First checkin of the Python XPCOM bindings.
This commit is contained in:
markh@activestate.com
211
extensions/python/xpcom/server/policy.py
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211
extensions/python/xpcom/server/policy.py
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# Copyright (c) 2000-2001 ActiveState Tool Corporation.
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# See the file LICENSE.txt for licensing information.
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from xpcom import xpcom_consts, _xpcom, client, nsError, ServerException, COMException
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import xpcom
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import traceback
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import xpcom.server
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import operator
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_supports_primitives_map_ = {} # Filled on first use.
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def _GetNominatedInterfaces(obj):
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ret = getattr(obj, "_com_interfaces_", None)
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if ret is None: return None
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# See if the user only gave one.
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try:
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ret[0]
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except TypeError:
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ret = [ret]
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real_ret = []
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# For each interface, walk to the root of the interface tree.
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iim = _xpcom.XPTI_GetInterfaceInfoManager()
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for interface in ret:
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try:
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interface_info = iim.GetInfoForIID(interface)
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except COMException:
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# Allow an interface name.
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interface_info = iim.GetInfoForName(interface)
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real_ret.append(interface_info.GetIID())
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parent = interface_info.GetParent()
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while parent is not None:
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real_ret.append(parent.GetIID())
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parent = parent.GetParent()
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return real_ret
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class DefaultPolicy:
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def __init__(self, instance, iid):
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self._obj_ = instance
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self._nominated_interfaces_ = ni = _GetNominatedInterfaces(instance)
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self._iid_ = iid
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if ni is None:
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raise ValueError, "The object '%r' can not be used as a COM object" % (instance,)
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if iid not in ni:
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# The object may delegate QI.
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try:
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delegate_qi = instance._query_interface_
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except AttributeError:
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delegate_qi = None
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# Perform the actual QI and throw away the result - the _real_
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# QI performed by the framework will set things right!
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if delegate_qi is None or not delegate_qi(iid):
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raise ServerException(nsError.NS_ERROR_NO_INTERFACE)
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# Stuff for the magic interface conversion.
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self._interface_info_ = None
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self._interface_iid_map_ = {} # Cache - Indexed by (method_index, param_index)
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def _QueryInterface_(self, com_object, iid):
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# Framework allows us to return a single boolean integer,
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# or a COM object.
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if iid in self._nominated_interfaces_:
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# We return the underlying object re-wrapped
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# in a new gateway - which is desirable, as one gateway should only support
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# one interface (this wont affect the users of this policy - we can have as many
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# gateways as we like pointing to the same Python objects - the users never
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# see what object the call came in from.
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# NOTE: We could have simply returned the instance and let the framework
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# do the auto-wrap for us - but this way we prevent a round-trip back into Python
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# code just for the autowrap.
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return xpcom.server.WrapObject(self._obj_, iid)
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# See if the instance has a QI
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# use lower-case "_query_interface_" as win32com does, and it doesnt really matter.
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delegate = getattr(self._obj_, "_query_interface_", None)
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if delegate is not None:
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# The COM object itself doesnt get passed to the child
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# (again, as win32com doesnt). It is rarely needed
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# (in win32com, we dont even pass it to the policy, although we have identified
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# one place where we should - for marshalling - so I figured I may as well pass it
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# to the policy layer here, but no all the way down to the object.
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return delegate(iid)
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# Finally see if we are being queried for one of the "nsISupports primitives"
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if not _supports_primitives_map_:
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iim = _xpcom.XPTI_GetInterfaceInfoManager()
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for (iid_name, attr, cvt) in _supports_primitives_data_:
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special_iid = iim.GetInfoForName(iid_name).GetIID()
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_supports_primitives_map_[special_iid] = (attr, cvt)
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attr, cvt = _supports_primitives_map_.get(iid, (None,None))
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if attr is not None and hasattr(self._obj_, attr):
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return xpcom.server.WrapObject(SupportsPrimitive(iid, self._obj_, attr, cvt), iid)
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# Out of clever things to try!
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return None # We dont support this IID.
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def _MakeInterfaceParam_(self, interface, iid, method_index, mi, param_index):
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# Wrap a "raw" interface object in a nice object. The result of this
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# function will be passed to one of the gateway methods.
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if iid is None:
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# look up the interface info - this will be true for all xpcom called interfaces.
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if self._interface_info_ is None:
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import xpcom.xpt
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self._interface_info_ = xpcom.xpt.Interface( self._iid_ )
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iid = self._interface_iid_map_.get( (method_index, param_index))
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if iid is None:
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iid = self._interface_info_.GetIIDForParam(method_index, param_index)
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self._interface_iid_map_[(method_index, param_index)] = iid
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# iid = _xpcom.IID_nsISupports
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return client.Interface(interface, iid)
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def _CallMethod_(self, com_object, index, info, params):
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# print "_CallMethod_", index, info, params
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flags, name, param_descs, ret = info
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assert ret[1][0] == xpcom_consts.TD_UINT32, "Expected an nsresult (%s)" % (ret,)
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if xpcom_consts.XPT_MD_IS_GETTER(flags):
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# Look for a function of that name
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func = getattr(self._obj_, "get_" + name, None)
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if func is None:
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assert len(param_descs)==1 and len(params)==0, "Can only handle a single [out] arg for a default getter"
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ret = getattr(self._obj_, name) # Let attribute error go here!
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else:
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ret = func(*params)
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return 0, ret
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elif xpcom_consts.XPT_MD_IS_SETTER(flags):
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# Look for a function of that name
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func = getattr(self._obj_, "set_" + name, None)
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if func is None:
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assert len(param_descs)==1 and len(params)==1, "Can only handle a single [in] arg for a default setter"
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setattr(self._obj_, name, params[0]) # Let attribute error go here!
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else:
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func(*params)
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return 0
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else:
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# A regular method.
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func = getattr(self._obj_, name)
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return 0, func(*params)
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def _doHandleException(self, func_name, exc_info):
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exc_val = exc_info[1]
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is_server_exception = isinstance(exc_val, ServerException)
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if is_server_exception:
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if xpcom.verbose:
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print "** Information: '%s' raised COM Exception %s" % (func_name, exc_val)
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traceback.print_exception(exc_info[0], exc_val, exc_info[2])
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print "** Returning nsresult from existing exception", exc_val
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return exc_val.errno
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# Unhandled exception - always print a warning.
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print "** Unhandled exception calling '%s'" % (func_name,)
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traceback.print_exception(exc_info[0], exc_val, exc_info[2])
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print "** Returning nsresult of NS_ERROR_FAILURE"
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return nsError.NS_ERROR_FAILURE
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# Called whenever an unhandled Python exception is detected as a result
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# of _CallMethod_ - this exception may have been raised during the _CallMethod_
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# invocation, or after its return, but when unpacking the results
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# eg, type errors, such as a Python integer being used as a string "out" param.
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def _CallMethodException_(self, com_object, index, info, params, exc_info):
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# Later we may want to have some smart "am I debugging" flags?
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# Or maybe just delegate to the actual object - it's probably got the best
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# idea what to do with them!
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flags, name, param_descs, ret = info
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exc_typ, exc_val, exc_tb = exc_info
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# use the xpt module to get a better repr for the method.
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# But if we fail, ignore it!
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try:
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import xpcom.xpt
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m = xpcom.xpt.Method(info, index, None)
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func_repr = m.Describe().lstrip()
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except:
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func_repr = "%s(%r)" % (name, param_descs)
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return self._doHandleException(func_repr, exc_info)
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# Called whenever a gateway fails due to anything other than _CallMethod_.
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# Really only used for the component loader etc objects, so most
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# users should never see exceptions triggered here.
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def _GatewayException_(self, name, exc_info):
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return self._doHandleException(name, exc_info)
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_supports_primitives_data_ = [
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("nsISupportsString", "__str__", str),
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("nsISupportsWString", "__str__", str),
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("nsISupportsPRUint64", "__long__", long),
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("nsISupportsPRInt64", "__long__", long),
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("nsISupportsPRUint32", "__int__", int),
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("nsISupportsPRInt32", "__int__", int),
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("nsISupportsPRUint16", "__int__", int),
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("nsISupportsPRInt16", "__int__", int),
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("nsISupportsPRUint8", "__int__", int),
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("nsISupportsPRBool", "__nonzero__", operator.truth),
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("nsISupportsDouble", "__float__", float),
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("nsISupportsFloat", "__float__", float),
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]
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# Support for the nsISupports primitives:
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class SupportsPrimitive:
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_com_interfaces_ = ["nsISupports"]
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def __init__(self, iid, base_ob, attr_name, converter):
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self.iid = iid
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self.base_ob = base_ob
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self.attr_name = attr_name
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self.converter = converter
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def _query_interface_(self, iid):
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if iid == self.iid:
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return 1
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return None
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def get_data(self):
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method = getattr(self.base_ob, self.attr_name)
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val = method()
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return self.converter(val)
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def set_data(self, val):
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raise ServerException(nsError.NS_ERROR_NOT_IMPLEMENTED)
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def toString(self):
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return str(self.get_data())
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