[kio_desktop] Implement SlaveBase::GetFileSystemFreeSpace

This enables reporting the actual free space info for desktop:/ in e.g.
the Dolphin status bar.

BUG: 417851

FIXED-IN: 5.19.80

kioslave/desktop/kio_desktop.cpp

@@ -23,8 +23,9 @@
 #include <KDesktopFile>
 #include <KDirNotify>
 #include <KLocalizedString>
-
-#include <kio/udsentry.h>
+#include <KDiskFreeSpaceInfo>
+#include <KIO/StatJob>
+#include <KIO/UDSEntry>
 
 #include <QCoreApplication>
 #include <QFile>
@@ -226,3 +227,27 @@ void DesktopProtocol::rename(const QUrl &_src, const QUrl &_dest, KIO::JobFlags
     }
 }
 
+void DesktopProtocol::virtual_hook(int id, void *data)
+{
+    switch(id) {
+        case SlaveBase::GetFileSystemFreeSpace: {
+            QUrl *url = static_cast<QUrl *>(data);
+            fileSystemFreeSpace(*url);
+        }   break;
+        default:
+            SlaveBase::virtual_hook(id, data);
+    }
+}
+
+void DesktopProtocol::fileSystemFreeSpace(const QUrl &url)
+{
+    const QString desktopPath = QStandardPaths::writableLocation(QStandardPaths::DesktopLocation);
+    const KDiskFreeSpaceInfo spaceInfo = KDiskFreeSpaceInfo::freeSpaceInfo(desktopPath);
+    if (spaceInfo.isValid()) {
+        setMetaData(QStringLiteral("total"), QString::number(spaceInfo.size()));
+        setMetaData(QStringLiteral("available"), QString::number(spaceInfo.available()));
+        finished();
+    } else {
+        error(KIO::ERR_CANNOT_STAT, desktopPath);
+    }
+}

kioslave/desktop/kio_desktop.h

@@ -36,6 +36,11 @@ protected:
     void listDir(const QUrl &url) override;
     void prepareUDSEntry(KIO::UDSEntry &entry, bool listing=false) const override;
     void rename(const QUrl &, const QUrl &, KIO::JobFlags flags) override;
+
+    void virtual_hook(int id, void *data) override;
+
+private:
+    void fileSystemFreeSpace(const QUrl &url);
 };
 
 #endif