WallpaperService.h

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// SPDX-FileCopyrightText: 2026 fuddlesworth
// SPDX-License-Identifier: LGPL-2.1-or-later
 
#pragma once
 
#include <PhosphorShell/phosphorshell_export.h>
 
#include <QImage>
#include <QObject>
#include <QString>
 
#include <memory>
 
namespace PhosphorShaders {
class IWallpaperProvider;
}
 
QT_BEGIN_NAMESPACE
class QFileSystemWatcher;
class QTimer;
QT_END_NAMESPACE
 
namespace PhosphorShell {
 
class PHOSPHORSHELL_EXPORT WallpaperService : public QObject
{
    Q_OBJECT
    Q_DISABLE_COPY_MOVE(WallpaperService)
 
    Q_PROPERTY(QImage image READ image NOTIFY imageChanged)
    Q_PROPERTY(QString path READ path NOTIFY imageChanged)
    Q_PROPERTY(bool available READ isAvailable NOTIFY imageChanged)
 
public:
    explicit WallpaperService(QObject* parent = nullptr);
    ~WallpaperService() override;
 
    [[nodiscard]] QImage image() const;
    [[nodiscard]] QString path() const;
    [[nodiscard]] bool isAvailable() const;
 
    Q_INVOKABLE void refresh();
 
Q_SIGNALS:
    void imageChanged();
 
private:
    void scheduleLoad(const QString& path);
    void installImage(QImage image, const QString& path);
 
    // Plasma config file is written via atomic rename, which can fire
    // QFileSystemWatcher::fileChanged several times for one save.
    // Debounce so a burst collapses to one refresh().
    static constexpr int kRefreshDebounceMs = 200;
    // QImageReader::setAllocationLimit unit is MiB. 512 MiB covers a
    // ~16K × 16K RGBA8888 wallpaper while rejecting decompression
    // bombs.
    static constexpr int kMaxImageBytesMib = 512;
    // Pixel-count cap: reject before decode runs, so a small-header
    // image with huge declared dimensions can't make it to allocation.
    static constexpr qint64 kMaxPixelCount = qint64(16384) * 16384;
 
    std::unique_ptr<PhosphorShaders::IWallpaperProvider> m_provider;
    QString m_currentPath;
    QImage m_image;
    QFileSystemWatcher* m_watcher = nullptr;
    QTimer* m_refreshDebounce = nullptr;
    // Generation counter discards out-of-order async-load results: a
    // rapid wallpaper-change sequence could queue multiple decode
    // tasks; only the most recently scheduled one's result is
    // installed. Incremented on every scheduleLoad.
    quint64 m_loadGeneration = 0;
};
 
} // namespace PhosphorShell