Class: Celluloid::Mailbox

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/celluloid/mailbox.rb

Overview

Actors communicate with asynchronous messages. Messages are buffered in Mailboxes until Actors can act upon them.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Mailbox

Returns a new instance of Mailbox.



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# File 'lib/celluloid/mailbox.rb', line 15

def initialize
  @messages = []
  @mutex = Mutex.new
  @dead = false
  @condition = ConditionVariable.new
end

Instance Method Details

#<<(message) ⇒ Object

Add a message to the Mailbox



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# File 'lib/celluloid/mailbox.rb', line 23

def <<(message)
  @mutex.lock
  begin
    raise MailboxError, "dead recipient" if @dead

    @messages << message
    @condition.signal
    nil
  ensure
    @mutex.unlock rescue nil
  end
end

#alive? ⇒ Boolean

Is the mailbox alive?

Returns:

  • (Boolean) 


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# File 'lib/celluloid/mailbox.rb', line 115

def alive?
  !@dead
end

#each(&block) ⇒ Object

Iterate through the mailbox



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# File 'lib/celluloid/mailbox.rb', line 125

def each(&block)
  to_a.each(&block)
end

#inspect ⇒ Object

Inspect the contents of the Mailbox



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# File 'lib/celluloid/mailbox.rb', line 130

def inspect
  "#<#{self.class}:#{object_id.to_s(16)} @messages=[#{map { |m| m.inspect }.join(', ')}]>"
end

#next_message ⇒ Object

Retrieve the next message in the mailbox



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# File 'lib/celluloid/mailbox.rb', line 82

def next_message
  message = nil

  if block_given?
    index = @messages.index do |msg|
      yield(msg) || msg.is_a?(SystemEvent)
    end

    message = @messages.slice!(index, 1).first if index
  else
    message = @messages.shift
  end

  raise message if message.is_a? SystemEvent
  message
end

#receive(timeout = nil, &block) ⇒ Object

Receive a message from the Mailbox



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# File 'lib/celluloid/mailbox.rb', line 51

def receive(timeout = nil, &block)
  message = nil

  @mutex.lock
  begin
    raise MailboxError, "attempted to receive from a dead mailbox" if @dead

    begin
      message = next_message(&block)

      unless message
        if timeout
          now = Time.now
          wait_until ||= now + timeout
          wait_interval = wait_until - now
          return if wait_interval <= 0
        else
          wait_interval = nil
        end

        @condition.wait(@mutex, wait_interval)
      end
    end until message

    message
  ensure
    @mutex.unlock rescue nil
  end
end

#shutdown ⇒ Object

Shut down this mailbox and clean up its contents



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# File 'lib/celluloid/mailbox.rb', line 100

def shutdown
  @mutex.lock
  begin
    messages = @messages
    @messages = []
    @dead = true
  ensure
    @mutex.unlock rescue nil
  end

  messages.each { |msg| msg.cleanup if msg.respond_to? :cleanup }
  true
end

#system_event(event) ⇒ Object

Add a high-priority system event to the Mailbox



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# File 'lib/celluloid/mailbox.rb', line 37

def system_event(event)
  @mutex.lock
  begin
    unless @dead # Silently fail if messages are sent to dead actors
      @messages.unshift event
      @condition.signal
    end
    nil
  ensure
    @mutex.unlock rescue nil
  end
end

#to_a ⇒ Object

Cast to an array



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# File 'lib/celluloid/mailbox.rb', line 120

def to_a
  @mutex.synchronize { @messages.dup }
end