Example Code for Detecting Schema Naming Collisions

This topic includes a code example that detects schema naming collisions.

The following C/C++ code example queries the schema for the key naming attributes on a classSchema or attributeSchema object.

It returns TRUE if conflicting attributes or classes are found. It returns FALSE if the attribute or class with the specified cn, lDAPDisplayName, OID, schemaIDGUID, or linkID does not conflict with the schema and, therefore, is safe to add to the schema.

/********************************************************************

    FindCollidingAttributesOrClasses()

********************************************************************/

HRESULT FindCollidingAttributesOrClasses(
    IDirectorySearch *pSchemaNC, // IDirectorySearch pointer to 
                                 // schema naming context.
    LPWSTR szName,
    LPWSTR szLDAPDisplayName,
    LPWSTR szOID,
    const GUID * pSchemaIDGUID,
    DWORD dwLinkID, // Value is zero (0) if the attribute is not linked,
                    // or if checking for class.
    BOOL *pfIsColliding)
{
    if (!pSchemaNC || 
        !szName ||
        !szLDAPDisplayName || 
        !szOID || 
        !pSchemaIDGUID)
    {
        return E_POINTER;
    }
 
    HRESULT hr = E_FAIL;
        
    LPWSTR szBuffer = NULL;
        
    hr = ADsEncodeBinaryData((LPBYTE)pSchemaIDGUID, 
                             sizeof(GUID), 
                             &szBuffer);
    if (SUCCEEDED(hr))
    {
        LPWSTR pwszFormatLinkID = L"(|(cn=%s)(lDAPDisplayName=%s)(attributeID=%s)(governsID=%s)(schemaIDGUID=%s)(linkID=%d))";
        LPWSTR pwszFormatNoLinkID = L"(|(cn=%s)(lDAPDisplayName=%s)(attributeID=%s)(governsID=%s)(schemaIDGUID=%s))";
        LPWSTR szFilter = new WCHAR[lstrlenW(pwszFormatLinkID) + 
                                    lstrlenW(szName) + 
                                    lstrlenW(szLDAPDisplayName) + 
                                    lstrlenW(szOID) + 
                                    lstrlenW(szOID) +
                                    lstrlenW(szBuffer) +
                                    20 +
                                    1];

        if(szFilter)
        {
            if (dwLinkID > 0L)
            {
                swprintf_s(szFilter,
                    pwszFormatLinkID,
                    szName,
                    szLDAPDisplayName,
                    szOID,
                    szOID,
                    szBuffer,
                    dwLinkID);
            }
            else
            {
                swprintf_s(szFilter,
                    pwszFormatNoLinkID,
                    szName,
                    szLDAPDisplayName,
                    szOID,
                    szOID,
                    szBuffer);
            }
            
            // Attributes are one-level deep in the Schema 
            // container so only search one level.
            ADS_SEARCHPREF_INFO SearchPrefs[2];
            SearchPrefs[0].dwSearchPref = ADS_SEARCHPREF_SEARCH_SCOPE;
            SearchPrefs[0].vValue.dwType = ADSTYPE_INTEGER;
            SearchPrefs[0].vValue.Integer = ADS_SCOPE_ONELEVEL;

            SearchPrefs[1].dwSearchPref = ADS_SEARCHPREF_PAGESIZE;
            SearchPrefs[1].vValue.dwType = ADSTYPE_INTEGER;
            SearchPrefs[1].vValue.Integer = 1000;
            
            int iCount = 0;
            
            // Set the search preference
            hr = pSchemaNC->SetSearchPreference(
                   SearchPrefs, 
                   sizeof(SearchPrefs)/sizeof(ADS_SEARCHPREF_INFO)
                 );
            if (SUCCEEDED(hr))
            {
                LPWSTR pszAttribs[] = {
                    L"lDAPDisplayName", 
                    L"cn", 
                    L"attributeID", 
                    L"governsID", 
                    L"schemaIDGUID", 
                    L"linkID", 
                    L"objectCategory"
                };

                // Handle used for searching
                ADS_SEARCH_HANDLE hSearch = NULL;
                DWORD x = 0L;
                
                hr = pSchemaNC->ExecuteSearch(szFilter,
                                pszAttribs,
                                sizeof(pszAttribs)/sizeof(LPWSTR),
                                &hSearch);
                if (SUCCEEDED(hr))
                {
                    // Call IDirectorySearch::GetNextRow() 
                    // to retrieve the next row  of data.
                    hr = pSchemaNC->GetFirstRow(hSearch);
                    while (hr != S_ADS_NOMORE_ROWS)
                    {
                        // Keep track of count.
                        iCount++;

                        // Get the next row
                        hr = pSchemaNC->GetNextRow(hSearch);
                    }
            
                    // Close the search handle to cleanup
                    pSchemaNC->CloseSearchHandle(hSearch);

                    if(SUCCEEDED(hr))
                    {
                        if (0 == iCount)
                        {
                            *pfIsColliding = FALSE;
                        }
                        else
                        {
                            *pfIsColliding = TRUE;
                        }

                        hr = S_OK;
                    }
                }
            }

            delete szFilter;
        }
            
        FreeADsMem(szBuffer);
    }
    
    return hr;
}