Open and save projects as .qetz (zipped, opt-in)

Third stage of the zipped project file (#1440). A project is saved as a
.qetz when its file name ends in .qetz -- Save As offers it as a second
file type, and --resave, --set-titleblock, the script API's save() and
the live-mode snapshot follow the name too. Saving a .qet project still
writes a .qet; nothing changes unless the user picks .qetz.

Opening recognises a .qetz by its content (a zip), not its name, and
reads it as bytes: text mode would alter it on Windows. The project
document is joined back and read by the same code as a .qet. Crash
backups stay plain XML. Drag and drop, the open dialog and the
numbering import accept .qetz; the database export names its file from
the project's name without assuming ".qet".

Parts are now written without added indentation (one line each): the
symbol definitions are kept as read, whitespace included, and parts
that gained indentation made the next save differ (five forum projects).

Tests: tst_resaveunchanged::containerSavesTheSameProject (four examples
saved as .qetz, then as .qet, equal the straight .qet; pictures checked
to fail without the fix), tst_qetcontainer::noWhitespaceAdded. Outside
ctest: 341 of 341 projects QET can open (examples, bugtracker, GitHub,
forum) give the same .qet through a .qetz; 181.6 MB of .qet became
36.9 MB of .qetz.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019Wga9B92BNurDEtxxtCDxf

sources/cli_export.cpp

@@ -870,6 +870,15 @@ int exportLinks(QETProject &project, const QString &output)
 int resaveProject(QETProject &project, const QString &output)
 {
 	const QDomDocument doc = project.toXml();
+	if (QETProject::isContainerPath(output)) {
+		QString error;
+		if (!QETProject::writeContainer(doc, output, &error)) {
+			err << "Cannot write '" << output << "': " << error << "\n";
+			return 1;
+		}
+		out << "Re-saved project -> " << output << "\n";
+		return 0;
+	}
 	QFile file(output);
 	if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
 		err << "Cannot open '" << output << "' for writing.\n";
@@ -955,14 +964,22 @@ int setTitleBlock(QETProject &project, const QString &output,
 	}
 
 	const QDomDocument doc = project.toXml();
-	QFile file(output);
-	if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
-		err << "Cannot open '" << output << "' for writing.\n";
-		return 1;
+	if (QETProject::isContainerPath(output)) {
+		QString error;
+		if (!QETProject::writeContainer(doc, output, &error)) {
+			err << "Cannot write '" << output << "': " << error << "\n";
+			return 1;
+		}
+	} else {
+		QFile file(output);
+		if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
+			err << "Cannot open '" << output << "' for writing.\n";
+			return 1;
+		}
+		QTextStream fout(&file);
+		fout << doc.toString(4);
+		file.close();
 	}
-	QTextStream fout(&file);
-	fout << doc.toString(4);
-	file.close();
 	out << "Stamped " << fields.size() << " field(s) on "
 		<< folios << " folio(s) -> " << output << "\n";
 	return 0;

sources/container/qetcontainer.cpp

@@ -34,7 +34,10 @@ void setError(QString *error, const QString &text)
 	if (error) *error = text;
 }
 
-	//An element on its own, as a .qet is written (QET::writeXmlFile())
+	//An element on its own, written without adding indentation: the
+	//whitespace text already in the document (QETProject keeps the symbol
+	//definitions as they were read, spacing included) must come back as it
+	//was, or the next save writes it differently. Parts are one line.
 QByteArray serialize(const QDomNode &node)
 {
 	QDomDocument document;
@@ -42,7 +45,7 @@ QByteArray serialize(const QDomNode &node)
 							 QStringLiteral("xml"),
 							 QStringLiteral("version=\"1.0\" encoding=\"UTF-8\"")));
 	document.appendChild(document.importNode(node, true));
-	return document.toString(4).toUtf8();
+	return document.toString(-1).toUtf8();
 }
 
 	//A file name from a name chosen by the user: no folders, nothing a zip
@@ -136,6 +139,30 @@ bool QetContainer::parse(const QByteArray &xml, QDomDocument *document, QString
 #endif
 }
 
+/**
+	@brief QetContainer::isZip
+	A .qetz is recognised by what it holds, not its name: a crash backup
+	of a .qetz project is plain XML, and a renamed file is still a zip.
+*/
+bool QetContainer::isZip(const QByteArray &content)
+{
+	return content.startsWith("PK\x03\x04");
+}
+
+/**
+	@brief QetContainer::readDocument
+	The project document held in @p content: unzipped and joined for a
+	.qetz, parsed for a .qet.
+*/
+bool QetContainer::readDocument(const QByteArray &content, QDomDocument *document, QString *error)
+{
+	if (!isZip(content))
+		return parse(content, document, error);
+	QList<QetZip::Entry> entries;
+	return QetZip::fromBytes(content, &entries, error)
+			&& join(entries, document, error);
+}
+
 /**
 	@brief QetContainer::split
 	@param project : the project document, as QETProject::toXml() makes it

sources/container/qetcontainer.h

@@ -54,6 +54,10 @@ namespace QetContainer
 
 		/// Parse @p xml as a .qet is read (QETProject::openFile)
 	bool parse(const QByteArray &xml, QDomDocument *document, QString *error = nullptr);
+		/// true if @p content is a zip, so a .qetz rather than a .qet
+	bool isZip(const QByteArray &content);
+		/// The project document in @p content, a .qet or a .qetz
+	bool readDocument(const QByteArray &content, QDomDocument *document, QString *error = nullptr);
 }
 
 #endif // QETCONTAINER_H

sources/dataBase/projectdatabase.cpp

@@ -2669,8 +2669,8 @@ void projectDataBase::exportDb(projectDataBase *db,
 		if (dir_.isEmpty()) {
 			dir_ = QETApp::documentDir() % "/" % tr("untitled") % ".sqlite";
 		} else {
-			dir_.remove(".qet");
-			dir_.append(".sqlite");
+			const QFileInfo project_file(dir_);
+			dir_ = project_file.path() % "/" % project_file.completeBaseName() % ".sqlite";
 		}
 	}
 

sources/projectview.cpp

@@ -339,11 +339,16 @@ int ProjectView::tryClosingDiagrams()
 */
 QString ProjectView::askUserForFilePath(bool assign) {
 	// ask the user for a filepath in order to save the project
+	const QString qet_filter = tr("Project QElectroTech (*.qet)", "filetypes allowed when saving a project file");
+	const QString qetz_filter = tr("Zipped project QElectroTech (*.qetz)", "filetypes allowed when saving a project file");
+	QString selected_filter = QETProject::isContainerPath(m_project->filePath()) ? qetz_filter : qet_filter;
 	QString filepath = QFileDialog::getSaveFileName(
 		this,
 		tr("Save as", "dialog title"),
-		m_project -> currentDir() + "/" + tr("untitled") + ".qet",
-		tr("Project QElectroTech (*.qet)", "filetypes allowed when saving a project file")
+		m_project -> currentDir() + "/" + tr("untitled")
+				+ (selected_filter == qetz_filter ? ".qetz" : ".qet"),
+		qet_filter + ";;" + qetz_filter,
+		&selected_filter
 	);
 
 	// if no filepath is provided, return an empty string
@@ -359,9 +364,15 @@ QString ProjectView::askUserForFilePath(bool assign) {
 	// extension at all whenever the portal didn't (bugtracker #270).
 	// Stripping any existing suffix first and re-appending it once is
 	// correct either way.
-	if (filepath.endsWith(".qet", Qt::CaseInsensitive))
+	// A .qetz is kept as typed, or chosen through its filter.
+	const bool zipped = filepath.endsWith(".qetz", Qt::CaseInsensitive)
+			|| (selected_filter == qetz_filter
+				&& !filepath.endsWith(".qet", Qt::CaseInsensitive));
+	if (filepath.endsWith(".qetz", Qt::CaseInsensitive))
+		filepath.chop(5);
+	else if (filepath.endsWith(".qet", Qt::CaseInsensitive))
 		filepath.chop(4);
-	filepath += ".qet";
+	filepath += zipped ? ".qetz" : ".qet";
 
 	if (assign) {
 		// assign the provided filepath to the currently edited project

sources/qetapp.cpp

@@ -1179,6 +1179,7 @@ QStringList QETApp::handledFileExtensions()
 	static QStringList ext;
 	if (!ext.count()) {
 		ext << "qet";
+		ext << "qetz";
 		ext << "elmt";
 		ext << QString(TITLEBLOCKS_FILE_EXTENSION).remove(QRegularExpression("^\\."));
 	}

sources/qetdiagrameditor.cpp

@@ -1745,7 +1745,7 @@ bool QETDiagramEditor::openProject()
 		this,
 		tr("Open a file"),
 		open_dialog_dir.absolutePath(),
-		tr("QElectroTech project(*.qet);;XML Files (*.xml);;All files (*)")
+		tr("QElectroTech project(*.qet *.qetz);;XML Files (*.xml);;All files (*)")
 	);
 	if (filepath.isEmpty()) return(false);
 

sources/qetproject.cpp

@@ -17,6 +17,7 @@
 */
 
 #include "qetproject.h"
+#include "container/qetcontainer.h"
 
 #include "ElementsCollection/xmlelementcollection.h"
 #include "autoNum/assignvariables.h"
@@ -385,10 +386,20 @@ QETProject::ProjectState QETProject::openFile(QFile *file)
 	load_timer.start();
 
 	bool opened_here = file->isOpen() ? false : true;
-	if (!file->isOpen()
-			&& !file->open(QIODevice::ReadOnly
-					   | QIODevice::Text)) {
-		return FileOpenFailed;
+	if (opened_here)
+	{
+			//A .qetz is a zip and is read as bytes: text mode would turn
+			//its CR LF pairs into LF on Windows. A .qet is read as text,
+			//as it always was.
+		if (!file->open(QIODevice::ReadOnly)) {
+			return FileOpenFailed;
+		}
+		if (!QetContainer::isZip(file->peek(4))) {
+			file->close();
+			if (!file->open(QIODevice::ReadOnly | QIODevice::Text)) {
+				return FileOpenFailed;
+			}
+		}
 	}
 	QFileInfo fi(*file);
 	setFilePath(fi.absoluteFilePath());
@@ -410,12 +421,12 @@ QETProject::ProjectState QETProject::openFile(QFile *file)
 	// call .text() on themselves -- which is exactly where the bug was.
 	// The option exists since Qt 6.5; older Qt always drops such nodes,
 	// so there an all-whitespace value still reloads as "".
-#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
-	if (!xml_project.setContent(content, QDomDocument::ParseOption::PreserveSpacingOnlyNodes))
-#else
-	if (!xml_project.setContent(content))
-#endif
+	// QetContainer::parse() does exactly that, for a .qet and for each part
+	// of a .qetz alike.
+	QString read_error;
+	if (!QetContainer::readDocument(content, &xml_project, &read_error))
 	{
+		qWarning().noquote() << "Unable to read" << fi.fileName() << ":" << read_error;
 		if(opened_here) {
 			file->close();
 		}
@@ -1617,6 +1628,30 @@ bool QETProject::close()
 	@see setFilePath()
 	@return true if the project was successfully saved, else false
 */
+/**
+	@brief QETProject::isContainerPath
+	@return true if @p path names a .qetz file: write() saves it zipped
+*/
+bool QETProject::isContainerPath(const QString &path)
+{
+	return path.endsWith(QLatin1String(".qetz"), Qt::CaseInsensitive);
+}
+
+/**
+	@brief QETProject::writeContainer
+	Write the project document @p project to @p path as a .qetz: the same
+	document, in parts, zipped (#1440). The file is replaced only once
+	the whole archive is written.
+*/
+bool QETProject::writeContainer(const QDomDocument &project, const QString &path, QString *error)
+{
+	const QList<QetZip::Entry> entries = QetContainer::split(
+				project,
+				QStringLiteral("QElectroTech %1").arg(QetVersion::currentVersion().toString()),
+				error);
+	return !entries.isEmpty() && QetZip::write(path, entries, error);
+}
+
 QETResult QETProject::write()
 {
 		// this operation requires a filepath
@@ -1639,7 +1674,12 @@ QETResult QETProject::write()
 
 	QDomDocument xml_project(toXml());
 	QString error_message;
-	if (!QET::writeXmlFile(xml_project, m_file_path, &error_message))
+	if (isContainerPath(m_file_path))
+	{
+		if (!writeContainer(xml_project, m_file_path, &error_message))
+			return(error_message);
+	}
+	else if (!QET::writeXmlFile(xml_project, m_file_path, &error_message))
 		return(error_message);
 
 		// The project has just been written to a writable file (e.g. saved to

sources/qetproject.h

@@ -345,6 +345,11 @@ class QETProject : public QObject
 		void writeBackup();
 		void init();
 		ProjectState openFile(QFile *file);
+	public:
+		static bool isContainerPath(const QString &path);
+		static bool writeContainer(const QDomDocument &project, const QString &path,
+								   QString *error = nullptr);
+	private:
 		static QUuid derivedUuid(const QByteArray &content);
 		void refresh();
 

sources/scripting/liveserver.cpp

@@ -921,7 +921,9 @@ QJsonObject LiveServer::snapshot(const QString &raw_path)
 	if (info.exists()) return failure(QStringLiteral("%1 already exists").arg(raw_path));
 	QDomDocument xml(project->toXml());
 	QString error;
-	if (!QET::writeXmlFile(xml, info.absoluteFilePath(), &error))
+	if (QETProject::isContainerPath(info.absoluteFilePath())
+			? !QETProject::writeContainer(xml, info.absoluteFilePath(), &error)
+			: !QET::writeXmlFile(xml, info.absoluteFilePath(), &error))
 		return failure(QStringLiteral("snapshot not written: %1").arg(error));
 	return {{QStringLiteral("ok"), true}, {QStringLiteral("path"), info.absoluteFilePath()},
 		{QStringLiteral("folio"), e->currentDiagramView()

sources/scripting/qetscriptapi.cpp

@@ -408,7 +408,9 @@ bool QetScriptApi::save(const QString &output)
 
 	QDomDocument xml_doc(m_project->toXml());
 	QString error_message;
-	if (!QET::writeXmlFile(xml_doc, output, &error_message)) {
+	if (QETProject::isContainerPath(output)
+			? !QETProject::writeContainer(xml_doc, output, &error_message)
+			: !QET::writeXmlFile(xml_doc, output, &error_message)) {
 		log(QStringLiteral("qet.save: %1").arg(error_message));
 		return false;
 	}

sources/ui/configpage/projectconfigpages.cpp

@@ -15,6 +15,7 @@
 	You should have received a copy of the GNU General Public License
 	along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
 */
+#include "../../container/qetcontainer.h"
 #include "projectconfigpages.h"
 
 #include "../autoNum/autonumschemecommand.h"
@@ -1054,7 +1055,7 @@ void ProjectAutoNumConfigPage::importFromProject()
 				this,
 				tr("Import numbering from a project"),
 				m_project->currentDir(),
-				tr("Project QElectroTech (*.qet)"));
+				tr("Project QElectroTech (*.qet *.qetz)"));
 	if (path.isEmpty()) {
 		return;
 	}
@@ -1067,7 +1068,7 @@ void ProjectAutoNumConfigPage::importFromProject()
 	}
 
 	QDomDocument doc;
-	if (!doc.setContent(&file)) {
+	if (!QetContainer::readDocument(file.readAll(), &doc)) {
 		QMessageBox::warning(this, tr("Import not possible"),
 					 tr("%1 is not a valid QElectroTech project.")
 					 .arg(QFileInfo(path).fileName()));