Migrate from QDomDocument to QXmlStreamReader

QDomDocument is deprecated in Qt6 and required a separate Qt module
(QtXml). Qt docs recommend to use QXmlStreamReader instead, which is
even part of QtCore.

Author: ubruhin

CMakeLists.txt

@@ -11,7 +11,7 @@ project(parseagle
 
 # If Qt version is not explicitly specified, automatically determine it
 if(NOT PARSEAGLE_QT_MAJOR_VERSION)
-    find_package(Qt NAMES Qt5 Qt6 REQUIRED COMPONENTS Core Xml)
+    find_package(Qt NAMES Qt5 Qt6 REQUIRED COMPONENTS Core)
     set(PARSEAGLE_QT_MAJOR_VERSION ${Qt_VERSION_MAJOR})
 endif()
 set(PARSEAGLE_QT "Qt${PARSEAGLE_QT_MAJOR_VERSION}")
@@ -26,7 +26,7 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
 # Find required Qt packages
-find_package(${PARSEAGLE_QT} REQUIRED COMPONENTS Core Xml)
+find_package(${PARSEAGLE_QT} REQUIRED COMPONENTS Core)
 message(STATUS "Building parseagle with Qt ${${PARSEAGLE_QT}_VERSION}")
 
 # Export library
@@ -119,11 +119,7 @@ add_library(parseagle STATIC
     parseagle/symbol/pin.h
     parseagle/symbol/symbol.h
 )
-target_link_libraries(parseagle
-    # Qt
-    ${PARSEAGLE_QT}::Core
-    ${PARSEAGLE_QT}::Xml
-)
+target_link_libraries(parseagle ${PARSEAGLE_QT}::Core)
 target_include_directories(parseagle INTERFACE "${CMAKE_CURRENT_SOURCE_DIR}")
 
 # Alias to namespaced variant

parseagle/board/board.cpp

@@ -28,15 +28,8 @@ Board::~Board() noexcept
 
 void Board::load(const QByteArray& content, QStringList* errors)
 {
-    QDomDocument doc;
-    doc.implementation().setInvalidDataPolicy(QDomImplementation::ReturnNullNode);
-    QString errMsg;
-    if (!doc.setContent(content, &errMsg)) {
-        throw std::runtime_error(
-            "Error while parsing EAGLE board: " + errMsg.toStdString());
-    }
-    DomElement root(doc.documentElement());
-    DomElement drawing = root.getFirstChild("drawing");
+    const DomElement root = DomElement::parse(content);
+    const DomElement drawing = root.getFirstChild("drawing");
 
     if (drawing.hasChild("grid")) {
         mGrid = Grid(drawing.getFirstChild("grid"));

parseagle/common/domelement.cpp

@@ -3,29 +3,68 @@
 
 namespace parseagle {
 
-DomElement::DomElement(const QDomElement& root)
+DomElement::DomElement(QXmlStreamReader& reader)
 {
-    if (root.isNull()) {
-        throw std::runtime_error("Invalid XML node!");
+    mName = reader.name().toString();
+    for (const QXmlStreamAttribute& attr : reader.attributes()) {
+        mAttributes.insert(attr.name().toString(), attr.value().toString());
     }
 
-    mName = root.tagName();
-    mText = root.text();
-
-    QDomNamedNodeMap map = root.attributes();
-    for (int i = 0; i < map.count(); i++) {
-        mAttributes.insert(map.item(i).nodeName(), map.item(i).nodeValue());
+    while (!reader.atEnd()) {
+        reader.readNext();
+        if (reader.isCharacters()) {
+            mText.append(reader.text().toString());
+        } else if (reader.isStartElement()) {
+            mChilds.append(DomElement(reader));
+        } else if (reader.isEndElement()) {
+            break;
+        }
     }
 
-    for (QDomElement c = root.firstChildElement(); !c.isNull(); c = c.nextSiblingElement()) {
-        mChilds.append(DomElement(c));
+    if (reader.hasError()) {
+        const QString err = "Failed to parse XML: " + reader.errorString();
+        throw std::runtime_error(err.toStdString());
     }
 }
 
 DomElement::~DomElement() noexcept
 {
 }
 
+DomElement DomElement::parse(QXmlStreamReader& reader)
+{
+    while (!reader.atEnd()) {
+        reader.readNext();
+        if (reader.isStartElement()) {
+            break;
+        }
+    }
+    if (reader.hasError() || (!reader.isStartElement())) {
+        const QString err = "Failed to find XML root element: " + reader.errorString();
+        throw std::runtime_error(err.toStdString());
+    }
+    const DomElement root(reader);
+    if (reader.hasError() || (!reader.isEndElement())) {
+        const QString err = "XML file seems incomplete: " + reader.errorString();
+        throw std::runtime_error(err.toStdString());
+    }
+    return root;
+}
+
+DomElement DomElement::parse(const QString& data)
+{
+    QXmlStreamReader reader;
+    reader.addData(data);
+    return parse(reader);
+}
+
+DomElement DomElement::parse(const QByteArray& data)
+{
+    QXmlStreamReader reader;
+    reader.addData(data);
+    return parse(reader);
+}
+
 QString DomElement::getAttributeAsString(const QString& name) const
 {
     if (mAttributes.contains(name)) {
@@ -37,7 +76,8 @@ QString DomElement::getAttributeAsString(const QString& name) const
     }
 }
 
-bool DomElement::getAttributeAsBool(const QString& name) const {
+bool DomElement::getAttributeAsBool(const QString& name) const
+{
   const QString value = getAttributeAsString(name);
   if (value == "yes") {
     return true;

parseagle/common/domelement.h

@@ -3,7 +3,6 @@
 
 #include <memory>
 #include <QtCore>
-#include <QtXml/QtXml>
 
 namespace parseagle {
 
@@ -13,9 +12,13 @@ class DomElement final
 
         // Constructors / Destructor
         DomElement() = delete;
-        explicit DomElement(const QDomElement& root);
         ~DomElement() noexcept;
 
+        // Parsers
+        static DomElement parse(QXmlStreamReader& reader);
+        static DomElement parse(const QString& data);
+        static DomElement parse(const QByteArray& data);
+
         // Getters
         const QString& getTagName() const noexcept {return mName;}
         const QString& getText() const noexcept {return mText;}
@@ -30,6 +33,8 @@ class DomElement final
 
 
     private:
+        explicit DomElement(QXmlStreamReader& reader);
+
         QString mName;
         QString mText;
         QHash<QString, QString> mAttributes;

parseagle/library.cpp

@@ -33,16 +33,9 @@ Library::~Library() noexcept
 
 void Library::load(const QByteArray& content, QStringList* errors)
 {
-    QDomDocument doc;
-    doc.implementation().setInvalidDataPolicy(QDomImplementation::ReturnNullNode);
-    QString errMsg;
-    if (!doc.setContent(content, &errMsg)) {
-        throw std::runtime_error(
-            "Error while parsing EAGLE library: " + errMsg.toStdString());
-    }
-    DomElement root(doc.documentElement());
-    DomElement drawing = root.getFirstChild("drawing");
-    DomElement library = drawing.getFirstChild("library");
+    const DomElement root = DomElement::parse(content);
+    const DomElement drawing = root.getFirstChild("drawing");
+    const DomElement library = drawing.getFirstChild("library");
     load(library, errors);
 }
 

parseagle/schematic/schematic.cpp

@@ -27,21 +27,14 @@ Schematic::~Schematic() noexcept
 }
 
 void Schematic::load(const QByteArray& content, QStringList* errors) {
-    QDomDocument doc;
-    doc.implementation().setInvalidDataPolicy(QDomImplementation::ReturnNullNode);
-    QString errMsg;
-    if (!doc.setContent(content, &errMsg)) {
-        throw std::runtime_error(
-            "Error while parsing EAGLE schematic: " + errMsg.toStdString());
-    }
-    DomElement root(doc.documentElement());
-    DomElement drawing = root.getFirstChild("drawing");
+    const DomElement root = DomElement::parse(content);
+    const DomElement drawing = root.getFirstChild("drawing");
 
     if (drawing.hasChild("grid")) {
         mGrid = Grid(drawing.getFirstChild("grid"));
     }
 
-    DomElement schematic = drawing.getFirstChild("schematic");
+    const DomElement schematic = drawing.getFirstChild("schematic");
     if (schematic.hasChild("description")) {
         mDescription = schematic.getFirstChild("description").getText();
     }