verdaccio/lib/streams.js

var stream = require('stream')
  , util = require('util')

//
// This stream is used to read tarballs from repository
//
function ReadTarball(options) {
	stream.PassThrough.call(this, options)

	// called when data is not needed anymore
	add_abstract_method(this, 'abort')
}

util.inherits(ReadTarball, stream.PassThrough)
module.exports.ReadTarballStream = ReadTarball

//
// This stream is used to upload tarballs to a repository
//
function UploadTarball(options) {
	stream.PassThrough.call(this, options)

	// called when user closes connection before upload finishes
	add_abstract_method(this, 'abort')

	// called when upload finishes successfully
	add_abstract_method(this, 'done')
}

util.inherits(UploadTarball, stream.PassThrough)
module.exports.UploadTarballStream = UploadTarball

//
// This function intercepts abstract calls and replays them allowing
// us to attach those functions after we are ready to do so
//
function add_abstract_method(self, name) {
	self._called_methods = self._called_methods || {}
	self.__defineGetter__(name, function() {
		return function() {
			self._called_methods[name] = true
		}
	})
	self.__defineSetter__(name, function(fn) {
		delete self[name]
		self[name] = fn
		if (self._called_methods && self._called_methods[name]) {
			delete self._called_methods[name]
			self[name]()
		}
	})
}

function __test() {
	var test = new ReadTarball()
	test.abort()
	setTimeout(function() {
		test.abort = function() {
			console.log('ok')
		}
		test.abort = function() {
			throw 'fail'
		}
	}, 100)
}