Rack::Lock

# File lib/rack/lock.rb, line 10
def initialize(app, mutex = Mutex.new)
  @app, @mutex = app, mutex
end

# File lib/rack/lock.rb, line 14
def call(env)
  old, env[FLAG] = env[FLAG], false
  @mutex.lock
  response = @app.call(env)
  body = BodyProxy.new(response[2]) { @mutex.unlock }
  response[2] = body
  response
ensure
  @mutex.unlock unless body
  env[FLAG] = old
end