KDE/kdelibs/kded

[David Faure]

SVN commit 1151848 by dfaure:

Make mimetype parsing 29% faster by using QXmlStreamReader instead of QDomDocument
before: 1962378 instructions per createEntry, 570 ms total (for kbuildsycoca --noincremental)
 after: 1378515 instructions per createEntry, 410 ms total (for kbuildsycoca --noincremental)

Impact on the overall kbuildsycoca --noincremental run: 8% speedup, and mimetype parsing
went down from 26% of the total cpu time to 20.2% of the now-shorter cpu time, moving it
below KConfig parsing and ksycoca saving.

CCMAIL: kde-optimize at kde.org


 M  +21 -17    kbuildmimetypefactory.cpp  


--- trunk/KDE/kdelibs/kded/kbuildmimetypefactory.cpp #1151847:1151848
@@ -31,7 +31,7 @@
 #include <kdesktopfile.h>
 #include <QtCore/QHash>
 #include <QtCore/QFile>
-#include <QtXml/QDomAttr>
+#include <QXmlStreamReader>
 
 KBuildMimeTypeFactory::KBuildMimeTypeFactory() :
     KMimeTypeFactory(), m_parser(this),
@@ -112,42 +112,46 @@
         QFile qfile(fullPath);
         if (!qfile.open(QFile::ReadOnly))
             continue;
-        QDomDocument doc;
-        if (!doc.setContent(&qfile)) {
-            kWarning() << "Parse error in " << fullPath;
+
+        QXmlStreamReader xml(&qfile);
+        if (xml.readNextStartElement()) {
+            if (xml.name() != "mime-type") {
             continue;
         }
-        const QDomElement mimeTypeElement = doc.documentElement();
-        if (mimeTypeElement.tagName() != "mime-type")
-            continue;
-        name = mimeTypeElement.attribute("type");
+            name = xml.attributes().value("type").toString();
         if (name.isEmpty())
             continue;
 
-        for ( QDomElement e = mimeTypeElement.firstChildElement();
-              !e.isNull();
-              e = e.nextSiblingElement() ) {
-            const QString tag = e.tagName();
+            while (xml.readNextStartElement()) {
+                const QStringRef tag = xml.name();
             if (tag == "comment") {
-                QString lang = e.attribute("xml:lang");
+                    QString lang = xml.attributes().value("xml:lang").toString();
+                    const QString text = xml.readElementText();
                 if (lang.isEmpty()) {
-                    comment = e.text();
+                        comment = text;
                     lang = "en";
                 }
-                commentsByLanguage.insert(lang, e.text());
+                    commentsByLanguage.insert(lang, text);
+                    continue; // we called readElementText, so we're at the EndElement already.
             } else if (tag == "icon") { // as written out by shared-mime-info >= 0.40
-                userIcon = e.attribute("name");
+                    userIcon = xml.attributes().value("name").toString();
             } else if (tag == "glob-deleteall") { // as written out by shared-mime-info > 0.60
                 mainPattern.clear();
                 m_parsedMimeTypes[name] = QString();
             } else if (tag == "glob" && mainPattern.isEmpty()) { // as written out by shared-mime-info > 0.60
-                const QString pattern = e.attribute("pattern");
+                    const QString pattern = xml.attributes().value("pattern").toString();
                 if (pattern.startsWith('*')) {
                     mainPattern = pattern;
                 }
             }
+                xml.skipCurrentElement();
         }
+            if (xml.name() != "mime-type") {
+                kFatal() << "Programming error in KBuildMimeTypeFactory::createEntry, please create a bug report on http://bugs.kde.org and attach the file" << fullPath;
     }
+        }
+    }
+
     if (name.isEmpty()) {
         return 0;
     }