Source Code for Module smach.util

  1   
  2  import smach 
  3  import threading 
  4   
  5   
  6  __all__ = ['is_shutdown','set_shutdown_cb',\ 
  7          'cb_interface','has_smach_interface','CBInterface'] 
  8   
  9 -def is_shutdown(): 
 10      return False 
 11   
 12 -def set_shutdown_check(cb): 
 13      smach.is_shutdown = cb 
 14   
 15 -def has_smach_interface(obj): 
 16      """Returns True if the object has SMACH interface accessors.""" 
 17      return hasattr(obj,'get_registered_input_keys')\ 
 18              and hasattr(obj,'get_registered_output_keys')\ 
 19              and hasattr(obj,'get_registered_outcomes') 
 20   
 21  # Callback decorator for describing userdata 
 22 -class cb_interface(object): 
 23 -    def __init__(self, outcomes=[], input_keys=[], output_keys=[]): 
 24          self._outcomes = outcomes 
 25          self._input_keys = input_keys 
 26          self._output_keys = output_keys 
 27       
 28 -    def __call__(self, cb): 
 29          return CBInterface(cb, self._outcomes, self._input_keys, self._output_keys) 
 30 -class CBInterface(object): 
 31      """Decorator to describe the extension of a state's SMACH userdata and outcome interface. 
 32       
 33      Some SMACH states can be extended with the use of user callbacks. Since 
 34      the SMACH interface and SMACH userdata are strictly controlled, the ways in 
 35      which these callbacks interact with SMACH must be delcared. This decorator 
 36      allows this information to be attached to a given callback function. 
 37   
 38      If a callback adds a potential outcome to a state, suppose 'critical_failure', 
 39      then one could write this when defining the callback: 
 40   
 41      >>> import smach 
 42      >>> @smach.cb_interface(outcomes=['critical_failure']) 
 43      >>> def my_cb(x,y,z): 
 44      >>>     # User code 
 45      >>>     return 'critical_failure' 
 46   
 47      Suppose a state retrieves data that it passes into a callback. If the user 
 48      wants to take that data and put some of all of it into userdata, this 
 49      interface must be declared. In this case, the user could write: 
 50   
 51      >>> import smach 
 52      >>> @smach.cb_interface(output_keys=['processed_res']) 
 53      >>> def my_cb(ud, data): 
 54      >>>     ud.processed_res = data 
 55   
 56      """ 
 57 -    def __init__(self, cb, outcomes=[], input_keys=[], output_keys=[], io_keys=[]): 
 58          """Describe callback SMACH interface. 
 59   
 60          @type outcomes: array of strings 
 61          @param outcomes: Custom outcomes for this state. 
 62   
 63          @type input_keys: array of strings 
 64          @param input_keys: The userdata keys from which this state might read 
 65          at runtime.  
 66   
 67          @type output_keys: array of strings 
 68          @param output_keys: The userdata keys to which this state might write 
 69          at runtime. 
 70   
 71          @type io_keys: array of strings 
 72          @param io_keys: The userdata keys to which this state might write or 
 73          from which it might read at runtime. 
 74          """ 
 75   
 76          self._input_keys = set(input_keys) 
 77          self._input_keys.union(io_keys) 
 78   
 79          self._output_keys = set(output_keys) 
 80          self._output_keys.union(io_keys) 
 81   
 82          self._outcomes = outcomes 
 83   
 84          self._cb = cb 
 85   
 86 -    def __call__(self, *args, **kwargs): 
 87          return self._cb(*args, **kwargs) 
 88   
 89      ### SMACH Interface API 
 90 -    def get_registered_input_keys(self): 
 91          """Get a tuple of registered input keys.""" 
 92          return tuple(self._input_keys) 
 93 -    def get_registered_output_keys(self): 
 94          """Get a tuple of registered output keys.""" 
 95          return tuple(self._output_keys) 
 96 -    def get_registered_outcomes(self): 
 97          """Get a list of registered outcomes. 
 98          @rtype: tuple of string 
 99          @return: Tuple of registered outcome strings. 
100          """ 
101          return tuple(self._outcomes) 
102