Merge pull request #1504 from ispyisail/feat/qetz-recover

Add recovering what can be read of a damaged .qetz project (--recover)

sources/cli_export.cpp

@@ -28,6 +28,7 @@
 #include "dxfexport.h"
 #include "exportproperties.h"
 #include "pdf_links.h"
+#include "container/qetcontainer.h"
 #include "qetgraphicsitem/conductor.h"
 #include "qetgraphicsitem/diagramimageitem.h"
 #include "qetgraphicsitem/element.h"
@@ -85,6 +86,7 @@ const QHash<QString, QString> &exportFlags()
 		{"--info", "info"},
 		{"--check-elements", "check"},
 		{"--resave", "resave"},
+		{"--recover", "recover"},
 		{"--set-titleblock", "settb"},
 	};
 	return flags;
@@ -870,6 +872,42 @@ int exportLinks(QETProject &project, const QString &output)
 
 /// Round-trip: load the project and write its XML back out, so an external
 /// diff can reveal markup QET silently normalises (tolerated-but-invalid XML).
+/// What can be read of the damaged .qetz @p input, written to the .qet
+/// @p output, and what was left out (QetContainer::recover()).
+int recoverProject(const QString &input, const QString &output)
+{
+	QFile file(input);
+	if (!file.open(QIODevice::ReadOnly)) {
+		err << "Cannot read '" << input << "': " << file.errorString() << "\n";
+		return 2;
+	}
+	const QByteArray content = file.readAll();
+	if (!QetContainer::isZip(content)) {
+		err << "'" << input << "' is not a .qetz project; a .qet opens as it is, or can be fixed in a text editor\n";
+		return 2;
+	}
+	QDomDocument document;
+	QStringList lost;
+	QString error;
+	if (!QetContainer::recover(content, &document, &lost, &error)) {
+		err << "Nothing can be recovered from '" << input << "': " << error << "\n";
+		return 1;
+	}
+	if (!QET::writeXmlFile(document, output, &error)) {
+		err << "Cannot write '" << output << "': " << error << "\n";
+		return 1;
+	}
+	out << "Recovered " << input << " -> " << output << "\n";
+	if (lost.isEmpty()) {
+		out << "Nothing was left out.\n";
+	} else {
+		out << "Left out:\n";
+		for (const QString &item : std::as_const(lost))
+			out << "  " << item << "\n";
+	}
+	return 0;
+}
+
 int resaveProject(QETProject &project, const QString &output)
 {
 	if (QETProject::isContainerPath(output)) {
@@ -1038,6 +1076,16 @@ int run(const QStringList &args)
 		return checkElements(rest.at(0));
 	}
 
+	// --recover reads what it can of a damaged .qetz, which a project
+	// cannot be opened from.
+	if (format == "recover") {
+		if (rest.size() < 2) {
+			err << "Usage: qelectrotech --recover <damaged.qetz> <output.qet>\n";
+			return 2;
+		}
+		return recoverProject(rest.at(0), rest.at(1));
+	}
+
 	const QString input = rest.value(0);
 	if (input.isEmpty()) {
 		err << "Usage: qelectrotech " << flag << " <project.qet> <output>\n";