Index: /trunk/src/VBox/Frontends/VirtualBox/Makefile.kmk
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/Makefile.kmk	(revision 48272)
+++ /trunk/src/VBox/Frontends/VirtualBox/Makefile.kmk	(revision 48273)
@@ -287,4 +287,5 @@
 	src/net/UIDownloaderExtensionPack.h \
 	src/net/UIDownloaderUserManual.h \
+	src/medium/UIMediumEnumerator.h \
 	src/medium/UIMediumManager.h \
 	src/runtime/UIActionPoolRuntime.h \
@@ -441,4 +442,5 @@
 	src/globals/UIExtraDataEventHandler.cpp \
 	src/globals/UIThreadPool.cpp \
+	src/medium/UIMediumEnumerator.cpp \
 	src/medium/UIMediumManager.cpp \
 	src/net/UINetworkReply.cpp \
@@ -522,4 +524,5 @@
 	src/medium/UIMediumDefs.cpp \
 	src/medium/UIMedium.cpp \
+	src/medium/UIMediumEnumerator.cpp \
 	src/medium/UIMediumManager.cpp \
 	src/net/UINetworkManager.cpp \
Index: /trunk/src/VBox/Frontends/VirtualBox/src/medium/UIMediumEnumerator.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/medium/UIMediumEnumerator.cpp	(revision 48273)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/medium/UIMediumEnumerator.cpp	(revision 48273)
@@ -0,0 +1,346 @@
+/* $Id$ */
+/** @file
+ *
+ * VBox frontends: Qt GUI ("VirtualBox"):
+ * UIMediumEnumerator class implementation
+ */
+
+/*
+ * Copyright (C) 2013 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ */
+
+/* GUI includes: */
+#include "UIMediumEnumerator.h"
+#include "UIThreadPool.h"
+#include "UIVirtualBoxEventHandler.h"
+#include "VBoxGlobal.h"
+
+/* COM includes: */
+#include "COMEnums.h"
+#include "CMachine.h"
+#include "CMediumAttachment.h"
+
+
+/* GUI task prototype: Medium enumeration.
+ * Extends UITask interface to be executed by the UIThreadWorker. */
+class UITaskMediumEnumeration : public UITask
+{
+    Q_OBJECT;
+
+public:
+
+    /* Constructor: */
+    UITaskMediumEnumeration(const UIMedium &medium)
+        : UITask(QVariant::fromValue(medium))
+    {}
+
+private:
+
+    /* Helper: Run stuff: */
+    void run();
+};
+
+
+UIMediumEnumerator::UIMediumEnumerator(ulong uWorkerCount /*= 3*/, ulong uWorkerTimeout /*= 5000*/)
+    : m_pThreadPool(0)
+    , m_fMediumEnumerationInProgress(false)
+{
+    /* Allow UIMedium to be used in inter-thread signals: */
+    qRegisterMetaType<UIMedium>();
+
+    /* Prepare Main event handlers: */
+    connect(gVBoxEvents, SIGNAL(sigMachineDataChange(QString)), this, SLOT(sltHandleMachineUpdate(QString)));
+    connect(gVBoxEvents, SIGNAL(sigMachineRegistered(QString, bool)), this, SLOT(sltHandleMachineUpdate(QString)));
+    connect(gVBoxEvents, SIGNAL(sigSnapshotChange(QString, QString)), this, SLOT(sltHandleMachineUpdate(QString)));
+
+    /* Prepare thread-pool: */
+    m_pThreadPool = new UIThreadPool(uWorkerCount, uWorkerTimeout);
+    connect(m_pThreadPool, SIGNAL(sigTaskComplete(UITask*)), this, SLOT(sltHandleMediumEnumerationTaskComplete(UITask*)));
+}
+
+UIMediumEnumerator::~UIMediumEnumerator()
+{
+    /* Delete thread-pool: */
+    delete m_pThreadPool;
+    m_pThreadPool = 0;
+
+    /* Delete all the tasks: */
+    while (!m_tasks.isEmpty())
+        delete m_tasks.takeFirst();
+}
+
+QList<QString> UIMediumEnumerator::mediumIDs() const
+{
+    /* Return keys of current medium-map: */
+    return m_mediums.keys();
+}
+
+UIMedium UIMediumEnumerator::medium(const QString &strMediumID)
+{
+    /* Search through current medium-map for the medium with passed ID: */
+    if (m_mediums.contains(strMediumID))
+        return m_mediums[strMediumID];
+    /* Return NULL medium otherwise: */
+    return UIMedium();
+}
+
+void UIMediumEnumerator::createMedium(const UIMedium &medium)
+{
+    /* Get medium ID: */
+    QString strMediumID = medium.id();
+//    printf("UIMediumEnumerator: Medium with ID={%s} created.\n", strMediumID.toAscii().constData());
+
+    /* Make sure medium doesn't exists already: */
+    AssertReturnVoid(!m_mediums.contains(strMediumID));
+
+    /* Insert medium: */
+    m_mediums[strMediumID] = medium;
+
+    /* Notify listener: */
+    emit sigMediumCreated(strMediumID);
+}
+
+void UIMediumEnumerator::updateMedium(const UIMedium &medium)
+{
+    /* Get medium ID: */
+    QString strMediumID = medium.id();
+//    printf("UIMediumEnumerator: Medium with ID={%s} updated.\n", strMediumID.toAscii().constData());
+
+    /* Make sure medium still exists: */
+    AssertReturnVoid(m_mediums.contains(strMediumID));
+
+    /* Update medium: */
+    m_mediums[strMediumID] = medium;
+
+    /* Notify listener: */
+    emit sigMediumUpdated(strMediumID);
+}
+
+void UIMediumEnumerator::deleteMedium(const QString &strMediumID)
+{
+//    printf("UIMediumEnumerator: Medium with ID={%s} removed.\n", strMediumID.toAscii().constData());
+
+    /* Make sure medium still exists: */
+    AssertReturnVoid(m_mediums.contains(strMediumID));
+
+    /* Remove medium: */
+    m_mediums.remove(strMediumID);
+
+    /* Notify listener: */
+    emit sigMediumDeleted(strMediumID);
+}
+
+void UIMediumEnumerator::enumerateMediums()
+{
+    /* Make sure we are not already in progress: */
+    AssertReturnVoid(!m_fMediumEnumerationInProgress);
+
+    /* Compose new map of all currently known mediums & their children.
+     * While composing we are using data from already existing mediums. */
+    UIMediumMap mediums;
+    addNullMediumToMap(mediums);
+    addHardDisksToMap(vboxGlobal().virtualBox().GetHardDisks(), mediums);
+    addMediumsToMap(vboxGlobal().host().GetDVDDrives(), mediums, UIMediumType_DVD);
+    addMediumsToMap(vboxGlobal().virtualBox().GetDVDImages(), mediums, UIMediumType_DVD);
+    addMediumsToMap(vboxGlobal().host().GetFloppyDrives(), mediums, UIMediumType_Floppy);
+    addMediumsToMap(vboxGlobal().virtualBox().GetFloppyImages(), mediums, UIMediumType_Floppy);
+    m_mediums = mediums;
+
+    /* Notify listener: */
+//    printf("UIMediumEnumerator: Medium-enumeration started...\n");
+    m_fMediumEnumerationInProgress = true;
+    emit sigMediumEnumerationStarted();
+
+    /* Start enumeration for all the new mediums: */
+    QList<QString> mediumIDs = m_mediums.keys();
+    foreach (QString strMediumID, mediumIDs)
+        createMediumEnumerationTask(m_mediums[strMediumID]);
+}
+
+void UIMediumEnumerator::sltHandleMachineUpdate(QString strMachineID)
+{
+//    printf("Machine event received, ID = %s\n", strMachineID.toAscii().constData());
+
+    /* Compose a map of previous usage: */
+    QStringList oldUsage;
+    foreach (const QString &strMediumID, mediumIDs())
+    {
+        const UIMedium &uimedium = m_mediums[strMediumID];
+        const QList<QString> &machineIDs = uimedium.machineIds();
+        if (machineIDs.contains(strMachineID))
+            oldUsage << strMediumID;
+    }
+//    printf("Old usage: %s\n", oldUsage.join(", ").toAscii().constData());
+
+    /* Compose a map of current usage: */
+    QStringList newUsage;
+    QMap<QString, CMedium> newMediumMap;
+    CMachine machine = vboxGlobal().virtualBox().FindMachine(strMachineID);
+    if (!machine.isNull())
+    {
+        CMediumAttachmentVector attachments = machine.GetMediumAttachments();
+        foreach (const CMediumAttachment &attachment, attachments)
+        {
+            CMedium cmedium = attachment.GetMedium();
+            if (cmedium.isNull())
+                continue;
+            QString strMediumID = cmedium.GetId();
+            newMediumMap.insert(strMediumID, cmedium);
+            newUsage << strMediumID;
+        }
+    }
+//    printf("New usage: %s\n", newUsage.join(", ").toAscii().constData());
+
+    /* Manipulations over the sets: */
+    QSet<QString> oldSet = oldUsage.toSet();
+    QSet<QString> newSet = newUsage.toSet();
+    QSet<QString> excludedSet = oldSet - newSet;
+    QSet<QString> includedSet = newSet - oldSet;
+    QStringList excludedList = excludedSet.toList();
+    QStringList includedList = includedSet.toList();
+//    printf("Excluded items of machine usage: %s\n", excludedList.join(", ").toAscii().constData());
+//    printf("Included items of machine usage: %s\n", includedList.join(", ").toAscii().constData());
+
+    /* For each of excluded items: */
+    foreach (const QString &strExcludedMediumID, excludedList)
+    {
+        /* Make sure this medium still in our map: */
+        if (!m_mediums.contains(strExcludedMediumID))
+            continue;
+        /* Remove UIMedium if it was closed already: */
+        const UIMedium &uimedium = m_mediums[strExcludedMediumID];
+        if (uimedium.medium().GetId() != strExcludedMediumID)
+        {
+            deleteMedium(strExcludedMediumID);
+            continue;
+        }
+        /* Enumerate UIMedium if CMedium still exists: */
+        createMediumEnumerationTask(m_mediums[strExcludedMediumID]);
+    }
+
+    /* For each of included items: */
+    foreach (const QString &strIncludedMediumID, includedList)
+    {
+        /* Create UIMedium if it is not in our map: */
+        if (!m_mediums.contains(strIncludedMediumID))
+        {
+            const CMedium &cmedium = newMediumMap[strIncludedMediumID];
+            UIMedium uimedium(cmedium, UIMediumDefs::mediumTypeToLocal(cmedium.GetDeviceType()));
+            createMedium(uimedium);
+        }
+        /* Enumerate UIMedium in any case: */
+        createMediumEnumerationTask(m_mediums[strIncludedMediumID]);
+    }
+
+//    printf("Machine event processed, ID = %s\n", strMachineID.toAscii().constData());
+}
+
+void UIMediumEnumerator::sltHandleMediumEnumerationTaskComplete(UITask *pTask)
+{
+    /* Make sure that is one of our tasks: */
+    int iIndexOfTask = m_tasks.indexOf(pTask);
+    AssertReturnVoid(iIndexOfTask != -1);
+
+    /* Get medium: */
+    UIMedium medium = pTask->data().value<UIMedium>();
+    QString strMediumID = medium.id();
+//    printf("UIMediumEnumerator: Medium with ID={%s} enumerated.\n", strMediumID.toAscii().constData());
+
+    /* Delete task: */
+    delete m_tasks.takeAt(iIndexOfTask);
+
+    /* Make sure such medium still exists: */
+    if (!m_mediums.contains(strMediumID))
+        return;
+
+    /* Update enumerated medium: */
+    m_mediums[strMediumID] = medium;
+
+    /* Notify listener: */
+    emit sigMediumEnumerated(strMediumID);
+
+    /* If there are no more tasks we know about: */
+    if (m_tasks.isEmpty())
+    {
+        /* Notify listener: */
+//        printf("UIMediumEnumerator: Medium-enumeration finished!\n");
+        m_fMediumEnumerationInProgress = false;
+        emit sigMediumEnumerationFinished();
+    }
+}
+
+void UIMediumEnumerator::createMediumEnumerationTask(const UIMedium &medium)
+{
+    /* Prepare medium-enumeration task: */
+    UITask *pTask = new UITaskMediumEnumeration(medium);
+    /* Append to internal list: */
+    m_tasks.append(pTask);
+    /* Post into thread-pool: */
+    m_pThreadPool->enqueueTask(pTask);
+}
+
+void UIMediumEnumerator::addNullMediumToMap(UIMediumMap &mediums)
+{
+    /* Insert NULL uimedium to the passed uimedium map.
+     * Get existing one from the previous map if any. */
+    QString strNullMediumID = UIMedium::nullID();
+    UIMedium uimedium = m_mediums.contains(strNullMediumID) ? m_mediums[strNullMediumID] : UIMedium();
+    mediums.insert(strNullMediumID, uimedium);
+}
+
+void UIMediumEnumerator::addMediumsToMap(const CMediumVector &inputMediums, UIMediumMap &outputMediums, UIMediumType mediumType)
+{
+    /* Insert hard-disks to the passed uimedium map.
+     * Get existing one from the previous map if any. */
+    foreach (CMedium medium, inputMediums)
+    {
+        /* Prepare uimedium on the basis of current medium: */
+        QString strMediumID = medium.GetId();
+        UIMedium uimedium = m_mediums.contains(strMediumID) ? m_mediums[strMediumID] :
+                                                              UIMedium(medium, mediumType);
+
+        /* Insert uimedium into map: */
+        outputMediums.insert(uimedium.id(), uimedium);
+    }
+}
+
+void UIMediumEnumerator::addHardDisksToMap(const CMediumVector &inputMediums, UIMediumMap &outputMediums)
+{
+    /* Insert hard-disks to the passed uimedium map.
+     * Get existing one from the previous map if any. */
+    foreach (CMedium medium, inputMediums)
+    {
+        /* Prepare uimedium on the basis of current medium: */
+        QString strMediumID = medium.GetId();
+        UIMedium uimedium = m_mediums.contains(strMediumID) ? m_mediums[strMediumID] :
+                                                              UIMedium(medium, UIMediumType_HardDisk);
+
+        /* Insert uimedium into map: */
+        outputMediums.insert(uimedium.id(), uimedium);
+
+        /* Insert medium children into map too: */
+        addHardDisksToMap(medium.GetChildren(), outputMediums);
+    }
+}
+
+void UITaskMediumEnumeration::run()
+{
+    /* Get medium: */
+    UIMedium medium = m_data.value<UIMedium>();
+    /* Enumerate it: */
+    medium.blockAndQueryState();
+    /* Put medium back: */
+    m_data = QVariant::fromValue(medium);
+}
+
+
+#include "UIMediumEnumerator.moc"
+
Index: /trunk/src/VBox/Frontends/VirtualBox/src/medium/UIMediumEnumerator.h
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/medium/UIMediumEnumerator.h	(revision 48273)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/medium/UIMediumEnumerator.h	(revision 48273)
@@ -0,0 +1,90 @@
+/** @file
+ *
+ * VBox frontends: Qt GUI ("VirtualBox"):
+ * UIMediumEnumerator class declaration
+ */
+
+/*
+ * Copyright (C) 2013 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ */
+
+#ifndef __UIMediumEnumerator_h__
+#define __UIMediumEnumerator_h__
+
+/* Qt includes: */
+#include <QObject>
+
+/* GUI includes: */
+#include "UIMedium.h"
+
+/* Forward declarations: */
+class UIThreadPool;
+class UITask;
+
+/* Medium-enumerator prototype.
+ * Manages access to medium information using thread-pool interface. */
+class UIMediumEnumerator : public QObject
+{
+    Q_OBJECT;
+
+signals:
+
+    /* Notifiers: Medium-operations stuff: */
+    void sigMediumCreated(QString strMediumID);
+    void sigMediumUpdated(QString strMediumID);
+    void sigMediumDeleted(QString strMediumID);
+
+    /* Notifiers: Medium-enumeration stuff: */
+    void sigMediumEnumerationStarted();
+    void sigMediumEnumerated(QString strMediumID);
+    void sigMediumEnumerationFinished();
+
+public:
+
+    /* Constructor/destructor: */
+    UIMediumEnumerator(ulong uWorkerCount = 3, ulong uWorkerTimeout = 5000);
+    ~UIMediumEnumerator();
+
+    /* API: Medium-access stuff: */
+    QList<QString> mediumIDs() const;
+    UIMedium medium(const QString &strMediumID);
+    void createMedium(const UIMedium &medium);
+    void updateMedium(const UIMedium &medium);
+    void deleteMedium(const QString &strMediumID);
+
+    /* API: Medium-enumeration stuff: */
+    bool isMediumEnumerationInProgress() const { return m_fMediumEnumerationInProgress; }
+    void enumerateMediums();
+
+private slots:
+
+    /* Handler: Machine stuff: */
+    void sltHandleMachineUpdate(QString strMachineID);
+
+    /* Handler: Medium-enumeration stuff: */
+    void sltHandleMediumEnumerationTaskComplete(UITask *pTask);
+
+private:
+
+    /* Helpers: Medium-enumeration stuff: */
+    void createMediumEnumerationTask(const UIMedium &medium);
+    void addNullMediumToMap(UIMediumMap &mediums);
+    void addMediumsToMap(const CMediumVector &inputMediums, UIMediumMap &outputMediums, UIMediumType mediumType);
+    void addHardDisksToMap(const CMediumVector &inputMediums, UIMediumMap &outputMediums);
+
+    /* Variables: */
+    UIThreadPool *m_pThreadPool;
+    bool m_fMediumEnumerationInProgress;
+    QList<UITask*> m_tasks;
+    UIMediumMap m_mediums;
+};
+
+#endif /* __UIMediumEnumerator_h__ */