # returns the event or `nil` when the event_queue is closed
       def _wait_until_events
-        # TODO: long sleep may not be a good idea?
-        _sleep(:waiting_for_events) while config.event_queue.empty?
-        @first_unprocessed_event_time ||= _timestamp
+        config.event_queue.pop.tap do |_event|
+          @first_unprocessed_event_time ||= _timestamp
+        end
       end
 
       def _flush_wakeup_reasons
-        reasons = @reasons
-        until reasons.empty?
-          reason = reasons.pop
+        until @reasons.empty?
+          reason = @reasons.pop
           yield reason if block_given?
         end
       end
@@ -98,14 +99,13 @@ def _timestamp
       end
 
       # for easier testing without sleep loop
-      def _process_changes
+      def _process_changes(event)
         _reset_no_unprocessed_events
 
-        changes = []
+        changes = [event]
         changes << config.event_queue.pop until config.event_queue.empty?
 
-        callable = config.callable?
-        return unless callable
+        return unless config.callable?
 
         hash = config.optimize_changes(changes)
         result = [hash[:modified], hash[:added], hash[:removed]]

lib/listen/event/queue.rb

@@ -17,9 +17,8 @@ def relative?
         end
       end
 
-      def initialize(config, &block)
+      def initialize(config)
         @event_queue = ::Queue.new
-        @block = block
         @config = config
       end
 
@@ -31,17 +30,15 @@ def <<(args)
 
         dir = _safe_relative_from_cwd(dir)
         event_queue.public_send(:<<, [type, change, dir, path, options])
-
-        block.call(args) if block
       end
 
       delegate empty?: :event_queue
       delegate pop: :event_queue
+      delegate close: :event_queue
 
       private
 
       attr_reader :event_queue
-      attr_reader :block
       attr_reader :config
 
       def _safe_relative_from_cwd(dir)