/// <remarks>
/// Use only with VBA-supplied <see cref="ITypeInfo"/> which may return a <see cref="VARDESC"/> that do not conform to
/// the MS-OAUT in describing the constants. See section 2.2.43 at: https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-oaut/ae7791d2-4399-4dff-b7c6-b0d4f3dce982
///
/// To further complicate the situation, on 64-bit platform, the <see cref="VARDESC.DESCUNION.oInst"/> is a 32-bit integer whereas
/// the <see cref="VARDESC.DESCUNION.lpvarValue"/> is a pointer. On 32-bit platform, the sizes of 2 members are exactly same so no
/// problem. But on 64-bit platform, setting the <c>oInst</c>to 0 does not necessarily zero-initialize the entire region. Thus, the
/// upper 32-bit part of the <c>lpvarValue</c> can contain garbage which will confound the simple null pointer check. Thus to guard
/// against this, we will check the <c>oInst</c> value to see if it's zero.
///
/// There is a small but non-zero chance that there might be a valid pointer that happens to be only in high half of the address...
/// in that case, it'll be wrong but since VBA is always writing <see cref="VARKIND.VAR_STATIC"/> to the <see cref="VARDESC.varkind"/>
/// field. To accommodate this unlikely possibility, we take advantage of VBA's other failure to comply with MS-OAUT specifications:
/// None of its constants has a valid member ID. Normally they are assigned <c>MEMBER_NIL</c> which makes them useless for enumeration. To
/// accommodate this, the TypeInfoWrapper in Rubberduck.VBEditor project will generate unique member IDs for those constants. Thus, we can use
/// the same range to infer that it's a constant assigned by the TypeInfoWrapper.
/// </remarks>
/// <param name="varDesc">The <see cref="VARDESC"/> from a VBA <see cref="ITypeInfo"/></param>
/// <returns>True if this is most likely a constant. False when it's definitely not.</returns>
public static bool IsValidVBAConstant(this VARDESC varDesc)
{
// TODO: Move the function to a better home and avoid duplication of constants (see TypeInfoWrapper)
const int _ourConstantsDispatchMemberIDRangeStart = unchecked ((int)0xFEDC0000);
const int _ourConstantsDispatchMemberIDRangeBitmaskCheck = unchecked ((int)0xFFFF0000);
return((varDesc.memid & _ourConstantsDispatchMemberIDRangeBitmaskCheck) >= _ourConstantsDispatchMemberIDRangeStart &&
varDesc.varkind == VARKIND.VAR_STATIC &&
varDesc.desc.oInst != 0);
}
/// <summary>
/// Helper method for retrieving type attributes for a given type info
/// This method needs to also return the native pointer to be released when we're done with our VARDESC.
/// It's not really possible to copy everything to a managed struct and then release the ptr immediately
/// here, since VARDESCs contain other native pointers we may need to access.
/// </summary>
internal static void GetVarDescForVarIndex(ITypeInfo typeInfo, int varIndex, out VARDESC varDesc, out IntPtr varDescHandle)
{
typeInfo.GetVarDesc(varIndex, out IntPtr pVarDesc);
// GetVarDesc should never return null, this is just to be safe
if (pVarDesc == IntPtr.Zero)
{
throw new COMException(
ResourceUtilities.GetResourceString("ResolveComReference.CannotRetrieveTypeInformation"));
}
varDesc = (VARDESC)Marshal.PtrToStructure(pVarDesc, typeof(VARDESC));
varDescHandle = pVarDesc;
}
public FieldInfo(VARDESC vardesc, ITypeInfo info, IVbaTypeRepository repo)
{
Name = ComHelper.GetMemberName(info, vardesc);
Type = repo.GetVbaType(vardesc.elemdescVar.tdesc, info);
IsConstant = ComHelper.IsConstant(vardesc);
if (IsConstant)
{
Value = ComHelper.GetConstantValue(vardesc);
}
else
{
// TODO handle other cases here. May need reference to parent type.
IsField = true;
}
}
public void GetVarDesc(int index, out IntPtr ppVarDesc)
{
// Fail BEFORE allocating the handle to avoid leaks. If the real COM object fails in this method
// and doesn't return the handle or clean it up itself there's not much we can do to avoid the leak.
_faultInjector.FailurePointThrow(MockTypeLibrariesFailurePoints.ITypeInfo_GetVarDesc);
ppVarDesc = _memoryHelper.AllocateHandle(Marshal.SizeOf <VARDESC>());
_memoryHelper.EnterSubAllocationScope(ppVarDesc);
VARDESC varDesc = new VARDESC();
varDesc.elemdescVar.tdesc = _definedVariables[index].CreateTypeDesc(new IntPtr(index + s_HREF_VARS_OFFSET), _memoryHelper);
_memoryHelper.ExitSubAllocationScope();
Marshal.StructureToPtr(varDesc, ppVarDesc, false);
}
static void DealWithTypeInfo(UCOMITypeInfo it)
{
// Get the names from ITypeInfo
string name;
string docstring;
Int32 ctxt;
string helpfile;
// TypeInfo name
it.GetDocumentation(-1, out name, out docstring, out ctxt, out helpfile);
IntPtr pa;
it.GetTypeAttr(out pa);
TYPEATTR ta = (TYPEATTR)Marshal.PtrToStructure(pa, typeof(TYPEATTR));
DealWithName(name, ta.guid);
// Deal with funcs
for (int i = 0; i < ta.cFuncs; i++)
{
IntPtr pfd;
it.GetFuncDesc(i, out pfd);
FUNCDESC fd = (FUNCDESC)Marshal.PtrToStructure(pfd, typeof(FUNCDESC));
it.GetDocumentation(fd.memid, out name, out docstring, out ctxt, out helpfile);
DealWithName(name, Guid.Empty);
}
// Deal with vars
for (int i = 0; i < ta.cVars; i++)
{
IntPtr pvd;
it.GetVarDesc(i, out pvd);
VARDESC vd = (VARDESC)Marshal.PtrToStructure(pvd, typeof(VARDESC));
it.GetDocumentation(vd.memid, out name, out docstring, out ctxt, out helpfile);
DealWithName(name, Guid.Empty);
}
}
public VarDesc(ITypeInfo typeinfo, int index)
{
m_typeinfo = typeinfo;
m_ipVarDesc = TypeLibResourceManager.GetDaemon().GetVarDesc(typeinfo, index);
m_vardesc = (VARDESC)Marshal.PtrToStructure(m_ipVarDesc, typeof(VARDESC));
}
public unsafe int RemoteGetVarDesc(uint index, VARDESC** ppVarDesc, CLEANLOCALSTORAGE* pDummy)
{
ITypeInfo_vtbl** @this = (ITypeInfo_vtbl**)reference;
ITypeInfo_vtbl* vtbl = *@this;
if (vtbl == null)
throw new InvalidComObjectException();
Delegate genericDelegate = Marshal.GetDelegateForFunctionPointer(vtbl->method_6, typeof(delegate_6));
delegate_6 method = (delegate_6)genericDelegate;
return method(@this, index, ppVarDesc, pDummy);
}
public unsafe int RemoteBind(char* szName, uint lHashVal, ushort wFlags, ITypeInfo* ppTInfo, DESCKIND* pDescKind, FUNCDESC** ppFuncDesc, VARDESC** ppVarDesc, ITypeComp* ppTypeComp, CLEANLOCALSTORAGE* pDummy)
{
ITypeComp_vtbl** @this = (ITypeComp_vtbl**)reference;
ITypeComp_vtbl* vtbl = *@this;
if (vtbl == null)
throw new InvalidComObjectException();
Delegate genericDelegate = Marshal.GetDelegateForFunctionPointer(vtbl->method_3, typeof(delegate_3));
delegate_3 method = (delegate_3)genericDelegate;
return method(@this, szName, lHashVal, wFlags, ppTInfo, pDescKind, ppFuncDesc, ppVarDesc, ppTypeComp, pDummy);
}
