Use static initialization for external-link regexp

Component::updateModelData() is invoked for every value change with any
component, which can result in hundreds of thousands calls when there
is a large number of components. We can avoid the repeated validity
checks for the QRegularExpression object by initializing it as a static
constant.

When refiltering the same repository categories, which omits the
metadata fetching part, there's a time reduction of some 10% from
the start to displaying the component tree again measured by hand,
which would match the results measured with callgrind.

Also add similar handling to the related string literal.

Change-Id: I90694f25e110b54a26ddd0fbc7f9319a6fb5314e
Reviewed-by: Katja Marttila <katja.marttila@qt.io>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/libs/installer/component.cpp b/src/libs/installer/component.cpp
index 36fadf451..5d21cd1da 100644
--- a/src/libs/installer/component.cpp
+++ b/src/libs/installer/component.cpp
@@ -1731,9 +1731,10 @@ void Component::updateModelData(const QString &key, const QString &data)
         tooltipText += QLatin1String("<br>") + tr("There was an error loading the selected component. "
                                                       "This component cannot be installed.");
     }
+    static const QRegularExpression externalLinkRegexp(QLatin1String("{external-link}='(.*?)'"));
+    static const QLatin1String externalLinkElement(QLatin1String("<a href=\"\\1\">\\1</a>"));
     // replace {external-link}='' fields in component description with proper link tags
-    tooltipText.replace(QRegularExpression(QLatin1String("{external-link}='(.*?)'")),
-        QLatin1String("<a href=\"\\1\">\\1</a>"));
+    tooltipText.replace(externalLinkRegexp, externalLinkElement);
 
     setData(tooltipText, Qt::ToolTipRole);
 }