Source Code for Module Ganga.Utility.util

  1  ################################################################################ 
  2  # Ganga Project. http://cern.ch/ganga 
  3  # 
  4  # $Id: util.py,v 1.1 2008-07-17 16:41:01 moscicki Exp $ 
  5  ################################################################################ 
  6   
  7  """ 
  8   This file contains general-purpose utilities, mainly Python Cookbook recipes. 
  9  """ 
 10   
 11  # based on Python Cookbook recipe 5.11 -- OK for new- and old-style classes 
 12 -def empty_obj(klass): 
 13      class Empty(klass): 
 14          def __init__(self) : pass 
 15      newcopy = Empty() 
 16      newcopy.__class__ = klass 
 17      return newcopy 
 18   
 19  # create a class based on klass but which may create empty objects 
 20  # based on Python Cookbook recipe 5.11 -- OK for new- and old-style classes 
 21 -def empty_class(klass): 
 22      class _Empty(klass): 
 23          def __init__(self) : pass 
 24      return _Empty 
 25   
 26  # remove the duplicates from a list. From the Python cook book recipe 17.3 
 27   
 28 -def unique(s): 
 29      """Return a list of elements in s in arbitrary order, but without 
 30      duplicates. """ 
 31   
 32      # get the special case of an empty list 
 33      n=len(s) 
 34      if n == 0: 
 35          return [] 
 36   
 37      # try to use a dict 
 38      u={} 
 39      try: 
 40          for x in s: 
 41              u[x]=1 
 42      except TypeError: 
 43              del u # move on th the next method 
 44      else: 
 45          return u.keys() 
 46   
 47          # Sort to bring duplicate elements together and weed out the  
 48          # duplcates in on sinle pass 
 49      try: 
 50              t=list(s) 
 51              t.sort() 
 52      except TypeError: 
 53              del t # move on to the next method 
 54      else: 
 55           assert n > 0 
 56           last = t[0] 
 57           lasti = i = 1 
 58           while i < n: 
 59              if t[i] != last: 
 60                  t[lasti] = last = t[i] 
 61                  lasti+= 1 
 62              i += 1 
 63           return t[:lasti] 
 64   
 65       # Brute foce 
 66      u=[] 
 67      for x in s: 
 68          if x not in u: 
 69              u.append(x) 
 70      return u 
 71   
 72  # based on Python Cookbook recipe 1.12 -- OK for python2.2 and greater 
 73 -def canLoopOver(maybeIterable): 
 74      try: 
 75          iter(maybeIterable) 
 76      except: return 0 
 77      else: return 1 
 78   
 79 -def isStringLike(obj): 
 80      try: obj+'' 
 81      except TypeError: return 0 
 82      else: return 1 
 83   
 84   
 85 -def containsGangaObjects(obj): 
 86      """Recursive call to find GangaObjects""" 
 87      from Ganga.GPIDev.Base.Proxy import isType 
 88      from Ganga.GPIDev.Base.Objects import GangaObject 
 89      if not isStringLike(obj) and canLoopOver(obj): 
 90          for o in obj: 
 91              if containsGangaObjects(o): 
 92                  return True 
 93      elif isType(obj,GangaObject): 
 94          #order is special here as we ignore GangaLists 
 95          return True 
 96      return False 
 97   
 98 -def isNestedList(obj): 
 99      if not isStringLike(obj) and canLoopOver(obj): 
100          for o in obj: 
101              if not isStringLike(o) and canLoopOver(o): 
102                  return True 
103      return False 
104   
105  # ------------------------ 
106   
107  __executed_frames = {} 
108   
109 -def execute_once(): 
110      """ Return True if this function was not yet executed from a certain line in the program code. 
111       Example: 
112        execute_once() # -> True 
113        execute_once() # -> True 
114   
115        for i in range(2): 
116         execute_once() # -> True (1st), False (2nd) 
117   
118        if execute_once() and execute_once():  # -> False 
119      """ 
120      import inspect 
121   
122      frame = inspect.stack()[1] 
123      fid = hash((frame[1],frame[2],frame[3],tuple(frame[4]),frame[5])) 
124      del frame 
125      if fid in __executed_frames: 
126          return False 
127      __executed_frames[fid] = 1 
128      return True 
129   
130  # ------------------------ 
131   
132 -def hostname(): 
133      """ Try to get the hostname in the most possible reliable way as described in the Python LibRef.""" 
134      import socket 
135      try: 
136          return socket.gethostbyaddr(socket.gethostname())[0] 
137      # [bugfix #20333]:  
138      # while working offline and with an improper /etc/hosts configuration        
139      # the localhost cannot be resolved  
140      except: 
141          return 'localhost' 
142  # ------------------------ 
143   
144 -class Borg( object ): 
145     """ 
146     *Python Cookbook recipe 6.16* 
147     Borg implementation 
148     """ 
149     _shared_state = {} 
150 -   def __new__( cls, *args, **kw ): 
151        obj = object.__new__( cls, *args, **kw ) 
152        obj.__dict__ = cls._shared_state 
153        return obj 
154      
155 -   def __eq__( self, other ): 
156        try: 
157           return self.__dict__ is other.__dict__ 
158        except AttributeError: 
159           return False 
160      
161 -   def __hash__( self ): 
162        return 0 
163   
164  # ------------------------ 
165   
166 -def setAttributesFromDict( d, prefix = None ): 
167     """ 
168     *Python Cookbook recipe 6.18* 
169     Helper function to automatically initialises instance variables  
170     from __init_ arguments. 
171     """ 
172     if prefix is None: 
173        prefix = '' 
174     self = d.pop( 'self' ) 
175     for n, v in d.iteritems(): 
176        setattr( self, prefix + n, v ) 
177   
178   
179  # ------------------------ 
180   
181 -def wrap_callable( any_callable, before, after ): 
182     def _wrapped( *args, **kwargs ): 
183        before() 
184        try: 
185           return any_callable( *args, **kwargs ) 
186        finally: 
187           after() 
188     return _wrapped 
189   
190 -def wrap_callable_filter( any_callable, before, after ): 
191     def _wrapped( *args, **kwargs ): 
192        print 'wrap_callable_filter', args,kwargs 
193        args,kwargs = before(list(args),kwargs) 
194        try: 
195           return any_callable( *args, **kwargs ) 
196        finally: 
197           after() 
198     return _wrapped 
199   
200 -class GenericWrapper( object ): 
201 -   def __init__( self, obj, before, after, ignore = (), forced = (), wrapper_function=wrap_callable): 
202        classname = 'GenericWrapper' 
203        self.__dict__[ '_%s__methods' % classname ] = {} 
204        self.__dict__[ '_%s__obj' % classname ] = obj 
205        import inspect 
206        for name, method in inspect.getmembers( obj, inspect.ismethod ): 
207           if name not in ignore and method not in ignore: 
208               if forced and (name in forced or method in forced): 
209                   self.__methods[ name ] = wrapper_function( method, before, after ) 
210      
211 -   def __getattr__( self, name ): 
212        try: 
213           return self.__methods[ name ] 
214        except KeyError: 
215           return getattr( self.__obj, name ) 
216      
217 -   def __setattr__( self, name, value ): 
218        setattr( self.__obj, name, value ) 
219   
220  # ------------------------ 
221   
222 -class Proxy( object ): 
223 -    def __init__( self, obj ): 
224          super( Proxy, self ).__init__( obj ) 
225          self._obj = obj 
226       
227 -    def __getattr__( self, attrib ): 
228          return getattr( self._obj, attrib ) 
229   
230 -def make_binder( unbounded_method ): 
231      def f( self, *a, **k ): return unbounded_method( self._obj, *a, **k ) 
232      return f 
233   
234  known_proxy_classes = {} 
235   
236 -def proxy( obj, *specials ): 
237      obj_cls = obj.__class__ 
238      key = obj_cls, specials 
239      cls = known_proxy_classes.get( key ) 
240      if cls is None: 
241          cls = type( "%sProxy" % obj_cls.__name__, ( Proxy, ), {} ) 
242          for name in specials: 
243              name = '__%s__' % name 
244              unbounded_method = getattr( obj_cls, name ) 
245              setattr( cls, name, make_binder( unbounded_method ) ) 
246          known_proxy_classes[ key ] = cls 
247      return cls( obj ) 
248   
249  # ------------------------ 
250  # cookbook recipe 
251 -def importName(modulename,name): 
252      try: 
253          module = __import__(modulename,globals(),locals(),[name]) 
254      except ImportError: 
255          return None 
256      try: 
257          return vars(module)[name] 
258      except KeyError: 
259          return None 
260  # ------------------------ 
261   
262 -class IList: 
263      """ 
264      Proxy class for list objects that enables breaking the elements iteration if the  
265      condition flag (sentinel) is set to False during this process 
266      All the other operations are delegated to the list object itself 
267      #note: the same functionality could be achieved by extending list object  
268      #and overriding the __iter__() method but unfortunately this is not exposed in Python2.2 
269      #TODO: review this implementation in a more OO way when min Python version in Ganga is 2.3 
270      """ 
271 -    def __init__(self, list, sentinel): 
272          self._list = list 
273          self.sentinel=sentinel 
274          self.iterator=None 
275   
276 -    def next(self): 
277          if self.sentinel.isSet():             
278              raise StopIteration 
279          return self.iterator.next() 
280   
281 -    def __myiter__(self): 
282          return self 
283   
284 -    def __getattr__(self, attrib): 
285          if attrib=='__iter__':             
286              self.iterator=iter(self._list) 
287              return getattr(self, '__myiter__') 
288          return getattr(self._list, attrib) 
289   
290   
291  if __name__ == "__main__": 
292      import Ganga.Utility.logic as logic 
293       
294      assert(execute_once()) 
295      assert(execute_once()) 
296   
297      if execute_once() and execute_once(): 
298          assert(0) 
299   
300      for i in range(5): 
301          assert(logic.equivalent(execute_once(),i==0)) 
302   
303      print "TestOK" 
304       
305  # 
306  # 
307  # $Log: not supported by cvs2svn $ 
308  # Revision 1.11.4.3  2008/03/12 17:31:29  moscicki 
309  # simplified recursion 
310  # 
311  # Revision 1.11.4.2  2008/03/12 12:42:39  wreece 
312  # Updates the splitters to check for File objects in the list 
313  # 
314  # Revision 1.11.4.1  2007/12/18 09:08:19  moscicki 
315  # factored out the importName cookbook recipe (for integrated typesystem from Alvin) 
316  # 
317  # Revision 1.11  2007/07/27 14:31:56  moscicki 
318  # credential and clean shutdown updates from Adrian (from Ganga-4-4-0-dev-branch) 
319  # 
320  # Revision 1.10.2.1  2007/07/27 08:46:07  amuraru 
321  # clean shutdown update 
322  # 
323  # Revision 1.10  2007/01/25 16:30:41  moscicki 
324  # mergefrom_Ganga-4-2-2-bugfix-branch_25Jan07 (GangaBase-4-14) 
325  # 
326  # Revision 1.9  2006/10/27 15:15:27  amuraru 
327  # [bugfix #20333] 
328  # 
329  # Revision 1.8.2.1  2006/10/27 15:31:08  amuraru 
330  # Bugfix #20545 
331  # 
332  # Revision 1.9  2006/10/27 15:15:27  amuraru 
333  # [bugfix #20333] 
334  # 
335  # Revision 1.8  2006/07/31 12:19:03  moscicki 
336  # added callable filter wrapper 
337  # 
338  # Revision 1.7  2006/07/10 14:03:28  moscicki 
339  # added many Cookbook patterns from Alvin 
340  # 
341  # Revision 1.6  2006/02/10 15:08:06  moscicki 
342  # hostname 
343  # 
344  # Revision 1.5  2006/01/09 16:41:44  moscicki 
345  # execute_once() function used to issue LEGACY warnings 
346  # 
347  # Revision 1.4  2005/11/01 16:40:04  moscicki 
348  # isStringLike 
349  # 
350  # Revision 1.3  2005/11/01 14:05:21  moscicki 
351  # canLoopOver 
352  # 
353  # Revision 1.2  2005/10/06 09:51:58  andrew 
354  # Added the unique method for clearing out duplicates in a list 
355  # (Python Cook book recipe 17.3) 
356  # 
357  # 
358  # 
359