diff options
Diffstat (limited to 'gdb/python')
| -rw-r--r-- | gdb/python/lib/gdb/__init__.py | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/gdb/python/lib/gdb/__init__.py b/gdb/python/lib/gdb/__init__.py index 4ea5d06..866c312 100644 --- a/gdb/python/lib/gdb/__init__.py +++ b/gdb/python/lib/gdb/__init__.py @@ -392,3 +392,121 @@ def _handle_missing_objfile(pspace, buildid, filename): return _handle_missing_files( pspace, "objfile", lambda h: h(pspace, buildid, filename) ) + + +class ParameterPrefix: + # A wrapper around gdb.Command for creating set/show prefixes. + # + # When creating a gdb.Parameter sub-classes, it is sometimes necessary + # to first create a gdb.Command object in order to create the needed + # command prefix. However, for parameters, we actually need two + # prefixes, a 'set' prefix, and a 'show' prefix. With this helper + # class, a single instance of this class will create both prefixes at + # once. + # + # It is important that this class-level documentation not be a __doc__ + # string. Users are expected to sub-class this ParameterPrefix class + # and add their own documentation. If they don't, then GDB will + # generate a suitable doc string. But, if this (parent) class has a + # __doc__ sting of its own, then sub-classes will inherit that __doc__ + # string, and GDB will not understand that it needs to generate one. + + class _PrefixCommand(Command): + """A gdb.Command used to implement both the set and show prefixes. + + This documentation string is not used as the prefix command + documentation as it is overridden in the __init__ method below.""" + + # This private method is connected to the 'invoke' attribute within + # this _PrefixCommand object if the containing ParameterPrefix + # object has an invoke_set or invoke_show method. + # + # This method records within self.__delegate which _PrefixCommand + # object is currently active, and then calls the correct invoke + # method on the delegat object (the ParameterPrefix sub-class + # object). + # + # Recording the currently active _PrefixCommand object is important; + # if from the invoke method the user calls dont_repeat, then this is + # forwarded to the currently active _PrefixCommand object. + def __invoke(self, args, from_tty): + + # A helper class for use as part of a Python 'with' block. + # Records which gdb.Command object is currently running its + # invoke method. + class MarkActiveCallback: + # The CMD is a _PrefixCommand object, and the DELEGATE is + # the ParameterPrefix class, or sub-class object. At this + # point we simple record both of these within the + # MarkActiveCallback object. + def __init__(self, cmd, delegate): + self.__cmd = cmd + self.__delegate = delegate + + # Record the currently active _PrefixCommand object within + # the outer ParameterPrefix sub-class object. + def __enter__(self): + self.__delegate.active_prefix = self.__cmd + + # Once the invoke method has completed, then clear the + # _PrefixCommand object that was stored into the outer + # ParameterPrefix sub-class object. + def __exit__(self, exception_type, exception_value, traceback): + self.__delegate.active_prefix = None + + # The self.__cb attribute is set when the _PrefixCommand object + # is created, and is either invoke_set or invoke_show within the + # ParameterPrefix sub-class object. + assert callable(self.__cb) + + # Record the currently active _PrefixCommand object within the + # ParameterPrefix sub-class object, then call the relevant + # invoke method within the ParameterPrefix sub-class object. + with MarkActiveCallback(self, self.__delegate): + self.__cb(args, from_tty) + + @staticmethod + def __find_callback(delegate, mode): + """The MODE is either 'set' or 'show'. Look for an invoke_MODE method + on DELEGATE, if a suitable method is found, then return it, otherwise, + return None. + """ + cb = getattr(delegate, "invoke_" + mode, None) + if callable(cb): + return cb + return None + + def __init__(self, mode, name, cmd_class, delegate, doc=None): + """Setup this gdb.Command. Mode is a string, either 'set' or 'show'. + NAME is the name for this prefix command, that is, the + words that appear after both 'set' and 'show' in the + command name. CMD_CLASS is the usual enum. And DELEGATE + is the gdb.ParameterPrefix object this prefix is part of. + """ + assert mode == "set" or mode == "show" + if doc is None: + self.__doc__ = delegate.__doc__ + else: + self.__doc__ = doc + self.__cb = self.__find_callback(delegate, mode) + self.__delegate = delegate + if not self.__cb is None: + self.invoke = self.__invoke + super().__init__(mode + " " + name, cmd_class, prefix=True) + + def __init__(self, name, cmd_class, doc=None): + """Create a _PrefixCommand for both the set and show prefix commands. + NAME is the command name without either the leading 'set ' or + 'show ' strings, and CMD_CLASS is the usual enum value. + """ + self.active_prefix = None + self._set_prefix_cmd = self._PrefixCommand("set", name, cmd_class, self, doc) + self._show_prefix_cmd = self._PrefixCommand("show", name, cmd_class, self, doc) + + # When called from within an invoke method the self.active_prefix + # attribute should be set to a gdb.Command sub-class (a _PrefixCommand + # object, see above). Forward the dont_repeat call to this object to + # register the actual command as none repeating. + def dont_repeat(self): + if self.active_prefix is not None: + self.active_prefix.dont_repeat() |