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openmedialibrary_platform_w.../Lib/site-packages/win32com/server/policy.py

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install pywin32-220
2016-04-14 19:54:42 +00:00
"""Policies
Note that Dispatchers are now implemented in "dispatcher.py", but
are still documented here.
Policies
A policy is an object which manages the interaction between a public
Python object, and COM . In simple terms, the policy object is the
object which is actually called by COM, and it invokes the requested
method, fetches/sets the requested property, etc. See the
@win32com.server.policy.CreateInstance@ method for a description of
how a policy is specified or created.
Exactly how a policy determines which underlying object method/property
is obtained is up to the policy. A few policies are provided, but you
can build your own. See each policy class for a description of how it
implements its policy.
There is a policy that allows the object to specify exactly which
methods and properties will be exposed. There is also a policy that
will dynamically expose all Python methods and properties - even those
added after the object has been instantiated.
Dispatchers
A Dispatcher is a level in front of a Policy. A dispatcher is the
thing which actually receives the COM calls, and passes them to the
policy object (which in turn somehow does something with the wrapped
object).
It is important to note that a policy does not need to have a dispatcher.
A dispatcher has the same interface as a policy, and simply steps in its
place, delegating to the real policy. The primary use for a Dispatcher
is to support debugging when necessary, but without imposing overheads
when not (ie, by not using a dispatcher at all).
There are a few dispatchers provided - "tracing" dispatchers which simply
prints calls and args (including a variation which uses
win32api.OutputDebugString), and a "debugger" dispatcher, which can
invoke the debugger when necessary.
Error Handling
It is important to realise that the caller of these interfaces may
not be Python. Therefore, general Python exceptions and tracebacks aren't
much use.
In general, there is an Exception class that should be raised, to allow
the framework to extract rich COM type error information.
The general rule is that the **only** exception returned from Python COM
Server code should be an Exception instance. Any other Python exception
should be considered an implementation bug in the server (if not, it
should be handled, and an appropriate Exception instance raised). Any
other exception is considered "unexpected", and a dispatcher may take
special action (see Dispatchers above)
Occasionally, the implementation will raise the policy.error error.
This usually means there is a problem in the implementation that the
Python programmer should fix.
For example, if policy is asked to wrap an object which it can not
support (because, eg, it does not provide _public_methods_ or _dynamic_)
then policy.error will be raised, indicating it is a Python programmers
problem, rather than a COM error.
"""
__author__ = "Greg Stein and Mark Hammond"
import win32api
import winerror
import sys
import types
import pywintypes
import win32con, pythoncom
#Import a few important constants to speed lookups.
from pythoncom import \
DISPATCH_METHOD, DISPATCH_PROPERTYGET, DISPATCH_PROPERTYPUT, DISPATCH_PROPERTYPUTREF, \
DISPID_UNKNOWN, DISPID_VALUE, DISPID_PROPERTYPUT, DISPID_NEWENUM, \
DISPID_EVALUATE, DISPID_CONSTRUCTOR, DISPID_DESTRUCTOR, DISPID_COLLECT,DISPID_STARTENUM
S_OK = 0
# Few more globals to speed things.
IDispatchType = pythoncom.TypeIIDs[pythoncom.IID_IDispatch]
IUnknownType = pythoncom.TypeIIDs[pythoncom.IID_IUnknown]
from .exception import COMException
error = __name__ + " error"
regSpec = 'CLSID\\%s\\PythonCOM'
regPolicy = 'CLSID\\%s\\PythonCOMPolicy'
regDispatcher = 'CLSID\\%s\\PythonCOMDispatcher'
regAddnPath = 'CLSID\\%s\\PythonCOMPath'
def CreateInstance(clsid, reqIID):
"""Create a new instance of the specified IID
The COM framework **always** calls this function to create a new
instance for the specified CLSID. This function looks up the
registry for the name of a policy, creates the policy, and asks the
policy to create the specified object by calling the _CreateInstance_ method.
Exactly how the policy creates the instance is up to the policy. See the
specific policy documentation for more details.
"""
# First see is sys.path should have something on it.
try:
addnPaths = win32api.RegQueryValue(win32con.HKEY_CLASSES_ROOT,
regAddnPath % clsid).split(';')
for newPath in addnPaths:
if newPath not in sys.path:
sys.path.insert(0, newPath)
except win32api.error:
pass
try:
policy = win32api.RegQueryValue(win32con.HKEY_CLASSES_ROOT,
regPolicy % clsid)
policy = resolve_func(policy)
except win32api.error:
policy = DefaultPolicy
try:
dispatcher = win32api.RegQueryValue(win32con.HKEY_CLASSES_ROOT,
regDispatcher % clsid)
if dispatcher: dispatcher = resolve_func(dispatcher)
except win32api.error:
dispatcher = None
if dispatcher:
retObj = dispatcher(policy, None)
else:
retObj = policy(None)
return retObj._CreateInstance_(clsid, reqIID)
class BasicWrapPolicy:
"""The base class of policies.
Normally not used directly (use a child class, instead)
This policy assumes we are wrapping another object
as the COM server. This supports the delegation of the core COM entry points
to either the wrapped object, or to a child class.
This policy supports the following special attributes on the wrapped object
_query_interface_ -- A handler which can respond to the COM 'QueryInterface' call.
_com_interfaces_ -- An optional list of IIDs which the interface will assume are
valid for the object.
_invoke_ -- A handler which can respond to the COM 'Invoke' call. If this attribute
is not provided, then the default policy implementation is used. If this attribute
does exist, it is responsible for providing all required functionality - ie, the
policy _invoke_ method is not invoked at all (and nor are you able to call it!)
_getidsofnames_ -- A handler which can respond to the COM 'GetIDsOfNames' call. If this attribute
is not provided, then the default policy implementation is used. If this attribute
does exist, it is responsible for providing all required functionality - ie, the
policy _getidsofnames_ method is not invoked at all (and nor are you able to call it!)
IDispatchEx functionality:
_invokeex_ -- Very similar to _invoke_, except slightly different arguments are used.
And the result is just the _real_ result (rather than the (hresult, argErr, realResult)
tuple that _invoke_ uses.
This is the new, prefered handler (the default _invoke_ handler simply called _invokeex_)
_getdispid_ -- Very similar to _getidsofnames_, except slightly different arguments are used,
and only 1 property at a time can be fetched (which is all we support in getidsofnames anyway!)
This is the new, prefered handler (the default _invoke_ handler simply called _invokeex_)
_getnextdispid_- uses self._name_to_dispid_ to enumerate the DISPIDs
"""
def __init__(self, object):
"""Initialise the policy object
Params:
object -- The object to wrap. May be None *iff* @BasicWrapPolicy._CreateInstance_@ will be
called immediately after this to setup a brand new object
"""
if object is not None:
self._wrap_(object)
def _CreateInstance_(self, clsid, reqIID):
"""Creates a new instance of a **wrapped** object
This method looks up a "@win32com.server.policy.regSpec@" % clsid entry
in the registry (using @DefaultPolicy@)
"""
try:
classSpec = win32api.RegQueryValue(win32con.HKEY_CLASSES_ROOT,
regSpec % clsid)
except win32api.error:
raise error("The object is not correctly registered - %s key can not be read" % (regSpec % clsid))
myob = call_func(classSpec)
self._wrap_(myob)
try:
return pythoncom.WrapObject(self, reqIID)
except pythoncom.com_error as xxx_todo_changeme:
(hr, desc, exc, arg) = xxx_todo_changeme.args
from win32com.util import IIDToInterfaceName
desc = "The object '%r' was created, but does not support the " \
"interface '%s'(%s): %s" \
% (myob, IIDToInterfaceName(reqIID), reqIID, desc)
raise pythoncom.com_error(hr, desc, exc, arg)
def _wrap_(self, object):
"""Wraps up the specified object.
This function keeps a reference to the passed
object, and may interogate it to determine how to respond to COM requests, etc.
"""
# We "clobber" certain of our own methods with ones
# provided by the wrapped object, iff they exist.
self._name_to_dispid_ = { }
ob = self._obj_ = object
if hasattr(ob, '_query_interface_'):
self._query_interface_ = ob._query_interface_
if hasattr(ob, '_invoke_'):
self._invoke_ = ob._invoke_
if hasattr(ob, '_invokeex_'):
self._invokeex_ = ob._invokeex_
if hasattr(ob, '_getidsofnames_'):
self._getidsofnames_ = ob._getidsofnames_
if hasattr(ob, '_getdispid_'):
self._getdispid_ = ob._getdispid_
# Allow for override of certain special attributes.
if hasattr(ob, '_com_interfaces_'):
self._com_interfaces_ = []
# Allow interfaces to be specified by name.
for i in ob._com_interfaces_:
if type(i) != pywintypes.IIDType:
# Prolly a string!
if i[0] != "{":
i = pythoncom.InterfaceNames[i]
else:
i = pythoncom.MakeIID(i)
self._com_interfaces_.append(i)
else:
self._com_interfaces_ = [ ]
# "QueryInterface" handling.
def _QueryInterface_(self, iid):
"""The main COM entry-point for QueryInterface.
This checks the _com_interfaces_ attribute and if the interface is not specified
there, it calls the derived helper _query_interface_
"""
if iid in self._com_interfaces_:
return 1
return self._query_interface_(iid)
def _query_interface_(self, iid):
"""Called if the object does not provide the requested interface in _com_interfaces,
and does not provide a _query_interface_ handler.
Returns a result to the COM framework indicating the interface is not supported.
"""
return 0
# "Invoke" handling.
def _Invoke_(self, dispid, lcid, wFlags, args):
"""The main COM entry-point for Invoke.
This calls the _invoke_ helper.
"""
#Translate a possible string dispid to real dispid.
if type(dispid) == type(""):
try:
dispid = self._name_to_dispid_[dispid.lower()]
except KeyError:
raise COMException(scode = winerror.DISP_E_MEMBERNOTFOUND, desc="Member not found")
return self._invoke_(dispid, lcid, wFlags, args)
def _invoke_(self, dispid, lcid, wFlags, args):
# Delegates to the _invokeex_ implementation. This allows
# a custom policy to define _invokeex_, and automatically get _invoke_ too.
return S_OK, -1, self._invokeex_(dispid, lcid, wFlags, args, None, None)
# "GetIDsOfNames" handling.
def _GetIDsOfNames_(self, names, lcid):
"""The main COM entry-point for GetIDsOfNames.
This checks the validity of the arguments, and calls the _getidsofnames_ helper.
"""
if len(names) > 1:
raise COMException(scode = winerror.DISP_E_INVALID, desc="Cannot support member argument names")
return self._getidsofnames_(names, lcid)
def _getidsofnames_(self, names, lcid):
### note: lcid is being ignored...
return (self._getdispid_(names[0], 0), )
# IDispatchEx support for policies. Most of the IDispathEx functionality
# by default will raise E_NOTIMPL. Thus it is not necessary for derived
# policies to explicitely implement all this functionality just to not implement it!
def _GetDispID_(self, name, fdex):
return self._getdispid_(name, fdex)
def _getdispid_(self, name, fdex):
try:
### TODO - look at the fdex flags!!!
return self._name_to_dispid_[name.lower()]
except KeyError:
raise COMException(scode = winerror.DISP_E_UNKNOWNNAME)
# "InvokeEx" handling.
def _InvokeEx_(self, dispid, lcid, wFlags, args, kwargs, serviceProvider):
"""The main COM entry-point for InvokeEx.
This calls the _invokeex_ helper.
"""
#Translate a possible string dispid to real dispid.
if type(dispid) == type(""):
try:
dispid = self._name_to_dispid_[dispid.lower()]
except KeyError:
raise COMException(scode = winerror.DISP_E_MEMBERNOTFOUND, desc="Member not found")
return self._invokeex_(dispid, lcid, wFlags, args, kwargs, serviceProvider)
def _invokeex_(self, dispid, lcid, wFlags, args, kwargs, serviceProvider):
"""A stub for _invokeex_ - should never be called.
Simply raises an exception.
"""
# Base classes should override this method (and not call the base)
raise error("This class does not provide _invokeex_ semantics")
def _DeleteMemberByName_(self, name, fdex):
return self._deletememberbyname_(name, fdex)
def _deletememberbyname_(self, name, fdex):
raise COMException(scode = winerror.E_NOTIMPL)
def _DeleteMemberByDispID_(self, id):
return self._deletememberbydispid(id)
def _deletememberbydispid_(self, id):
raise COMException(scode = winerror.E_NOTIMPL)
def _GetMemberProperties_(self, id, fdex):
return self._getmemberproperties_(id, fdex)
def _getmemberproperties_(self, id, fdex):
raise COMException(scode = winerror.E_NOTIMPL)
def _GetMemberName_(self, dispid):
return self._getmembername_(dispid)
def _getmembername_(self, dispid):
raise COMException(scode = winerror.E_NOTIMPL)
def _GetNextDispID_(self, fdex, dispid):
return self._getnextdispid_(fdex, dispid)
def _getnextdispid_(self, fdex, dispid):
ids = list(self._name_to_dispid_.values())
ids.sort()
if DISPID_STARTENUM in ids: ids.remove(DISPID_STARTENUM)
if dispid==DISPID_STARTENUM:
return ids[0]
else:
try:
return ids[ids.index(dispid)+1]
except ValueError: # dispid not in list?
raise COMException(scode = winerror.E_UNEXPECTED)
except IndexError: # No more items
raise COMException(scode = winerror.S_FALSE)
def _GetNameSpaceParent_(self):
return self._getnamespaceparent()
def _getnamespaceparent_(self):
raise COMException(scode = winerror.E_NOTIMPL)
class MappedWrapPolicy(BasicWrapPolicy):
"""Wraps an object using maps to do its magic
This policy wraps up a Python object, using a number of maps
which translate from a Dispatch ID and flags, into an object to call/getattr, etc.
It is the responsibility of derived classes to determine exactly how the
maps are filled (ie, the derived classes determine the map filling policy.
This policy supports the following special attributes on the wrapped object
_dispid_to_func_/_dispid_to_get_/_dispid_to_put_ -- These are dictionaries
(keyed by integer dispid, values are string attribute names) which the COM
implementation uses when it is processing COM requests. Note that the implementation
uses this dictionary for its own purposes - not a copy - which means the contents of
these dictionaries will change as the object is used.
"""
def _wrap_(self, object):
BasicWrapPolicy._wrap_(self, object)
ob = self._obj_
if hasattr(ob, '_dispid_to_func_'):
self._dispid_to_func_ = ob._dispid_to_func_
else:
self._dispid_to_func_ = { }
if hasattr(ob, '_dispid_to_get_'):
self._dispid_to_get_ = ob._dispid_to_get_
else:
self._dispid_to_get_ = { }
if hasattr(ob, '_dispid_to_put_'):
self._dispid_to_put_ = ob._dispid_to_put_
else:
self._dispid_to_put_ = { }
def _getmembername_(self, dispid):
if dispid in self._dispid_to_func_:
return self._dispid_to_func_[dispid]
elif dispid in self._dispid_to_get_:
return self._dispid_to_get_[dispid]
elif dispid in self._dispid_to_put_:
return self._dispid_to_put_[dispid]
else:
raise COMException(scode = winerror.DISP_E_MEMBERNOTFOUND)
class DesignatedWrapPolicy(MappedWrapPolicy):
"""A policy which uses a mapping to link functions and dispid
A MappedWrappedPolicy which allows the wrapped object to specify, via certain
special named attributes, exactly which methods and properties are exposed.
All a wrapped object need do is provide the special attributes, and the policy
will handle everything else.
Attributes:
_public_methods_ -- Required, unless a typelib GUID is given -- A list
of strings, which must be the names of methods the object
provides. These methods will be exposed and callable
from other COM hosts.
_public_attrs_ A list of strings, which must be the names of attributes on the object.
These attributes will be exposed and readable and possibly writeable from other COM hosts.
_readonly_attrs_ -- A list of strings, which must also appear in _public_attrs. These
attributes will be readable, but not writable, by other COM hosts.
_value_ -- A method that will be called if the COM host requests the "default" method
(ie, calls Invoke with dispid==DISPID_VALUE)
_NewEnum -- A method that will be called if the COM host requests an enumerator on the
object (ie, calls Invoke with dispid==DISPID_NEWENUM.)
It is the responsibility of the method to ensure the returned
object conforms to the required Enum interface.
_typelib_guid_ -- The GUID of the typelibrary with interface definitions we use.
_typelib_version_ -- A tuple of (major, minor) with a default of 1,1
_typelib_lcid_ -- The LCID of the typelib, default = LOCALE_USER_DEFAULT
_Evaluate -- Dunno what this means, except the host has called Invoke with dispid==DISPID_EVALUATE!
See the COM documentation for details.
"""
def _wrap_(self, ob):
# If we have nominated universal interfaces to support, load them now
tlb_guid = getattr(ob, '_typelib_guid_', None)
if tlb_guid is not None:
tlb_major, tlb_minor = getattr(ob, '_typelib_version_', (1,0))
tlb_lcid = getattr(ob, '_typelib_lcid_', 0)
from win32com import universal
# XXX - what if the user wants to implement interfaces from multiple
# typelibs?
# Filter out all 'normal' IIDs (ie, IID objects and strings starting with {
interfaces = [i for i in getattr(ob, '_com_interfaces_', [])
if type(i) != pywintypes.IIDType and not i.startswith("{")]
universal_data = universal.RegisterInterfaces(tlb_guid, tlb_lcid,
tlb_major, tlb_minor, interfaces)
else:
universal_data = []
MappedWrapPolicy._wrap_(self, ob)
if not hasattr(ob, '_public_methods_') and not hasattr(ob, "_typelib_guid_"):
raise error("Object does not support DesignatedWrapPolicy, as it does not have either _public_methods_ or _typelib_guid_ attributes.")
# Copy existing _dispid_to_func_ entries to _name_to_dispid_
for dispid, name in self._dispid_to_func_.items():
self._name_to_dispid_[name.lower()]=dispid
for dispid, name in self._dispid_to_get_.items():
self._name_to_dispid_[name.lower()]=dispid
for dispid, name in self._dispid_to_put_.items():
self._name_to_dispid_[name.lower()]=dispid
# Patch up the universal stuff.
for dispid, invkind, name in universal_data:
self._name_to_dispid_[name.lower()]=dispid
if invkind == DISPATCH_METHOD:
self._dispid_to_func_[dispid] = name
elif invkind in (DISPATCH_PROPERTYPUT, DISPATCH_PROPERTYPUTREF):
self._dispid_to_put_[dispid] = name
elif invkind == DISPATCH_PROPERTYGET:
self._dispid_to_get_[dispid] = name
else:
raise ValueError("unexpected invkind: %d (%s)" % (invkind,name))
# look for reserved methods
if hasattr(ob, '_value_'):
self._dispid_to_get_[DISPID_VALUE] = '_value_'
self._dispid_to_put_[DISPID_PROPERTYPUT] = '_value_'
if hasattr(ob, '_NewEnum'):
self._name_to_dispid_['_newenum'] = DISPID_NEWENUM
self._dispid_to_func_[DISPID_NEWENUM] = '_NewEnum'
if hasattr(ob, '_Evaluate'):
self._name_to_dispid_['_evaluate'] = DISPID_EVALUATE
self._dispid_to_func_[DISPID_EVALUATE] = '_Evaluate'
next_dispid = self._allocnextdispid(999)
# note: funcs have precedence over attrs (install attrs first)
if hasattr(ob, '_public_attrs_'):
if hasattr(ob, '_readonly_attrs_'):
readonly = ob._readonly_attrs_
else:
readonly = [ ]
for name in ob._public_attrs_:
dispid = self._name_to_dispid_.get(name.lower())
if dispid is None:
dispid = next_dispid
self._name_to_dispid_[name.lower()] = dispid
next_dispid = self._allocnextdispid(next_dispid)
self._dispid_to_get_[dispid] = name
if name not in readonly:
self._dispid_to_put_[dispid] = name
for name in getattr(ob, "_public_methods_", []):
dispid = self._name_to_dispid_.get(name.lower())
if dispid is None:
dispid = next_dispid
self._name_to_dispid_[name.lower()] = dispid
next_dispid = self._allocnextdispid(next_dispid)
self._dispid_to_func_[dispid] = name
self._typeinfos_ = None # load these on demand.
def _build_typeinfos_(self):
# Can only ever be one for now.
tlb_guid = getattr(self._obj_, '_typelib_guid_', None)
if tlb_guid is None:
return []
tlb_major, tlb_minor = getattr(self._obj_, '_typelib_version_', (1,0))
tlb = pythoncom.LoadRegTypeLib(tlb_guid, tlb_major, tlb_minor)
typecomp = tlb.GetTypeComp()
# Not 100% sure what semantics we should use for the default interface.
# Look for the first name in _com_interfaces_ that exists in the typelib.
for iname in self._obj_._com_interfaces_:
try:
type_info, type_comp = typecomp.BindType(iname)
if type_info is not None:
return [type_info]
except pythoncom.com_error:
pass
return []
def _GetTypeInfoCount_(self):
if self._typeinfos_ is None:
self._typeinfos_ = self._build_typeinfos_()
return len(self._typeinfos_)
def _GetTypeInfo_(self, index, lcid):
if self._typeinfos_ is None:
self._typeinfos_ = self._build_typeinfos_()
if index < 0 or index >= len(self._typeinfos_):
raise COMException(scode=winerror.DISP_E_BADINDEX)
return 0, self._typeinfos_[index]
def _allocnextdispid(self, last_dispid):
while 1:
last_dispid = last_dispid + 1
if last_dispid not in self._dispid_to_func_ and \
last_dispid not in self._dispid_to_get_ and \
last_dispid not in self._dispid_to_put_:
return last_dispid
def _invokeex_(self, dispid, lcid, wFlags, args, kwArgs, serviceProvider):
### note: lcid is being ignored...
if wFlags & DISPATCH_METHOD:
try:
funcname = self._dispid_to_func_[dispid]
except KeyError:
if not wFlags & DISPATCH_PROPERTYGET:
raise COMException(scode=winerror.DISP_E_MEMBERNOTFOUND) # not found
else:
try:
func = getattr(self._obj_, funcname)
except AttributeError:
# May have a dispid, but that doesnt mean we have the function!
raise COMException(scode=winerror.DISP_E_MEMBERNOTFOUND)
# Should check callable here
try:
return func(*args)
except TypeError as v:
# Particularly nasty is "wrong number of args" type error
# This helps you see what 'func' and 'args' actually is
if str(v).find("arguments")>=0:
print("** TypeError %s calling function %r(%r)" % (v, func, args))
raise
if wFlags & DISPATCH_PROPERTYGET:
try:
name = self._dispid_to_get_[dispid]
except KeyError:
raise COMException(scode=winerror.DISP_E_MEMBERNOTFOUND) # not found
retob = getattr(self._obj_, name)
if type(retob)==types.MethodType: # a method as a property - call it.
retob = retob(*args)
return retob
if wFlags & (DISPATCH_PROPERTYPUT | DISPATCH_PROPERTYPUTREF): ### correct?
try:
name = self._dispid_to_put_[dispid]
except KeyError:
raise COMException(scode=winerror.DISP_E_MEMBERNOTFOUND) # read-only
# If we have a method of that name (ie, a property get function), and
# we have an equiv. property set function, use that instead.
if type(getattr(self._obj_, name, None)) == types.MethodType and \
type(getattr(self._obj_, "Set" + name, None)) == types.MethodType:
fn = getattr(self._obj_, "Set" + name)
fn( *args )
else:
# just set the attribute
setattr(self._obj_, name, args[0])
return
raise COMException(scode=winerror.E_INVALIDARG, desc="invalid wFlags")
class EventHandlerPolicy(DesignatedWrapPolicy):
"""The default policy used by event handlers in the win32com.client package.
In addition to the base policy, this provides argument conversion semantics for
params
* dispatch params are converted to dispatch objects.
* Unicode objects are converted to strings (1.5.2 and earlier)
NOTE: Later, we may allow the object to override this process??
"""
def _transform_args_(self, args, kwArgs, dispid, lcid, wFlags, serviceProvider):
ret = []
for arg in args:
arg_type = type(arg)
if arg_type == IDispatchType:
import win32com.client
arg = win32com.client.Dispatch(arg)
elif arg_type == IUnknownType:
try:
import win32com.client
arg = win32com.client.Dispatch(arg.QueryInterface(pythoncom.IID_IDispatch))
except pythoncom.error:
pass # Keep it as IUnknown
ret.append(arg)
return tuple(ret), kwArgs
def _invokeex_(self, dispid, lcid, wFlags, args, kwArgs, serviceProvider):
# transform the args.
args, kwArgs = self._transform_args_(args, kwArgs, dispid, lcid, wFlags, serviceProvider)
return DesignatedWrapPolicy._invokeex_( self, dispid, lcid, wFlags, args, kwArgs, serviceProvider)
class DynamicPolicy(BasicWrapPolicy):
"""A policy which dynamically (ie, at run-time) determines public interfaces.
A dynamic policy is used to dynamically dispatch methods and properties to the
wrapped object. The list of objects and properties does not need to be known in
advance, and methods or properties added to the wrapped object after construction
are also handled.
The wrapped object must provide the following attributes:
_dynamic_ -- A method that will be called whenever an invoke on the object
is called. The method is called with the name of the underlying method/property
(ie, the mapping of dispid to/from name has been resolved.) This name property
may also be '_value_' to indicate the default, and '_NewEnum' to indicate a new
enumerator is requested.
"""
def _wrap_(self, object):
BasicWrapPolicy._wrap_(self, object)
if not hasattr(self._obj_, '_dynamic_'):
raise error("Object does not support Dynamic COM Policy")
self._next_dynamic_ = self._min_dynamic_ = 1000
self._dyn_dispid_to_name_ = {DISPID_VALUE:'_value_', DISPID_NEWENUM:'_NewEnum' }
def _getdispid_(self, name, fdex):
# TODO - Look at fdex flags.
lname = name.lower()
try:
return self._name_to_dispid_[lname]
except KeyError:
dispid = self._next_dynamic_ = self._next_dynamic_ + 1
self._name_to_dispid_[lname] = dispid
self._dyn_dispid_to_name_[dispid] = name # Keep case in this map...
return dispid
def _invoke_(self, dispid, lcid, wFlags, args):
return S_OK, -1, self._invokeex_(dispid, lcid, wFlags, args, None, None)
def _invokeex_(self, dispid, lcid, wFlags, args, kwargs, serviceProvider):
### note: lcid is being ignored...
### note: kwargs is being ignored...
### note: serviceProvider is being ignored...
### there might be assigned DISPID values to properties, too...
try:
name = self._dyn_dispid_to_name_[dispid]
except KeyError:
raise COMException(scode = winerror.DISP_E_MEMBERNOTFOUND, desc="Member not found")
return self._obj_._dynamic_(name, lcid, wFlags, args)
DefaultPolicy = DesignatedWrapPolicy
def resolve_func(spec):
"""Resolve a function by name
Given a function specified by 'module.function', return a callable object
(ie, the function itself)
"""
try:
idx = spec.rindex(".")
mname = spec[:idx]
fname = spec[idx+1:]
# Dont attempt to optimize by looking in sys.modules,
# as another thread may also be performing the import - this
# way we take advantage of the built-in import lock.
module = _import_module(mname)
return getattr(module, fname)
except ValueError: # No "." in name - assume in this module
return globals()[spec]
def call_func(spec, *args):
"""Call a function specified by name.
Call a function specified by 'module.function' and return the result.
"""
return resolve_func(spec)(*args)
def _import_module(mname):
"""Import a module just like the 'import' statement.
Having this function is much nicer for importing arbitrary modules than
using the 'exec' keyword. It is more efficient and obvious to the reader.
"""
__import__(mname)
# Eeek - result of _import_ is "win32com" - not "win32com.a.b.c"
# Get the full module from sys.modules
return sys.modules[mname]
#######
#
# Temporary hacks until all old code moves.
#
# These have been moved to a new source file, but some code may
# still reference them here. These will end up being removed.
try:
from .dispatcher import DispatcherTrace, DispatcherWin32trace
except ImportError: # Quite likely a frozen executable that doesnt need dispatchers
pass
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