Source Code for Module eventHandler

  1  #eventHandler.py 
  2  #A part of NonVisual Desktop Access (NVDA) 
  3  #This file is covered by the GNU General Public License. 
  4  #See the file COPYING for more details. 
  5  #Copyright (C) 2007-2010 Michael Curran <mick@kulgan.net>, James Teh <jamie@jantrid.net> 
  6   
  7  import queueHandler 
  8  import api 
  9  import speech 
 10  import appModuleHandler 
 11  import treeInterceptorHandler 
 12  import globalVars 
 13  import controlTypes 
 14  from logHandler import log 
 15  import globalPluginHandler 
 16   
 17  #Some dicts to store event counts by name and or obj 
 18  _pendingEventCountsByName={} 
 19  _pendingEventCountsByObj={} 
 20  _pendingEventCountsByNameAndObj={} 
 21   
 22  #: the last object queued for a gainFocus event. Useful for code running outside NVDA's core queue  
 23  lastQueuedFocusObject=None 
 24   
 25 -def queueEvent(eventName,obj,**kwargs): 
 26          """Queues an NVDA event to be executed. 
 27          @param eventName: the name of the event type (e.g. 'gainFocus', 'nameChange') 
 28          @type eventName: string 
 29          """ 
 30          global lastQueuedFocusObject 
 31          queueHandler.queueFunction(queueHandler.eventQueue,_queueEventCallback,eventName,obj,kwargs) 
 32          if eventName=="gainFocus": 
 33                  lastQueuedFocusObject=obj 
 34          _pendingEventCountsByName[eventName]=_pendingEventCountsByName.get(eventName,0)+1 
 35          _pendingEventCountsByObj[obj]=_pendingEventCountsByObj.get(obj,0)+1 
 36          _pendingEventCountsByNameAndObj[(eventName,obj)]=_pendingEventCountsByNameAndObj.get((eventName,obj),0)+1 
 37   
 38 -def _queueEventCallback(eventName,obj,kwargs): 
 39          curCount=_pendingEventCountsByName.get(eventName,0) 
 40          if curCount>1: 
 41                  _pendingEventCountsByName[eventName]=(curCount-1) 
 42          elif curCount==1: 
 43                  del _pendingEventCountsByName[eventName] 
 44          curCount=_pendingEventCountsByObj.get(obj,0) 
 45          if curCount>1: 
 46                  _pendingEventCountsByObj[obj]=(curCount-1) 
 47          elif curCount==1: 
 48                  del _pendingEventCountsByObj[obj] 
 49          curCount=_pendingEventCountsByNameAndObj.get((eventName,obj),0) 
 50          if curCount>1: 
 51                  _pendingEventCountsByNameAndObj[(eventName,obj)]=(curCount-1) 
 52          elif curCount==1: 
 53                  del _pendingEventCountsByNameAndObj[(eventName,obj)] 
 54          executeEvent(eventName,obj,**kwargs) 
 55   
 56 -def isPendingEvents(eventName=None,obj=None): 
 57          """Are there currently any events queued? 
 58          @param eventName: an optional name of an event type. If given then only if there are events of this type queued will it return True. 
 59          @type eventName: string 
 60          @param obj: the NVDAObject the event is for 
 61          @type obj: L{NVDAObjects.NVDAObject} 
 62          @returns: True if there are events queued, False otherwise. 
 63          @rtype: boolean 
 64          """ 
 65          if not eventName and not obj: 
 66                  return bool(len(_pendingEventCountsByName)) 
 67          elif not eventName and obj: 
 68                  return obj in _pendingEventCountsByObj 
 69          elif eventName and not obj: 
 70                  return eventName in _pendingEventCountsByName 
 71          elif eventName and obj: 
 72                  return (eventName,obj) in _pendingEventCountsByNameAndObj 
 73   
 74 -class _EventExecuter(object): 
 75          """Facilitates execution of a chain of event functions. 
 76          L{gen} generates the event functions and positional arguments. 
 77          L{next} calls the next function in the chain. 
 78          """ 
 79   
 80 -        def __init__(self, eventName, obj, kwargs): 
 81                  self.kwargs = kwargs 
 82                  self._gen = self.gen(eventName, obj) 
 83                  try: 
 84                          self.next() 
 85                  except StopIteration: 
 86                          pass 
 87                  del self._gen 
 88   
 89 -        def next(self): 
 90                  func, args = next(self._gen) 
 91                  return func(*args, **self.kwargs) 
 92   
 93 -        def gen(self, eventName, obj): 
 94                  funcName = "event_%s" % eventName 
 95   
 96                  # Global plugin level. 
 97                  for plugin in globalPluginHandler.runningPlugins: 
 98                          func = getattr(plugin, funcName, None) 
 99                          if func: 
100                                  yield func, (obj, self.next) 
101   
102                  # App module level. 
103                  app = obj.appModule 
104                  if app: 
105                          func = getattr(app, funcName, None) 
106                          if func: 
107                                  yield func, (obj, self.next) 
108   
109                  # Tree interceptor level. 
110                  treeInterceptor = obj.treeInterceptor 
111                  if treeInterceptor: 
112                          func = getattr(treeInterceptor, funcName, None) 
113                          if func and (getattr(func,'ignoreIsReady',False) or treeInterceptor.isReady): 
114                                  yield func, (obj, self.next) 
115   
116                  # NVDAObject level. 
117                  func = getattr(obj, funcName, None) 
118                  if func: 
119                          yield func, () 
120   
121 -def executeEvent(eventName,obj,**kwargs): 
122          """Executes an NVDA event. 
123          @param eventName: the name of the event type (e.g. 'gainFocus', 'nameChange') 
124          @type eventName: string 
125          @param obj: the object the event is for 
126          @type obj: L{NVDAObjects.NVDAObject} 
127          @param kwargs: Additional event parameters as keyword arguments. 
128          """ 
129          try: 
130                  sleepMode=obj.appModule.sleepMode if obj and obj.appModule else False 
131                  if eventName=="gainFocus" and not doPreGainFocus(obj,sleepMode=sleepMode): 
132                          return 
133                  elif not sleepMode and eventName=="documentLoadComplete" and not doPreDocumentLoadComplete(obj): 
134                          return 
135                  elif not sleepMode: 
136                          _EventExecuter(eventName,obj,kwargs) 
137          except: 
138                  log.exception("error executing event: %s on %s with extra args of %s"%(eventName,obj,kwargs)) 
139   
140 -def doPreGainFocus(obj,sleepMode=False): 
141          oldForeground=api.getForegroundObject() 
142          oldFocus=api.getFocusObject() 
143          oldTreeInterceptor=oldFocus.treeInterceptor if oldFocus else None 
144          api.setFocusObject(obj) 
145          if globalVars.focusDifferenceLevel<=1: 
146                  newForeground=api.getDesktopObject().objectInForeground() 
147                  if not newForeground: 
148                          log.debugWarning("Can not get real foreground, resorting to focus ancestors") 
149                          ancestors=api.getFocusAncestors() 
150                          if len(ancestors)>1: 
151                                  newForeground=ancestors[1] 
152                          else: 
153                                  newForeground=obj 
154                  api.setForegroundObject(newForeground) 
155                  executeEvent('foreground',newForeground) 
156          if sleepMode: return True 
157          #Fire focus entered events for all new ancestors of the focus if this is a gainFocus event 
158          for parent in globalVars.focusAncestors[globalVars.focusDifferenceLevel:]: 
159                  executeEvent("focusEntered",parent) 
160          if obj.treeInterceptor is not oldTreeInterceptor: 
161                  if hasattr(oldTreeInterceptor,"event_treeInterceptor_loseFocus"): 
162                          oldTreeInterceptor.event_treeInterceptor_loseFocus() 
163                  if obj.treeInterceptor and obj.treeInterceptor.isReady and hasattr(obj.treeInterceptor,"event_treeInterceptor_gainFocus"): 
164                          obj.treeInterceptor.event_treeInterceptor_gainFocus() 
165          return True 
166    
167 -def doPreDocumentLoadComplete(obj): 
168          focusObject=api.getFocusObject() 
169          if (not obj.treeInterceptor or not obj.treeInterceptor.isAlive or obj.treeInterceptor.shouldPrepare) and (obj==focusObject or obj in api.getFocusAncestors()): 
170                  ti=treeInterceptorHandler.update(obj) 
171                  if ti: 
172                          obj.treeInterceptor=ti 
173                          #Focus may be in this new treeInterceptor, so force focus to look up its treeInterceptor 
174                          focusObject.treeInterceptor=treeInterceptorHandler.getTreeInterceptor(focusObject) 
175          return True 
176