Added handy new function parseXMLIfTagMatches(), and refactored a lot of old code that was parsing XML in a more clunky way

examples/Plugins/AudioPluginDemo.h

@@ -293,9 +293,7 @@ public:
     {
         // Restore our plug-in's state from the xml representation stored in the above
         // method.
-        std::unique_ptr<XmlElement> xmlState (getXmlFromBinary (data, sizeInBytes));
-
-        if (xmlState.get() != nullptr)
+        if (auto xmlState = getXmlFromBinary (data, sizeInBytes))
             state.replaceState (ValueTree::fromXml (*xmlState));
     }
 

examples/Plugins/InterAppAudioEffectPluginDemo.h

@@ -236,9 +236,7 @@ public:
 
     void setStateInformation (const void* data, int sizeInBytes) override
     {
-        auto xmlState = std::unique_ptr<XmlElement> (getXmlFromBinary (data, sizeInBytes));
-
-        if (xmlState.get() != nullptr)
+        if (auto xmlState = getXmlFromBinary (data, sizeInBytes))
             if (xmlState->hasTagName (parameters.state.getType()))
                 parameters.state = ValueTree::fromXml (*xmlState);
     }

examples/Utilities/AnalyticsCollectionDemo.h

@@ -212,11 +212,10 @@ private:
         // a binary format may be more suitable if it is faster - remember that this
         // method is called on app shutdown so it needs to complete quickly!
 
-        XmlDocument previouslySavedEvents (savedEventsFile);
-        std::unique_ptr<XmlElement> xml (previouslySavedEvents.getDocumentElement());
+        auto xml = parseXMLIfTagMatches (savedEventsFile, "events");
 
-        if (xml.get() == nullptr || xml->getTagName() != "events")
-            xml.reset (new XmlElement ("events"));
+        if (xml == nullptr)
+            xml = std::make_unique<XmlElement> ("events");
 
         for (auto& event : eventsToSave)
         {
@@ -248,45 +247,42 @@ private:
 
     void restoreUnloggedEvents (std::deque<AnalyticsEvent>& restoredEventQueue) override
     {
-        XmlDocument savedEvents (savedEventsFile);
-        std::unique_ptr<XmlElement> xml (savedEvents.getDocumentElement());
-
-        if (xml.get() == nullptr || xml->getTagName() != "events")
-            return;
+        if (auto xml = parseXMLIfTagMatches (savedEventsFile, "events"))
+        {
+            auto numEvents = xml->getNumChildElements();
 
-        auto numEvents = xml->getNumChildElements();
+            for (auto iEvent = 0; iEvent < numEvents; ++iEvent)
+            {
+                auto* xmlEvent = xml->getChildElement (iEvent);
+
+                StringPairArray parameters;
+                auto* xmlParameters = xmlEvent->getChildByName ("parameters");
+                auto numParameters = xmlParameters->getNumAttributes();
+
+                for (auto iParam = 0; iParam < numParameters; ++iParam)
+                    parameters.set (xmlParameters->getAttributeName (iParam),
+                                    xmlParameters->getAttributeValue (iParam));
+
+                StringPairArray userProperties;
+                auto* xmlUserProperties = xmlEvent->getChildByName ("user_properties");
+                auto numUserProperties = xmlUserProperties->getNumAttributes();
+
+                for (auto iProp = 0; iProp < numUserProperties; ++iProp)
+                    userProperties.set (xmlUserProperties->getAttributeName (iProp),
+                                        xmlUserProperties->getAttributeValue (iProp));
+
+                restoredEventQueue.push_back ({
+                    xmlEvent->getStringAttribute ("name"),
+                    xmlEvent->getIntAttribute ("type"),
+                    static_cast<uint32> (xmlEvent->getIntAttribute ("timestamp")),
+                    parameters,
+                    xmlEvent->getStringAttribute ("user_id"),
+                    userProperties
+                });
+            }
 
-        for (auto iEvent = 0; iEvent < numEvents; ++iEvent)
-        {
-            auto* xmlEvent = xml->getChildElement (iEvent);
-
-            StringPairArray parameters;
-            auto* xmlParameters = xmlEvent->getChildByName ("parameters");
-            auto numParameters = xmlParameters->getNumAttributes();
-
-            for (auto iParam = 0; iParam < numParameters; ++iParam)
-                parameters.set (xmlParameters->getAttributeName (iParam),
-                                xmlParameters->getAttributeValue (iParam));
-
-            StringPairArray userProperties;
-            auto* xmlUserProperties = xmlEvent->getChildByName ("user_properties");
-            auto numUserProperties = xmlUserProperties->getNumAttributes();
-
-            for (auto iProp = 0; iProp < numUserProperties; ++iProp)
-                userProperties.set (xmlUserProperties->getAttributeName (iProp),
-                                    xmlUserProperties->getAttributeValue (iProp));
-
-            restoredEventQueue.push_back ({
-                xmlEvent->getStringAttribute ("name"),
-                xmlEvent->getIntAttribute ("type"),
-                static_cast<uint32> (xmlEvent->getIntAttribute ("timestamp")),
-                parameters,
-                xmlEvent->getStringAttribute ("user_id"),
-                userProperties
-            });
+            savedEventsFile.deleteFile();
         }
-
-        savedEventsFile.deleteFile();
     }
 
     const int initialPeriodMs = 1000;

extras/AudioPluginHost/Source/Filters/FilterGraph.cpp

@@ -221,26 +221,26 @@ void FilterGraph::newDocument()
 
 Result FilterGraph::loadDocument (const File& file)
 {
-    XmlDocument doc (file);
-    std::unique_ptr<XmlElement> xml (doc.getDocumentElement());
-
-    if (xml == nullptr || ! xml->hasTagName ("FILTERGRAPH"))
-        return Result::fail ("Not a valid filter graph file");
+    if (auto xml = parseXMLIfTagMatches (file, "FILTERGRAPH"))
+    {
+        graph.removeChangeListener (this);
+        restoreFromXml (*xml);
 
-    graph.removeChangeListener (this);
-    restoreFromXml (*xml);
+        MessageManager::callAsync ([this]
+        {
+            setChangedFlag (false);
+            graph.addChangeListener (this);
+        });
 
-    MessageManager::callAsync ([this] () {
-        setChangedFlag (false);
-        graph.addChangeListener (this);
-    } );
+        return Result::ok();
+    }
 
-    return Result::ok();
+    return Result::fail ("Not a valid filter graph file");
 }
 
 Result FilterGraph::saveDocument (const File& file)
 {
-    std::unique_ptr<XmlElement> xml (createXml());
+    auto xml = createXml();
 
     if (! xml->writeTo (file, {}))
         return Result::fail ("Couldn't write to the file");

extras/Projucer/Source/Application/jucer_ProjucerAnalytics.cpp

@@ -178,11 +178,10 @@ void ProjucerAnalyticsDestination::stopLoggingEvents()
 //==============================================================================
 void ProjucerAnalyticsDestination::saveUnloggedEvents (const std::deque<AnalyticsEvent>& eventsToSave)
 {
-    XmlDocument previouslySavedEvents (savedEventsFile);
-    std::unique_ptr<XmlElement> xml (previouslySavedEvents.getDocumentElement());
+    auto xml = parseXMLIfTagMatches (savedEventsFile, "events");
 
-    if (xml.get() == nullptr || xml->getTagName() != "events")
-        xml.reset (new XmlElement ("events"));
+    if (xml == nullptr)
+        xml = std::make_unique<XmlElement> ("events");
 
     for (auto& event : eventsToSave)
     {
@@ -214,10 +213,9 @@ void ProjucerAnalyticsDestination::saveUnloggedEvents (const std::deque<Analytic
 
 void ProjucerAnalyticsDestination::restoreUnloggedEvents (std::deque<AnalyticsEvent>& restoredEventQueue)
 {
-    XmlDocument savedEvents (savedEventsFile);
-    std::unique_ptr<XmlElement> xml (savedEvents.getDocumentElement());
+    auto xml = parseXMLIfTagMatches (savedEventsFile, "events");
 
-    if (xml.get() == nullptr || xml->getTagName() != "events")
+    if (xml == nullptr)
         return;
 
     auto numEvents = xml->getNumChildElements();

extras/Projucer/Source/ComponentEditor/jucer_ComponentLayout.cpp

@@ -271,10 +271,7 @@ void ComponentLayout::copySelectedToClipboard()
 
 void ComponentLayout::paste()
 {
-    XmlDocument clip (SystemClipboard::getTextFromClipboard());
-    std::unique_ptr<XmlElement> doc (clip.getDocumentElement());
-
-    if (doc != nullptr && doc->hasTagName (clipboardXmlTag))
+    if (auto doc = parseXMLIfTagMatches (SystemClipboard::getTextFromClipboard(), clipboardXmlTag))
     {
         selected.deselectAll();
 

extras/Projucer/Source/ComponentEditor/jucer_JucerDocument.cpp

@@ -624,16 +624,14 @@ void JucerDocument::extractCustomPaintSnippetsFromCppFile (const String& cppCont
 std::unique_ptr<XmlElement> JucerDocument::pullMetaDataFromCppFile (const String& cpp)
 {
     auto lines = StringArray::fromLines (cpp);
-
-    const int startLine = indexOfLineStartingWith (lines, "BEGIN_JUCER_METADATA", 0);
+    auto startLine = indexOfLineStartingWith (lines, "BEGIN_JUCER_METADATA", 0);
 
     if (startLine > 0)
     {
-        const int endLine = indexOfLineStartingWith (lines, "END_JUCER_METADATA", startLine);
+        auto endLine = indexOfLineStartingWith (lines, "END_JUCER_METADATA", startLine);
 
         if (endLine > startLine)
-            return XmlDocument::parse (lines.joinIntoString ("\n", startLine + 1,
-                                                             endLine - startLine - 1));
+            return parseXML (lines.joinIntoString ("\n", startLine + 1, endLine - startLine - 1));
     }
 
     return nullptr;

extras/Projucer/Source/ComponentEditor/jucer_PaintRoutine.cpp

@@ -302,10 +302,7 @@ void PaintRoutine::copySelectedToClipboard()
 
 void PaintRoutine::paste()
 {
-    XmlDocument clip (SystemClipboard::getTextFromClipboard());
-    std::unique_ptr<XmlElement> doc (clip.getDocumentElement());
-
-    if (doc != nullptr && doc->hasTagName (clipboardXmlTag))
+    if (auto doc = parseXMLIfTagMatches (SystemClipboard::getTextFromClipboard(), clipboardXmlTag))
     {
         selectedElements.deselectAll();
         selectedPoints.deselectAll();

extras/Projucer/Source/ProjectSaving/jucer_ProjectExport_Android.h

@@ -1543,7 +1543,7 @@ private:
 
     std::unique_ptr<XmlElement> createManifestElement() const
     {
-        auto manifest = XmlDocument::parse (androidManifestCustomXmlElements.get());
+        auto manifest = parseXML (androidManifestCustomXmlElements.get());
 
         if (manifest == nullptr)
             manifest = std::make_unique<XmlElement> ("manifest");

extras/Projucer/Source/ProjectSaving/jucer_ProjectExport_CLion.h

@@ -1013,9 +1013,8 @@ private:
                 if (targetAttributeKeys.contains ("INFOPLIST_FILE"))
                 {
                     auto plistFile = exporter.getTargetFolder().getChildFile (targetAttributes["INFOPLIST_FILE"]);
-                    XmlDocument infoPlistData (plistFile);
 
-                    if (auto plist = std::unique_ptr<XmlElement> (infoPlistData.getDocumentElement()))
+                    if (auto plist = parseXML (plistFile))
                     {
                         if (auto* dict = plist->getChildByName ("dict"))
                         {

modules/juce_audio_processors/format_types/juce_VST3PluginFormat.cpp

@@ -2292,9 +2292,7 @@ public:
 
     void setStateInformation (const void* data, int sizeInBytes) override
     {
-        std::unique_ptr<XmlElement> head (AudioProcessor::getXmlFromBinary (data, sizeInBytes));
-
-        if (head != nullptr)
+        if (auto head = AudioProcessor::getXmlFromBinary (data, sizeInBytes))
         {
             auto componentStream (createMemoryStreamForState (*head, "IComponent"));
 

modules/juce_audio_processors/processors/juce_AudioProcessor.cpp

@@ -1121,8 +1121,8 @@ std::unique_ptr<XmlElement> AudioProcessor::getXmlFromBinary (const void* data,
         auto stringLength = (int) ByteOrder::littleEndianInt (addBytesToPointer (data, 4));
 
         if (stringLength > 0)
-            return XmlDocument::parse (String::fromUTF8 (static_cast<const char*> (data) + 8,
-                                                         jmin ((sizeInBytes - 8), stringLength)));
+            return parseXML (String::fromUTF8 (static_cast<const char*> (data) + 8,
+                                                jmin ((sizeInBytes - 8), stringLength)));
     }
 
     return {};

modules/juce_core/containers/juce_PropertySet.cpp

@@ -112,7 +112,7 @@ bool PropertySet::getBoolValue (StringRef keyName, bool defaultValue) const noex
 
 std::unique_ptr<XmlElement> PropertySet::getXmlValue (StringRef keyName) const
 {
-    return XmlDocument::parse (getValue (keyName));
+    return parseXML (getValue (keyName));
 }
 
 void PropertySet::setValue (const String& keyName, const var& v)

modules/juce_core/network/juce_URL.cpp

@@ -790,7 +790,7 @@ String URL::readEntireTextStream (bool usePostCommand) const
 
 std::unique_ptr<XmlElement> URL::readEntireXmlStream (bool usePostCommand) const
 {
-    return XmlDocument::parse (readEntireTextStream (usePostCommand));
+    return parseXML (readEntireTextStream (usePostCommand));
 }
 
 //==============================================================================

modules/juce_core/xml/juce_XmlDocument.cpp

@@ -30,24 +30,32 @@ XmlDocument::~XmlDocument() {}
 
 std::unique_ptr<XmlElement> XmlDocument::parse (const File& file)
 {
-    XmlDocument doc (file);
-    return doc.getDocumentElement();
+    return XmlDocument (file).getDocumentElement();
 }
 
-std::unique_ptr<XmlElement> XmlDocument::parse (const String& xmlData)
+std::unique_ptr<XmlElement> XmlDocument::parse (const String& textToParse)
 {
-    XmlDocument doc (xmlData);
-    return doc.getDocumentElement();
+    return XmlDocument (textToParse).getDocumentElement();
 }
 
 std::unique_ptr<XmlElement> parseXML (const String& textToParse)
 {
-    return std::unique_ptr<XmlElement> (XmlDocument::parse (textToParse));
+    return XmlDocument (textToParse).getDocumentElement();
 }
 
-std::unique_ptr<XmlElement> parseXML (const File& fileToParse)
+std::unique_ptr<XmlElement> parseXML (const File& file)
 {
-    return std::unique_ptr<XmlElement> (XmlDocument::parse (fileToParse));
+    return XmlDocument (file).getDocumentElement();
+}
+
+std::unique_ptr<XmlElement> parseXMLIfTagMatches (const String& textToParse, StringRef requiredTag)
+{
+    return XmlDocument (textToParse).getDocumentElementIfTagMatches (requiredTag);
+}
+
+std::unique_ptr<XmlElement> parseXMLIfTagMatches (const File& file, StringRef requiredTag)
+{
+    return XmlDocument (file).getDocumentElementIfTagMatches (requiredTag);
 }
 
 void XmlDocument::setInputSource (InputSource* newSource) noexcept
@@ -139,6 +147,15 @@ std::unique_ptr<XmlElement> XmlDocument::getDocumentElement (const bool onlyRead
     return parseDocumentElement (originalText.getCharPointer(), onlyReadOuterDocumentElement);
 }
 
+std::unique_ptr<XmlElement> XmlDocument::getDocumentElementIfTagMatches (StringRef requiredTag)
+{
+    if (auto xml = getDocumentElement (true))
+        if (xml->hasTagName (requiredTag))
+            return getDocumentElement (false);
+
+    return {};
+}
+
 const String& XmlDocument::getLastParseError() const noexcept
 {
     return lastError;

modules/juce_core/xml/juce_XmlDocument.h

@@ -98,12 +98,17 @@ public:
                                                 tag, without having to parse the entire file
         @returns    a new XmlElement which the caller will need to delete, or null if
                     there was an error.
-        @see getLastParseError
+        @see getLastParseError, getDocumentElementIfTagMatches
     */
     std::unique_ptr<XmlElement> getDocumentElement (bool onlyReadOuterDocumentElement = false);
 
-    /** Returns the parsing error that occurred the last time getDocumentElement was called.
+    /** Does an inexpensive check to see whether the outer element has the given tag name, and
+        then does a full parse if it matches.
+        If the tag is different, or the XML parse fails, this will return nullptr.
+    */
+    std::unique_ptr<XmlElement> getDocumentElementIfTagMatches (StringRef requiredTag);
 
+    /** Returns the parsing error that occurred the last time getDocumentElement was called.
         @returns the error, or an empty string if there was no error.
     */
     const String& getLastParseError() const noexcept;
@@ -178,18 +183,31 @@ private:
 //==============================================================================
 /** Attempts to parse some XML text, returning a new XmlElement if it was valid.
     If the parse fails, this will return a nullptr - if you need more information about
-    errors or more parsing options, see the XmlDocument instead.
-    @see XmlDocument
+    errors or more parsing options, see the XmlDocument class instead.
+    @see XmlDocument, parseXMLIfTagMatches
 */
 std::unique_ptr<XmlElement> parseXML (const String& textToParse);
 
 /** Attempts to parse some XML text, returning a new XmlElement if it was valid.
     If the parse fails, this will return a nullptr - if you need more information about
-    errors or more parsing options, see the XmlDocument instead.
-    @see XmlDocument
+    errors or more parsing options, see the XmlDocument class instead.
+    @see XmlDocument, parseXMLIfTagMatches
 */
 std::unique_ptr<XmlElement> parseXML (const File& fileToParse);
 
+/** Does an inexpensive check to see whether the top-level element has the given tag
+    name, and if that's true, does a full parse and returns the result.
+    If the outer tag doesn't match, or the XML has errors, this will return nullptr;
+    @see parseXML
+*/
+std::unique_ptr<XmlElement> parseXMLIfTagMatches (const String& textToParse, StringRef requiredTag);
+
+/** Does an inexpensive check to see whether the top-level element has the given tag
+    name, and if that's true, does a full parse and returns the result.
+    If the outer tag doesn't match, or the XML has errors, this will return nullptr;
+    @see parseXML
+*/
+std::unique_ptr<XmlElement> parseXMLIfTagMatches (const File& fileToParse, StringRef requiredTag);
 
 
 } // namespace juce

modules/juce_core/xml/juce_XmlElement.h

@@ -130,7 +130,7 @@ namespace juce
     auto xmlString = animalsList.toString();
     @endcode
 
-    @see XmlDocument
+    @see parseXML, parseXMLIfTagMatches, XmlDocument
 
     @tags{Core}
 */

modules/juce_data_structures/app_properties/juce_PropertiesFile.cpp

@@ -186,35 +186,20 @@ bool PropertiesFile::save()
 
 bool PropertiesFile::loadAsXml()
 {
-    XmlDocument parser (file);
-
-    if (auto doc = parser.getDocumentElement (true))
+    if (auto doc = parseXMLIfTagMatches (file, PropertyFileConstants::fileTag))
     {
-        if (doc->hasTagName (PropertyFileConstants::fileTag))
+        forEachXmlChildElementWithTagName (*doc, e, PropertyFileConstants::valueTag)
         {
-            doc = parser.getDocumentElement();
-
-            if (doc != nullptr)
-            {
-                forEachXmlChildElementWithTagName (*doc, e, PropertyFileConstants::valueTag)
-                {
-                    auto name = e->getStringAttribute (PropertyFileConstants::nameAttribute);
-
-                    if (name.isNotEmpty())
-                        getAllProperties().set (name,
-                                                e->getFirstChildElement() != nullptr
-                                                    ? e->getFirstChildElement()->toString (XmlElement::TextFormat().singleLine().withoutHeader())
-                                                    : e->getStringAttribute (PropertyFileConstants::valueAttribute));
-                }
-
-                return true;
-            }
-
-            // must be a pretty broken XML file we're trying to parse here,
-            // or a sign that this object needs an InterProcessLock,
-            // or just a failure reading the file.  This last reason is why
-            // we don't jassertfalse here.
+            auto name = e->getStringAttribute (PropertyFileConstants::nameAttribute);
+
+            if (name.isNotEmpty())
+                getAllProperties().set (name,
+                                        e->getFirstChildElement() != nullptr
+                                            ? e->getFirstChildElement()->toString (XmlElement::TextFormat().singleLine().withoutHeader())
+                                            : e->getStringAttribute (PropertyFileConstants::valueAttribute));
         }
+
+        return true;
     }
 
     return false;
@@ -231,7 +216,7 @@ bool PropertiesFile::saveAsXml()
         e->setAttribute (PropertyFileConstants::nameAttribute, props.getAllKeys() [i]);
 
         // if the value seems to contain xml, store it as such..
-        if (auto childElement = XmlDocument::parse (props.getAllValues() [i]))
+        if (auto childElement = parseXML (props.getAllValues() [i]))
             e->addChildElement (childElement.release());
         else
             e->setAttribute (PropertyFileConstants::valueAttribute, props.getAllValues() [i]);

modules/juce_gui_basics/drawables/juce_Drawable.cpp

@@ -180,14 +180,8 @@ std::unique_ptr<Drawable> Drawable::createFromImageData (const void* data, const
     }
     else
     {
-        auto asString = String::createStringFromData (data, (int) numBytes);
-
-        XmlDocument doc (asString);
-        std::unique_ptr<XmlElement> outer (doc.getDocumentElement (true));
-
-        if (outer != nullptr && outer->hasTagName ("svg"))
-            if (auto svg = doc.getDocumentElement())
-                result = Drawable::createFromSVG (*svg);
+        if (auto svg = parseXMLIfTagMatches (String::createStringFromData (data, (int) numBytes), "svg"))
+            result = Drawable::createFromSVG (*svg);
     }
 
     return result;

modules/juce_gui_basics/drawables/juce_SVGParser.cpp

@@ -1702,24 +1702,13 @@ std::unique_ptr<Drawable> Drawable::createFromSVG (const XmlElement& svgDocument
         return {};
 
     SVGState state (&svgDocument);
-    return std::unique_ptr<Drawable> (state.parseSVGElement (SVGState::XmlPath (&svgDocument, nullptr)));
+    return std::unique_ptr<Drawable> (state.parseSVGElement (SVGState::XmlPath (&svgDocument, {})));
 }
 
 std::unique_ptr<Drawable> Drawable::createFromSVGFile (const File& svgFile)
 {
-    XmlDocument doc (svgFile);
-
-    if (auto outer = doc.getDocumentElement (true))
-    {
-        if (outer->hasTagName ("svg"))
-        {
-            if (auto svgDocument = doc.getDocumentElement())
-            {
-                SVGState state (svgDocument.get(), svgFile);
-                return std::unique_ptr<Drawable> (state.parseSVGElement (SVGState::XmlPath (svgDocument.get(), nullptr)));
-            }
-        }
-    }
+    if (auto xml = parseXMLIfTagMatches (svgFile, "svg"))
+        return createFromSVG (*xml);
 
     return {};
 }