Fix infinite loop in stylesheetloader

Fixes #361

src/CMakeLists.txt

@@ -294,6 +294,7 @@ set(HEADERS
   core/standarditemiconloader.h
   core/systemtrayicon.h
   core/mimedata.h
+  core/stylesheetloader.h
 
   engine/enginebase.h
   engine/devicefinders.h

src/core/mainwindow.cpp

@@ -758,7 +758,6 @@ MainWindow::MainWindow(Application *app, SystemTrayIcon *tray_icon, OSD *osd, co
   app_->appearance()->LoadUserTheme();
   StyleSheetLoader *css_loader = new StyleSheetLoader(this);
   css_loader->SetStyleSheet(this, ":/style/strawberry.css");
-  RefreshStyleSheet();
 
   // Load playlists
   app_->playlist_manager()->Init(app_->collection_backend(), app_->playlist_backend(), ui_->playlist_sequence, ui_->playlist);
@@ -859,8 +858,6 @@ MainWindow::MainWindow(Application *app, SystemTrayIcon *tray_icon, OSD *osd, co
   }
   if (app_->scrobbler()->IsEnabled() && !app_->scrobbler()->IsOffline()) app_->scrobbler()->Submit();
 
-  RefreshStyleSheet();
-
   qLog(Debug) << "Started" << QThread::currentThread();
   initialised_ = true;
 
@@ -964,7 +961,6 @@ void MainWindow::ReloadAllSettings() {
 
 void MainWindow::RefreshStyleSheet() {
   QString contents(styleSheet());
-  setStyleSheet("");
   setStyleSheet(contents);
 }
 

src/core/stylesheetloader.cpp

@@ -24,6 +24,7 @@
 #include <QtGlobal>
 #include <QObject>
 #include <QWidget>
+#include <QTimer>
 #include <QIODevice>
 #include <QTextStream>
 #include <QFile>
@@ -36,22 +37,16 @@
 #include "core/logging.h"
 #include "stylesheetloader.h"
 
-StyleSheetLoader::StyleSheetLoader(QObject *parent) : QObject(parent) {}
+StyleSheetLoader::StyleSheetLoader(QObject *parent) : QObject(parent), timer_reset_counter_(new QTimer(this)) {
 
-void StyleSheetLoader::SetStyleSheet(QWidget *widget, const QString &filename) {
+  timer_reset_counter_->setSingleShot(true);
+  timer_reset_counter_->setInterval(1000);
 
-  widgets_[widget] = qMakePair(filename, QString());
+  connect(timer_reset_counter_, SIGNAL(timeout()), this, SLOT(ResetCounters()));
-  widget->installEventFilter(this);
-  UpdateStyleSheet(widget);
 
 }
 
-void StyleSheetLoader::UpdateStyleSheet(QWidget *widget) {
+void StyleSheetLoader::SetStyleSheet(QWidget *widget, const QString &filename) {
-
-  if (!widget || !widgets_.contains(widget)) return;
-
-  QString filename(widgets_[widget].first);
-  QString stylesheet(widgets_[widget].second);
 
   // Load the file
   QFile file(filename);
@@ -60,56 +55,71 @@ void StyleSheetLoader::UpdateStyleSheet(QWidget *widget) {
     return;
   }
   QTextStream stream(&file);
-  QString contents;
+  QString stylesheet;
   forever {
     QString line = stream.readLine();
-    contents.append(line);
+    stylesheet.append(line);
     if (stream.atEnd()) break;
   }
   file.close();
 
+  StyleSheetData styledata;
+  styledata.filename_ = filename;
+  styledata.stylesheet_template_ = stylesheet;
+  styledata.stylesheet_current_ = widget->styleSheet();
+  styledata_[widget] = styledata;
+
+  widget->installEventFilter(this);
+  UpdateStyleSheet(widget, styledata);
+
+}
+
+void StyleSheetLoader::UpdateStyleSheet(QWidget *widget, StyleSheetData styledata) {
+
+  QString stylesheet = styledata.stylesheet_template_;
+
   // Replace %palette-role with actual colours
   QPalette p(widget->palette());
 
   QColor alt = p.color(QPalette::AlternateBase);
   alt.setAlpha(50);
-  contents.replace("%palette-alternate-base", QString("rgba(%1,%2,%3,%4%)")
+  stylesheet.replace("%palette-alternate-base", QString("rgba(%1,%2,%3,%4%)")
                                                   .arg(alt.red())
                                                   .arg(alt.green())
                                                   .arg(alt.blue())
                                                   .arg(alt.alpha()));
 
-  ReplaceColor(&contents, "Window", p, QPalette::Window);
+  ReplaceColor(&stylesheet, "Window", p, QPalette::Window);
-  ReplaceColor(&contents, "Background", p, QPalette::Background);
+  ReplaceColor(&stylesheet, "Background", p, QPalette::Background);
-  ReplaceColor(&contents, "WindowText", p, QPalette::WindowText);
+  ReplaceColor(&stylesheet, "WindowText", p, QPalette::WindowText);
-  ReplaceColor(&contents, "Foreground", p, QPalette::Foreground);
+  ReplaceColor(&stylesheet, "Foreground", p, QPalette::Foreground);
-  ReplaceColor(&contents, "Base", p, QPalette::Base);
+  ReplaceColor(&stylesheet, "Base", p, QPalette::Base);
-  ReplaceColor(&contents, "AlternateBase", p, QPalette::AlternateBase);
+  ReplaceColor(&stylesheet, "AlternateBase", p, QPalette::AlternateBase);
-  ReplaceColor(&contents, "ToolTipBase", p, QPalette::ToolTipBase);
+  ReplaceColor(&stylesheet, "ToolTipBase", p, QPalette::ToolTipBase);
-  ReplaceColor(&contents, "ToolTipText", p, QPalette::ToolTipText);
+  ReplaceColor(&stylesheet, "ToolTipText", p, QPalette::ToolTipText);
-  ReplaceColor(&contents, "Text", p, QPalette::Text);
+  ReplaceColor(&stylesheet, "Text", p, QPalette::Text);
-  ReplaceColor(&contents, "Button", p, QPalette::Button);
+  ReplaceColor(&stylesheet, "Button", p, QPalette::Button);
-  ReplaceColor(&contents, "ButtonText", p, QPalette::ButtonText);
+  ReplaceColor(&stylesheet, "ButtonText", p, QPalette::ButtonText);
-  ReplaceColor(&contents, "BrightText", p, QPalette::BrightText);
+  ReplaceColor(&stylesheet, "BrightText", p, QPalette::BrightText);
-  ReplaceColor(&contents, "Light", p, QPalette::Light);
+  ReplaceColor(&stylesheet, "Light", p, QPalette::Light);
-  ReplaceColor(&contents, "Midlight", p, QPalette::Midlight);
+  ReplaceColor(&stylesheet, "Midlight", p, QPalette::Midlight);
-  ReplaceColor(&contents, "Dark", p, QPalette::Dark);
+  ReplaceColor(&stylesheet, "Dark", p, QPalette::Dark);
-  ReplaceColor(&contents, "Mid", p, QPalette::Mid);
+  ReplaceColor(&stylesheet, "Mid", p, QPalette::Mid);
-  ReplaceColor(&contents, "Shadow", p, QPalette::Shadow);
+  ReplaceColor(&stylesheet, "Shadow", p, QPalette::Shadow);
-  ReplaceColor(&contents, "Highlight", p, QPalette::Highlight);
+  ReplaceColor(&stylesheet, "Highlight", p, QPalette::Highlight);
-  ReplaceColor(&contents, "HighlightedText", p, QPalette::HighlightedText);
+  ReplaceColor(&stylesheet, "HighlightedText", p, QPalette::HighlightedText);
-  ReplaceColor(&contents, "Link", p, QPalette::Link);
+  ReplaceColor(&stylesheet, "Link", p, QPalette::Link);
-  ReplaceColor(&contents, "LinkVisited", p, QPalette::LinkVisited);
+  ReplaceColor(&stylesheet, "LinkVisited", p, QPalette::LinkVisited);
 
 #ifdef Q_OS_MACOS
-  contents.replace("macos", "*");
+  stylesheet.replace("macos", "*");
 #endif
 
-  if (contents == stylesheet) return;
+  if (stylesheet != styledata.stylesheet_current_) {
-
+    widget->setStyleSheet(stylesheet);
-  widget->setStyleSheet("");
+    styledata.stylesheet_current_ = widget->styleSheet();
-  widget->setStyleSheet(contents);
+    styledata_[widget] = styledata;
-  widgets_[widget] = qMakePair(filename, contents);
+  }
 
 }
 
@@ -126,9 +136,23 @@ bool StyleSheetLoader::eventFilter(QObject *obj, QEvent *event) {
   if (event->type() != QEvent::PaletteChange) return false;
 
   QWidget *widget = qobject_cast<QWidget*>(obj);
-  if (!widget || !widgets_.contains(widget)) return false;
+  if (!widget || !styledata_.contains(widget)) return false;
 
-  UpdateStyleSheet(widget);
+  StyleSheetData styledata = styledata_[widget];
+  ++styledata.count_;
+  styledata_[widget] = styledata;
+  timer_reset_counter_->start();
+  if (styledata.count_ < 5) {
+    UpdateStyleSheet(widget, styledata);
+  }
   return false;
 
 }
+
+void StyleSheetLoader::ResetCounters() {
+
+  for (QMap<QWidget*, StyleSheetData>::iterator i = styledata_.begin() ; i != styledata_.end() ; ++i) {
+    i.value().count_ = 0;
+  }
+
+}

src/core/stylesheetloader.h

@@ -31,9 +31,12 @@
 #include <QString>
 
 class QWidget;
+class QTimer;
 class QEvent;
 
 class StyleSheetLoader : public QObject {
+ Q_OBJECT
+
  public:
   explicit StyleSheetLoader(QObject *parent = nullptr);
 
@@ -46,12 +49,24 @@ class StyleSheetLoader : public QObject {
   bool eventFilter(QObject *obj, QEvent *event);
 
  private:
-  void UpdateStyleSheet(QWidget *widget);
+  struct StyleSheetData {
-  void ReplaceColor(QString *css, const QString name, const QPalette &palette, QPalette::ColorRole role) const;
+    StyleSheetData() : count_(0) {}
+    QString filename_;
+    QString stylesheet_template_;
+    QString stylesheet_current_;
+    int count_;
+  };
 
  private:
-  QMap<QWidget*, QPair<QString, QString>> widgets_;
+  void UpdateStyleSheet(QWidget *widget, StyleSheetData styledata);
+  void ReplaceColor(QString *css, const QString name, const QPalette &palette, QPalette::ColorRole role) const;
+
+ private slots:
+  void ResetCounters();
+
+ private:
+  QMap<QWidget*, StyleSheetData> styledata_;
+  QTimer *timer_reset_counter_;
 };
 
 #endif  // STYLESHEETLOADER_H
-