Actors communicate with asynchronous messages. Messages are buffered in Mailboxes until Actors can act upon them.
A unique address at which this mailbox can be found
# File lib/celluloid/mailbox.rb, line 16 def initialize @address = Celluloid.uuid @messages = [] @mutex = Mutex.new @dead = false @condition = ConditionVariable.new @max_size = nil end
Add a message to the Mailbox
# File lib/celluloid/mailbox.rb, line 26 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 @mutex.unlock rescue nil end end
Is the mailbox alive?
# File lib/celluloid/mailbox.rb, line 106 def alive? !@dead end
Receive a message from the Mailbox. May return nil and may return before the specified timeout.
# File lib/celluloid/mailbox.rb, line 50 def check(timeout = nil, &block) message = nil @mutex.lock begin fail 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 @mutex.unlock rescue nil end message end
Iterate through the mailbox
# File lib/celluloid/mailbox.rb, line 116 def each(&block) to_a.each(&block) end
Inspect the contents of the Mailbox
# File lib/celluloid/mailbox.rb, line 121 def inspect "#<#{self.class}:#{object_id.to_s(16)} @messages=[#{map(&:inspect).join(', ')}]>" end
Receive a letter from the mailbox. Guaranteed to return a message. If timeout is exceeded, raise a TaskTimeout.
# File lib/celluloid/mailbox.rb, line 74 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 fail TaskTimeout.new("receive timeout exceeded") end
Shut down this mailbox and clean up its contents
# File lib/celluloid/mailbox.rb, line 85 def shutdown fail MailboxDead, "mailbox already shutdown" if @dead @mutex.lock begin yield if block_given? messages = @messages @messages = [] @dead = true ensure @mutex.unlock rescue nil end messages.each do |msg| dead_letter msg msg.cleanup if msg.respond_to? :cleanup end true end
Number of messages in the Mailbox
# File lib/celluloid/mailbox.rb, line 126 def size @mutex.synchronize { @messages.size } end
Cast to an array
# File lib/celluloid/mailbox.rb, line 111 def to_a @mutex.synchronize { @messages.dup } end
# File lib/celluloid/mailbox.rb, line 149 def dead_letter(message) Internals::Logger.debug "Discarded message (mailbox is dead): #{message}" if $CELLULOID_DEBUG end
# File lib/celluloid/mailbox.rb, line 153 def mailbox_full @max_size && @messages.size >= @max_size end
Retrieve the next message in the mailbox
# File lib/celluloid/mailbox.rb, line 133 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 message end