How to Load Saved XCAF XML Documents Back into the Structure Tree and Display Geometry in Mayo?

[fksclx]

I have saved all open documents as XCAF XML files in my MainWindow code as shown below:

auto docs = m_guiApp->guiDocuments();
for (int i = 0; i < docs.size(); i++) {
    auto doc = docs[i]->document();
    if (doc.IsNull())
        continue;
    Handle(TDocStd_Document) doc1 = Handle(TDocStd_Document)::DownCast(doc);
    Handle(XmlXCAFDrivers_DocumentStorageDriver) storageDriver = new XmlXCAFDrivers_DocumentStorageDriver(TCollection_ExtendedString("MyApp Copyright"));
    std::string filename = "a.xml";
    storageDriver->Write(doc1, filename.c_str());
}

Now I want to load the saved XML files back into the structure tree and display the corresponding geometry in the viewer.

However, I find it difficult to properly associate the loaded XCAF document with the Mayo Document class and update the UI accordingly.

Could you please advise on the correct approach to:

Load the XCAF XML document from file,
Synchronize it with the Mayo Document instance,
Update the structure tree in the UI,
And display the loaded geometry?
Any example code or guidance would be greatly appreciated!

[HuguesDelorme]

Some good solution would be to provide new reader and writer for the XML XCAF file format and register them in the I/O system.

Another solution is to provide additional Load/Save commands in the File menu.
I would rewrite the Save command like this:

auto app = AppModule::get()->application();
doc->ChangeStorageFormat(Document::NameFormatXml);
const PCDM_StoreStatus saveStatus = app->SaveAs(doc, filepathTo<TCollection_ExtendedString>(filepath));
if (saveStatus != PCDM_SS_OK)
        throw std::runtime_error("XCAFApp_Application::SaveAs() failed");

The Load command would be like;

auto app = AppModule::get()->application();
auto doc = app->newDocument(Document::Format::Xml);
doc->setName(filepath.filename().u8string());
doc->setFilePath(filepath);
const PCDM_ReaderStatus openStatus = app->Open(filepathTo<TCollection_ExtendedString>(filepath), doc);
if (openStatus != PCDM_RS_OK)
    throw std::runtime_error("Application::Open() failed"); // TODO Handle error

doc->addEntityTreeNodeSequence(doc->xcaf().topLevelFreeShapes());

Please note I didn't test the code above, let me know your experiments

[fksclx]

//! Retrieves the document from specified file.
//! In order not to override a version of the document which is already in memory,
//! this method can be made to depend on the value returned by IsInSession.
//! @param[in] thePath file path to open
//! @param[out] theDoc result document
//! @param[in] theRange optional progress indicator
//! @return reading status
PCDM_ReaderStatus Open (const TCollection_ExtendedString& thePath,
Handle(TDocStd_Document)& theDoc,
const Message_ProgressRange& theRange = Message_ProgressRange())
{
return Open (thePath, theDoc, Handle(PCDM_ReaderFilter)(), theRange);
}

Currently, storing (saving) works fine, but the parameter type required by the Open function does not match DocumentPtr. Even after performing the conversion, I still encounter runtime errors.

Handle(TDocStd_Document) doc1 = Handle(TDocStd_Document)::DownCast(doc);
Handle(TDocStd_Document) baseDoc = doc;

[fksclx]

// Loading module
auto app = AppModule::get()->application();
std::string filename = "C:/Users/work/Desktop/document_0.xml.myx";

auto doc = app->newDocument(Document::Format::Xml);
doc->ChangeStorageFormat(Document::NameFormatXml);
doc->setName("doc");
doc->setFilePath(filename);

Handle(TDocStd_Document) doc1 = Handle(TDocStd_Document)::DownCast(doc);
const PCDM_ReaderStatus openStatus = app->Open(filename.c_str(), doc1);
if (openStatus != PCDM_RS_OK)
    throw std::runtime_error("Application::Open() failed");

// Tried to update Mayo document tree and visualization
doc->addEntityTreeNodeSequence(doc->xcaf().topLevelFreeShapes());
doc->rebuildModelTree();

Problem:

Although no errors occur during saving or opening, and the XML file appears correct, the loaded document does not show any nodes or shapes in the Mayo framework UI or the 3D viewer.

Questions:

Am I missing a step to properly populate the document tree or update the viewer after loading?
Is there any required method call to refresh or initialize the Mayo document GUI after loading from XML?
Could the issue be related to the way I create or cast the document (Handle(TDocStd_Document)::DownCast(doc)) before opening?
Any advice or example on the correct workflow to load an XML document and have it correctly displayed by Mayo would be highly appreciated.

[fksclx]

After a successful load, m_labelMain in xcaf is still a null pointer. I think there might still be something wrong with the loading process.

[fksclx]

I have successfully saved and loaded the file tree as XML. The default format requires the extension .myx in order to work correctly. However, after successfully loading the file, when I add shapes to the document tree with the following code, I end up with an empty document and two identical root nodes:

cpp
shapeTool->GetFreeShapes(topLevelShapes);
doc->addEntityTreeNodeSequence(topLevelShapes);
Is this not the correct way to add shapes to the document tree?

Below is the relevant code for saving and loading:

cpp
void MainWindow::saveTreeNode()
{
QString selectedDir = QFileDialog::getExistingDirectory(this, "Choose directory", "");
if (selectedDir.isEmpty())
return;

auto app = AppModule::get()->application();
auto docs = m_guiApp->guiDocuments();
for (int i = 0; i < docs.size(); i++)
{
    auto doc = docs[i]->document();
    if (doc.IsNull())
        continue;
    doc->ChangeStorageFormat(Document::NameFormatXml);
    std::string filePath = selectedDir.toStdString() + "/document_" + QString::number(i).toStdString() + ".myx";
    const PCDM_StoreStatus saveStatus = app->SaveAs(doc, filePath.c_str());
    if (saveStatus != PCDM_SS_OK)
        throw std::runtime_error("XCAFApp_Application::SaveAs() failed");
}
QMessageBox::information(this, tr("Information"), tr("Save successful"));

}

void MainWindow::loadTreeNode()
{
QString selectedDir = QFileDialog::getExistingDirectory(this, "Choose directory", "");
if (selectedDir.isEmpty())
return;
QDir dir(selectedDir);
if (!dir.exists())
{
QMessageBox::warning(this, tr("Warning"), tr("Directory does not exist!"));
return;
}
dir.setFilter(QDir::Files);
QFileInfoList fileList = dir.entryInfoList();
if (fileList.isEmpty())
{
QMessageBox::information(this, tr("Information"), tr("No files in directory"));
return;
}
for (const QFileInfo &fileInfo : fileList)
{
std::string filename = fileInfo.absoluteFilePath().toStdString();
auto app = AppModule::get()->application();
PCDM_ReaderStatus openStatus = PCDM_RS_NoDriver;
auto doc = app->openDocument(filename.c_str(), &openStatus);
doc->setName(fileInfo.fileName().toStdString());
if (openStatus != PCDM_RS_OK)
throw std::runtime_error("Application::Open() failed"); // TODO: Handle error properly
auto shapeTool = doc->xcaf().shapeTool();
TDF_LabelSequence topLevelShapes;
shapeTool->GetFreeShapes(topLevelShapes);
doc->addEntityTreeNodeSequence(topLevelShapes);
}
}
Could you please advise if I am adding the shapes to the document tree incorrectly? How should I properly add entities from the loaded document to avoid duplications and empty documents?

Thanks in advance!

If you want, I can help you polish or shorten it further!

[HuguesDelorme]

Hello, forgot to let you know I have made a branch to experiment XCAF save/open in Mayo:
https://github.com/fougue/mayo/tree/lab/xcaf-io
It contains a single commit:
256d8d2

It provides two new File commands to open/saveAs a Document, it might be worth you try it on your side.

[fksclx]

I have tried compiling your project and confirmed that it works fine without issues. The problem is likely caused by some modifications I made in certain parts of the code on my side.

[fksclx]

DocumentPtr Application::newDocument(Document::Format docFormat)
{
const char* docNameFormat = Document::toNameFormat(docFormat);
#if OCC_VERSION_HEX >= OCC_VERSION_CHECK(7, 6, 0)
OccHandle<CDM_Document> stdDoc;
#else
OccHandle<TDocStd_Document> stdDoc;
#endif
this->NewDocument(docNameFormat, stdDoc);
return DocumentPtr::DownCast(stdDoc);
}

DocumentPtr Application::openDocument(const FilePath& filepath, PCDM_ReaderStatus* ptrReadStatus)
{
OccHandle<TDocStd_Document> stdDoc;
const PCDM_ReaderStatus readStatus = this->Open(filepathTo<TCollection_ExtendedString>(filepath), stdDoc);
if (ptrReadStatus)
*ptrReadStatus = readStatus;

DocumentPtr doc = DocumentPtr::DownCast(stdDoc);
doc->initXCaf();
doc->setName(filepath.filename().u8string());
doc->setFilePath(filepath);
return doc;

} The line doc->initXCaf(); is very important.