Module: Parley

Included in:
IO
Defined in:
lib/parley.rb

Overview

TODO: line oriented reading option Greediness control

Instance Method Summary collapse

Instance Method Details

#parley(t_out, *actions) ⇒ Object 



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# File 'lib/parley.rb', line 41

def parley (t_out, *actions)
  # t_out = nil; # wait forever for next data
  # t_out = 0; # timeout immediately if no data available
  # t_out > 0; # timeout after t_out seconds
  # t_out < 0; # deadline is in the past, same as t_out = 0
  STDOUT.print "\n------\nparley t_out=#{t_out}\n" if parley_verbose
  if (t_out == nil)
    deadline = nil
  else
    deadline = Time.now + t_out
  end
  buf = ''
  unused_buf = '' if not unused_buf

  loop_count = 0

  # STDOUT.puts "class=#{self.class}"

  # Compatible hack. There are changes coming w.r.t. respond_to? for
  # protected methods. Just do a simple poll, and see if it works.
  begin
    result = IO.select([self], [], [], 0)
    has_select = true;
  rescue Exception
    has_select = false;
    # STDOUT.puts "Exception: #{Exception}"
  end
  # STDOUT.puts "has_select=#{has_select}"

  begin
    loop_count = loop_count + 1
    # If it is possible to wait for data, then wait for data
    t = (deadline ? (deadline - Time.now) : nil)
    t = (t.nil? || t >= 0) ? t : 0
    if unused_buf.length == 0 && has_select && !IO.select([self], nil, nil, t)
      # Timeout condition returns nil
      STDOUT.print "TIMEOUT=\"#{buf}\"\n" if parley_verbose
      timeout_handled = nil
      result = nil
      result = actions.each do|act|
        case act[0]
        when :timeout
          timeout_handled = true
          if act[1].respond_to?(:call)
            /.*/.match(buf) # get the buffer contents into a Regexp.last_match
            result = act[1].call(Regexp.last_match)
          else
            result = act[1]
          end
          break result
        end
      end
      if (!timeout_handled)
        # XXX need to prepend buf to @unusedbuf
        unused_buf = buf  # save data for next time
        raise "timeout" # XXX use TimeoutException
      end
      STDOUT.print "TIMEOUT RESULT=\"#{result}\"\n" if parley_verbose
      return result unless result == :reset_timeout
    else

      # We've waited, if that was possible, check for data present
      if unused_buf.length == 0 && eof?
        STDOUT.print "EOF Buffer=\"#{buf}\"\n" if parley_verbose
        result = nil
        eof_handled = false
        actions.each do |act|
          case act[0]
          when :eof
            eof_handled = true
            if act[1].respond_to?(:call)
              /.*/m.match(buf)  # Game end, match everything remaining
              result = act[1].call(Regexp.last_match)
            else
              result = act[1]
            end
            break result
          end
        end
        if not eof_handled
          # XXX need to prepend buf to @unusedbuf
          unused_buf = buf  # save data for next time
          raise :eof if not eof_handled
        end
        return result
      end

      # Greedy read:
      # buf << self.read_nonblock(maxlen)
      if (unused_buf.length > 0)
        c = unused_buf.slice!(0..parley_maxread)
      elsif (parley_maxread > 1 && self.respond_to?(:read_nonblock))
        c = read_nonblock(parley_maxread)
      else
        c = getc.chr
      end
      buf << c

      # Look for matches to the current buffer content
      result = :continue
      matched = false
      result = actions.each_with_index do |act,i|
        # STDOUT.print "buf=\"#{buf}\"\tact=#{act[0]}\n" if parley_verbose
        m = case act[0]
            when Regexp
              act[0].match(buf) and Regexp.last_match
            when String
              act[0] = Regexp.new(act[0]) # caching the regexp conversion, XXX any problem?
              act[0].match(buf) and Regexp.last_match
            else
              nil
            end
        if m
          STDOUT.print "match[#{i}]=\"#{buf}\"\n" if parley_verbose
          matched = true
          if act[1]
            if act[1].respond_to?(:call)
              result = act[1].call(m)
            else
              result = act[1] # no block, just a result
            end
          else
            result = m # no action supplied, return last match
          end
          buf = ''  # consume the buffer (XXX only the part that matched?)
          # XXX if the regex had post context, don't consume that.
          STDOUT.puts "result=#{result}" if parley_verbose
          break result
        end
        result
      end
    end

    if matched == true
      result = case result
               when :continue
                 :continue
               when nil  # explicit end
                 break nil
               when :reset_timeout
                 deadline = Time.now + t_out # XXX vs deadline in lambda closure?
                 STDOUT.puts "deadline=#{deadline.to_s}, continue" if parley_verbose
                 :continue
               else  # return with result
                 break result
               end
    else
      result = :continue
    end
  end while result == :continue
end

#parley_maxread ⇒ Object 



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# File 'lib/parley.rb', line 36

def parley_maxread
  @parley_maxread = 1 unless defined? @parley_maxread
  @parley_maxread
end

#parley_maxread=(v) ⇒ Object 



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# File 'lib/parley.rb', line 32

def parley_maxread= (v)
  @parley_maxread = (v > 0) ? v : 1
end

#parley_verbose ⇒ Object 



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# File 'lib/parley.rb', line 27

def parley_verbose
  @parley_verbose = false unless defined? @parley_verbose
  @parley_verbose
end

#parley_verbose=(v) ⇒ Object 



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# File 'lib/parley.rb', line 23

def parley_verbose= (v)
  @parley_verbose = (v ? true : false)
end

#unused_buf ⇒ Object 



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# File 'lib/parley.rb', line 18

def unused_buf
  @unused_buf = nil unless defined? @unused_buf
  @unused_buf
end

#unused_buf=(v) ⇒ Object

Initialize() is usually not called or doesn’t call super(), so do implicit instance variable initialization



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# File 'lib/parley.rb', line 14

def unused_buf= (v)
  @unused_buf = v
end