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 202

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 291

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 302

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 356

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 259

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

#is_closing ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 349

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 266

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 213

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 312

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 323

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 275

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

#taking_reads ⇒ Object 



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# File 'lib/pg_versions/pg_versions.rb', line 283

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 336

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 253

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