Add "qt.quick.controls.style" logging category for style lookup

Helps to debug where the .qml files are selected from. Especially with
the upcoming Qt Quick Compiler and QRC changes, it will be important to
be able to verify which files are being used, but this also helps
investigating issues with custom styles.

Change-Id: I2b2b4f57b3288e0ab204c624ef6d8eb92268698b
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/quickcontrols2/qquickstyleselector.cpp b/src/quickcontrols2/qquickstyleselector.cpp
index 1dee4dcc..d11a95bd 100644
--- a/src/quickcontrols2/qquickstyleselector.cpp
+++ b/src/quickcontrols2/qquickstyleselector.cpp
@@ -43,10 +43,13 @@
 
 #include <QtCore/qfileinfo.h>
 #include <QtCore/qlocale.h>
+#include <QtCore/qloggingcategory.h>
 #include <QtCore/private/qfileselector_p.h>
 
 QT_BEGIN_NAMESPACE
 
+Q_LOGGING_CATEGORY(lcQtQuickControlsStyle, "qt.quick.controls.style")
+
 static QString ensureSlash(const QString &path)
 {
     if (path.isEmpty() || path.endsWith(QLatin1Char('/')))
@@ -130,6 +133,7 @@ QUrl QQuickStyleSelector::select(const QString &fileName) const
     // 1) requested style (e.g. "MyStyle", included in d->selectors)
     // 2) fallback style (e.g. "Material", included in d->selectors)
     // 3) default style (empty selector, not in d->selectors)
+    qCDebug(lcQtQuickControlsStyle) << "selecting" << fileName << "from" << d->paths << "with selectors" << d->selectors;
 
     int to = d->selectors.count() - 1;
     if (d->selectors.isEmpty() || !d->selectors.first().isEmpty())
@@ -140,8 +144,10 @@ QUrl QQuickStyleSelector::select(const QString &fileName) const
         const QString selector = d->selectors.value(i);
         for (const QString &path : d->paths) {
             const QUrl selectedUrl = d->select(ensureSlash(path) + selector + QLatin1Char('/') + fileName);
-            if (selectedUrl.isValid())
+            if (selectedUrl.isValid()) {
+                qCDebug(lcQtQuickControlsStyle) << "==>" << selectedUrl << "from" << path << "with selector" << selector;
                 return selectedUrl;
+            }
         }
     }