Class: Celluloid::Mailbox

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

Overview

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

Direct Known Subclasses

Evented

Defined Under Namespace

Classes: Evented

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initializeMailbox

Returns a new instance of Mailbox.


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# File 'lib/celluloid/mailbox.rb', line 14

def initialize
  @address   = Celluloid.uuid
  @messages  = []
  @mutex     = Mutex.new
  @dead      = false
  @condition = ConditionVariable.new
  @max_size  = nil
end

Instance Attribute Details

#addressObject (readonly)

A unique address at which this mailbox can be found


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# File 'lib/celluloid/mailbox.rb', line 11

def address
  @address
end

#max_sizeObject

Returns the value of attribute max_size


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# File 'lib/celluloid/mailbox.rb', line 12

def max_size
  @max_size
end

Instance Method Details

#<<(message) ⇒ Object

Add a message to the Mailbox


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# File 'lib/celluloid/mailbox.rb', line 24

def <<(message)
  @mutex.lock
  begin
    if mailbox_full || @dead
      dead_letter(message)
      return
    end
    if message.is_a?(SystemEvent)
      # SystemEvents are high priority messages so they get added to the
      # head of our message queue instead of the end
      @messages.unshift message
    else
      @messages << message
    end

    @condition.signal
    nil
  ensure
    begin
      @mutex.unlock
    rescue
      nil
    end
  end
end

#alive?Boolean

Is the mailbox alive?

Returns:

  • (Boolean)

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# File 'lib/celluloid/mailbox.rb', line 116

def alive?
  !@dead
end

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

Receive a message from the Mailbox. May return nil and may return before the specified timeout.


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# File 'lib/celluloid/mailbox.rb', line 52

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

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

    message = nil
    Timers::Wait.for(timeout) do |remaining|
      message = next_message(&block)

      break if message

      @condition.wait(@mutex, remaining)
    end
  ensure
    begin
      @mutex.unlock
    rescue
      nil
    end
  end

  message
end

#each(&block) ⇒ Object

Iterate through the mailbox


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# File 'lib/celluloid/mailbox.rb', line 126

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

#inspectObject

Inspect the contents of the Mailbox


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# File 'lib/celluloid/mailbox.rb', line 131

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

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

Receive a letter from the mailbox. Guaranteed to return a message. If timeout is exceeded, raise a TaskTimeout.

Raises:


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# File 'lib/celluloid/mailbox.rb', line 80

def receive(timeout = nil, &block)
  message = nil
  Timers::Wait.for(timeout) do |_remaining|
    message = check(timeout, &block)
    break if message
  end
  return message if message
  raise TaskTimeout, "receive timeout exceeded"
end

#shutdownObject

Shut down this mailbox and clean up its contents

Raises:


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# File 'lib/celluloid/mailbox.rb', line 91

def shutdown
  raise MailboxDead, "mailbox already shutdown" if @dead

  @mutex.lock
  begin
    yield if block_given?
    messages = @messages
    @messages = []
    @dead = true
  ensure
    begin
      @mutex.unlock
    rescue
      nil
    end
  end

  messages.each do |msg|
    dead_letter msg
    msg.cleanup if msg.respond_to? :cleanup
  end
  true
end

#sizeObject

Number of messages in the Mailbox


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# File 'lib/celluloid/mailbox.rb', line 136

def size
  @mutex.synchronize { @messages.size }
end

#to_aObject

Cast to an array


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# File 'lib/celluloid/mailbox.rb', line 121

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