From 67168c3ab5cebdfb994fc01ef2a8e87dcf9e295f Mon Sep 17 00:00:00 2001 From: Richard Taylor Date: Tue, 5 Apr 2005 13:33:39 +0000 Subject: [PATCH] 2005-04-01 Richard Taylor * src/GrampsDBCallback.py: added support for disconnecting callbacks, better test code and lots of logging. Improved the comments. svn: r4298 --- gramps2/ChangeLog | 4 + gramps2/src/GrampsDBCallback.py | 316 +++++++++++++++++++++++++++----- 2 files changed, 277 insertions(+), 43 deletions(-) diff --git a/gramps2/ChangeLog b/gramps2/ChangeLog index 3c0f0936c..c8aa0db9c 100644 --- a/gramps2/ChangeLog +++ b/gramps2/ChangeLog @@ -1,3 +1,7 @@ +2005-04-01 Richard Taylor + * src/GrampsDBCallback.py: added support for disconnecting callbacks, + better test code and lots of logging. Improved the comments. + 2005-04-04 Alex Roitman * src/Marriage.py: proper window management on delete event. * src/RelLib.py (Event.are_equal): Correction. diff --git a/gramps2/src/GrampsDBCallback.py b/gramps2/src/GrampsDBCallback.py index c551ec6f3..9ee06e5d7 100644 --- a/gramps2/src/GrampsDBCallback.py +++ b/gramps2/src/GrampsDBCallback.py @@ -20,9 +20,26 @@ # $Id$ +""" + Introduction + ============ + + Gramps is devided into two parts. The database code, that does not + require any particular GUI libraries, and the gtk-based UI code + that requires gtk and gnome libraries. The gtk-based code can use + the gobject signal support to manage callback signals but the database + code can not. + + The module provides a subset of the signal mechanisms that are available + from the gobject framework. It enables the database code to use signals + to communicate events to any callback methods in either the database code + or the UI code. +""" import types import sys +log = sys.stderr.write + #------------------------------------------------------------------------- # # Callback signal support for non-gtk parts of Gramps @@ -33,17 +50,117 @@ class GrampsDBCallback(object): """ Callback and signal support for non-gtk parts of gramps. - Classes that want to emit signals need to inherit from this - class and call its __init__ method. They then need to declare - the signals that they can emit and the types of their - arguments. + Declaring signals + ================= + + Classes that want to emit signals need to inherit from the + GrampsDBCallback class and ensure that its __init__ method + is called. They then need to declare the signals that they + can emit and the types of each callbacks arguments. e.g. class TestSignals(GrampsDBCallback): __signals__ = { - 'test-signal' : (int,) + 'test-signal' : (int,), + 'test-noarg' : None + } + + def __init__(self): + GrampsDBCallback.__init__(self) + + The type signature is a tuple of types or classes. The type + checking code uses the isinstance method to check that the + argument passed to the emit call is an instance of the type + in the signature declaration. + + If the signal does not have an argument use None as the + signature. + + The signals will be inherited by any subclasses. Duplicate + signal names in subclasses are not alowed. + + + Emitting signals + ================ + + Signals are emitted using the emit method. + + e.g. + + def emit_signal(self): + self.emit('test-signal',(1,)) + + The parameters are passed as a tuple so a single parameter + must be passed as a 1 element tuple. + + + + Connecting callbacks to signals + ============================== + + Attaching a callback to the signals is similar to the gtk + connect methods. e.g. + + # connect to a function. + def fn(i): + print "got signal value = ", i + + t = TestSignals() + t.connect('test-signal', fn) + + # connect to a bound method + class C(object): + + def cb_func(self, i): + print "got class signal = ", 1 + + r = R() + t.connect('test-signal', r.cb_func) + + + Disconnecting callbacks + ======================= + + If you want to disconnect a callback from a signals you must remember the + key returned from the connect call. This key can be passed to the disconnect + method to remove the callback from the signals callback list. + + e.g. + + t = TestSignals() + + # connect to a bound method + class C(object): + + def cb_func(self, i): + print "got class signal = ", 1 + + r = R() + key = t.connect('test-signal', r.cb_func) + + ... + + t.disconnect(key) + + + Stopping and starting signals + ============================= + + Signals can be blocked on a per instance bassis or they can be blocked + for all instances of the GrampsDBCallback class. disable_signals() can + be used to block the signals for a single instance and disable_all_signals() + can be used to block signals for the class: + + e.g. + + + class TestSignals(GrampsDBCallback): + + __signals__ = { + 'test-signal' : (int,), + 'test-noarg' : None } def __init__(self): @@ -52,47 +169,69 @@ class GrampsDBCallback(object): def emit_signal(self): self.emit('test-signal',(1,)) - The signals will be inherited by any subclasses. + t = TestSignals() - Attaching a callback to the signals is similar to the gtk - connect methods. e.g. + # block signals from instance t + t.disable_signals() - class C(object): + ... + + # unblock + t.enable_signals() - def cb_func(self, i): - print "got class signal = ", 1 + # block all signals + GrampsDBCallback.disable_all_signals() - def fn(i): - print "got signal value = ", i + ... + + # unblock all signals + GrampsDBCallback.enable_all_signals() - t = TestSignals() - # connect to a function. - t.connect('test-signal', fn) - - t.emit_signal() + Any signals emited whilst signals are blocked will be lost. + + + Debugging signal callbacks + ========================== - r = R() + + To help with debugging the signals and callbacks you can turn on + lots of logging information. To switch on logging for a single + instance call self.enable_logging(), to switch it off again call + self.disable_logging(). To switch on logging for all instance + you can toggle GrampsDBCallback.__LOG_ALL to True. + """ # If this True no signals will be emitted from any instance of # any class derived from this class. This should be toggled using # the class methods, dissable_all_signals() and enable_all_signals(). __BLOCK_ALL_SIGNALS = False + + + # If this is True logging will be turned on for all instances + # whether or not instance based logging is enabled. + __LOG_ALL = False def __init__(self): + self.__enable_logging = False # controls whether lots of debug + # information will be produced. self.__block_instance_signals = False # controls the blocking of # signals from this instance self.__callback_map = {} # dictionary containing all the connected # callback functions. The keys are the - # signal names and the values are the - # bound methods that will be called when - # the signal is emitted + # signal names and the values are tuples + # of the form (key,bound_method), where + # the key is unique within the instance + # and the bound_method is the callback + # that will be called when the signal is + # emitted self.__signal_map = {} # dictionary contains all the signals that # this instance can emit. The keys are the # signal names and the values are tuples # containing the list of types of the arguments # that the callback methods must accept. + self._current_key = 0 # counter to give a unique key to each callback. # To speed up the signal type checking the signals declared by # each of the classes in the inheritance tree of this instance @@ -125,20 +264,59 @@ class GrampsDBCallback(object): # self.__signal_map now contains the connonical list # of signals that this instance can emit. + + self._log("registed signals: \n %s\n" % + "\n ".join([ "%s: %s" % (k,v) for (k,v) + in self.__signal_map.items() ])) def connect(self, signal_name, callback): + """ + Connect a callable to a signal_name. The callable will be called + with the signal is emitted. The callable must accept the argument + types declared in the signals signature. + + returns a unique key that can be passed to disconnect(). + """ # Check that signal exists. if signal_name not in self.__signal_map.keys(): - sys.stderr.write("Warning: attempt to connect to unknown signal: %s\n" % str(signal_name)) + self._log("Warning: attempt to connect to unknown signal: %s\n" % str(signal_name)) return # Add callable to callback_map if signal_name not in self.__callback_map.keys(): self.__callback_map[signal_name] = [] - self.__callback_map[signal_name].append(callback) + self._current_key += 1 + self._log("Connecting callback to signal: " + "%s with key: %s\n" + % (signal_name,str(self._current_key))) + self.__callback_map[signal_name].append((self._current_key,callback)) + + return self._current_key + + def disconnect(self,key): + """ + Disconnect a callback. + """ + + # Find the key in the callback map. + for signal_name in self.__callback_map.keys(): + for cb in self.__callback_map[signal_name]: + (skey,fn) = cb + if skey == key: + # delete the callback from the map. + self._log("Disconnecting callback from signal" + ": %s with key: %s\n" % (signal_name, + str(key))) + self.__callback_map[signal_name].remove(cb) + + def emit(self, signal_name, args=tuple()): + """ + Emit the signal called signal_name. The args must be a tuple of + arguments that match the types declared for the signals signature. + """ # Check that signals are not blocked if GrampsDBCallback.__BLOCK_ALL_SIGNALS or \ self.__block_instance_signals: @@ -146,45 +324,47 @@ class GrampsDBCallback(object): # Check signal exists if signal_name not in self.__signal_map.keys(): - sys.stderr.write("Warning: attempt to emit to unknown signal: %s\n" + self._log("Warning: attempt to emit to unknown signal: %s\n" % str(signal_name)) return # type check arguments arg_types = self.__signal_map[signal_name] if arg_types == None and len(args) > 0: - sys.stderr.write("Warning: signal emitted with "\ + self._log("Warning: signal emitted with "\ "wrong number of args: %s\n" % str(signal_name)) return if len(args) > 0: if len(args) != len(arg_types): - sys.stderr.write("Warning: signal emitted with "\ + self._log("Warning: signal emitted with "\ "wrong number of args: %s\n" % str(signal_name)) return if arg_types != None: for i in range(0,len(arg_types)): if not isinstance(args[i],arg_types[i]): - sys.stderr.write("Warning: signal emitted with "\ + self._log("Warning: signal emitted with "\ "wrong arg types: %s\n" % (str(signal_name),)) - sys.stderr.write(" arg passed was: %s, type should be: %s\n" + self._log(" arg passed was: %s, type should be: %s\n" % (args[i],repr(arg_types[i]))) return if signal_name in self.__callback_map.keys(): + self._log("emmitting signal: %s\n" % (signal_name,)) # Don't bother if there are no callbacks. - for cb in self.__callback_map[signal_name]: + for (key,fn) in self.__callback_map[signal_name]: + self._log("Calling callback with key: %s\n" % (key,)) try: - if type(cb) == tuple: # call class method - cb[0](cb[1],*args) - elif type(cb) == types.FunctionType or \ - type(cb) == types.MethodType: # call func - cb(*args) + if type(fn) == tuple: # call class method + cb[0](fn[1],*args) + elif type(fn) == types.FunctionType or \ + type(fn) == types.MethodType: # call func + fn(*args) else: - sys.stderr.write("Warning: badly formed entry in callback map.\n") + self._log("Warning: badly formed entry in callback map.\n") except: - sys.stderr.write("Warning: exception occured in callback function.\n") + self._log("Warning: exception occured in callback function.\n") # # instance signals control methods @@ -194,7 +374,20 @@ class GrampsDBCallback(object): def enable_signals(self): self.__block_instance_signals = False - + + + # logging methods + + def disable_logging(self): + self.__enable_logging = False + + def enable_logging(self): + self.__enable_logging = True + + def _log(self,msg): + if GrampsDBCallback.__LOG_ALL or self.__enable_logging: + log("%s: %s" % (self.__class__.__name__, str(msg))) + # # Class methods # @@ -241,6 +434,33 @@ if __name__ == "__main__": assert len(rl) == 1, "No signal emitted" assert rl[0] == 1, "Wrong argument recieved" + def test_disconnect(self): + + class TestSignals(GrampsDBCallback): + + __signals__ = { + 'test-signal' : (int,) + } + + rl = [] + def fn(i,r=rl): + rl.append(i) + + t = TestSignals() + key = t.connect('test-signal',fn) + t.emit('test-signal',(1,)) + + + assert len(rl) == 1, "No signal emitted" + assert rl[0] == 1, "Wrong argument recieved" + + t.disconnect(key) + + t.emit('test-signal',(1,)) + + assert len(rl) == 1, "Callback not disconnected" + assert rl[0] == 1, "Callback not disconnected" + def test_noargs(self): class TestSignals(GrampsDBCallback): @@ -261,6 +481,17 @@ if __name__ == "__main__": assert len(rl) == 1, "No signal emitted" assert rl[0] == 1, "Wrong argument recieved" + def test_no_callback(self): + + class TestSignals(GrampsDBCallback): + + __signals__ = { + 'test-noargs' : None + } + + t = TestSignals() + t.emit('test-noargs') + def test_subclassing(self): class TestSignals(GrampsDBCallback): @@ -367,12 +598,11 @@ if __name__ == "__main__": # This should fail because the type of arg1 is wrong res=[] - class C: - def write(self,s,r=res): - res.append(s) - sys.stderr = C() + def fn(s,r=res): + res.append(s) + t._log = fn t.connect('test-lots',fn2), t.emit('test-lots',('a','a',[1,2],t,1.2)) - assert res[0][0:8] == "Warning:", "Type error not detected" + assert res[1][0:8] == "Warning:", "Type error not detected" unittest.main()