Class: Safer::Protocol::Signature

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

Overview

Hash of method_name => method.arity, describing a set of methods that we expect to see implemented in another class. Protocol will contain two of these objects - one describing class methods, and one describing instance methods.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(table) ⇒ Signature

Create a Protocol::Signature object.



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# File 'lib/safer/protocol.rb', line 180

def initialize(table)
  self.safer_protocol_signature__table = table
end

Class Method Details

.create(object, get_methods, get_method, &filter) ⇒ Object

Derive a Signature from an object.



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# File 'lib/safer/protocol.rb', line 222

def self.create(object, get_methods, get_method, &filter)
  method_names = object.send(get_methods)
  method_table = Safer::Protocol._array_to_table(method_names) do
    |h, method_name|
    if filter.call(method_name)
      m = object.send(get_method, method_name)
      m.arity
    end
  end
  self.new(method_table)
end

Instance Method Details

#==(other_object) ⇒ Object

Compare two Protocol::Signature objects for content equality.



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# File 'lib/safer/protocol.rb', line 185

def ==(other_object)
  self.class == other_object.class &&
    self.safer_protocol_signature__table == other_object.safer_protocol_signature__table
end

#find_violations(object, get_method) ⇒ Object

Given an object, and the name of the method for getting a named method from that object, check that the object implements this function signature.



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# File 'lib/safer/protocol.rb', line 194

def find_violations(object, get_method)
  report = ''
  have_error = false
  error_table = Hash.new
  self.safer_protocol_signature__table.each_pair do |name, arity|
    begin
      m = object.send(get_method, name)
      if m.arity != arity
        report += "#{get_method}(#{name}) arity #{m.arity} != desired #{arity}.\n"
        error_table[name] = m.arity
        have_error = true
      end
    rescue NameError => e
      report += "#{get_method}(#{name}) unimplemented.\n"
      error_table[name] = true
      have_error = true
    end
  end

  if have_error
    Safer::Protocol::Violation.new(error_table, report)
  else
    nil
  end
end

#self ⇒ Object

:attr_reader: table Hash object, in which the keys are the names of methods, and the value for a key is the required arity of that method.



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# File 'lib/safer/protocol.rb', line 176

Safer::IVar.export_reader(self, :table)