Move heavy SystemProperties loads to an opt-in model

This avoids heavyweight operations when we're not actually running config checks.

app/backend/systemproperties.cpp

@@ -98,13 +98,82 @@ SystemProperties::SystemProperties()
     hasDiscordIntegration = false;
 #endif
 
-    unmappedGamepads = SdlInputHandler::getUnmappedGamepads();
-
     // These will be queried asynchronously to avoid blocking the UI
     hasHardwareAcceleration = true;
     rendererAlwaysFullScreen = false;
     supportsHdr = true;
     maximumResolution = QSize(0, 0);
+}
+
+SystemProperties::~SystemProperties()
+{
+    waitForAsyncLoad();
+}
+
+void SystemProperties::updateDecoderProperties(bool hasHardwareAcceleration, bool rendererAlwaysFullScreen, QSize maximumResolution, bool supportsHdr)
+{
+    SDL_assert(testWindow);
+
+    if (hasHardwareAcceleration != this->hasHardwareAcceleration) {
+        this->hasHardwareAcceleration = hasHardwareAcceleration;
+        emit hasHardwareAccelerationChanged();
+    }
+
+    if (rendererAlwaysFullScreen != this->rendererAlwaysFullScreen) {
+        this->rendererAlwaysFullScreen = rendererAlwaysFullScreen;
+        emit rendererAlwaysFullScreenChanged();
+    }
+
+    if (maximumResolution != this->maximumResolution) {
+        this->maximumResolution = maximumResolution;
+        emit maximumResolutionChanged();
+    }
+
+    if (supportsHdr != this->supportsHdr) {
+        this->supportsHdr = supportsHdr;
+        emit supportsHdrChanged();
+    }
+
+    SDL_DestroyWindow(testWindow);
+    testWindow = nullptr;
+    SDL_QuitSubSystem(SDL_INIT_VIDEO);
+}
+
+QRect SystemProperties::getNativeResolution(int displayIndex)
+{
+    // Returns default constructed QRect if out of bounds
+    Q_ASSERT(!monitorNativeResolutions.isEmpty());
+    return monitorNativeResolutions.value(displayIndex);
+}
+
+QRect SystemProperties::getSafeAreaResolution(int displayIndex)
+{
+    // Returns default constructed QRect if out of bounds
+    Q_ASSERT(!monitorSafeAreaResolutions.isEmpty());
+    return monitorSafeAreaResolutions.value(displayIndex);
+}
+
+int SystemProperties::getRefreshRate(int displayIndex)
+{
+    // Returns 0 if out of bounds
+    Q_ASSERT(!monitorRefreshRates.isEmpty());
+    return monitorRefreshRates.value(displayIndex);
+}
+
+void SystemProperties::startAsyncLoad()
+{
+    if (systemPropertyQueryThread) {
+        // Already started/completed
+        return;
+    }
+
+    // This isn't actually asynchronous (due to the need to synchronize with
+    // SdlGamepadKeyNavigation), but we don't query it in the constructor
+    // because it's expensive.
+    unmappedGamepads = SdlInputHandler::getUnmappedGamepads();
+    if (!unmappedGamepads.isEmpty()) {
+        emit unmappedGamepadsChanged();
+    }
 
     // We initialize the video subsystem and test window on the main thread
     // because some platforms (macOS) do not support window creation on
@@ -140,62 +209,11 @@ SystemProperties::SystemProperties()
     systemPropertyQueryThread->start();
 }
 
-SystemProperties::~SystemProperties()
+void SystemProperties::waitForAsyncLoad()
 {
+    if (systemPropertyQueryThread) {
         systemPropertyQueryThread->wait();
-}
-
-void SystemProperties::updateDecoderProperties(bool hasHardwareAcceleration, bool rendererAlwaysFullScreen, QSize maximumResolution, bool supportsHdr)
-{
-    SDL_assert(testWindow);
-
-    if (hasHardwareAcceleration != this->hasHardwareAcceleration) {
-        this->hasHardwareAcceleration = hasHardwareAcceleration;
-        emit hasHardwareAccelerationChanged();
     }
-
-    if (rendererAlwaysFullScreen != this->rendererAlwaysFullScreen) {
-        this->rendererAlwaysFullScreen = rendererAlwaysFullScreen;
-        emit rendererAlwaysFullScreenChanged();
-    }
-
-    if (maximumResolution != this->maximumResolution) {
-        this->maximumResolution = maximumResolution;
-        emit maximumResolutionChanged();
-    }
-
-    if (supportsHdr != this->supportsHdr) {
-        this->supportsHdr = supportsHdr;
-        emit supportsHdrChanged();
-    }
-
-    SDL_DestroyWindow(testWindow);
-    testWindow = nullptr;
-    SDL_QuitSubSystem(SDL_INIT_VIDEO);
-}
-
-QRect SystemProperties::getNativeResolution(int displayIndex)
-{
-    // Returns default constructed QRect if out of bounds
-    systemPropertyQueryThread->wait();
-    Q_ASSERT(!monitorNativeResolutions.isEmpty());
-    return monitorNativeResolutions.value(displayIndex);
-}
-
-QRect SystemProperties::getSafeAreaResolution(int displayIndex)
-{
-    // Returns default constructed QRect if out of bounds
-    systemPropertyQueryThread->wait();
-    Q_ASSERT(!monitorSafeAreaResolutions.isEmpty());
-    return monitorSafeAreaResolutions.value(displayIndex);
-}
-
-int SystemProperties::getRefreshRate(int displayIndex)
-{
-    // Returns 0 if out of bounds
-    systemPropertyQueryThread->wait();
-    Q_ASSERT(!monitorRefreshRates.isEmpty());
-    return monitorRefreshRates.value(displayIndex);
 }
 
 void SystemProperties::refreshDisplays()

app/backend/systemproperties.h

@@ -26,18 +26,22 @@ public:
     Q_PROPERTY(bool usesMaterial3Theme MEMBER usesMaterial3Theme CONSTANT)
     Q_PROPERTY(QString versionString MEMBER versionString CONSTANT)
 
-    // Properties queried asynchronously
+    // Properties queried asynchronously (startAsyncLoad() must be called!)
     Q_PROPERTY(bool hasHardwareAcceleration MEMBER hasHardwareAcceleration NOTIFY hasHardwareAccelerationChanged)
     Q_PROPERTY(bool rendererAlwaysFullScreen MEMBER rendererAlwaysFullScreen NOTIFY rendererAlwaysFullScreenChanged)
     Q_PROPERTY(QString unmappedGamepads MEMBER unmappedGamepads NOTIFY unmappedGamepadsChanged)
     Q_PROPERTY(QSize maximumResolution MEMBER maximumResolution NOTIFY maximumResolutionChanged)
     Q_PROPERTY(bool supportsHdr MEMBER supportsHdr NOTIFY supportsHdrChanged)
 
-    Q_INVOKABLE void refreshDisplays();
+    // Either startAsyncLoad()+waitForAsyncLoad() or refreshDisplays() must be invoked first
     Q_INVOKABLE QRect getNativeResolution(int displayIndex);
     Q_INVOKABLE QRect getSafeAreaResolution(int displayIndex);
     Q_INVOKABLE int getRefreshRate(int displayIndex);
 
+    Q_INVOKABLE void startAsyncLoad();
+    Q_INVOKABLE void waitForAsyncLoad();
+    Q_INVOKABLE void refreshDisplays();
+
 signals:
     void unmappedGamepadsChanged();
     void hasHardwareAccelerationChanged();
@@ -49,8 +53,8 @@ private slots:
     void updateDecoderProperties(bool hasHardwareAcceleration, bool rendererAlwaysFullScreen, QSize maximumResolution, bool supportsHdr);
 
 private:
-    QThread* systemPropertyQueryThread;
-    SDL_Window* testWindow;
+    QThread* systemPropertyQueryThread = nullptr;
+    SDL_Window* testWindow = nullptr;
 
     // Properties set by the constructor
     bool isRunningWayland;
@@ -60,15 +64,15 @@ private:
     bool hasDesktopEnvironment;
     bool hasBrowser;
     bool hasDiscordIntegration;
-    QString unmappedGamepads;
     QString versionString;
     bool usesMaterial3Theme;
 
-    // Properties set by updateDecoderProperties()
+    // Properties only set if startAsyncLoad() is called
     bool hasHardwareAcceleration;
     bool rendererAlwaysFullScreen;
     QSize maximumResolution;
     bool supportsHdr;
+    QString unmappedGamepads;
 
     // Properties set by refreshDisplays()
     QList<QRect> monitorNativeResolutions;

app/gui/StreamSegue.qml

@@ -4,6 +4,7 @@ import QtQuick.Window 2.2
 
 import SdlGamepadKeyNavigation 1.0
 import Session 1.0
+import SystemProperties 1.0
 
 Item {
     property Session session
@@ -120,6 +121,10 @@ Item {
         session.sessionFinished.connect(sessionFinished)
         session.readyForDeletion.connect(sessionReadyForDeletion)
 
+        // Ensure the SystemProperties async thread is finished,
+        // since it may currently be using the SDL video subsystem
+        SystemProperties.waitForAsyncLoad()
+
         // Kick off the stream
         spinnerTimer.start()
         streamLoader.active = true

app/gui/main.qml

@@ -56,13 +56,10 @@ ApplicationWindow {
                 wow64Dialog.open()
             }
 
-            if (SystemProperties.unmappedGamepads) {
-                unmappedGamepadDialog.unmappedGamepads = SystemProperties.unmappedGamepads
-                unmappedGamepadDialog.open()
-            }
-
-            // Hardware acceleration is checked asynchronously
+            // Hardware acceleration and unmapped gamepads are checked asynchronously
             SystemProperties.hasHardwareAccelerationChanged.connect(hasHardwareAccelerationChanged)
+            SystemProperties.unmappedGamepadsChanged.connect(hasUnmappedGamepadsChanged)
+            SystemProperties.startAsyncLoad()
         }
     }
 
@@ -77,6 +74,13 @@ ApplicationWindow {
         }
     }
 
+    function hasUnmappedGamepadsChanged() {
+        if (SystemProperties.unmappedGamepads) {
+            unmappedGamepadDialog.unmappedGamepads = SystemProperties.unmappedGamepads
+            unmappedGamepadDialog.open()
+        }
+    }
+
     // It would be better to use TextMetrics here, but it always lays out
     // the text slightly more compactly than real Text does in ToolTip,
     // causing unexpected line breaks to be inserted