gui, spline-widget, compat/options: ensure no qsettings IO when not modified

Turns out every MainWindow::save() and friends were doing useless IO
several times during each save. I blame the bundle abstraction.

For bundles we track the modified state, but the spline widget needs
equality check since it doesn't use the options api.

It was found by accident when adding qDebug() into the slider_value
{de,}serializer code. The .ini file was being rewritten over and over
again causing hundres of milliseconds pauses on Windows.

Remove the save timer kludge from gui. Saves are now fast.

5 files changed, 56 insertions, 39 deletions

diff --git a/gui/ui.cpp b/gui/ui.cpp
index fabcb5e4..40ac6c8d 100644
--- a/gui/ui.cpp
+++ b/gui/ui.cpp
@@ -74,9 +74,6 @@ MainWindow::MainWindow() :
     connect(&pose_update_timer, SIGNAL(timeout()), this, SLOT(showHeadPose()));
     connect(&kbd_quit, SIGNAL(activated()), this, SLOT(exit()));
 
-    save_timer.setSingleShot(true);
-    connect(&save_timer, SIGNAL(timeout()), this, SLOT(_save()));
-
     profile_menu.addAction("Create new empty config", this, SLOT(make_empty_config()));
     profile_menu.addAction("Create new copied config", this, SLOT(make_copied_config()));
     profile_menu.addAction("Open configuration directory", this, SLOT(open_config_directory()));
@@ -156,11 +153,10 @@ bool MainWindow::get_new_config_name_from_dialog(QString& ret)
 
 MainWindow::~MainWindow()
 {
-    maybe_save();
-
     if (tray)
         tray->hide();
     stopTracker();
+    save();
 }
 
 void MainWindow::set_working_directory()
@@ -168,30 +164,15 @@ void MainWindow::set_working_directory()
     QDir::setCurrent(QCoreApplication::applicationDirPath());
 }
 
-void MainWindow::save_mappings() {
+void MainWindow::save_mappings()
+{
     pose.save_mappings();
 }
 
 void MainWindow::save()
 {
-    save_timer.stop();
-    save_timer.start(5000);
-}
-
-void MainWindow::maybe_save()
-{
-    if (save_timer.isActive())
-    {
-        save_timer.stop();
-        _save();
-    }
-}
-
-void MainWindow::_save() {
     s.b->save();
     save_mappings();
-    mem<QSettings> settings = group::ini_file();
-    settings->sync();
 
 #if defined(__unix) || defined(__linux)
     QString currentFile = group::ini_pathname();
diff --git a/gui/ui.h b/gui/ui.h
index fbfd1237..42c4630c 100644
--- a/gui/ui.h
+++ b/gui/ui.h
@@ -38,7 +38,7 @@ using namespace options;
 class MainWindow : public QMainWindow, private State
 {
     Q_OBJECT
-    
+
     Shortcuts global_shortcuts;
 
     Ui::OpentrackUI ui;
@@ -55,7 +55,6 @@ class MainWindow : public QMainWindow, private State
     process_detector_worker det;
     QMenu profile_menu;
     bool is_refreshing_profiles;
-    QTimer save_timer;
 
     mem<dylib> current_tracker()
     {
@@ -79,10 +78,8 @@ class MainWindow : public QMainWindow, private State
     void set_title(const QString& game_title = QStringLiteral(""));
     static bool get_new_config_name_from_dialog(QString &ret);
     void set_profile(const QString& profile);
-    void maybe_save();
     void register_shortcuts();
 private slots:
-    void _save();
     void save();
     void exit();
     void profileSelected(QString name);
diff --git a/opentrack-compat/options.cpp b/opentrack-compat/options.cpp
index 55a4b795..785698de 100644
--- a/opentrack-compat/options.cpp
+++ b/opentrack-compat/options.cpp
@@ -88,7 +88,7 @@ const mem<QSettings> group::ini_file()
     return std::make_shared<QSettings>();
 }
 
-impl_bundle::impl_bundle(const QString &group_name)
+impl_bundle::impl_bundle(const QString& group_name)
     :
       mtx(QMutex::Recursive),
       group_name(group_name),
@@ -101,20 +101,25 @@ void impl_bundle::reload()
 {
     {
         QMutexLocker l(&mtx);
-        saved = group(group_name);
-        transient = saved;
-        modified = false;
+        if (modified)
+        {
+            saved = group(group_name);
+            transient = saved;
+            modified = false;
+        }
     }
     emit reloading();
 }
 
-void impl_bundle::store_kv(const QString &name, const QVariant &datum)
+void impl_bundle::store_kv(const QString& name, const QVariant& datum)
 {
     QMutexLocker l(&mtx);
 
     auto old = transient.get<QVariant>(name);
     if (!transient.contains(name) || datum != old)
     {
+        if (!modified)
+            qDebug() << "bundle" << group_name << "modified" << "key" << name << "to" << datum << "from" << old;
         modified = true;
         transient.put(name, datum);
     }
@@ -128,13 +133,20 @@ bool impl_bundle::contains(const QString &name) const
 
 void impl_bundle::save()
 {
+    bool modified_ = false;
     {
         QMutexLocker l(&mtx);
-        modified = false;
-        saved = transient;
-        transient.save();
+        if (modified)
+        {
+            qDebug() << "bundle" << group_name << "saved";
+            modified_ = true;
+            modified = false;
+            saved = transient;
+            transient.save();
+        }
     }
-    emit saving();
+    if (modified_)
+        emit saving();
 }
 
 bool impl_bundle::modifiedp() const
@@ -220,7 +232,6 @@ custom_type_initializer custom_type_initializer::singleton = custom_type_initial
 QDataStream& operator <<(QDataStream& out, const options::slider_value& v)
 {
     out << v.cur() << v.min() << v.max();
-    qDebug() << "out cur" << v.cur();
     return out;
 }
 
@@ -231,6 +242,5 @@ QDataStream& operator >>(QDataStream& in, options::slider_value& v)
     in >> min;
     in >> max;
     v = options::slider_value(cur, min, max);
-    qDebug() << "in cur" << v.cur();
     return in;
 }
diff --git a/spline-widget/functionconfig.cpp b/spline-widget/functionconfig.cpp
index 1acea958..8cfce7ae 100644
--- a/spline-widget/functionconfig.cpp
+++ b/spline-widget/functionconfig.cpp
@@ -15,6 +15,7 @@
 #include <QtAlgorithms>
 #include <QSettings>
 #include <QPixmap>
+#include <QString>
 #include <algorithm>
 #include <cmath>
 
@@ -271,10 +272,36 @@ void Map::loadSettings(QSettings& settings, const QString& title)
     saved = cur;
 }
 
+bool Map::State::operator==(const State& other) const
+{
+    if (input.size() != other.input.size())
+        return false;
+
+    const int sz = input.size();
+
+    using std::fabs;
+
+    for (int i = 0; i < sz; i++)
+    {
+        const qreal eps = 1e-3;
+
+        if (fabs(input[i].x() - other.input[i].x()) > eps ||
+            fabs(input[i].y() - other.input[i].y()) > eps)
+        {
+            return false;
+        }
+    }
+    return true;
+}
+
 void Map::saveSettings(QSettings& settings, const QString& title)
 {
     QMutexLocker foo(&_mutex);
-    settings.beginGroup(QString("Curves-%1").arg(title));
+
+    if (cur == saved)
+        return;
+
+    settings.beginGroup(QStringLiteral("Curves-%1").arg(title));
 
     if (cur.input.size() == 0)
         cur.input.push_back(QPointF(max_x, max_y));
diff --git a/spline-widget/functionconfig.h b/spline-widget/functionconfig.h
index 6c039831..5c9eeb2b 100644
--- a/spline-widget/functionconfig.h
+++ b/spline-widget/functionconfig.h
@@ -28,9 +28,11 @@ class SPLINE_WIDGET_EXPORT Map {
 private:
     static constexpr int value_count = 10000;
 
-    struct State {
+    struct State
+    {
         QList<QPointF> input;
         std::vector<float> data;
+        bool operator==(const State& s) const;
     };
 
     int precision() const;