oleaut32: implement underscore-prefix overload (was Re: oleaut32:
ITypeInfo_fnInvoke behavior on PARAMFLAG_FOPT without PARAMFLAG_FHASDEFAULT)
Alex Villacís Lasso
a_villacis at palosanto.com
Mon Nov 13 10:17:48 CST 2006
Alex Villacís Lasso escribió:
> Robert Shearman escribió:
>> a_villacis at palosanto.com wrote:
>>> In a tax app written in Visual Basic/ADO, I found the following
>>> problem:
>>>
>>> In dlls/oleaut32/typelib.c, in function ITypeInfo_fnInvoke(), the
>>> following code is found (around line 5569).
>>>
>>> VARIANTARG *missing_arg = INVBUF_GET_MISSING_ARG_ARRAY(buffer,
>>> func_desc->cParams);
>>>
>>> V_VT(arg) = VT_VARIANT | VT_BYREF;
>>> V_VARIANTREF(arg) = &missing_arg[i];
>>> V_VT(V_VARIANTREF(arg)) = VT_ERROR;
>>> V_ERROR(V_VARIANTREF(arg)) = DISP_E_PARAMNOTFOUND;
>>>
>>> This code runs when a parameter is found that has the PARAMFLAG_FIN and
>>> PARAMFLAG_FOPT flags, but not the PARAMFLAG_FHASDEFAULT flag. As far
>>> as I
>>> understand, this code is supposed to supply a variant that might
>>> hold an
>>> output value. However, in the Append method of the Fields object within
>>> the Recordset object of Microsoft ADODB 2.7, the following
>>> declaration is
>>> found:
>>>
>>> trace:ole:ITypeInfo_fnInvoke invoking:
>>> L"Append"(5)
>>> parm0: L"Name"
>>> parm1: L"Type"
>>> parm2: L"DefinedSize"
>>> parm3: L"Attrib"
>>> parm4: L"FieldValue"
>>> memid is 00000003
>>> Param 0:
>>> tdesc.vartype 8 (VT_BSTR)
>>> u.paramdesc.wParamFlags PARAMFLAG_FIN
>>> u.paramdesc.lpex (nil)
>>> Param 1:
>>> tdesc.vartype 29 (VT_USERDEFINED ref = 2bc)
>>> u.paramdesc.wParamFlags PARAMFLAG_FIN
>>> u.paramdesc.lpex (nil)
>>> Param 2:
>>> tdesc.vartype 29 (VT_USERDEFINED ref = 1c84)
>>> u.paramdesc.wParamFlags PARAMFLAG_FIN PARAMFLAG_FOPT
>>> PARAMFLAG_FHASDEFAULT
>>> u.paramdesc.lpex 0x199868
>>> Param 3:
>>> tdesc.vartype 29 (VT_USERDEFINED ref = 320)
>>> u.paramdesc.wParamFlags PARAMFLAG_FIN PARAMFLAG_FOPT
>>> PARAMFLAG_FHASDEFAULT
>>> u.paramdesc.lpex 0x1998d0
>>> Param 4:
>>> tdesc.vartype 12 (VT_VARIANT)
>>> u.paramdesc.wParamFlags PARAMFLAG_FIN PARAMFLAG_FOPT
>>> u.paramdesc.lpex (nil)
>>> funckind: 1 (pure virtual)
>>> invkind: 1 (func)
>>> callconv: 4 (stdcall)
>>> oVft: 52
>>> cParamsOpt: 1
>>> wFlags: 0
>>> elemdescFunc (return value type):
>>> tdesc.vartype 25 (VT_HRESULT)
>>> u.paramdesc.wParamFlags PARAMFLAGS_NONE
>>> u.paramdesc.lpex (nil)
>>> helpstring: (null)
>>> entry (ordinal): 0x0000
>>>
>>> The implementation of the method in Microsoft ADODB 2.7 last parameter
>>> (FieldValue) absolutely refuses to accept a VT_VARIANT | VT_BYREF
>>> variant.
>>> This result is not dependent of the type of variant pointed to by the
>>> first-level variant - changing VT_ERROR to VT_EMPTY has no effect.
>>> Only by
>>> passing a VT_EMPTY instead of a VT_VARIANT | VT_BYREF can the
>>> application
>>> proceed normally. All oleaut32 tests still pass. Please comment if
>>> this is
>>> an appropriate fix for this issue.
>>>
>>> Changelog:
>>> * (PARAMFLAG_FIN | PARAMFLAG_FOPT) & ~PARAMFLAG_FHASDEFAULT should
>>> result
>>> in a default parameter of VT_EMPTY, not a VT_VARIANT | VT_BYREF in
>>> ITypeInfo_fnInvoke
>>>
>>>
>>
>> I don't believe this is fix is correct. See the tests not included in
>> Wine yet here:
>> http://www.winehq.org/pipermail/wine-patches/2006-August/029511.html
>>
>> In particular, this code:
>>> +HRESULT WINAPI Widget_DoSomething(
>>> + IWidget __RPC_FAR * iface,
>>> + /* [in] */ double number,
>>> + /* [out] */ BSTR *str1,
>>> + /* [defaultvalue][in] */ BSTR str2,
>>> + /* [optional][in] */ VARIANT __RPC_FAR *opt)
>>> +{
>>> + static const WCHAR szString[] = { 'S','t','r','i','n','g',0 };
>>> + trace("DoSomething()\n");
>>> +
>>> + ok(number == 3.141, "number(%f) != 3.141\n", number);
>>> + ok(*str2 == '\0', "str2(%s) != \"\"\n", wine_dbgstr_w(str2));
>>> + ok(V_VT(opt) == VT_ERROR, "V_VT(opt) should be VT_ERROR instead
>>> of 0x%x\n", V_VT(opt));
>>> + ok(V_ERROR(opt) == DISP_E_PARAMNOTFOUND, "V_ERROR(opt) should
>>> be DISP_E_PARAMNOTFOUND instead of 0x%08lx\n", V_ERROR(opt));
>>> + *str1 = SysAllocString(szString);
>>> +
>>> + return S_FALSE;
>>> +}
>>
>>
> Bug http://bugs.winehq.org/show_bug.cgi?id=6638 was opened for this
> problem. I have reasons to believe that this is a case of
> (undocumented?) overloading with builtin oleaut32 calling the wrong
> version of a method. The bug report has a full explanation of this,
> and the reasons why I arrived at the overloading theory. However I
> need an OLE Automation expert to verify my hypothesis. Please comment
> on this (especially from the Codeweavers people).
>
Here is a patch that implements my hunch. This patch fixes the problem
on both my test app at bug #6638 and the tax app I try to run.
Changelog:
* When there are not enough actual parameters for invoking, look for a
possible overload with underscore prefix before trying the original
function.
--
The following cryptic message was allegedly found in the inner edge of a Windows
XP installation CD:
4F6E65204F5320746F2072756C65207468656D20616C6C2C204F6E65204F5320746F2066696E6420
7468656D2C0D0A4F6E65204F5320746F206272696E67207468656D20616C6C20616E6420696E2074
6865206461726B6E6573732062696E64207468656D2E0A
It is rumored that only a true Unix Wizard can decypher this mysterious message,
which supposedly encodes the true nature and purpose of the software.
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