/// <summary>
        /// Set custom field data for one field (specified by owner HVO and field ID).
        /// </summary>
        /// <returns><c>true</c>, if custom field data was set, <c>false</c> otherwise (e.g., if value hadn't changed,
        /// or value was null, or field type was one not implemented in LCM, such as CellarPropertyType.Float).</returns>
        /// <param name="hvo">HVO of object whose field we're setting.</param>
        /// <param name="flid">Field ID of custom field to set.</param>
        /// <param name="value">Field's new value (as returned by GetCustomFieldData).</param>
        /// <param name="guidOrGuids">GUID or guids associated with new value (as returned by GetCustomFieldData).
        /// May be null or BsonNull.Value if no GUIDs associated with this value.</param>
        public bool SetCustomFieldData(int hvo, int flid, BsonValue value, BsonValue guidOrGuids)
        {
            if ((value == null) || (value == BsonNull.Value) ||
                ((value.BsonType == BsonType.Array) && (value.AsBsonArray.Count == 0)))
            {
                return(false);
            }
            List <Guid> fieldGuids = new List <Guid>();

            if (guidOrGuids == null || guidOrGuids == BsonNull.Value)
            {
                // Leave fieldGuids as an empty list
            }
            else
            {
                if (guidOrGuids is BsonArray)
                {
                    fieldGuids.AddRange(guidOrGuids.AsBsonArray.Select(bsonValue => ParseGuidOrDefault(bsonValue.AsString)));
                }
                else
                {
                    fieldGuids.Add(ParseGuidOrDefault(guidOrGuids.AsString));
                }
            }
            ISilDataAccessManaged data      = (ISilDataAccessManaged)cache.DomainDataByFlid;
            CellarPropertyType    fieldType = (CellarPropertyType)lcmMetaData.GetFieldType(flid);
            string fieldName = lcmMetaData.GetFieldNameOrNull(flid);

//			logger.Debug("Custom field named {0} has type {1}", fieldName, fieldType.ToString());
            if (fieldName == null)
            {
                return(false);
            }

            // Valid field types in LCM are GenDate, Integer, String, OwningAtomic, ReferenceAtomic, and ReferenceCollection, so that's all we implement.
            switch (fieldType)
            {
            case CellarPropertyType.GenDate:
            {
                var    valueAsMultiText = BsonSerializer.Deserialize <LfMultiText>(value.AsBsonDocument);
                string valueAsString    = valueAsMultiText.BestString(new string[] { MagicStrings.LanguageCodeForGenDateFields });
                if (string.IsNullOrEmpty(valueAsString))
                {
                    return(false);
                }
                GenDate valueAsGenDate;
                if (GenDate.TryParse(valueAsString, out valueAsGenDate))
                {
                    GenDate oldValue = data.get_GenDateProp(hvo, flid);
                    if (oldValue == valueAsGenDate)
                    {
                        return(false);
                    }
                    else
                    {
                        data.SetGenDate(hvo, flid, valueAsGenDate);
                        return(true);
                    }
                }
                return(false);
            }

            case CellarPropertyType.Integer:
            {
                var    valueAsMultiText = BsonSerializer.Deserialize <LfMultiText>(value.AsBsonDocument);
                string valueAsString    = valueAsMultiText.BestString(new string[] { MagicStrings.LanguageCodeForIntFields });
                if (string.IsNullOrEmpty(valueAsString))
                {
                    return(false);
                }
                int valueAsInt;
                if (int.TryParse(valueAsString, out valueAsInt))
                {
                    int oldValue = data.get_IntProp(hvo, flid);
                    if (oldValue == valueAsInt)
                    {
                        return(false);
                    }
                    else
                    {
                        data.SetInt(hvo, flid, valueAsInt);
                        return(true);
                    }
                }
                return(false);
            }

            case CellarPropertyType.OwningAtomic:
            {
                // Custom field is a MultiparagraphText, which is an IStText object in LCM
                IStTextRepository textRepo = servLoc.GetInstance <IStTextRepository>();
                Guid    fieldGuid          = fieldGuids.FirstOrDefault();
                IStText text;
                if (!textRepo.TryGetObject(fieldGuid, out text))
                {
                    int currentFieldContentsHvo = data.get_ObjectProp(hvo, flid);
                    if (currentFieldContentsHvo != LcmCache.kNullHvo)
                    {
                        text = (IStText)cache.GetAtomicPropObject(currentFieldContentsHvo);
                    }
                    else
                    {
                        // NOTE: I don't like the "magic" -2 number below, but LCM doesn't seem to have an enum for this. 2015-11 RM
                        int newStTextHvo = data.MakeNewObject(cache.GetDestinationClass(flid), hvo, flid, -2);
                        text = (IStText)cache.GetAtomicPropObject(newStTextHvo);
                    }
                }
                // Shortcut: if text contents haven't changed, we don't want to change anything at all
                BsonValue currentLcmTextContents = ConvertUtilities.GetCustomStTextValues(text, flid,
                                                                                          servLoc.WritingSystemManager, lcmMetaData, cache.DefaultUserWs);
                if ((currentLcmTextContents == BsonNull.Value || currentLcmTextContents == null) &&
                    (value == BsonNull.Value || value == null))
                {
                    return(false);
                }
                if (currentLcmTextContents != null && currentLcmTextContents.Equals(value))
                {
                    // No changes needed.
                    return(false);
                }
                // BsonDocument passed in contains "paragraphs". ParseCustomStTextValuesFromBson wants only a "value" element
                // inside the doc, so we'll need to construct a new doc for the StTextValues.
                BsonDocument     doc       = value.AsBsonDocument;
                LfMultiParagraph multiPara = BsonSerializer.Deserialize <LfMultiParagraph>(doc);
                // Now we have another way to check for "old value and new value were the same": if the LCM multiparagraph was empty,
                // GetCustomStTextValues will have returned null -- so if this multiPara has no paragraphs, that's also an unchanged situation
                if ((multiPara.Paragraphs == null || multiPara.Paragraphs.Count <= 0) &&
                    (currentLcmTextContents == BsonNull.Value || currentLcmTextContents == null))
                {
                    return(false);
                }
                int wsId;
                if (multiPara.InputSystem == null)
                {
                    wsId = lcmMetaData.GetFieldWs(flid);
                }
                else
                {
                    wsId = servLoc.WritingSystemFactory.GetWsFromStr(multiPara.InputSystem);
                }
                ConvertUtilities.SetCustomStTextValues(text, multiPara.Paragraphs, wsId);

                return(true);
            }

            case CellarPropertyType.ReferenceAtomic:
                if (fieldGuids.FirstOrDefault() != Guid.Empty)
                {
                    int referencedHvo = data.get_ObjFromGuid(fieldGuids.FirstOrDefault());
                    int oldHvo        = data.get_ObjectProp(hvo, flid);
                    if (referencedHvo == oldHvo)
                    {
                        return(false);
                    }
                    else
                    {
                        data.SetObjProp(hvo, flid, referencedHvo);
                        // TODO: What if the value of the referenced object has changed in LanguageForge? (E.g., change that possibility's text from "foo" to "bar")
                        // Need to implement that scenario.
                        return(true);
                    }
                }
                else
                {
                    // It's a reference to an ICmPossibility instance: create a new entry in appropriate PossibilityList
                    LfStringField valueAsLfStringField = BsonSerializer.Deserialize <LfStringField>(value.AsBsonDocument);
                    string        nameHierarchy        = valueAsLfStringField.Value;
                    if (nameHierarchy == null)
                    {
                        return(false);
                    }
                    int fieldWs = lcmMetaData.GetFieldWs(flid);
                    // Oddly, this can return 0 for some custom fields. TODO: Find out why: that seems like it would be an error.
                    if (fieldWs == 0)
                    {
                        fieldWs = cache.DefaultUserWs;                         // TODO: Investigate, because this should probably be wsEn instead so that we can create correct keys.
                    }
                    if (fieldWs < 0)
                    {
                        // FindOrCreatePossibility has a bug where it doesn't handle "magic" writing systems (e.g., -1 for default analysis, etc) and
                        // throws an exception instead. So we need to get a real ws here.
                        fieldWs = WritingSystemServices.ActualWs(cache, fieldWs, hvo, flid);
                    }
                    ICmPossibilityList parentList = GetParentListForField(flid);
                    ICmPossibility     newPoss    = parentList.FindOrCreatePossibility(nameHierarchy, fieldWs);

                    int oldHvo = data.get_ObjectProp(hvo, flid);
                    if (newPoss.Hvo == oldHvo)
                    {
                        return(false);
                    }
                    else
                    {
                        data.SetObjProp(hvo, flid, newPoss.Hvo);
                        return(true);
                    }
                }

            case CellarPropertyType.ReferenceCollection:
            case CellarPropertyType.ReferenceSequence:
            {
                if (value == null || value == BsonNull.Value)
                {
                    // Can't write null to a collection or sequence in LCM; it's forbidden. So data.SetObjProp(hvo, flid, LcmCache.kNullHvo) will not work.
                    // Instead, we delete all items from the existing collection or sequence, and thus store an empty coll/seq in LCM.
                    int oldSize = data.get_VecSize(hvo, flid);
                    if (oldSize == 0)
                    {
                        // It was already empty, so leave it unchanged so we don't cause unnecessary changes in the .fwdata XML (and unnecessary Mercurial commits).
                        return(false);
                    }
                    else
                    {
                        data.Replace(hvo, flid, 0, oldSize, null, 0);                                 // This is how you set an empty array
                        return(true);
                    }
                }
                int fieldWs = lcmMetaData.GetFieldWs(flid);
                // TODO: Investigate why this is sometimes coming back as 0 instead of as a real writing system ID
                if (fieldWs == 0)
                {
                    fieldWs = cache.DefaultUserWs;
                }
                ICmPossibilityList parentList = GetParentListForField(flid);

                LfStringArrayField valueAsStringArray = BsonSerializer.Deserialize <LfStringArrayField>(value.AsBsonDocument);

                // Step 1: Get ICmPossibility instances from the string keys that LF gave us

                // First go through all the GUIDs we have and match them up to the keys. If they match up,
                // then remove the keys from the list. Any remaining keys get looked up with FindOrCreatePossibility(), so now we
                // have a complete set of GUIDs (or ICmPossibility objects, which works out to the same thing).

                // TODO: This is all kind of ugly, and WAY too long for one screen. I could put it in its own function,
                // but there's really no real gain from that, as it simply moves the logic even further away from where
                // it needs to be. There's not really a *good* way to achieve simplicity with this code design, unfortunately.
                // The only thing that would be close to simple would be to call some functions from the LcmToMongo option list
                // converters, and that's pulling in code from the "wrong" direction, which has its own ugliness. Ugh.

                HashSet <string> keysFromLF = new HashSet <string>(valueAsStringArray.Values);
                var fieldObjs = new List <ICmPossibility>();
                foreach (Guid guid in fieldGuids)
                {
                    ICmPossibility poss;
                    string         key = "";
                    if (guid != default(Guid))
                    {
                        poss = servLoc.GetInstance <ICmPossibilityRepository>().GetObject(guid);
                        if (poss == null)
                        {
                            // TODO: Decide what to do with possibilities deleted from LCM
                            key = "";
                        }
                        else
                        {
                            if (poss.Abbreviation == null)
                            {
                                key = "";
                            }
                            else
                            {
                                ITsString keyTss = poss.Abbreviation.get_String(wsEn);
                                key = keyTss == null ? "" : keyTss.Text ?? "";
                            }
                            fieldObjs.Add(poss);
                        }
                    }
                    keysFromLF.Remove(key);
                    // Ignoring return value (HashSet.Remove returns false if the key wasn't present), because false could mean one of two things:
                    // 1. The CmPossibility had its English abbreviation changed in LCM, but LF doesn't know this yet.
                    //    If this is the case, the LF key won't match, but the GUID will still match. So we might end up creating
                    //    duplicate entries below with the FindOrCreatePossibility. TODO: Need to verify that LCM->LF possibility lists
                    //    get updated correctly if renames happen! (... Or use the OptionList converters, that's what they were for.)
                    // 2. The CmPossibility was just created in LF and isn't in LCM yet. In which case we should have been using the
                    //    OptionList converters, which would hopefully have handled creating the ICmPossibility instane in LCM.
                    // Either way, we can't really use that fact later, since we can't be certain if the possibility was renamed or created.
                }
                // Any remaining keysFromLF strings did not have corresponding GUIDs in Mongo.
                // This is most likely because they were added by LF, which doesn't write to the customFieldGuids field.
                // So we assume they exist in FW, and just look them up.
                foreach (string key in keysFromLF)
                {
                    ICmPossibility poss = parentList.FindOrCreatePossibility(key, wsEn);
                    // TODO: If this is a new possibility, then we need to populate it with ALL the corresponding data from LF,
                    // which we don't necessarily have at this point. Need to make that a separate step in the Send/Receive: converting option lists first.
                    fieldObjs.Add(poss);
                }
                // logger.Debug("Custom field {0} for CmObject {1}: BSON list was [{2}] and customFieldGuids was [{3}]. This was translated to keysFromLF = [{4}] and fieldObjs = [{5}]",
                //  fieldName,
                //  hvo,
                //  String.Join(", ", valueAsStringArray.Values),
                //  String.Join(", ", fieldGuids.Select(g => g.ToString())),
                //  String.Join(", ", keysFromLF.AsEnumerable()),
                //  String.Join(", ", fieldObjs.Select(poss => poss.AbbrAndName))
                // );
                // Step 2: Remove any objects from the "old" list that weren't in the "new" list
                // We have to look them up by HVO because that's the only public API available in LCM
                // Following logic inspired by XmlImportData.CopyCustomFieldData in FieldWorks source
                int[] oldHvosArray = data.VecProp(hvo, flid);
                int[] newHvosArray = fieldObjs.Select(poss => poss.Hvo).ToArray();
                // Shortcut check
                if (oldHvosArray.SequenceEqual(newHvosArray))
                {
                    // Nothing to do, so return now so that we don't cause unnecessary changes and commits in Mercurial
                    return(false);
                }
                HashSet <int> newHvos      = new HashSet <int>(newHvosArray);
                HashSet <int> combinedHvos = new HashSet <int>();
                // Loop backwards so deleting items won't mess up indices of subsequent deletions
                for (int idx = oldHvosArray.Length - 1; idx >= 0; idx--)
                {
                    int oldHvo = oldHvosArray[idx];
                    if (newHvos.Contains(oldHvo))
                    {
                        combinedHvos.Add(oldHvo);
                    }
                    else
                    {
                        data.Replace(hvo, flid, idx, idx + 1, null, 0);                                 // Important to pass *both* null *and* 0 here to remove items
                    }
                }

                // Step 3: Add any objects from the "new" list that weren't in the "old" list
                foreach (int newHvo in newHvosArray)
                {
                    if (combinedHvos.Contains(newHvo))
                    {
                        continue;
                    }
                    // This item was added in the new list
                    data.Replace(hvo, flid, combinedHvos.Count, combinedHvos.Count, new int[] { newHvo }, 1);
                    combinedHvos.Add(newHvo);
                }
                return(true);
            }

            case CellarPropertyType.String:
            {
                var    valueAsMultiText          = BsonSerializer.Deserialize <LfMultiText>(value.AsBsonDocument);
                int    wsIdForField              = lcmMetaData.GetFieldWs(flid);
                string wsStrForField             = servLoc.WritingSystemFactory.GetStrFromWs(wsIdForField);
                KeyValuePair <string, string> kv = valueAsMultiText.BestStringAndWs(new string[] { wsStrForField });
                string foundWs   = kv.Key ?? string.Empty;
                string foundData = kv.Value ?? string.Empty;
                int    foundWsId = servLoc.WritingSystemFactory.GetWsFromStr(foundWs);
                if (foundWsId == 0)
                {
                    return(false);                            // Skip any unidentified writing systems
                }
                ITsString oldValue = data.get_StringProp(hvo, flid);
                ITsString newValue = ConvertMongoToLcmTsStrings.SpanStrToTsString(foundData, foundWsId, servLoc.WritingSystemFactory);
                if (oldValue != null && TsStringUtils.GetDiffsInTsStrings(oldValue, newValue) == null)                         // GetDiffsInTsStrings() returns null when there are no changes
                {
                    return(false);
                }
                else
                {
                    data.SetString(hvo, flid, newValue);
                    return(true);
                }
            }

            default:
                return(false);
                // TODO: Maybe issue a proper warning (or error) log message for "field type not recognized"?
            }
        }
Ejemplo n.º 2
0
        /// <summary>
        /// Gets the data for one custom field, and any relevant GUIDs.
        /// </summary>
        /// <param name="hvo">Hvo of object we're getting the field for.</param>
        /// <param name="flid">Flid for this field.</param>
        /// <param name="fieldSourceType">Either "entry", "senses" or "examples". Could also be "allomorphs", eventually.</param>
        /// <param name="bsonForThisField">Output of a BsonDocument with the following structure: <br />
        /// { fieldName: { "value": BsonValue, "guid": "some-guid-as-a-string" } } <br />
        /// -OR- <br />
        /// { fieldName: { "value": BsonValue, "guid": ["guid1", "guid2", "guid3"] } } <br />
        /// The format of the fieldName key will be "customField_FOO_field_name_with_underscores",
        /// where FOO is one of "entry", "senses", or "examples". <br />
        /// The type of the "guid" value (array or string) will determine whether there is a single GUID,
        /// or a list of GUIDs that happens to contain only one entry.
        /// If there is no "guid" key, that field has no need for a GUID. (E.g., a number).
        /// </param>
        /// <param name="listConverters">Dictionary of ConvertLcmToMongoOptionList instances, keyed by list code</param>
        private BsonDocument GetCustomFieldData(int hvo, int flid, string fieldSourceType,
                                                IDictionary <string, ConvertLcmToMongoOptionList> listConverters)
        {
            BsonValue             fieldValue   = null;
            BsonValue             fieldGuid    = null; // Might be a single value, might be a list (as a BsonArray)
            ISilDataAccessManaged data         = (ISilDataAccessManaged)cache.DomainDataByFlid;
            CellarPropertyType    LcmFieldType = (CellarPropertyType)LcmMetaData.GetFieldType(flid);
            var dataGuids = new List <Guid>();

            // Valid field types in Lcm are GenDate, Integer, String, OwningAtomic, ReferenceAtomic, and ReferenceCollection, so that's all we implement.
            switch (LcmFieldType)
            {
            case CellarPropertyType.GenDate:
                GenDate genDate    = data.get_GenDateProp(hvo, flid);
                string  genDateStr = genDate.ToLongString();
                // LF wants single-string fields in the format { "ws": { "value": "contents" } }
                fieldValue = String.IsNullOrEmpty(genDateStr) ? null :
                             LfMultiText.FromSingleStringMapping(
                    MagicStrings.LanguageCodeForGenDateFields, genDateStr).AsBsonDocument();
                break;
            // When parsing, will use GenDate.TryParse(str, out genDate)

            case CellarPropertyType.Integer:
                fieldValue = new BsonInt32(data.get_IntProp(hvo, flid));
                if (fieldValue.AsInt32 == default(Int32))
                {
                    fieldValue = null;                     // Suppress int fields with 0 in them, to save Mongo DB space
                }
                else
                {
                    // LF wants single-string fields in the format { "ws": { "value": "contents" } }
                    fieldValue = LfMultiText.FromSingleStringMapping(
                        MagicStrings.LanguageCodeForIntFields, fieldValue.AsInt32.ToString()).AsBsonDocument();
                }
                break;

            case CellarPropertyType.OwningAtomic:
            case CellarPropertyType.ReferenceAtomic:
                int ownedHvo = data.get_ObjectProp(hvo, flid);
                fieldValue = GetCustomReferencedObject(ownedHvo, flid, listConverters, ref dataGuids);
                if (fieldValue != null && LcmFieldType == CellarPropertyType.ReferenceAtomic)
                {
                    // Single CmPossiblity reference - LF expects format like { "value": "key of possibility" }
                    fieldValue = new BsonDocument("value", fieldValue);
                }
                fieldGuid = new BsonString(dataGuids.FirstOrDefault().ToString());
                break;

            case CellarPropertyType.MultiUnicode:
                ITsMultiString tss = data.get_MultiStringProp(hvo, flid);
                if (tss != null && tss.StringCount > 0)
                {
                    fieldValue = LfMultiText.FromMultiITsString(tss, servLoc.WritingSystemManager).AsBsonDocument();
                }
                break;

            case CellarPropertyType.OwningCollection:
            case CellarPropertyType.OwningSequence:
            case CellarPropertyType.ReferenceCollection:
            case CellarPropertyType.ReferenceSequence:
                int[] listHvos    = data.VecProp(hvo, flid);
                var   innerValues = new BsonArray(listHvos.Select(listHvo => GetCustomReferencedObject(listHvo, flid, listConverters, ref dataGuids)).Where(x => x != null));
                if (innerValues.Count == 0)
                {
                    fieldValue = null;
                }
                else
                {
                    fieldValue = new BsonDocument("values", innerValues);
                    fieldGuid  = new BsonArray(dataGuids.Select(guid => guid.ToString()));
                }
                break;

            case CellarPropertyType.String:
                ITsString iTsValue = data.get_StringProp(hvo, flid);
                if (iTsValue == null || String.IsNullOrEmpty(iTsValue.Text))
                {
                    fieldValue = null;
                }
                else
                {
                    fieldValue = LfMultiText.FromSingleITsString(iTsValue, servLoc.WritingSystemManager).AsBsonDocument();
                }
                break;

            default:
                fieldValue = null;
                if (logger != null)
                {
                    logger.Warning("Lcm CellarPropertyType.{0} not recognized for LF custom field", LcmFieldType.ToString());
                }
                break;
            }

            if (fieldValue == null)
            {
                return(null);
            }
            else
            {
                var result = new BsonDocument();
                result.Add("value", fieldValue ?? BsonNull.Value);                 // BsonValues aren't allowed to have C# nulls; they have their own null representation
                if (fieldGuid is BsonArray)
                {
                    result.Add("guid", fieldGuid, ((BsonArray)fieldGuid).Count > 0);
                }
                else
                {
                    result.Add("guid", fieldGuid, fieldGuid != null);
                }
                return(result);
            }
        }
Ejemplo n.º 3
0
        public int Compare(object x1, object y1)
        {
            var x    = (IManyOnePathSortItem)x1;
            var y    = (IManyOnePathSortItem)y1;
            int hvoX = m_sda.get_ObjectProp(x.KeyObject, ConcDecorator.kflidTextObject);
            int hvoY = m_sda.get_ObjectProp(y.KeyObject, ConcDecorator.kflidTextObject);

            if (hvoX == hvoY)
            {
                // In the same text object, we can compare offsets.
                int offsetX = m_sda.get_IntProp(x.KeyObject, ConcDecorator.kflidBeginOffset);
                int offsetY = m_sda.get_IntProp(y.KeyObject, ConcDecorator.kflidBeginOffset);
                return(offsetX - offsetY);
            }
            hvoX = m_sda.get_ObjectProp(x.KeyObject, ConcDecorator.kflidParagraph);
            hvoY = m_sda.get_ObjectProp(y.KeyObject, ConcDecorator.kflidParagraph);
            if (hvoX == hvoY)
            {
                // In the same paragraph (and not nested in the same caption), we can compare offsets.
                int offsetX = m_sda.get_IntProp(x.KeyObject, ConcDecorator.kflidBeginOffset);
                int offsetY = m_sda.get_IntProp(y.KeyObject, ConcDecorator.kflidBeginOffset);
                return(offsetX - offsetY);
            }

            // While owning objects are the same type, get the owner of each, if they are the same,
            // compare their position in owner. Special case to put heading before body.
            // If owners are not the same type, do some trick that will make FLEx texts come before Scripture.
            var       paraRepo = m_cache.ServiceLocator.GetInstance <IStTxtParaRepository>();
            ICmObject objX     = paraRepo.GetObject(hvoX);
            ICmObject objY     = paraRepo.GetObject(hvoY);

            for (;;)
            {
                var ownerX = objX.Owner;
                var ownerY = objY.Owner;
                if (ownerX == null)
                {
                    if (ownerY == null)
                    {
                        return(hvoY - hvoX);       // totally arbitrary but at least consistent
                    }
                    return(-1);                    // also arbitrary
                }
                if (ownerY == null)
                {
                    return(1);                    // arbitrary, object with shorter chain comes first.
                }
                if (ownerX == ownerY)
                {
                    var flidX = objX.OwningFlid;
                    var flidY = objY.OwningFlid;
                    if (flidX != flidY)
                    {
                        return(flidX - flidY);                        // typically body and heading.
                    }
                    var indexX = m_cache.MainCacheAccessor.GetObjIndex(ownerX.Hvo, flidX, objX.Hvo);
                    var indexY = m_cache.MainCacheAccessor.GetObjIndex(ownerY.Hvo, flidX, objY.Hvo);
                    return(indexX - indexY);
                }
                var clsX = ownerX.ClassID;
                var clsY = ownerY.ClassID;
                if (clsX != clsY)
                {
                    // Typically one is in Scripture, the other in a Text.
                    // Arbitrarily order things by the kind of parent they're in.
                    // Enhance JohnT: this will need improvement if we go to hierarchical
                    // structures like nested sections or a folder organization of texts.
                    // We could loop all the way up, and then back down till we find a pair
                    // of owners that are different.
                    // (We reverse the usual X - Y in order to put Texts before Scripture
                    // in this list as in the Texts list in FLEx.)
                    return(clsY - clsX);
                }
                objX = ownerX;
                objY = ownerY;
            }
        }