Class: EMDirWatcher::Invokers::SubprocessInvoker

Inherits:
Object
  • Object
show all
Defined in:
lib/em-dir-watcher/invokers/subprocess_invoker.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(subprocess, &input_handler) ⇒ SubprocessInvoker

Returns a new instance of SubprocessInvoker.


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# File 'lib/em-dir-watcher/invokers/subprocess_invoker.rb', line 13

def initialize subprocess, &input_handler
    @subprocess = subprocess
    @input_handler = input_handler
    @active = true
    @ready_to_use = false
    @ready_to_use_handlers = []
    @additional_delay = 0.1
    start_subprocess
end

Instance Attribute Details

#activeObject (readonly)

Returns the value of attribute active


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# File 'lib/em-dir-watcher/invokers/subprocess_invoker.rb', line 9

def active
  @active
end

#additional_delayObject

Returns the value of attribute additional_delay


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# File 'lib/em-dir-watcher/invokers/subprocess_invoker.rb', line 11

def additional_delay
  @additional_delay
end

#input_handlerObject (readonly)

Returns the value of attribute input_handler


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# File 'lib/em-dir-watcher/invokers/subprocess_invoker.rb', line 10

def input_handler
  @input_handler
end

Instance Method Details

#killObject


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# File 'lib/em-dir-watcher/invokers/subprocess_invoker.rb', line 47

def kill
    if @io
        Process.kill 'TERM', @io.pid 
        Process.waitpid @io.pid
        @io = nil
    end
end

#ready_to_use!Object

private methods


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# File 'lib/em-dir-watcher/invokers/subprocess_invoker.rb', line 38

def ready_to_use!
    return if @ready_to_use
    @ready_to_use = true
    EM.add_timer @additional_delay do
        @ready_to_use_handlers.each { |handler| handler.call() }
        @ready_to_use_handlers = nil
    end
end

#start_subprocessObject


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# File 'lib/em-dir-watcher/invokers/subprocess_invoker.rb', line 55

def start_subprocess
    io = open('|-', 'r')
    if io.nil?
        $stdout.sync = true
        ready  = lambda { puts }
        output = lambda { |single_line_string| puts single_line_string.strip }
        @subprocess.call ready, output
        exit
    end
    @io = io
    @io.nonblock = true

    @connection = EM.watch io do |conn|
        class << conn
            attr_accessor :invoker
            
            def notify_readable
                @invoker.ready_to_use!
                @data_received ||= ""
                @data_received << @io.read
                while line = @data_received.slice!(/^[^\n]*[\n]/m)
                    @invoker.input_handler.call line.strip
                end
            rescue EOFError
                detach
                @invoker.kill  # waitpid to cleanup zombie
                if @invoker.active
                    EM.next_tick do
                        @invoker.start_subprocess
                    end
                end
            end

            def unbind
                @invoker.kill
            end
        end
        conn.invoker = self
        conn.notify_readable = true
    end
end

#stopObject


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# File 'lib/em-dir-watcher/invokers/subprocess_invoker.rb', line 31

def stop
    @active = false
    kill
end

#when_ready_to_use(&ready_to_use_handler) ⇒ Object


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# File 'lib/em-dir-watcher/invokers/subprocess_invoker.rb', line 23

def when_ready_to_use &ready_to_use_handler
  if @ready_to_use_handlers.nil?
      ready_to_use_handler.call()
  else
      @ready_to_use_handlers << ready_to_use_handler
  end
end