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Issue #2352 - Undo list is disabled when change focus from multi-selection to ordinar...
[modules/shaper.git] / src / XGUI / XGUI_DataModel.cpp
index 7dc78aa87730e78ad8d4ff780290c12757b52e13..baf49e20b1b0b40ee3618ac2cb2208b12a1795d1 100644 (file)
+// Copyright (C) 2014-2017  CEA/DEN, EDF R&D
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+//
+// See http://www.salome-platform.org/ or
+// email : webmaster.salome@opencascade.com<mailto:webmaster.salome@opencascade.com>
+//
+
 #include "XGUI_DataModel.h"
+#include "XGUI_Workshop.h"
+#include "XGUI_ObjectsBrowser.h"
+#include "XGUI_Displayer.h"
+
+#include <ModuleBase_IconFactory.h>
+
+#include <ModelAPI_Session.h>
+#include <ModelAPI_Events.h>
+#include <ModelAPI_ResultParameter.h>
+#include <ModelAPI_AttributeDouble.h>
+#include <ModelAPI_ResultPart.h>
+#include <ModelAPI_Feature.h>
+#include <ModelAPI_CompositeFeature.h>
+#include <ModelAPI_ResultCompSolid.h>
+#include <ModelAPI_ResultField.h>
+#include <ModelAPI_Tools.h>
+#include <ModelAPI_Folder.h>
+#include <ModelAPI_AttributeReference.h>
+
+#include <Config_FeatureMessage.h>
+#include <Config_DataModelReader.h>
+
+#include <Events_Loop.h>
+
+#include <QIcon>
+#include <QBrush>
+
+#define ACTIVE_COLOR QColor(Qt::black)
+//#define ACTIVE_COLOR QColor(0,72,140)
+//#define PASSIVE_COLOR Qt::black
+
+/// Returns ResultPart object if the given object is a Part feature
+/// Otherwise returns NULL
+
+#define SELECTABLE_COLOR QColor(80, 80, 80)
+#define DISABLED_COLOR QColor(200, 200, 200)
 
 
-XGUI_DataModel::XGUI_DataModel(QObject* theParent)
-  : QAbstractItemModel(theParent)
+ResultPartPtr getPartResult(ModelAPI_Object* theObj)
 {
+  ModelAPI_Feature* aFeature = dynamic_cast<ModelAPI_Feature*>(theObj);
+  if (aFeature) {
+    ResultPtr aRes = aFeature->firstResult();
+    if (aRes.get() && (aRes->groupName() == ModelAPI_ResultPart::group())) {
+      ResultPartPtr aPartRes = std::dynamic_pointer_cast<ModelAPI_ResultPart>(aRes);
+      // Use only original parts, not a placement results
+      if (aPartRes == aPartRes->original())
+      return aPartRes;
+    }
+  }
+  return ResultPartPtr();
 }
 
+/// Returns pointer on document if the given object is document object
+ModelAPI_Document* getSubDocument(void* theObj)
+{
+  ModelAPI_Document* aDoc = 0;
+  try {
+    aDoc = dynamic_cast<ModelAPI_Document*>((ModelAPI_Entity*)theObj);
+  } catch(...) {}
+  return aDoc;
+}
+
+
+
+
+// Constructor *************************************************
+XGUI_DataModel::XGUI_DataModel(QObject* theParent) : QAbstractItemModel(theParent)//,
+  //myIsEventsProcessingBlocked(false)
+{
+  XGUI_ObjectsBrowser* aOB = qobject_cast<XGUI_ObjectsBrowser*>(theParent);
+  myWorkshop = aOB->workshop();
+
+  Events_Loop* aLoop = Events_Loop::loop();
+  aLoop->registerListener(this, Events_Loop::eventByName(EVENT_OBJECT_CREATED));
+  aLoop->registerListener(this, Events_Loop::eventByName(EVENT_OBJECT_DELETED));
+  aLoop->registerListener(this, Events_Loop::eventByName(EVENT_OBJECT_UPDATED));
+  aLoop->registerListener(this, Events_Loop::eventByName(EVENT_ORDER_UPDATED));
+  aLoop->registerListener(this, Events_Loop::eventByName(EVENT_DOCUMENT_CHANGED));
+}
 
 XGUI_DataModel::~XGUI_DataModel()
 {
+  clear();
+}
+
+//******************************************************
+void XGUI_DataModel::processEvent(const std::shared_ptr<Events_Message>& theMessage)
+{
+  //if (myIsEventsProcessingBlocked)
+  //  return;
+  DocumentPtr aRootDoc = ModelAPI_Session::get()->moduleDocument();
+  std::string aRootType = myXMLReader->rootType();
+  std::string aSubType = myXMLReader->subType();
+  int aNbFolders = foldersCount();
+
+  // Created object event *******************
+  if (theMessage->eventID() == Events_Loop::loop()->eventByName(EVENT_OBJECT_CREATED)) {
+    std::shared_ptr<ModelAPI_ObjectUpdatedMessage> aUpdMsg =
+        std::dynamic_pointer_cast<ModelAPI_ObjectUpdatedMessage>(theMessage);
+    std::set<ObjectPtr> aObjects = aUpdMsg->objects();
+
+    std::set<ObjectPtr>::const_iterator aIt;
+    std::string aObjType;
+    for (aIt = aObjects.begin(); aIt != aObjects.end(); ++aIt) {
+      ObjectPtr aObject = (*aIt);
+      // We do not show objects which does not need to be shown in object browser
+      if (!aObject->isInHistory())
+        continue;
+
+      aObjType = aObject->groupName();
+      DocumentPtr aDoc = aObject->document();
+      if (aDoc == aRootDoc) {
+        // Check that new folders could appear
+        QStringList aNotEmptyFolders = listOfShowNotEmptyFolders();
+        foreach (QString aNotEmptyFolder, aNotEmptyFolders) {
+          if ((aNotEmptyFolder.toStdString() == aObjType) && (aRootDoc->size(aObjType) > 0)) {
+            // Appears first object in folder which can not be shown empty
+            if (!hasShownFolder(aRootDoc, aNotEmptyFolder)) {
+              insertRow(myXMLReader->rootFolderId(aObjType));
+              addShownFolder(aRootDoc, aNotEmptyFolder);
+            }
+          }
+        }
+        // Insert new object
+        int aRow = aRootDoc->size(aObjType) - 1;
+        if (aRow != -1) {
+          if ((aObjType == aRootType) || (aObjType == ModelAPI_Folder::group())) {
+            insertRow(aRow + aNbFolders + 1);
+          } else {
+            int aFolderId = myXMLReader->rootFolderId(aObjType);
+            if (aFolderId != -1) {
+              insertRow(aRow, createIndex(aFolderId, 0, (void*)Q_NULLPTR));
+            }
+          }
+        }
+      } else {
+        // Object created in sub-document
+        QModelIndex aDocRoot = findDocumentRootIndex(aDoc.get(), 0);
+        if (aDocRoot.isValid()) {
+          // Check that new folders could appear
+          QStringList aNotEmptyFolders = listOfShowNotEmptyFolders(false);
+          foreach (QString aNotEmptyFolder, aNotEmptyFolders) {
+            if ((aNotEmptyFolder.toStdString() == aObjType) && (aDoc->size(aObjType) > 0)) {
+              // Appears first object in folder which can not be shown empty
+              if (!hasShownFolder(aDoc, aNotEmptyFolder)) {
+                insertRow(myXMLReader->subFolderId(aObjType), aDocRoot);
+                addShownFolder(aDoc, aNotEmptyFolder);
+              }
+            }
+         }
+          int aRow = aDoc->index(aObject, true);
+          if (aRow != -1) {
+            int aNbSubFolders = foldersCount(aDoc.get());
+            if ((aObjType == aSubType) || (aObjType == ModelAPI_Folder::group())) {
+              // List of objects under document root
+              insertRow(aRow + aNbSubFolders, aDocRoot);
+            } else {
+              // List of objects under a folder
+              if (aRow != -1) {
+                int aFolderId = folderId(aObjType, aDoc.get());
+                if (aFolderId != -1) {
+                  QModelIndex aParentFolder = createIndex(aFolderId, 0, aDoc.get());
+                  insertRow(aRow, aParentFolder);
+                  emit dataChanged(aParentFolder, aParentFolder);
+                }
+              }
+            }
+          } else {
+            rebuildDataTree();
+            break;
+          }
+        } else {
+          rebuildDataTree();
+          break;
+        }
+      }
+    }
+    // Deleted object event ***********************
+  } else if (theMessage->eventID() == Events_Loop::loop()->eventByName(EVENT_OBJECT_DELETED)) {
+    std::shared_ptr<ModelAPI_ObjectDeletedMessage> aUpdMsg =
+        std::dynamic_pointer_cast<ModelAPI_ObjectDeletedMessage>(theMessage);
+    DocumentPtr aDoc = aUpdMsg->document();
+    std::set<std::string> aMsgGroups = aUpdMsg->groups();
+
+    /// Sort groups because RootType deletion has to be done after others
+    std::string aType = (aDoc == aRootDoc)? aRootType : aSubType;
+    std::list<std::string> aGroups;
+    std::set<std::string>::const_iterator aSetIt;
+    for (aSetIt = aMsgGroups.begin(); aSetIt != aMsgGroups.end(); ++aSetIt) {
+      std::string aGroup = (*aSetIt);
+      if (aGroup == aType)
+        aGroups.push_back(aGroup);
+      else
+        aGroups.push_front(aGroup);
+    }
+
+    std::list<std::string>::const_iterator aIt;
+    for (aIt = aGroups.begin(); aIt != aGroups.end(); ++aIt) {
+      std::string aGroup = (*aIt);
+      if (aDoc == aRootDoc) {  // If root objects
+        int aRow = aRootDoc->size(aGroup, true);
+        if ((aGroup == aRootType) || (aGroup == ModelAPI_Folder::group())) {
+          // Process root folder
+          removeRow(aRow + aNbFolders);
+          rebuildBranch(aNbFolders, aRow);
+        } else {
+          // Process root sub-folder
+          int aFolderId = myXMLReader->rootFolderId(aGroup);
+          if (aFolderId != -1) {
+            QModelIndex aFolderIndex = createIndex(aFolderId, 0, (void*)Q_NULLPTR);
+            removeRow(aRow, aFolderIndex);
+            //rebuildBranch(0, aRow);
+          }
+        }
+        // Check that some folders could erased
+        QStringList aNotEmptyFolders = listOfShowNotEmptyFolders();
+        foreach (QString aNotEmptyFolder, aNotEmptyFolders) {
+          if ((aNotEmptyFolder.toStdString() == aGroup) && (aRootDoc->size(aGroup, true) == 0)) {
+            // Appears first object in folder which can not be shown empty
+            removeRow(myXMLReader->rootFolderId(aGroup));
+            removeShownFolder(aRootDoc, aNotEmptyFolder);
+            //rebuildBranch(0, aNbFolders + aDoc->size(myXMLReader->rootType()));
+            break;
+          }
+        }
+      } else {
+        // Remove row for sub-document
+        QModelIndex aDocRoot = findDocumentRootIndex(aDoc.get(), 0);
+        if (aDocRoot.isValid()) {
+          int aRow = aDoc->size(aGroup, true);
+          int aNbSubFolders = foldersCount(aDoc.get());
+          if ((aGroup == aSubType) || (aGroup == ModelAPI_Folder::group())) {
+            // List of objects under document root
+            removeRow(aRow + aNbSubFolders, aDocRoot);
+            rebuildBranch(aNbSubFolders, aRow, aDocRoot);
+          } else {
+            // List of objects under a folder
+            int aFolderId = folderId(aGroup, aDoc.get());
+            if (aFolderId != -1) {
+              QModelIndex aFolderRoot = createIndex(aFolderId, 0, aDoc.get());
+              removeRow(aRow, aFolderRoot);
+              //rebuildBranch(0, aRow, aFolderRoot);
+            }
+          }
+          // Check that some folders could disappear
+          QStringList aNotEmptyFolders = listOfShowNotEmptyFolders(false);
+          int aSize = aDoc->size(aGroup, true);
+          foreach (QString aNotEmptyFolder, aNotEmptyFolders) {
+            if ((aNotEmptyFolder.toStdString() == aGroup) && (aSize == 0)) {
+              // Appears first object in folder which can not be shown empty
+              removeRow(myXMLReader->subFolderId(aGroup), aDocRoot);
+              removeShownFolder(aDoc, aNotEmptyFolder);
+              //rebuildBranch(0, aNbSubFolders + aDoc->size(myXMLReader->subType()), aDocRoot);
+              break;
+            }
+          }
+        } else {
+          rebuildDataTree();
+          break;
+        }
+      }
+    }
+  } else if (theMessage->eventID() == Events_Loop::loop()->eventByName(EVENT_OBJECT_UPDATED)) {
+    std::shared_ptr<ModelAPI_ObjectUpdatedMessage> aUpdMsg =
+        std::dynamic_pointer_cast<ModelAPI_ObjectUpdatedMessage>(theMessage);
+    std::set<ObjectPtr> aObjects = aUpdMsg->objects();
+
+    std::set<ObjectPtr>::const_iterator aIt;
+    for (aIt = aObjects.begin(); aIt != aObjects.end(); ++aIt) {
+      ObjectPtr aObject = (*aIt);
+      if (aObject->data()->isValid()) {
+        FeaturePtr aFeature = std::dynamic_pointer_cast<ModelAPI_Feature>(aObject);
+        if (aFeature.get() && aFeature->firstResult().get()
+          && (aFeature->firstResult()->groupName() == ModelAPI_ResultField::group())) {
+            ResultFieldPtr aResult =
+              std::dynamic_pointer_cast<ModelAPI_ResultField>(aFeature->firstResult());
+            QModelIndex aIndex = objectIndex(aResult, 0);
+            removeRows(0, aResult->stepsSize(), aIndex);
+        } else {
+          if (aObject->groupName() == ModelAPI_Folder::group()) {
+            rebuildDataTree();
+          } else {
+            QModelIndex aIndex = objectIndex(aObject, 0);
+            if (aIndex.isValid()) {
+              emit dataChanged(aIndex, aIndex);
+            }
+          }
+        }
+      } else {
+        rebuildDataTree();
+        break;
+      }
+    }
+  } else if (theMessage->eventID() == Events_Loop::loop()->eventByName(EVENT_ORDER_UPDATED)) {
+    std::shared_ptr<ModelAPI_OrderUpdatedMessage> aUpdMsg =
+        std::dynamic_pointer_cast<ModelAPI_OrderUpdatedMessage>(theMessage);
+    if (aUpdMsg->reordered().get()) {
+      DocumentPtr aDoc = aUpdMsg->reordered()->document();
+      std::string aGroup = aUpdMsg->reordered()->group();
+
+      QModelIndex aParent;
+      int aStartId = 0;
+      if (aDoc == aRootDoc) {
+        // Update a group under root
+        if (aGroup == myXMLReader->rootType()) // Update objects under root
+          aStartId = foldersCount();
+        else // Update objects in folder under root
+          aParent = createIndex(folderId(aGroup), 0, (void*)Q_NULLPTR);
+      } else {
+        // Update a sub-document
+        if (aGroup == myXMLReader->subType()) {
+          // Update sub-document root
+          aParent = findDocumentRootIndex(aDoc.get(), 0);
+          aStartId = foldersCount(aDoc.get());
+        } else
+          // update folder in sub-document
+          aParent = createIndex(folderId(aGroup, aDoc.get()), 0, aDoc.get());
+      }
+      int aChildNb = rowCount(aParent);
+      rebuildBranch(aStartId, aChildNb - aStartId, aParent);
+    } else {
+      rebuildDataTree();
+    }
+  } else if (theMessage->eventID() == Events_Loop::loop()->eventByName(EVENT_DOCUMENT_CHANGED)) {
+    DocumentPtr aDoc = ModelAPI_Session::get()->activeDocument();
+    if (aDoc != aRootDoc) {
+      QModelIndex aDocRoot = findDocumentRootIndex(aDoc.get(), 0);
+      if (aDocRoot.isValid())
+        emit dataChanged(aDocRoot, aDocRoot);
+      else
+        // We have got a new document
+        rebuildDataTree();
+    }
+  }
+}
+
+//******************************************************
+void XGUI_DataModel::clear()
+{
+  beginResetModel();
+  endResetModel();
+}
+
+//******************************************************
+void XGUI_DataModel::rebuildDataTree()
+{
+  beginResetModel();
+  endResetModel();
+  emit treeRebuilt();
+}
+
+//******************************************************
+ObjectPtr XGUI_DataModel::object(const QModelIndex& theIndex) const
+{
+  if (theIndex.internalId() == 0) // this is a folder
+    return ObjectPtr();
+  ModelAPI_Object* aObj =
+    dynamic_cast<ModelAPI_Object*>((ModelAPI_Entity*)theIndex.internalPointer());
+  if (!aObj)
+    return ObjectPtr();
+  if (getSubDocument(aObj)) // the selected index is a folder of sub-document
+    return ObjectPtr();
+
+  return aObj->data()->owner();
+}
+
+//******************************************************
+QModelIndex XGUI_DataModel::objectIndex(const ObjectPtr theObject, int theColumn) const
+{
+  std::string aType = theObject->groupName();
+  DocumentPtr aDoc = theObject->document();
+  int aRow = aDoc->index(theObject, true);
+  if (aRow == -1) {
+    // it could be a part of complex object
+    FeaturePtr aFeature = std::dynamic_pointer_cast<ModelAPI_Feature>(theObject);
+    if (aFeature.get()) {
+      CompositeFeaturePtr aCompFea = ModelAPI_Tools::compositeOwner(aFeature);
+      if (aCompFea.get()) {
+        for (int i = 0; i < aCompFea->numberOfSubs(true); i++) {
+          if (aCompFea->subFeature(i, true) == theObject) {
+            aRow = i;
+            break;
+          }
+        }
+      }
+      int aFRow = -1;
+      FolderPtr aFolder = aDoc->findContainingFolder(aFeature, aFRow);
+      if (aFolder.get())
+        aRow = aFRow;
+    } else {
+      ResultPtr aResult = std::dynamic_pointer_cast<ModelAPI_Result>(theObject);
+      if (aResult.get()) {
+        ResultCompSolidPtr aCompRes = ModelAPI_Tools::compSolidOwner(aResult);
+        if (aCompRes.get()) {
+          aRow = ModelAPI_Tools::compSolidIndex(aResult);
+        }
+      }
+    }
+    if (aRow == -1)
+      return QModelIndex();
+    else
+      return createIndex(aRow, theColumn, theObject.get());
+  }
+  SessionPtr aSession = ModelAPI_Session::get();
+  DocumentPtr aRootDoc = aSession->moduleDocument();
+  if (aDoc == aRootDoc &&
+    ((myXMLReader->rootType() == aType) || (aType == ModelAPI_Folder::group()))) {
+    // The object from root document
+    aRow += foldersCount();
+  } else if ((myXMLReader->subType() == aType) || (aType == ModelAPI_Folder::group())) {
+    // The object from sub document
+    aRow += foldersCount(aDoc.get());
+  }
+  return createIndex(aRow, theColumn, theObject.get());
+}
+
+//******************************************************
+QVariant XGUI_DataModel::data(const QModelIndex& theIndex, int theRole) const
+{
+  SessionPtr aSession = ModelAPI_Session::get();
+  DocumentPtr aRootDoc = aSession->moduleDocument();
+  int aNbFolders = foldersCount();
+  int theIndexRow = theIndex.row();
+
+  if (theRole == Qt::DecorationRole) {
+    if (theIndex == lastHistoryIndex())
+      return QIcon(":pictures/arrow.png");
+    else if (theIndex.column() == 0) {
+      VisibilityState aState = getVisibilityState(theIndex);
+      switch (aState) {
+      case NoneState:
+        return QIcon();
+      case Visible:
+        return QIcon(":pictures/eyeopen.png");
+      case SemiVisible:
+        return QIcon(":pictures/eyemiclosed.png");
+      case Hidden:
+        return QIcon(":pictures/eyeclosed.png");
+      }
+    }
+  }
+
+  //if (theIndex.column() == 1)
+  if (theIndex.column() != 1)
+    return QVariant();
+
+  quintptr aParentId = theIndex.internalId();
+  if (aParentId == 0) { // root folders
+    switch (theRole) {
+      case Qt::DisplayRole:
+        return QString(myXMLReader->rootFolderName(theIndexRow).c_str()) +
+          QString(" (%1)").arg(rowCount(theIndex));
+      case Qt::DecorationRole:
+        return QIcon(myXMLReader->rootFolderIcon(theIndexRow).c_str());
+      case Qt::ForegroundRole:
+        {
+          Qt::ItemFlags aFlags = theIndex.flags();
+          if (aFlags == Qt::ItemFlags())
+            return QBrush(DISABLED_COLOR);
+          if (!aFlags.testFlag(Qt::ItemIsEditable))
+            return QBrush(SELECTABLE_COLOR);
+        }
+        return ACTIVE_COLOR;
+    }
+  } else { // an object or sub-document
+    if (theRole == Qt::ForegroundRole) {
+      Qt::ItemFlags aFlags = theIndex.flags();
+      if (aFlags == Qt::ItemFlags())
+        return QBrush(DISABLED_COLOR);
+      if (!aFlags.testFlag(Qt::ItemIsEditable))
+        return QBrush(SELECTABLE_COLOR);
+      return ACTIVE_COLOR;
+    }
+
+    ModelAPI_Document* aSubDoc = getSubDocument(theIndex.internalPointer());
+    if (aSubDoc) { // this is a folder of sub document
+      QIntList aMissedIdx = missedFolderIndexes(aSubDoc);
+      int aRow = theIndexRow;
+      while (aMissedIdx.contains(aRow))
+        aRow++;
+      if (aRow < myXMLReader->subFoldersNumber()) {
+        switch (theRole) {
+          case Qt::DisplayRole:
+            return QString(myXMLReader->subFolderName(aRow).c_str()) +
+              QString(" (%1)").arg(rowCount(theIndex));
+          case Qt::DecorationRole:
+            return QIcon(myXMLReader->subFolderIcon(aRow).c_str());
+        }
+      }
+    } else {
+      ObjectPtr aObj = object(theIndex);
+      if (aObj) {
+        switch (theRole) {
+        case Qt::DisplayRole:
+          {
+            if (aObj->groupName() == ModelAPI_ResultParameter::group()) {
+              ResultParameterPtr aParam = std::dynamic_pointer_cast<ModelAPI_ResultParameter>(aObj);
+              AttributeDoublePtr aValueAttribute =
+                aParam->data()->real(ModelAPI_ResultParameter::VALUE());
+              QString aVal = QString::number(aValueAttribute->value());
+              QString aTitle = QString(aObj->data()->name().c_str());
+              return aTitle + " = " + aVal;
+            }
+            QString aSuffix;
+            if (aObj->groupName() == myXMLReader->subType()) {
+              ResultPartPtr aPartRes = getPartResult(aObj.get());
+              if (aPartRes.get()) {
+                if (aPartRes->partDoc().get() == NULL)
+                  aSuffix = " (Not loaded)";
+              }
+            }
+            return aObj->data()->name().c_str() + aSuffix;
+          }
+        case Qt::DecorationRole:
+          {
+            if (aObj->groupName() == ModelAPI_Folder::group())
+              return QIcon(":pictures/features_folder.png");
+            else
+              return ModuleBase_IconFactory::get()->getIcon(aObj);
+          }
+        }
+      } else {
+        switch (theRole) {
+        case Qt::DisplayRole:
+          {
+            ModelAPI_ResultField::ModelAPI_FieldStep* aStep =
+              dynamic_cast<ModelAPI_ResultField::ModelAPI_FieldStep*>
+              ((ModelAPI_Entity*)theIndex.internalPointer());
+            if (aStep) {
+              return "Step " + QString::number(aStep->id() + 1) + " " +
+                aStep->field()->textLine(aStep->id()).c_str();
+            }
+          }
+          break;
+        }
+      }
+    }
+  }
+  return QVariant();
+}
+
+//******************************************************
+QVariant XGUI_DataModel::headerData(int theSection, Qt::Orientation theOrient, int theRole) const
+{
+  return QVariant();
+}
+
+//******************************************************
+int XGUI_DataModel::rowCount(const QModelIndex& theParent) const
+{
+  SessionPtr aSession = ModelAPI_Session::get();
+  if (!aSession->hasModuleDocument())
+    return 0;
+  DocumentPtr aRootDoc = aSession->moduleDocument();
+
+  if (!theParent.isValid()) {
+    // Return number of items in root
+    int aNbFolders = foldersCount();
+    int aNbItems = 0;
+    std::string aType = myXMLReader->rootType();
+    if (!aType.empty())
+      aNbItems = aRootDoc->size(aType, true);
+    return aNbFolders + aNbItems;
+  }
+
+  quintptr aId = theParent.internalId();
+  if (aId == 0) {
+    // this is a folder under root
+    int aParentPos = theParent.row();
+    std::string aType = myXMLReader->rootFolderType(aParentPos);
+    return aRootDoc->size(aType);
+  } else {
+    // It is an object which could have children
+    ModelAPI_Document* aDoc = getSubDocument(theParent.internalPointer());
+    if (aDoc) {
+      // a folder of sub-document
+      QIntList aMissedIdx = missedFolderIndexes(aDoc);
+      int aRow = theParent.row();
+      while (aMissedIdx.contains(aRow))
+        aRow++;
+      if (aRow < myXMLReader->subFoldersNumber()) {
+        std::string aType = myXMLReader->subFolderType(aRow);
+        return aDoc->size(aType);
+      }
+    } else {
+      ModelAPI_Object* aObj =
+        dynamic_cast<ModelAPI_Object*>((ModelAPI_Entity*)theParent.internalPointer());
+      // Check for Part feature
+      ResultPartPtr aPartRes = getPartResult(aObj);
+      if (aPartRes.get()) {
+        DocumentPtr aSubDoc = aPartRes->partDoc();
+        if (!aSubDoc.get())
+          return 0;
+
+        int aNbSubFolders = foldersCount(aSubDoc.get());
+        int aNbSubItems = 0;
+        std::string aSubType = myXMLReader->subType();
+        if (!aSubType.empty())
+          aNbSubItems = aSubDoc->size(aSubType, true);
+        return aNbSubItems + aNbSubFolders;
+      } else {
+        // Check for composite object
+        ModelAPI_CompositeFeature* aCompFeature = dynamic_cast<ModelAPI_CompositeFeature*>(aObj);
+        if (aCompFeature)
+          return aCompFeature->numberOfSubs(true);
+        ModelAPI_ResultCompSolid* aCompRes = dynamic_cast<ModelAPI_ResultCompSolid*>(aObj);
+        if (aCompRes)
+          return aCompRes->numberOfSubs(true);
+        ModelAPI_ResultField* aFieldRes = dynamic_cast<ModelAPI_ResultField*>(aObj);
+        if (aFieldRes)
+          return aFieldRes->stepsSize();
+        ModelAPI_Folder* aFolder = dynamic_cast<ModelAPI_Folder*>(aObj);
+        if (aFolder)
+          return getNumberOfFolderItems(aFolder);
+      }
+    }
+  }
+  return 0;
+}
+
+//******************************************************
+int XGUI_DataModel::columnCount(const QModelIndex& theParent) const
+{
+  return 3;
+}
+
+//******************************************************
+QModelIndex XGUI_DataModel::index(int theRow, int theColumn, const QModelIndex &theParent) const
+{
+  SessionPtr aSession = ModelAPI_Session::get();
+  DocumentPtr aRootDoc = aSession->moduleDocument();
+  int aNbFolders = foldersCount();
+
+  QModelIndex aIndex;
+
+  if (!theParent.isValid()) {
+    if (theRow < aNbFolders) // Return first level folder index
+      return createIndex(theRow, theColumn, (void*)Q_NULLPTR);
+    else { // return object under root index
+      std::string aType = myXMLReader->rootType();
+      int aObjId = theRow - aNbFolders;
+      if (aObjId < aRootDoc->size(aType, true)) {
+        ObjectPtr aObj = aRootDoc->object(aType, aObjId, true);
+        aIndex = objectIndex(aObj, theColumn);
+      }
+    }
+  } else {
+    quintptr aId = theParent.internalId();
+    int aParentPos = theParent.row();
+    if (aId == 0) { // return object index inside of first level of folders
+      std::string aType = myXMLReader->rootFolderType(aParentPos);
+      if (theRow < aRootDoc->size(aType)) {
+        ObjectPtr aObj = aRootDoc->object(aType, theRow, true);
+        aIndex = objectIndex(aObj, theColumn);
+      }
+    } else {
+      // It is an object which could have children
+      ModelAPI_Document* aDoc = getSubDocument(theParent.internalPointer());
+      if (aDoc) {
+        // It is a folder of sub-document
+        int aParentRow = aParentPos;
+        QIntList aMissedIdx = missedFolderIndexes(aDoc);
+        while (aMissedIdx.contains(aParentRow))
+          aParentRow++;
+        if (aParentRow < myXMLReader->subFoldersNumber()) {
+          std::string aType = myXMLReader->subFolderType(aParentRow);
+          if (theRow < aDoc->size(aType)) {
+            ObjectPtr aObj = aDoc->object(aType, theRow);
+            aIndex = objectIndex(aObj, theColumn);
+          }
+        }
+      } else {
+        ModelAPI_Object* aParentObj =
+          dynamic_cast<ModelAPI_Object*>((ModelAPI_Entity*)theParent.internalPointer());
+
+        // Check for Part feature
+        ResultPartPtr aPartRes = getPartResult(aParentObj);
+        if (aPartRes.get()) {
+          DocumentPtr aSubDoc = aPartRes->partDoc();
+          int aNbSubFolders = foldersCount(aSubDoc.get());
+          if (theRow < aNbSubFolders) { // Create a Folder of sub-document
+            aIndex = createIndex(theRow, theColumn, aSubDoc.get());
+          } else {
+            // this is an object under sub document root
+            std::string aType = myXMLReader->subType();
+            ObjectPtr aObj = aSubDoc->object(aType, theRow - aNbSubFolders, true);
+            aIndex = objectIndex(aObj, theColumn);
+          }
+        } else {
+          // Check for composite object
+          ModelAPI_CompositeFeature* aCompFeature =
+            dynamic_cast<ModelAPI_CompositeFeature*>(aParentObj);
+          if (aCompFeature) {
+            aIndex = objectIndex(aCompFeature->subFeature(theRow), theColumn);
+          } else {
+            ModelAPI_ResultCompSolid* aCompRes =
+              dynamic_cast<ModelAPI_ResultCompSolid*>(aParentObj);
+            if (aCompRes)
+              aIndex = objectIndex(aCompRes->subResult(theRow), theColumn);
+            else {
+              ModelAPI_ResultField* aFieldRes =
+                dynamic_cast<ModelAPI_ResultField*>(aParentObj);
+              if (aFieldRes) {
+                aIndex = createIndex(theRow, theColumn, aFieldRes->step(theRow));
+              } else {
+                ModelAPI_Folder* aFolder = dynamic_cast<ModelAPI_Folder*>(aParentObj);
+                ObjectPtr aObj = getObjectInFolder(aFolder, theRow);
+                if (aObj.get())
+                  aIndex = objectIndex(aObj, theColumn);
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+  return aIndex;
+}
+
+//******************************************************
+static QModelIndex MYLastDeleted;
+QModelIndex XGUI_DataModel::parent(const QModelIndex& theIndex) const
+{
+  if (!theIndex.isValid())
+    return QModelIndex();
+  // To avoid additional request about index which was already deleted
+  if (theIndex == MYLastDeleted)
+    return QModelIndex();
+
+  SessionPtr aSession = ModelAPI_Session::get();
+  quintptr aId = theIndex.internalId();
+  if (aId != 0) { // The object is not a root folder
+    ModelAPI_Document* aDoc = getSubDocument(theIndex.internalPointer());
+    if (aDoc) {
+      // It is a folder of sub-document
+      return findDocumentRootIndex(aDoc);
+    }
+    ObjectPtr aObj = object(theIndex);
+    if (!aObj.get()) {
+      // It can be a step of a field
+      ModelAPI_ResultField::ModelAPI_FieldStep* aStep =
+        dynamic_cast<ModelAPI_ResultField::ModelAPI_FieldStep*>
+        ((ModelAPI_Entity*)theIndex.internalPointer());
+      if (aStep) {
+        ModelAPI_ResultField* aField = aStep->field();
+        DocumentPtr aDoc = aSession->activeDocument();
+        ObjectPtr aFld;
+        for(int i = 0; i < aDoc->size(ModelAPI_ResultField::group()); i++) {
+          aFld = aDoc->object(ModelAPI_ResultField::group(), i);
+          if (aFld.get() == aField)
+            return objectIndex(aFld);
+        }
+      }
+      // To avoid additional request about index which was already deleted
+      // If deleted it causes a crash on delete object from Part
+      MYLastDeleted = theIndex;
+      return QModelIndex();
+    }
+    // Check is it object a sub-object of a complex object
+    FeaturePtr aFeature = std::dynamic_pointer_cast<ModelAPI_Feature>(aObj);
+    if (aFeature.get()) {
+      CompositeFeaturePtr aCompFea = ModelAPI_Tools::compositeOwner(aFeature);
+      if (aCompFea.get()) {
+        return objectIndex(aCompFea);
+      }
+      DocumentPtr aDoc = aFeature->document();
+      int aRow;
+      FolderPtr aFolder = aDoc->findContainingFolder(aFeature, aRow);
+      if (aFolder.get())
+        return objectIndex(aFolder);
+    }
+    ResultPtr aResult = std::dynamic_pointer_cast<ModelAPI_Result>(aObj);
+    if (aResult.get()) {
+      ResultCompSolidPtr aCompRes = ModelAPI_Tools::compSolidOwner(aResult);
+      if (aCompRes.get()) {
+        return objectIndex(aCompRes);
+      }
+    }
+    // Use as ordinary object
+    std::string aType = aObj->groupName();
+    DocumentPtr aRootDoc = aSession->moduleDocument();
+    DocumentPtr aSubDoc = aObj->document();
+    if (aSubDoc == aRootDoc) {
+      if ((aType == myXMLReader->rootType()) || (aType == ModelAPI_Folder::group()))
+        return QModelIndex();
+      else {
+        // return first level of folder index
+        int aFolderId = myXMLReader->rootFolderId(aType);
+        // Items in a one row must have the same parent
+        return createIndex(aFolderId, 1, (void*)Q_NULLPTR);
+      }
+    } else {
+      if ((aType == myXMLReader->subType()) || (aType == ModelAPI_Folder::group()))
+        return findDocumentRootIndex(aSubDoc.get());
+      else {
+        // return first level of folder index
+        int aFolderId = folderId(aType, aSubDoc.get());
+        // Items in a one row must have the same parent
+        return createIndex(aFolderId, 1, aSubDoc.get());
+      }
+    }
+  }
+  return QModelIndex();
+}
+
+//******************************************************
+bool XGUI_DataModel::hasChildren(const QModelIndex& theParent) const
+{
+  return rowCount(theParent) > 0;
+}
+
+//******************************************************
+bool XGUI_DataModel::insertRows(int theRow, int theCount, const QModelIndex& theParent)
+{
+  beginInsertRows(theParent, theRow, theRow + theCount - 1);
+  endInsertRows();
+
+  return true;
+}
+
+//******************************************************
+bool XGUI_DataModel::removeRows(int theRow, int theCount, const QModelIndex& theParent)
+{
+  beginRemoveRows(theParent, theRow, theRow + theCount - 1);
+  endRemoveRows();
+  return true;
+}
+
+//******************************************************
+Qt::ItemFlags XGUI_DataModel::flags(const QModelIndex& theIndex) const
+{
+  quintptr aIt = theIndex.internalId();
+  ModelAPI_Object* aObj = 0;
+  ModelAPI_Document* aDoc = 0;
+  SessionPtr aSession = ModelAPI_Session::get();
+  DocumentPtr aActiveDoc = aSession->activeDocument();
+
+  Qt::ItemFlags aNullFlag;
+  Qt::ItemFlags aDefaultFlag = Qt::ItemIsSelectable | Qt::ItemIsEnabled;
+  Qt::ItemFlags aEditingFlag = Qt::ItemIsSelectable | Qt::ItemIsEnabled | Qt::ItemIsEditable;
+
+
+  if (aIt == 0) {
+    // Folders under root
+    DocumentPtr aRootDoc = aSession->moduleDocument();
+    if (aRootDoc != aActiveDoc)
+      return aDefaultFlag;
+  } else {
+    aDoc = getSubDocument(theIndex.internalPointer());
+    if (!aDoc)
+      aObj = dynamic_cast<ModelAPI_Object*>((ModelAPI_Entity*)theIndex.internalPointer());
+  }
+
+  if (aObj) {
+    // An object
+    if (aObj->isDisabled())
+      return theIndex.column() == 2? Qt::ItemIsSelectable : aNullFlag;
+
+    if (aSession->moduleDocument() != aObj->document())
+      if (aActiveDoc != aObj->document())
+        return theIndex.column() == 2? Qt::ItemIsSelectable : aNullFlag;
+
+    bool isCompositeSub = false;
+    // An object which is sub-object of a composite object can not be accessible in column 2
+    if (theIndex.column() == 2) {
+      ObjectPtr aObjPtr = aObj->data()->owner();
+      FeaturePtr aFeature = std::dynamic_pointer_cast<ModelAPI_Feature>(aObjPtr);
+      if (aFeature.get()) {
+        CompositeFeaturePtr aCompFea = ModelAPI_Tools::compositeOwner(aFeature);
+        if (aCompFea.get())
+          isCompositeSub = true;
+      } else {
+        ResultPtr aResult = std::dynamic_pointer_cast<ModelAPI_Result>(aObjPtr);
+        if (aResult.get()) {
+          ResultCompSolidPtr aCompRes = ModelAPI_Tools::compSolidOwner(aResult);
+          if (aCompRes.get())
+            isCompositeSub = true;
+        }
+      }
+    }
+    if (isCompositeSub)
+      return Qt::ItemIsSelectable;
+
+    if (aObj->document() != aActiveDoc) {
+      // The object could be a root of sub-tree
+      ResultPartPtr aPartRes = getPartResult(aObj);
+      if (aPartRes.get()) {
+        if (aPartRes->partDoc() == aActiveDoc)
+          return aEditingFlag;
+      }
+      return aDefaultFlag;
+    }
+  } else if (aDoc) {
+    // A folder under sub-document
+    if (aActiveDoc.get() != aDoc)
+      return aNullFlag;
+  }
+  return aEditingFlag;
+}
+
+//******************************************************
+QModelIndex
+  XGUI_DataModel::findDocumentRootIndex(const ModelAPI_Document* theDoc, int aColumn) const
+{
+  SessionPtr aSession = ModelAPI_Session::get();
+  DocumentPtr aRootDoc = aSession->moduleDocument();
+  if (myXMLReader->isAttachToResult()) { // If document is attached to result
+    int aNb = aRootDoc->size(ModelAPI_ResultPart::group());
+    ObjectPtr aObj;
+    ResultPartPtr aPartRes;
+    for (int i = 0; i < aNb; i++) {
+      aObj = aRootDoc->object(ModelAPI_ResultPart::group(), i);
+      aPartRes = std::dynamic_pointer_cast<ModelAPI_ResultPart>(aObj);
+      if (aPartRes.get() && (aPartRes->partDoc().get() == theDoc)) {
+        int aRow = i;
+        if (myXMLReader->rootType() == ModelAPI_Feature::group()) {
+          aRow += foldersCount();
+        }
+        return createIndex(aRow, aColumn, aObj.get());
+      }
+    }
+  } else { // If document is attached to feature
+    int aNb = aRootDoc->size(ModelAPI_Feature::group(), true);
+    ObjectPtr aObj;
+    ResultPartPtr aPartRes;
+    for (int i = 0; i < aNb; i++) {
+      aObj = aRootDoc->object(ModelAPI_Feature::group(), i, true);
+      aPartRes = getPartResult(aObj.get());
+      if (aPartRes.get() && (aPartRes->partDoc().get() == theDoc)) {
+        int aRow = i;
+        if (myXMLReader->rootType() == ModelAPI_Feature::group())
+          aRow += foldersCount();
+        return createIndex(aRow, aColumn, aObj.get());
+      }
+    }
+  }
+  return QModelIndex();
+}
+
+//******************************************************
+QModelIndex XGUI_DataModel::documentRootIndex(DocumentPtr theDoc, int theColumn) const
+{
+  SessionPtr aSession = ModelAPI_Session::get();
+  DocumentPtr aRootDoc = aSession->moduleDocument();
+  if (theDoc == aRootDoc)
+    return QModelIndex();
+  else
+    return findDocumentRootIndex(theDoc.get(), theColumn);
+}
+
+//******************************************************
+int XGUI_DataModel::foldersCount(ModelAPI_Document* theDoc) const
+{
+  int aNb = 0;
+  SessionPtr aSession = ModelAPI_Session::get();
+  DocumentPtr aRootDoc = aSession->moduleDocument();
+  if ((theDoc == 0) || (theDoc == aRootDoc.get())) {
+    for (int i = 0; i < myXMLReader->rootFoldersNumber(); i++) {
+      if (myXMLReader->rootShowEmpty(i))
+        aNb++;
+      else {
+        if (aRootDoc->size(myXMLReader->rootFolderType(i)) > 0)
+          aNb++;
+      }
+    }
+  } else {
+    for (int i = 0; i < myXMLReader->subFoldersNumber(); i++) {
+      if (myXMLReader->subShowEmpty(i))
+        aNb++;
+      else {
+        if (theDoc->size(myXMLReader->subFolderType(i)) > 0)
+          aNb++;
+      }
+    }
+  }
+  return aNb;
+}
+
+
+//******************************************************
+QIntList XGUI_DataModel::missedFolderIndexes(ModelAPI_Document* theDoc) const
+{
+  QIntList aList;
+  SessionPtr aSession = ModelAPI_Session::get();
+  DocumentPtr aRootDoc = aSession->moduleDocument();
+  if ((theDoc == 0) || (theDoc == aRootDoc.get())) {
+    for (int i = 0; i < myXMLReader->rootFoldersNumber(); i++) {
+      if (!myXMLReader->rootShowEmpty(i)) {
+        if (aRootDoc->size(myXMLReader->rootFolderType(i)) == 0)
+          aList.append(i);
+      }
+    }
+  } else {
+    for (int i = 0; i < myXMLReader->subFoldersNumber(); i++) {
+      if (!myXMLReader->subShowEmpty(i)) {
+        if (theDoc->size(myXMLReader->subFolderType(i)) == 0)
+          aList.append(i);
+      }
+    }
+  }
+  return aList;
+}
+
+
+//******************************************************
+QStringList XGUI_DataModel::listOfShowNotEmptyFolders(bool fromRoot) const
+{
+  QStringList aResult;
+  if (fromRoot) {
+    for (int i = 0; i < myXMLReader->rootFoldersNumber(); i++) {
+      if (!myXMLReader->rootShowEmpty(i))
+        aResult << myXMLReader->rootFolderType(i).c_str();
+    }
+  } else {
+    for (int i = 0; i < myXMLReader->subFoldersNumber(); i++) {
+      if (!myXMLReader->subShowEmpty(i))
+        aResult << myXMLReader->subFolderType(i).c_str();
+    }
+  }
+  return aResult;
+}
+
+//******************************************************
+QModelIndex XGUI_DataModel::lastHistoryIndex() const
+{
+  SessionPtr aSession = ModelAPI_Session::get();
+  DocumentPtr aCurDoc = aSession->activeDocument();
+  FeaturePtr aFeature = aCurDoc->currentFeature(true);
+  if (aFeature.get()) {
+    QModelIndex aInd = objectIndex(aFeature);
+    return createIndex(aInd.row(), 2, aInd.internalPointer());
+  } else {
+    if (aCurDoc == aSession->moduleDocument())
+      return createIndex(foldersCount() - 1, 2, -1);
+    else
+      return createIndex(foldersCount(aCurDoc.get()) - 1, 2, aCurDoc.get());
+  }
+}
+
+//******************************************************
+bool XGUI_DataModel::hasHiddenState(const QModelIndex& theIndex)
+{
+  return getVisibilityState(theIndex) == Hidden;
+}
+
+//******************************************************
+int XGUI_DataModel::folderId(std::string theType, ModelAPI_Document* theDoc) const
+{
+  SessionPtr aSession = ModelAPI_Session::get();
+  ModelAPI_Document* aDoc = theDoc;
+  if (aDoc == 0)
+    aDoc = aSession->moduleDocument().get();
+
+  bool aUseSubDoc = (aDoc != aSession->moduleDocument().get());
+
+  int aRes = -1;
+  if (aUseSubDoc) {
+    int aId = myXMLReader->subFolderId(theType);
+    aRes = aId;
+    for (int i = 0; i < aId; i++) {
+      if (!myXMLReader->subShowEmpty(i)) {
+        if (aDoc->size(myXMLReader->subFolderType(i)) == 0)
+          aRes--;
+      }
+    }
+  } else {
+    int aId = myXMLReader->rootFolderId(theType);
+    aRes = aId;
+    for (int i = 0; i < aId; i++) {
+      if (!myXMLReader->rootShowEmpty(i)) {
+        if (aDoc->size(myXMLReader->rootFolderType(i)) == 0)
+          aRes--;
+      }
+    }
+  }
+  return aRes;
+}
+
+//******************************************************
+void XGUI_DataModel::rebuildBranch(int theRow, int theCount, const QModelIndex& theParent)
+{
+  if (theCount > 0) {
+    removeRows(theRow, theCount, theParent);
+    insertRows(theRow, theCount, theParent);
+  }
+}
+
+//******************************************************
+//bool XGUI_DataModel::blockEventsProcessing(const bool theState)
+//{
+//  bool aPreviousState = myIsEventsProcessingBlocked;
+//  myIsEventsProcessingBlocked = theState;
+//  return aPreviousState;
+//}
+
+//******************************************************
+XGUI_DataModel::VisibilityState
+  XGUI_DataModel::getVisibilityState(const QModelIndex& theIndex) const
+{
+  Qt::ItemFlags aFlags = theIndex.flags();
+  if (aFlags == Qt::ItemFlags())
+    return NoneState;
+
+  ObjectPtr aObj = object(theIndex);
+  if (aObj.get()) {
+    if (aObj->groupName() == ModelAPI_ResultParameter::group())
+      return NoneState;
+    ResultPtr aResObj = std::dynamic_pointer_cast<ModelAPI_Result>(aObj);
+    if (aResObj.get()) {
+      XGUI_Displayer* aDisplayer = myWorkshop->displayer();
+      ResultCompSolidPtr aCompRes = std::dynamic_pointer_cast<ModelAPI_ResultCompSolid>(aResObj);
+      if (aCompRes.get()) {
+        VisibilityState aState = aCompRes->numberOfSubs(true) == 0 ?
+          (aDisplayer->isVisible(aCompRes)? Visible : Hidden) : NoneState;
+        for (int i = 0; i < aCompRes->numberOfSubs(true); i++) {
+          ResultPtr aSubRes = aCompRes->subResult(i, true);
+          VisibilityState aS = aDisplayer->isVisible(aSubRes)? Visible : Hidden;
+          if (aState == NoneState)
+            aState = aS;
+          else if (aState != aS) {
+            aState = SemiVisible;
+            break;
+          }
+        }
+        return aState;
+      } else {
+        if (aDisplayer->isVisible(aResObj))
+          return Visible;
+        else
+          return Hidden;
+      }
+    }
+  }
+  return NoneState;
+}
+
+
+int XGUI_DataModel::getNumberOfFolderItems(const ModelAPI_Folder* theFolder) const
+{
+  DocumentPtr aDoc = theFolder->document();
+
+  FeaturePtr aFirstFeatureInFolder;
+  AttributeReferencePtr aFirstFeatAttr =
+      theFolder->data()->reference(ModelAPI_Folder::FIRST_FEATURE_ID());
+  if (aFirstFeatAttr)
+    aFirstFeatureInFolder = ModelAPI_Feature::feature(aFirstFeatAttr->value());
+  if (!aFirstFeatureInFolder.get())
+    return 0;
+
+  FeaturePtr aLastFeatureInFolder;
+  AttributeReferencePtr aLastFeatAttr =
+      theFolder->data()->reference(ModelAPI_Folder::LAST_FEATURE_ID());
+  if (aLastFeatAttr)
+    aLastFeatureInFolder = ModelAPI_Feature::feature(aLastFeatAttr->value());
+  if (!aLastFeatureInFolder.get())
+    return 0;
+
+  int aFirst = aDoc->index(aFirstFeatureInFolder);
+  int aLast = aDoc->index(aLastFeatureInFolder);
+  return aLast - aFirst + 1;
+}
+
+ObjectPtr XGUI_DataModel::getObjectInFolder(const ModelAPI_Folder* theFolder, int theId) const
+{
+  DocumentPtr aDoc = theFolder->document();
+
+  FeaturePtr aFirstFeatureInFolder;
+  AttributeReferencePtr aFirstFeatAttr =
+      theFolder->data()->reference(ModelAPI_Folder::FIRST_FEATURE_ID());
+  if (aFirstFeatAttr)
+    aFirstFeatureInFolder = ModelAPI_Feature::feature(aFirstFeatAttr->value());
+  if (!aFirstFeatureInFolder.get())
+    return ObjectPtr();
+
+  int aFirst = aDoc->index(aFirstFeatureInFolder);
+  return aDoc->object(ModelAPI_Feature::group(), aFirst + theId);
 }