Module: Rumai::IXP::Struct

Included in:
Fcall, Qid, Stat
Defined in:
lib/rumai/ixp/message.rb

Overview

A serializable 9P2000 data structure.

Defined Under Namespace

Classes: ClassField, Field, Integer8Field, StringField

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#fields ⇒ Object (readonly)

Returns the value of attribute fields.



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# File 'lib/rumai/ixp/message.rb', line 46

def fields
  @fields
end

Class Method Details

.included(target) ⇒ Object

Provides a convenient DSL (for defining fields) to all objects which include this module.



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# File 'lib/rumai/ixp/message.rb', line 80

def self.included target
  class << target
    ##
    # Returns a list of fields which compose this Struct.
    #
    def fields
      @fields ||=
        if superclass.respond_to? :fields
          superclass.fields.dup
        else
          []
        end
    end

    ##
    # Defines a new field in this Struct.
    #
    # @param args
    #   arguments for {Field.new}
    #
    def field name, format = nil, *args
      klass = Field.factory(format)
      field = klass.new(name.to_sym, format, *args)

      # register field as being part of this structure
      fields << field

      # provide accessor methods to field values
      self.class_eval <<-EOS, __FILE__, __LINE__
        def #{field.name}
          @values[#{field.name.inspect}]
        end

        def #{field.name}= value
          @values[#{field.name.inspect}] = value
        end
      EOS

      field
    end

    ##
    # Creates a new instance of this class from the
    # given 9P2000 byte stream and returns the instance.
    #
    def from_9p stream, msg_class = self
      msg = msg_class.new
      msg.load_9p(stream)
      msg
    end
  end
end

Instance Method Details

#initialize(field_values = {}) ⇒ Object

Allows field values to be initialized via the constructor.

Parameters:

  • field_values (defaults to: {}) —

    a mapping from field name to field value



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# File 'lib/rumai/ixp/message.rb', line 54

def initialize field_values = {}
  @fields = self.class.fields
  @values = field_values
end

#load_9p(stream) ⇒ Object

Populates this object with information from the given 9P2000 byte stream.



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# File 'lib/rumai/ixp/message.rb', line 70

def load_9p stream
  @fields.each do |f|
    f.load_9p stream, @values
  end
end

#to_9p ⇒ Object

Transforms this object into a string of 9P2000 bytes.



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# File 'lib/rumai/ixp/message.rb', line 62

def to_9p
  @fields.map {|f| f.to_9p(@values) }.join
end