Class: Contracts::AnnotatedMethod

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

Instance Method Summary collapse

Constructor Details

#initialize(method, annotations) ⇒ AnnotatedMethod

Returns a new instance of AnnotatedMethod.



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# File 'lib/contracts.rb', line 55

def initialize(method, annotations)
  @method = method

  @before_annotations     = annotations.select { |annotation| annotation.respond_to?(:before_call) }
  @after_annotations      = annotations.select { |annotation| annotation.respond_to?(:after_call) }
  @exception_annotations  = annotations.select { |annotation| annotation.respond_to?(:on_exception) }

  annotations.each do |annotation|
    annotation.method = method
  end
end

Instance Method Details

#invoke(receiver, *args, &blk) ⇒ Object 



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# File 'lib/contracts.rb', line 67

def invoke(receiver, *args, &blk)
  #
  # Some contracts might need a per-invocation scope. If that is the take
  # their before_call method will return their specific scope, and we'll
  # carry that over to the after_call and on_exception calls.
  #
  # Since this is potentially costly we do rather not create a combined
  # scope object unless we really need it; also there is an optimized
  # code path for after_call's in effect. (Not for on_exception though;
  # since they should only occur in exceptional situations they can carry
  # a bit of performance penalty just fine.)
  #
  # TODO: This could be improved by having a each annotation take care of
  # each individual call; a first experiment to do that, however, failed.
  annotation_scopes = nil

  @before_annotations.each do |annotation|
    next unless annotation_scope = annotation.before_call(receiver, *args, &blk)
    annotation_scopes ||= {}
    annotation_scopes[annotation.object_id] = annotation_scope
  end

  # instance methods are UnboundMethod, class methods are Method.
  rv = @method.is_a?(Method) ? @method.call(*args, &blk)
                             : @method.bind(receiver).call(*args, &blk)

  if annotation_scopes
    @after_annotations.each do |annotation|
      annotation.after_call(annotation_scopes[annotation.object_id], rv, receiver, *args, &blk)
    end
  else
    @after_annotations.each do |annotation|
      annotation.after_call(nil, rv, receiver, *args, &blk)
    end
  end

  return rv
rescue StandardError => exc
  @exception_annotations.each do |annotation|
    annotation.on_exception(annotation_scopes && annotation_scopes[annotation.object_id], exc, receiver, *args, &blk)
  end
  raise exc
end