Display which process blocks unmount/eject in a plasmoid notification

REVIEW: 125248
BUG: 96107

dataengines/devicenotifications/CMakeLists.txt

@@ -12,6 +12,7 @@ target_link_libraries(plasma_engine_devicenotifications
     KF5::Plasma
     KF5::Solid
     KF5::I18n
+    KF5::ProcessCore
 ) # todo: add kworkspace once ported
 
 kcoreaddons_desktop_to_json(plasma_engine_devicenotifications plasma-dataengine-devicenotifications.desktop)

dataengines/devicenotifications/ksolidnotify.cpp

@@ -31,6 +31,11 @@
 #include <Solid/Predicate>
 
 #include <KLocalizedString>
+#include <processcore/process.h>
+#include <processcore/processes.h>
+
+#include <QStringList>
+#include <QProcess>
 
 KSolidNotify::KSolidNotify(QObject* parent):
     QObject(parent)
@@ -113,12 +118,60 @@ void KSolidNotify::storageSetupDone(Solid::ErrorType error, QVariant errorData,
     }
 }
 
+void KSolidNotify::queryBlockingApps(const QString &devicePath)
+{
+    QProcess *p = new QProcess;
+    connect(p, static_cast<void (QProcess::*)(QProcess::ProcessError)>(&QProcess::error), [=](QProcess::ProcessError) {
+                emit blockingAppsReady({});
+                p->deleteLater();
+            });
+    connect(p, static_cast<void (QProcess::*)(int,QProcess::ExitStatus)>(&QProcess::finished), [=](int,QProcess::ExitStatus) {
+                QStringList blockApps;
+                QString out(p->readAll());
+                const QStringList &pidList = out.split(QRegExp("\\s+"), QString::SkipEmptyParts);
+                KSysGuard::Processes procs;
+                Q_FOREACH (const QString &pidStr, pidList) {
+                    int pid = pidStr.toInt();
+                    if (!pid) {
+                        continue;
+                    }
+                    procs.updateOrAddProcess(pid);
+                    KSysGuard::Process *proc = procs.getProcess(pid);
+                    if (!blockApps.contains(proc->name())) {
+                        blockApps << proc->name();
+                    }
+                }
+                blockApps.removeDuplicates();
+                emit blockingAppsReady(blockApps);
+                p->deleteLater();
+            });
+    p->start(QStringLiteral("lsof"), {QStringLiteral("-t"), devicePath});
+//    p.start(QStringLiteral("fuser"), {QStringLiteral("-m"), devicePath});
+}
+
 void KSolidNotify::storageTeardownDone(Solid::ErrorType error, QVariant errorData, const QString &udi)
 {
     if (error) {
         Solid::Device device(udi);
-        const QString errorMessage = i18n("Could not unmount the following device: %1\nOne or more files on this device are open within an application ", device.description());
-        emit notify(error, errorMessage, errorData.toString(), udi);
+        Solid::StorageAccess *access = device.as<Solid::StorageAccess>();
+        // Without that, our lambda function would capture an uninitialized object, resulting in UB
+        // and random crashes
+        QMetaObject::Connection *c = new QMetaObject::Connection();
+        *c = connect(this, &KSolidNotify::blockingAppsReady,
+                [=] (const QStringList &blockApps) {
+                    QString errorMessage;
+                    if (blockApps.isEmpty()) {
+                        errorMessage = i18n("Could not safely remove the following device: %1\nOne or more files on this device are open within an application", device.description());
+                    } else {
+                        errorMessage = i18np("Could not safely remove the following device: %1\nOne or more files on this device are opened in application \"%3\"\nPlease close it and try again",
+                                "Could not safely remove the following device: %1\nOne or more files on this device are opened in following applications: %3\nPlease close it and try again",
+                                device.description(), blockApps.size(), blockApps.join(i18nc("separator in list of apps blocking device unmount", ", ")));
+                    }
+                    emit notify(error, errorMessage, errorData.toString(), udi);
+                    disconnect(*c);
+                    delete c;
+                });
+        queryBlockingApps(access->filePath());
     } else if (isSafelyRemovable(udi)) {
         Solid::Device device(udi);
         const QString errorMessage = i18nc("The term \"remove\" here means \"physically disconnect the device from the computer\", whereas \"safely\" means \"without risk of data loss\"", "The following device can now be safely removed: %1", device.description());
@@ -143,8 +196,25 @@ void KSolidNotify::storageEjectDone(Solid::ErrorType error, QVariant errorData,
         }
 
         Solid::Device discDevice(discUdi);
-        const QString errorMessage = i18n("Could not eject the following device: %1\nOne or more files on this device are open within an application ", discDevice.description());
-        emit notify(error, errorMessage, errorData.toString(), udi);
+        Solid::StorageAccess *access = discDevice.as<Solid::StorageAccess>();
+        // Without that, our lambda function would capture an uninitialized object, resulting in UB
+        // and random crashes
+        QMetaObject::Connection *c = new QMetaObject::Connection();
+        *c = connect(this, &KSolidNotify::blockingAppsReady,
+                [=] (const QStringList &blockApps) {
+                    QString errorMessage;
+                    if (blockApps.isEmpty()) {
+                        errorMessage = i18n("Could not eject the following device: %1\nOne or more files on this device are open within an application", discDevice.description());
+                    } else {
+                        errorMessage = i18np("Could not eject the following device: %1\nOne or more files on this device are opened in application \"%3\"\nPlease close it and try again",
+                                "Could not eject the following device: %1\nOne or more files on this device are opened in following applications: %3\nPlease close it and try again",
+                                discDevice.description(), blockApps.size(), blockApps.join(i18nc("separator in list of apps blocking device unmount", ", ")));
+                    }
+                    emit notify(error, errorMessage, errorData.toString(), udi);
+                    disconnect(*c);
+                    delete c;
+                });
+        queryBlockingApps(access->filePath());
     } else if (isSafelyRemovable(udi)) {
         Solid::Device device(udi);
         const QString errorMessage = i18n("The following device can now be safely removed: %1", device.description());

dataengines/devicenotifications/ksolidnotify.h

@@ -47,6 +47,7 @@ public:
 
 signals:
     void notify(Solid::ErrorType solidError, const QString& error, const QString& errorDetails, const QString &udi);
+    void blockingAppsReady(const QStringList &apps);
 
 protected slots:
     void onDeviceAdded(const QString &udi);
@@ -60,6 +61,7 @@ private slots:
 private:
     void connectSignals(Solid::Device* device);
     bool isSafelyRemovable(const QString &udi);
+    void queryBlockingApps(const QString &devicePath);
 
     QHash<QString, Solid::Device> m_devices;
 };