Class: PgVersions::ConnectionInner

Inherits:
Object
  • Object
show all
Defined in:
lib/pg_versions/pg_versions.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ ConnectionInner

Returns a new instance of ConnectionInner.



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# File 'lib/pg_versions/pg_versions.rb', line 200

def initialize()
	@mutex = Mutex.new
	@command_notify_w = nil
	@subscriptions = {}
	@bumps = []
	@reads = []
	@closers = []
	@state = :idle # idle, processing, closing, closed
end

Instance Method Details

#bump(channels) ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 289

def bump(channels)
	result = Queue.new
	@mutex.synchronize {
		raise ConnectionClosed  if @state == :closing || @state == :closed
		@bumps << [result, channels]
	}
	wake_processor
	result.pop
end

#bump_nonblock(channels) ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 300

def bump_nonblock(channels)
	@mutex.synchronize {
		raise ConnectionClosed  if @state == :closing || @state == :closed
		@bumps << [nil, channels]
	}
	wake_processor
	nil
end

#close ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 354

def close
	result = Queue.new
	@mutex.synchronize {
		case @state
		when :idle
			@state = :closed
			return
		when :processing 
			@state = :closing
			@closers << result
			wake_processor
		when :closing
			@closers << result
		when :closed
			return
		end
	}
	result.pop
end

#get_channels ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 257

def get_channels
	@mutex.synchronize {
		return @subscriptions.keys
	}
end

#is_closing ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 347

def is_closing
	@mutex.synchronize {
		return @state == :closing
	}
end

#notify(channel, version) ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 264

def notify(channel, version)
	@mutex.synchronize {
		(@subscriptions[channel] or []).each { |subscriber|
			subscriber.notify({ channel => version })
		}
	}
end

#process ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 211

def process
	Thread.handle_interrupt(Object => :never) do
		command_notify_r = nil
		@mutex.synchronize {
			case @state
			when :idle
				@state = :processing
			when :processing
				raise "Attempt to run processing on a connection that is already being processed"
			when :closing, :closed
				return
			end
		}
		begin
			command_notify_r, @command_notify_w = IO.pipe					
			Thread.handle_interrupt(Object => :immediate) {
				yield command_notify_r
			}
		ensure
			@mutex.synchronize {
				command_notify_r&.close
				@command_notify_w&.close
				@command_notify_w = nil
				case @state
				when :idle, :closed
					raise "'processor exit in #{@state} state. Please inform the developer of this gem."
				when :processing
					@state = :idle
				when :closing
					@state = :closed
					@closers.each { |closer|
						closer.push true
					}
				end
			}
		end
	end
end

#read(channels) ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 310

def read(channels)
	result = Queue.new
	@mutex.synchronize {
		raise ConnectionClosed  if @state == :closing || @state == :closed
		@reads << [result, channels]
	}
	wake_processor
	result.pop
end

#subscribe(subscriber, channels) ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 321

def subscribe(subscriber, channels)
	@mutex.synchronize {
		raise ConnectionClosed  if @state == :closing || @state == :closed
		channels.each { |channel|
			@subscriptions[channel] = []  if @subscriptions[channel].nil?
			@subscriptions[channel].push(subscriber)
		}
	}
	subscriber.notify(read(channels))  # this runs wake_processor, so not doing it explicitly
	true
end

#taking_bumps ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 273

def taking_bumps
	@mutex.synchronize {
		yield @bumps
		@bumps = []
	}
end

#taking_reads ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 281

def taking_reads
	@mutex.synchronize {
		yield @reads
		@reads = []
	}
end

#unsubscribe(subscriber, channels) ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 334

def unsubscribe(subscriber, channels)
	@mutex.synchronize {
		raise ConnectionClosed  if @state == :closing || @state == :closed
		channels.each { |channel|
			@subscriptions[channel].delete(subscriber)
			@subscriptions.delete(channel)  if @subscriptions[channel].size == 0
		}
	}
	wake_processor
	true
end

#wake_processor ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 251

def wake_processor
	@command_notify_w&.write('!')
	@command_notify_w&.flush
end