1 files changed, 140 insertions, 0 deletions
diff --git a/src/quickcontrols/qquickstyleplugin.cpp b/src/quickcontrols/qquickstyleplugin.cpp
new file mode 100644
index 0000000000..caae034970
--- /dev/null
+++ b/src/quickcontrols/qquickstyleplugin.cpp
@@ -0,0 +1,140 @@
+// Copyright (C) 2020 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include "qquickstyle.h"
+#include "qquickstyle_p.h"
+#include "qquickstyleplugin_p.h"
+
+#include <QtCore/private/qfileselector_p.h>
+#include <QtCore/qloggingcategory.h>
+#include <QtGui/qstylehints.h>
+#include <QtGui/qguiapplication.h>
+#include <QtQml/qqmlengine.h>
+#include <QtQml/qqmlfile.h>
+#include <QtQml/private/qqmlmetatype_p.h>
+#include <QtQuickTemplates2/private/qquicktheme_p_p.h>
+
+QT_BEGIN_NAMESPACE
+
+Q_LOGGING_CATEGORY(lcStylePlugin, "qt.quick.controls.styleplugin")
+
+QQuickStylePlugin::QQuickStylePlugin(QObject *parent)
+    : QQmlExtensionPlugin(parent)
+{
+}
+
+QQuickStylePlugin::~QQuickStylePlugin()
+{
+}
+
+void QQuickStylePlugin::registerTypes(const char *uri)
+{
+    qCDebug(lcStylePlugin).nospace() << "registerTypes called with uri " << uri << "; plugin name is " << name();
+
+    const QTypeRevision latestControlsRevision = QQmlMetaType::latestModuleVersion(QLatin1String("QtQuick.Controls"));
+    // Use the private function because we don't want to cause resolve() to be called,
+    // as the logic that assigns a default style if one wasn't set would interfere with compile-time style selection.
+    QString styleName = QQuickStylePrivate::style();
+    if (!latestControlsRevision.isValid() && styleName.isEmpty()) {
+        // The user hasn't imported QtQuick.Controls, nor set a style via the runtime methods.
+        qCDebug(lcStylePlugin).nospace() << uri << " imported before QtQuick.Controls; using compile-time style selection";
+        QQuickStyle::setStyle(name());
+        styleName = name();
+    }
+
+    // Even if this style plugin isn't for the style set by the user,
+    // we still want to create the theme object, because that function
+    // is also responsible for reading values from qtquickcontrols2.conf.
+    // So, even if a style doesn't have a QQuickTheme, it can still have
+    // values set for (e.g. fonts and palettes) in qtquickcontrols2.conf.
+    const QString effectiveCurrentStyleName = QQuickStylePrivate::effectiveStyleName(styleName);
+    auto theme = QQuickTheme::instance();
+    if (!theme) {
+        qCDebug(lcStylePlugin) << "creating theme";
+        theme = createTheme(effectiveCurrentStyleName);
+    }
+
+    // The primary fallback is the style set by the user. We need to check for that here
+    // so that we can ensure that fallback styles' themes are initialized (QTBUG-117403)
+    // without also allowing the Basic style to be initialized, as it is a secondary fallback
+    // for every built-in style (and only built-in styles can be fallbacks).
+    const bool thisPluginBelongsToCurrentStyle = name() == effectiveCurrentStyleName;
+    const bool isPrimaryFallback = name() == QQuickStylePrivate::fallbackStyle();
+    if (!thisPluginBelongsToCurrentStyle && !isPrimaryFallback) {
+        qCDebug(lcStylePlugin).nospace() << "this style plugin does not belong to the current ("
+            << effectiveCurrentStyleName << ") or fallback (" << QQuickStylePrivate::fallbackStyle()
+            << ") style; not calling initializeTheme()";
+        return;
+    }
+
+    if (thisPluginBelongsToCurrentStyle) {
+        qCDebug(lcStylePlugin).nospace() << "this style plugin belongs to the current style "
+            << effectiveCurrentStyleName << "; calling initializeTheme()";
+    } else {
+        qCDebug(lcStylePlugin).nospace() << "this style plugin belongs to the fallback style "
+            << QQuickStylePrivate::fallbackStyle() << "; calling initializeTheme()";
+    }
+    initializeTheme(theme);
+    connect(QGuiApplication::styleHints(), &QStyleHints::colorSchemeChanged,
+                                     this, &QQuickStylePlugin::updateTheme);
+
+    if (!isPrimaryFallback && !styleName.isEmpty())
+        QFileSelectorPrivate::addStatics(QStringList() << styleName);
+}
+
+void QQuickStylePlugin::unregisterTypes()
+{
+    qCDebug(lcStylePlugin) << "unregisterTypes called; plugin name is" << name();
+    if (!QQuickThemePrivate::instance)
+        return;
+
+    disconnect(QGuiApplication::styleHints(), &QStyleHints::colorSchemeChanged,
+                                        this, &QQuickStylePlugin::updateTheme);
+
+    // Not every style has a plugin - some styles are QML-only. So, we clean this
+    // stuff up when the first style plugin is unregistered rather than when the
+    // plugin for the current style is unregistered.
+    QQuickThemePrivate::instance.reset();
+    QQuickStylePrivate::reset();
+}
+
+/*!
+    \internal
+
+    Responsible for setting the font and palette settings that were specified in the
+    qtquickcontrols2.conf file.
+
+    Style-specific settings (e.g. Variant=Dense) are read in the constructor of the
+    appropriate style plugin (e.g. QtQuickControls2MaterialStylePlugin).
+
+    Implicit style-specific font and palette values are assigned in the relevant theme
+    (e.g. QQuickMaterialTheme).
+*/
+QQuickTheme *QQuickStylePlugin::createTheme(const QString &name)
+{
+    qCDebug(lcStylePlugin) << "creating QQuickTheme instance to be initialized by style-specific theme of" << name;
+
+    QQuickTheme *theme = new QQuickTheme;
+#if QT_CONFIG(settings)
+    QQuickThemePrivate *p = QQuickThemePrivate::get(theme);
+    QSharedPointer<QSettings> settings = QQuickStylePrivate::settings(name);
+    if (settings) {
+        p->defaultFont.reset(QQuickStylePrivate::readFont(settings));
+        // Set the default font as the System scope, because that's what
+        // QQuickControlPrivate::parentFont() uses as its fallback if no
+        // parent item has a font explicitly set. QQuickControlPrivate::parentFont()
+        // is used as the starting point for font inheritance/resolution.
+        // The same goes for palettes below.
+        theme->setFont(QQuickTheme::System, *p->defaultFont);
+
+        p->defaultPalette.reset(QQuickStylePrivate::readPalette(settings));
+        theme->setPalette(QQuickTheme::System, *p->defaultPalette);
+    }
+#endif
+    QQuickThemePrivate::instance.reset(theme);
+    return theme;
+}
+
+QT_END_NAMESPACE
+
+#include "moc_qquickstyleplugin_p.cpp"