[nightcolor] Introduce inhibition API

Summary:
The new API allows to block Night Color temporarily. This can be useful
for applications such as video games and plasma applets.

CCBUG: 400418

Test Plan: Called inhibit() and uninhibit() from D-Feet.

Reviewers: #kwin, davidedmundson

Reviewed By: #kwin, davidedmundson

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D25786

colorcorrection/colorcorrectdbusinterface.cpp

@@ -23,18 +23,51 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include "manager.h"
 
+#include <QDBusMessage>
+
 namespace KWin {
 namespace ColorCorrect {
 
 ColorCorrectDBusInterface::ColorCorrectDBusInterface(Manager *parent)
     : QObject(parent)
     , m_manager(parent)
+    , m_inhibitorWatcher(new QDBusServiceWatcher(this))
 {
+    m_inhibitorWatcher->setConnection(QDBusConnection::sessionBus());
+    m_inhibitorWatcher->setWatchMode(QDBusServiceWatcher::WatchForUnregistration);
+    connect(m_inhibitorWatcher, &QDBusServiceWatcher::serviceUnregistered,
+            this, &ColorCorrectDBusInterface::removeInhibitorService);
+
+    // Argh, all this code is just to send one innocent signal...
+    connect(m_manager, &Manager::inhibitedChanged, this, [this] {
+        QVariantMap changedProperties;
+        changedProperties.insert(QStringLiteral("inhibited"), m_manager->isInhibited());
+
+        QDBusMessage message = QDBusMessage::createSignal(
+            QStringLiteral("/ColorCorrect"),
+            QStringLiteral("org.freedesktop.DBus.Properties"),
+            QStringLiteral("PropertiesChanged")
+        );
+
+        message.setArguments({
+            QStringLiteral("org.kde.kwin.ColorCorrect"),
+            changedProperties,
+            QStringList(), // invalidated_properties
+        });
+
+        QDBusConnection::sessionBus().send(message);
+    });
+
     connect(m_manager, &Manager::configChange, this, &ColorCorrectDBusInterface::nightColorConfigChanged);
     new ColorCorrectAdaptor(this);
     QDBusConnection::sessionBus().registerObject(QStringLiteral("/ColorCorrect"), this);
 }
 
+bool ColorCorrectDBusInterface::isInhibited() const
+{
+    return m_manager->isInhibited();
+}
+
 QHash<QString, QVariant> ColorCorrectDBusInterface::nightColorInfo()
 {
     return m_manager->info();
@@ -50,5 +83,49 @@ void ColorCorrectDBusInterface::nightColorAutoLocationUpdate(double latitude, do
     m_manager->autoLocationUpdate(latitude, longitude);
 }
 
+uint ColorCorrectDBusInterface::inhibit()
+{
+    const QString serviceName = QDBusContext::message().service();
+
+    if (m_inhibitors.values(serviceName).isEmpty()) {
+        m_inhibitorWatcher->addWatchedService(serviceName);
+    }
+
+    m_inhibitors.insert(serviceName, ++m_lastInhibitionCookie);
+
+    m_manager->inhibit();
+
+    return m_lastInhibitionCookie;
+}
+
+void ColorCorrectDBusInterface::uninhibit(uint cookie)
+{
+    const QString serviceName = QDBusContext::message().service();
+
+    uninhibit(serviceName, cookie);
+}
+
+void ColorCorrectDBusInterface::uninhibit(const QString &serviceName, uint cookie)
+{
+    const int removedCount = m_inhibitors.remove(serviceName, cookie);
+    if (!removedCount) {
+        return;
+    }
+
+    if (m_inhibitors.values(serviceName).isEmpty()) {
+        m_inhibitorWatcher->removeWatchedService(serviceName);
+    }
+
+    m_manager->uninhibit();
+}
+
+void ColorCorrectDBusInterface::removeInhibitorService(const QString &serviceName)
+{
+    const auto cookies = m_inhibitors.values(serviceName);
+    for (const uint &cookie : cookies) {
+        uninhibit(serviceName, cookie);
+    }
+}
+
 }
 }

colorcorrection/colorcorrectdbusinterface.h

@@ -32,15 +32,18 @@ namespace ColorCorrect
 
 class Manager;
 
-class ColorCorrectDBusInterface : public QObject
+class ColorCorrectDBusInterface : public QObject, public QDBusContext
 {
     Q_OBJECT
     Q_CLASSINFO("D-Bus Interface", "org.kde.kwin.ColorCorrect")
+    Q_PROPERTY(bool inhibited READ isInhibited)
 
 public:
     explicit ColorCorrectDBusInterface(Manager *parent);
     ~ColorCorrectDBusInterface() override = default;
 
+    bool isInhibited() const;
+
 public Q_SLOTS:
     /**
      * @brief Gives information about the current state of Night Color.
@@ -101,6 +104,16 @@ public Q_SLOTS:
      * @since 5.12
      */
     void nightColorAutoLocationUpdate(double latitude, double longitude);
+    /**
+     * @brief Temporarily blocks Night Color.
+     * @since 5.18
+     */
+    uint inhibit();
+    /**
+     * @brief Cancels the previous call to inhibit().
+     * @since 5.18
+     */
+    void uninhibit(uint cookie);
 
 Q_SIGNALS:
     /**
@@ -115,8 +128,16 @@ Q_SIGNALS:
      */
     void nightColorConfigChanged(QHash<QString, QVariant> data);
 
+private Q_SLOTS:
+    void removeInhibitorService(const QString &serviceName);
+
 private:
+    void uninhibit(const QString &serviceName, uint cookie);
+
     Manager *m_manager;
+    QDBusServiceWatcher *m_inhibitorWatcher;
+    QMultiHash<QString, uint> m_inhibitors;
+    uint m_lastInhibitionCookie = 0;
 };
 
 }

colorcorrection/manager.cpp

@@ -61,6 +61,27 @@ Manager::Manager(QObject *parent)
 {
     m_iface = new ColorCorrectDBusInterface(this);
     connect(kwinApp(), &Application::workspaceCreated, this, &Manager::init);
+
+    // Display a message when Night Color is (un)inhibited.
+    connect(this, &Manager::inhibitedChanged, this, [this] {
+        // TODO: Maybe use different icons?
+        const QString iconName = isInhibited()
+            ? QStringLiteral("preferences-desktop-display-nightcolor-off")
+            : QStringLiteral("preferences-desktop-display-nightcolor-on");
+
+        const QString text = isInhibited()
+            ? i18nc("Night Color was disabled", "Night Color Off")
+            : i18nc("Night Color was enabled", "Night Color On");
+
+        QDBusMessage message = QDBusMessage::createMethodCall(
+            QStringLiteral("org.kde.plasmashell"),
+            QStringLiteral("/org/kde/osdService"),
+            QStringLiteral("org.kde.osdService"),
+            QStringLiteral("showText"));
+        message.setArguments({ iconName, text });
+
+        QDBusConnection::sessionBus().asyncCall(message);
+    });
 }
 
 void Manager::init()
@@ -145,7 +166,7 @@ void Manager::hardReset()
         updateSunTimings(true);
     }
 
-    if (kwinApp()->platform()->supportsGammaControl() && m_active) {
+    if (kwinApp()->platform()->supportsGammaControl() && m_active && !isInhibited()) {
         m_running = true;
         commitGammaRamps(currentTargetTemp());
     }
@@ -159,41 +180,35 @@ void Manager::reparseConfigAndReset()
     hardReset();
 }
 
-// FIXME: The internal OSD service doesn't work on X11 right now. Once the QPA
-// is ported away from Wayland, drop this function in favor of the internal
-// OSD service.
-static void showStatusOsd(bool enabled)
-{
-    // TODO: Maybe use different icons?
-    const QString iconName = enabled
-        ? QStringLiteral("preferences-desktop-display-nightcolor-on")
-        : QStringLiteral("preferences-desktop-display-nightcolor-off");
-
-    const QString text = enabled
-        ? i18nc("Night Color was enabled", "Night Color On")
-        : i18nc("Night Color was disabled", "Night Color Off");
-
-    QDBusMessage message = QDBusMessage::createMethodCall(
-        QStringLiteral("org.kde.plasmashell"),
-        QStringLiteral("/org/kde/osdService"),
-        QStringLiteral("org.kde.osdService"),
-        QStringLiteral("showText"));
-    message.setArguments({ iconName, text });
-
-    QDBusConnection::sessionBus().asyncCall(message);
-}
-
 void Manager::toggle()
 {
-    if (!kwinApp()->platform()->supportsGammaControl()) {
-        return;
+    m_isGloballyInhibited = !m_isGloballyInhibited;
+    m_isGloballyInhibited ? inhibit() : uninhibit();
+}
+
+bool Manager::isInhibited() const
+{
+    return m_inhibitReferenceCount;
+}
+
+void Manager::inhibit()
+{
+    m_inhibitReferenceCount++;
+
+    if (m_inhibitReferenceCount == 1) {
+        resetAllTimers();
+        emit inhibitedChanged();
     }
+}
 
-    m_active = !m_active;
+void Manager::uninhibit()
+{
+    m_inhibitReferenceCount--;
 
-    showStatusOsd(m_active);
-
-    resetAllTimers();
+    if (!m_inhibitReferenceCount) {
+        resetAllTimers();
+        emit inhibitedChanged();
+    }
 }
 
 void Manager::initShortcuts()
@@ -279,9 +294,7 @@ void Manager::resetAllTimers()
 {
     cancelAllTimers();
     if (kwinApp()->platform()->supportsGammaControl()) {
-        if (m_active) {
-            m_running = true;
-        }
+        m_running = m_active && !isInhibited();
         // we do this also for active being false in order to reset the temperature back to the day value
         resetQuickAdjustTimer();
     } else {
@@ -542,7 +555,7 @@ bool Manager::daylight() const
 
 int Manager::currentTargetTemp() const
 {
-    if (!m_active) {
+    if (!m_running) {
         return NEUTRAL_TEMPERATURE;
     }
 

colorcorrection/manager.h

@@ -126,6 +126,24 @@ public:
      */
     void toggle();
 
+    /**
+     * Returns @c true if the night color manager is blocked; otherwise @c false.
+     */
+    bool isInhibited() const;
+
+    /**
+     * Temporarily blocks the night color manager.
+     *
+     * After calling this method, the screen color temperature will be reverted
+     * back to 6500C. When you're done, call uninhibit() method.
+     */
+    void inhibit();
+
+    /**
+     * Attempts to unblock the night color manager.
+     */
+    void uninhibit();
+
     // for auto tests
     void reparseConfigAndReset();
 
@@ -136,6 +154,11 @@ public Q_SLOTS:
 Q_SIGNALS:
     void configChange(QHash<QString, QVariant> data);
 
+    /**
+     * Emitted whenever the night color manager is blocked or unblocked.
+     */
+    void inhibitedChanged();
+
 private:
     void initShortcuts();
     void readConfig();
@@ -162,9 +185,15 @@ private:
 
     ColorCorrectDBusInterface *m_iface;
 
+    // Specifies whether Night Color is enabled.
     bool m_active;
+
+    // Specifies whether Night Color is currently running.
     bool m_running = false;
 
+    // Specifies whether Night Color is inhibited globally.
+    bool m_isGloballyInhibited = false;
+
     NightColorMode m_mode = NightColorMode::Automatic;
 
     // the previous and next sunrise/sunset intervals - in UTC time
@@ -192,6 +221,7 @@ private:
     int m_nightTargetTemp = DEFAULT_NIGHT_TEMPERATURE;
 
     int m_failedCommitAttempts = 0;
+    int m_inhibitReferenceCount = 0;
 
     // The Workspace class needs to call initShortcuts during initialization.
     friend class KWin::Workspace;

org.kde.kwin.ColorCorrect.xml

@@ -18,5 +18,39 @@
         <annotation name="org.qtproject.QtDBus.QtTypeName.Out0" value="QHash&lt;QString,QVariant&gt;"/>
         <arg type="a{sv}" direction="out"/>
     </signal>
+
+    <!--
+        Creates an inhibition lock for Night Color.
+
+        You can use this method to temporarily disable Night Color feature.
+        After calling this method, the screen color temperature will be set
+        back to the neutral temperature (6500K).
+
+        This method returns a cookie that uniquely identifies the inhibition
+        request. You must pass the cookie to uninhibit() when you're done.
+
+        Note that the inhibition lock will be released automatically when
+        the service, which requested it, is unregistered.
+
+        A client is allowed to hold more than just one inhibition lock.
+    -->
+    <method name="inhibit">
+        <arg name="cookie" type="u" direction="out"/>
+    </method>
+
+    <!--
+        Releases an inhibition lock identified by the given cookie.
+
+        Note that the inhibition lock will be released automatically when
+        the service, which requested it, is unregistered.
+    -->
+    <method name="uninhibit">
+        <arg name="cookie" type="u" direction="in"/>
+    </method>
+
+    <!--
+        This property holds a value to indicate whether Night Color is inhibited.
+    -->
+    <property name="inhibited" type="b" access="read"/>
   </interface>
 </node>