Method: Handshake::Proxy#method_missing

Defined in:
lib/handshake.rb

#method_missing ⇒ Object

Override the send method, and alias method_missing to same. This method intercepts all method calls and runs them through the contract filter. The order of contract checks is as follows:

  • Before: invariants, method signature, precondition

  • Method is called

  • After: method signature, postcondition, invariants



550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
 
# File 'lib/handshake.rb', line 550

def send(meth_name, *args, &block)
  meth_string = "#{@proxied.class}##{meth_name}"
  contract = @proxied.class.contract_for(meth_name)
  return_val = nil
  # Use throw/catch rather than raise/rescue in order to pull exceptions
  # once and only once from within the stack trace.
  Handshake.catch_contract("Contract violated in call to #{meth_string}") do
    @proxied.check_invariants!
    contract.check_accepts!(*args, &block)
    contract.check_pre! @proxied, *args
  end
    
  # make actual call, wrapping the given block in a new block so that
  # contract checks work if receiver uses yield.
  return_val = nil
  if contract.expects_block?
    cp = CheckedProc.new(contract.block_contract, &block)
    return_val = @proxied.send(meth_name, *args) { |*argz| cp.call(*argz) }
  else
    return_val = @proxied.send(meth_name, *args, &block)
  end
     
  Handshake.catch_contract("Contract violated by #{meth_string}") do
    contract.check_returns! return_val
    contract.check_post! @proxied, *(args << return_val)
    @proxied.check_invariants!
  end

  return return_val
end