Changeset 97734 in vbox

Timestamp:

Dec 2, 2022 7:58:41 PM (2 years ago)

Author:

vboxsync

Message:

DnD/VBoxClient: Now uses similar debug / verbose messages via system notifications when the users starts it in verbose mode (like VBoxTray). Also added easier to read (verbose release) logging to see what's going on with release builds.

File:

• trunk/src/VBox/Additions/x11/VBoxClient/draganddrop.cpp (modified) (50 diffs)

trunk/src/VBox/Additions/x11/VBoxClient/draganddrop.cpp

@@ -50 +50 @@
 #include <VBox/log.h>
 #include <VBox/VBoxGuestLib.h>
+#include <VBox/version.h>
 
 #include "VBox/HostServices/DragAndDropSvc.h"
 #include "VBoxClient.h"
 
-/* Enable this define to see the proxy window(s) when debugging
- * their behavior. Don't have this enabled in release builds! */
-#ifdef DEBUG
-//# define VBOX_DND_DEBUG_WND
-#endif
 
 /* Enable this to handle drag'n drop "promises".
@@ -131 +127 @@
 /** How many X properties our proxy window can hold. */
 #define VBOX_MAX_XPROPERTIES (LONG_MAX-1)
+
+/** The notification header text for VBClShowNotify(). */
+#define VBOX_DND_SHOWNOTIFY_HEADER              VBOX_PRODUCT " Drag'n Drop"
 
 /**
@@ -199 +198 @@
 
 /**
- * Xdnd message value indexes, sorted by message type.
+ * Xdnd message value indices, sorted by message type.
  */
 typedef enum XdndMsg
@@ -251 +250 @@
     /** XdndFinished. */
     XdndFinishedWindow = 0,         /* Target window (sender). */
-    XdndFinishedFlags,              /* Version 5: Bit 0 is set if the current target accepted the drop. */
-    XdndFinishedAction              /* Version 5: Contains the action performed by the target. */
+    XdndFinishedFlags,              /* Since version 5: Bit 0 is set if the current target accepted the drop. */
+    XdndFinishedAction              /* Since version 5: Contains the action performed by the target. */
 
 } XdndMsg;
@@ -628 +627 @@
     /** Current source/target window handle. */
     Window                      m_wndCur;
-    /** The XDnD protocol version the current
-     *  source/target window is using. */
+    /** The XDnD protocol version the current source/target window is using. */
     long                        m_curVer;
-    /** List of (Atom) formats the source window supports. */
+    /** List of (Atom) formats the current source/target window supports. */
     VBoxDnDAtomList             m_lstAtomFormats;
-    /** List of (Atom) actions the source window supports. */
+    /** List of (Atom) actions the current source/target window supports. */
     VBoxDnDAtomList             m_lstAtomActions;
     /** Buffer for answering the target window's selection request. */
@@ -645 +643 @@
     /** The instance's own X event queue. */
     RTCMTList<WrappedXEvent>    m_eventQueueList;
-    /** Critical section for providing serialized access to list
-     *  event queue's contents. */
+    /** Critical section for providing serialized access to list event queue's contents. */
     RTCRITSECT                  m_eventQueueCS;
-    /** Event for notifying this instance in case of a new
-     *  event. */
+    /** Event for notifying this instance in case of a new event. */
     RTSEMEVENT                  m_eventQueueEvent;
     /** Critical section for data access. */
@@ -824 +820 @@
         RTCritSectLeave(&m_dataCS);
     }
+
+    LogFlowFuncLeave();
 }
 
@@ -838 +836 @@
     if (rc != VINF_SUCCESS)
         return rc;
+
+    if (g_cVerbosity)
+    {
+        RTCString strBody = RTCStringFmt("Connected (screen %RU32, verbosity %u)", uScreenID, g_cVerbosity);
+        VBClShowNotify(VBOX_DND_SHOWNOTIFY_HEADER, strBody.c_str());
+    }
 
     do
@@ -891 +895 @@
         attr.override_redirect     = True;
         attr.do_not_propagate_mask = NoEventMask;
-#ifdef VBOX_DND_DEBUG_WND
-        attr.background_pixel      = XWhitePixel(m_pDisplay, m_screenID);
-        attr.border_pixel          = XBlackPixel(m_pDisplay, m_screenID);
-        m_wndProxy.hWnd = XCreateWindow(m_pDisplay, m_wndRoot                /* Parent */,
-                                   100, 100,                                 /* Position */
-                                   100, 100,                                 /* Width + height */
-                                   2,                                        /* Border width */
-                                   CopyFromParent,                           /* Depth */
-                                   InputOutput,                              /* Class */
-                                   CopyFromParent,                           /* Visual */
-                                     CWBackPixel
-                                   | CWBorderPixel
-                                   | CWOverrideRedirect
-                                   | CWDontPropagate,                        /* Value mask */
-                                   &attr);                                   /* Attributes for value mask */
-#else
-        m_wndProxy.hWnd = XCreateWindow(m_pDisplay, m_wndRoot            /* Parent */,
-                                   0, 0,                                 /* Position */
-                                   1, 1,                                 /* Width + height */
-                                   0,                                    /* Border width */
-                                   CopyFromParent,                       /* Depth */
-                                   InputOnly,                            /* Class */
-                                   CopyFromParent,                       /* Visual */
-                                   CWOverrideRedirect | CWDontPropagate, /* Value mask */
-                                   &attr);                               /* Attributes for value mask */
-#endif
+
+        if (g_cVerbosity >= 3)
+        {
+            attr.background_pixel      = XWhitePixel(m_pDisplay, m_screenID);
+            attr.border_pixel          = XBlackPixel(m_pDisplay, m_screenID);
+            m_wndProxy.hWnd = XCreateWindow(m_pDisplay, m_wndRoot               /* Parent */,
+                                            100, 100,                           /* Position */
+                                            100, 100,                           /* Width + height */
+                                            2,                                  /* Border width */
+                                            CopyFromParent,                     /* Depth */
+                                            InputOutput,                        /* Class */
+                                            CopyFromParent,                     /* Visual */
+                                              CWBackPixel
+                                            | CWBorderPixel
+                                            | CWOverrideRedirect
+                                            | CWDontPropagate,                  /* Value mask */
+                                            &attr);                             /* Attributes for value mask */
+        }
+
+        m_wndProxy.hWnd = XCreateWindow(m_pDisplay, m_wndRoot                   /* Parent */,
+                                        0, 0,                                   /* Position */
+                                        1, 1,                                   /* Width + height */
+                                        0,                                      /* Border width */
+                                        CopyFromParent,                         /* Depth */
+                                        InputOnly,                              /* Class */
+                                        CopyFromParent,                         /* Visual */
+                                        CWOverrideRedirect | CWDontPropagate,   /* Value mask */
+                                        &attr);                                 /* Attributes for value mask */
+
         if (!m_wndProxy.hWnd)
         {
@@ -931 +938 @@
         }
 
-#ifdef VBOX_DND_DEBUG_WND
-        XFlush(m_pDisplay);
-        XMapWindow(m_pDisplay, m_wndProxy.hWnd);
-        XRaiseWindow(m_pDisplay, m_wndProxy.hWnd);
-        XFlush(m_pDisplay);
-#endif
-        VBClLogInfo("Proxy window=%RU32, root window=%RU32 ...\n", m_wndProxy.hWnd, m_wndRoot);
+        if (g_cVerbosity >= 3) /* Make debug window visible. */
+        {
+            XFlush(m_pDisplay);
+            XMapWindow(m_pDisplay, m_wndProxy.hWnd);
+            XRaiseWindow(m_pDisplay, m_wndProxy.hWnd);
+            XFlush(m_pDisplay);
+        }
+
+        VBClLogInfo("Proxy window=%#x (debug mode: %RTbool), root window=%#x ...\n",
+                    m_wndProxy.hWnd, RT_BOOL(g_cVerbosity >= 3), m_wndRoot);
 
         /* Set the window's name for easier lookup. */
@@ -974 +984 @@
     int rc = VINF_SUCCESS;
 
+    char *pszWndCurName = wndX11GetNameA(m_wndCur);
+    AssertPtrReturn(pszWndCurName, VERR_NO_MEMORY);
+
     switch (m_enmMode)
     {
@@ -982 +995 @@
              * window, in response of some events we send to them.
              */
+
+            /* The target window informs us of the current Xdnd status. */
             if (e.xclient.message_type == xAtom(XA_XdndStatus))
             {
-                Window wndTarget = static_cast<Window>(e.xclient.data.l[XdndStatusWindow]);
+                Window wndTgt = static_cast<Window>(e.xclient.data.l[XdndStatusWindow]);
+
+                char *pszWndTgtName = wndX11GetNameA(wndTgt);
+                AssertPtrBreakStmt(pszWndTgtName, VERR_NO_MEMORY);
 
                 /* Does the target accept the drop? */
@@ -991 +1009 @@
                 const bool fWantsPosition = e.xclient.data.l[XdndStatusFlags] & VBOX_XDND_STATUS_FLAG_WANTS_POS;
                 RT_NOREF(fWantsPosition);
-
-                char *pszWndName = wndX11GetNameA(m_wndCur);
-                AssertPtr(pszWndName);
 
                 /*
@@ -1002 +1017 @@
                 RTCString strActions = xAtomToString(e.xclient.data.l[XdndStatusAction]);
 
-                VBClLogInfo("Target window %#x ('%s') %s accept data with actions '%s'\n",
-                            wndTarget, pszWndName, fAcceptDrop ? "does" : "does not", strActions.c_str());
-
-                const uint16_t x  = RT_HI_U16((uint32_t)e.xclient.data.l[XdndStatusNoMsgXY]);
-                const uint16_t y  = RT_LO_U16((uint32_t)e.xclient.data.l[XdndStatusNoMsgXY]);
-                const uint16_t cx = RT_HI_U16((uint32_t)e.xclient.data.l[XdndStatusNoMsgWH]);
-                const uint16_t cy = RT_LO_U16((uint32_t)e.xclient.data.l[XdndStatusNoMsgWH]);
+                VBClLogInfo("Target window %#x ('%s')\n", wndTgt, pszWndTgtName);
+                VBClLogInfo("    - %s accept data (actions '%s')\n", fAcceptDrop ? "does" : "does not", strActions.c_str());
+                VBClLogInfo("    - %s want position messages\n", fWantsPosition ? "does" : "does not");
+
+                uint16_t const x  = RT_HI_U16((uint32_t)e.xclient.data.l[XdndStatusNoMsgXY]);
+                uint16_t const y  = RT_LO_U16((uint32_t)e.xclient.data.l[XdndStatusNoMsgXY]);
+                uint16_t const cx = RT_HI_U16((uint32_t)e.xclient.data.l[XdndStatusNoMsgWH]);
+                uint16_t const cy = RT_LO_U16((uint32_t)e.xclient.data.l[XdndStatusNoMsgWH]);
 
                 if (cx && cy)
                 {
                     VBClLogInfo("Target window %#x ('%s') reported dead area at %RU16,%RU16 (%RU16 x %RU16)\n",
-                                wndTarget, pszWndName, x, y, cx, cy);
+                                wndTgt, pszWndTgtName, x, y, cx, cy);
                     /** @todo Save dead area and don't send XdndPosition messages anymore into it. */
                 }
 
-                if (m_wndCur == wndTarget)
+                if (m_wndCur == wndTgt)
                 {
                     VBOXDNDACTION dndAction = VBOX_DND_ACTION_IGNORE; /* Default is ignoring. */
@@ -1027 +1043 @@
                 }
                 else
-                    VBClLogInfo("Target window %#x ('%s') is not our current window, skipping\n", wndTarget, pszWndName);
-
-                RTStrFree(pszWndName);
+                    VBClLogInfo("Target window %#x ('%s') is not our current window, skipping\n", wndTgt, pszWndTgtName);
+
+                RTStrFree(pszWndTgtName);
             }
+            /* The target window informs us that it finished the Xdnd operation and that we may free all data. */
             else if (e.xclient.message_type == xAtom(XA_XdndFinished))
             {
                 Window wndTarget = static_cast<Window>(e.xclient.data.l[XdndFinishedWindow]);
 
-                const bool fSucceeded = e.xclient.data.l[XdndFinishedFlags] & VBOX_XDND_FINISHED_FLAG_SUCCEEDED;
-
-                char *pszWndName = wndX11GetNameA(wndTarget);
-                AssertPtr(pszWndName);
-
-                const char *pcszAction = xAtomToString(e.xclient.data.l[XdndFinishedAction]).c_str();
-
-                /* This message is sent on an un/successful DnD drop request. */
-                LogFlowThisFunc(("XA_XdndFinished: wnd=%#x ('%s'), success=%RTbool, action=%s\n",
-                                 wndTarget, pszWndName, fSucceeded, pcszAction));
-
-                VBClLogInfo("Target window %#x ('%s') has %s the data with action '%s'\n",
-                            wndTarget, pszWndName, fSucceeded ? "accepted" : "rejected", pcszAction ? "<None>" : pcszAction);
-
-                RTStrFree(pszWndName);
+                char *pszWndTgtName = wndX11GetNameA(wndTarget);
+                AssertPtrBreakStmt(pszWndTgtName, VERR_NO_MEMORY);
+
+                if (m_curVer >= 5)
+                {
+                    const bool  fSucceeded = e.xclient.data.l[XdndFinishedFlags] & VBOX_XDND_FINISHED_FLAG_SUCCEEDED;
+            #if 0 /** @todo Returns garbage -- investigate this! */
+                    //const char *pcszAction = fSucceeded ? xAtomToString(e.xclient.data.l[XdndFinishedAction]).c_str() : NULL;
+            #endif
+                    VBClLogInfo("Target window %#x ('%s') has %s the data\n",
+                                wndTarget, pszWndTgtName, fSucceeded ? "accepted" : "rejected");
+                }
+                else /* Xdnd < version 5 did not have the XdndFinishedFlags / XdndFinishedAction properties. */
+                    VBClLogInfo("Target window %#x ('%s') has accepted the data\n", wndTarget, pszWndTgtName);
+
+                RTStrFree(pszWndTgtName);
 
                 reset();
@@ -1063 +1081 @@
 
         case Unknown: /* Mode not set (yet). */
+            RT_FALL_THROUGH();
         case GH:
         {
@@ -1071 +1090 @@
             if (e.xclient.message_type == xAtom(XA_XdndEnter))
             {
-                LogFlowFunc(("XA_XdndEnter\n"));
-
                 /*
                  * Get the window which currently has the XA_XdndSelection
                  * bit set.
                  */
-                Window wndSelection = XGetSelectionOwner(m_pDisplay, xAtom(XA_XdndSelection));
-
-                char *pszWndName = wndX11GetNameA(wndSelection);
-                AssertPtr(pszWndName);
-                LogFlowThisFunc(("wndSelection=%RU32 ('%s'), wndProxy=%RU32\n", wndSelection, pszWndName, m_wndProxy.hWnd));
-                RTStrFree(pszWndName);
+                Window wndSel = XGetSelectionOwner(m_pDisplay, xAtom(XA_XdndSelection));
+                char *pszWndSelName = wndX11GetNameA(wndSel);
+                AssertPtrBreakStmt(pszWndSelName, VERR_NO_MEMORY);
 
                 mouseButtonSet(m_wndProxy.hWnd, -1, -1, 1, true /* fPress */);
@@ -1089 +1103 @@
                  * Update our state and the window handle to process.
                  */
-                int rc2 = RTCritSectEnter(&m_dataCS);
-                if (RT_SUCCESS(rc2))
+                rc = RTCritSectEnter(&m_dataCS);
+                if (RT_SUCCESS(rc))
                 {
-                    m_wndCur = wndSelection;
-                    m_curVer = e.xclient.data.l[XdndEnterFlags] >> XdndEnterVersionRShift;
-                    Assert(m_wndCur == (Window)e.xclient.data.l[XdndEnterWindow]); /* Source window. */
+                    long const xdndVer = e.xclient.data.l[XdndEnterFlags] >> XdndEnterVersionRShift;
+
+                    VBClLogInfo("Entered new source window %#x ('%s'), supports Xdnd version %ld\n", wndSel, pszWndSelName, xdndVer);
 #ifdef DEBUG
                     XWindowAttributes xwa;
@@ -1107 +1121 @@
                      * to fetch the XdndTypeList property from the window. */
                     bool fMoreTypes = e.xclient.data.l[XdndEnterFlags] & XdndEnterMoreTypesFlag;
-                    LogFlowThisFunc(("XdndVer=%d, fMoreTypes=%RTbool\n", m_curVer, fMoreTypes));
                     if (!fMoreTypes)
                     {
@@ -1121 +1134 @@
                     {
                         /* More than 3 format types supported. */
-                        rc = wndXDnDGetFormatList(wndSelection, m_lstAtomFormats);
+                        rc = wndXDnDGetFormatList(wndSel, m_lstAtomFormats);
+                    }
+
+                    if (RT_FAILURE(rc))
+                    {
+                        VBClLogError("Error retrieving supported formats, rc=%Rrc\n", rc);
+                        break;
                     }
 
@@ -1127 +1146 @@
                      * Retrieve supported actions.
                      */
-                    if (RT_SUCCESS(rc))
+                    if (xdndVer >= 2) /* More than one action allowed since protocol version 2. */
                     {
-                        if (m_curVer >= 2) /* More than one action allowed since protocol version 2. */
-                        {
-                            rc = wndXDnDGetActionList(wndSelection, m_lstAtomActions);
-                        }
-                        else /* Only "copy" action allowed on legacy applications. */
-                            m_lstAtomActions.append(XA_XdndActionCopy);
+                        rc = wndXDnDGetActionList(wndSel, m_lstAtomActions);
                     }
-
-                    if (RT_SUCCESS(rc))
+                    else /* Only "copy" action allowed on legacy applications. */
+                        m_lstAtomActions.append(XA_XdndActionCopy);
+
+                    if (RT_FAILURE(rc))
                     {
-                        m_enmMode  = GH;
-                        m_enmState = Dragging;
+                        VBClLogError("Error retrieving supported actions, rc=%Rrc\n", rc);
+                        break;
                     }
+
+                    VBClLogInfo("Source window %#x ('%s')\n", wndSel, pszWndSelName);
+                    VBClLogInfo("    - supports the formats ");
+                    for (size_t i = 0; i < m_lstAtomFormats.size(); i++)
+                    {
+                        if (i > 0)
+                            VBClLogInfo(", ");
+                        VBClLogInfo("%s", gX11->xAtomToString(m_lstAtomFormats[i]).c_str());
+                    }
+                    VBClLogInfo("\n");
+                    VBClLogInfo("    - supports the actions ");
+                    for (size_t i = 0; i < m_lstAtomActions.size(); i++)
+                    {
+                        if (i > 0)
+                            VBClLogInfo(", ");
+                        VBClLogInfo("%s", gX11->xAtomToString(m_lstAtomActions[i]).c_str());
+                    }
+                    VBClLogInfo("\n");
+
+                    AssertBreakStmt(wndSel == (Window)e.xclient.data.l[XdndEnterWindow],
+                                    rc = VERR_INVALID_PARAMETER); /* Source window. */
+
+                    m_wndCur   = wndSel;
+                    m_curVer   = xdndVer;
+                    m_enmMode  = GH;
+                    m_enmState = Dragging;
 
                     RTCritSectLeave(&m_dataCS);
                 }
+
+                RTStrFree(pszWndSelName);
             }
             else if (   e.xclient.message_type == xAtom(XA_XdndPosition)
@@ -1158 +1202 @@
                 Atom    atmAction = m_curVer >= 2 /* Actions other than "copy" or only supported since protocol version 2. */
                                   ? e.xclient.data.l[XdndPositionAction] : xAtom(XA_XdndActionCopy);
-                LogFlowThisFunc(("XA_XdndPosition: wndProxy=%RU32, wndCur=%RU32, x=%RI32, y=%RI32, strAction=%s\n",
+                LogFlowThisFunc(("XA_XdndPosition: wndProxy=%#x, wndCur=%#x, x=%RI32, y=%RI32, strAction=%s\n",
                                  m_wndProxy.hWnd, m_wndCur, RT_HIWORD(iPos), RT_LOWORD(iPos),
                                  xAtomToString(atmAction).c_str()));
 #endif
-
                 bool fAcceptDrop = true;
 
@@ -1188 +1231 @@
                                      False /* Propagate */, NoEventMask, reinterpret_cast<XEvent *>(&m));
                 if (xRc == 0)
-                    VBClLogError("Error sending position XA_XdndStatus event to current window=%#x: %s\n",
-                                 m_wndCur, gX11->xErrorToString(xRc).c_str());
+                    VBClLogError("Error sending position status event to current window %#x ('%s'): %s\n",
+                                 m_wndCur, pszWndCurName, gX11->xErrorToString(xRc).c_str());
             }
             else if (   e.xclient.message_type == xAtom(XA_XdndLeave)
@@ -1241 +1284 @@
         }
     }
+
+    RTStrFree(pszWndCurName);
 
     LogFlowThisFunc(("Returning rc=%Rrc\n", rc));
@@ -1327 +1372 @@
     const XSelectionRequestEvent *pEvReq = &evReq.xselectionrequest;
 
+    char *pszWndSrcName = wndX11GetNameA(pEvReq->owner);
+    AssertPtrReturn(pszWndSrcName, VERR_INVALID_POINTER);
+    char *pszWndTgtName = wndX11GetNameA(pEvReq->requestor);
+    AssertPtrReturn(pszWndTgtName, VERR_INVALID_POINTER);
+
     LogFlowThisFunc(("mode=%RU32, state=%RU32\n", m_enmMode, m_enmState));
-    LogFlowThisFunc(("Event owner=%#x, requestor=%#x, selection=%s, target=%s, prop=%s, time=%u\n",
-                     pEvReq->owner,
-                     pEvReq->requestor,
+    LogFlowThisFunc(("Event owner=%#x ('%s'), requestor=%#x ('%s'), selection=%s, target=%s, prop=%s, time=%u\n",
+                     pEvReq->owner, pszWndSrcName,
+                     pEvReq->requestor, pszWndTgtName,
                      xAtomToString(pEvReq->selection).c_str(),
                      xAtomToString(pEvReq->target).c_str(),
                      xAtomToString(pEvReq->property).c_str(),
                      pEvReq->time));
+
+    VBClLogInfo("Window '%s' is asking '%s' for '%s' / '%s'\n",
+                pszWndTgtName, pszWndSrcName, xAtomToString(pEvReq->selection).c_str(), xAtomToString(pEvReq->property).c_str());
+
+    RTStrFree(pszWndSrcName);
+    /* Note: pszWndTgtName will be free'd below. */
+
     int rc;
 
@@ -1342 +1399 @@
         {
             rc = VINF_SUCCESS;
-
-            char *pszWndName = wndX11GetNameA(pEvReq->requestor);
-            AssertPtr(pszWndName);
 
             /*
@@ -1364 +1418 @@
             pEvResp->time      = pEvReq->time;
 
-#ifdef DEBUG
-            LogFlowFunc(("Supported formats:\n"));
-            for (size_t i = 0; i < m_lstAtomFormats.size(); i++)
-                LogFlowFunc(("\t%s\n", xAtomToString(m_lstAtomFormats.at(i)).c_str()));
-#endif
+            if (g_cVerbosity)
+            {
+                VBClLogVerbose(1, "Supported formats by VBoxClient:\n");
+                for (size_t i = 0; i < m_lstAtomFormats.size(); i++)
+                    VBClLogVerbose(1, "\t%s\n", xAtomToString(m_lstAtomFormats.at(i)).c_str());
+            }
+
             /* Is the requestor asking for the possible MIME types? */
             if (pEvReq->target == xAtom(XA_TARGETS))
             {
-                VBClLogInfo("Target window %#x ('%s') asking for target list\n", pEvReq->requestor, pszWndName);
+                VBClLogInfo("Target window %#x ('%s') asking for target list\n", pEvReq->requestor, pszWndTgtName);
 
                 /* If so, set the window property with the formats on the requestor
@@ -1384 +1440 @@
             {
                 VBClLogInfo("Target window %#x ('%s') is asking for data as '%s'\n",
-                            pEvReq->requestor, pszWndName, xAtomToString(pEvReq->target).c_str());
+                            pEvReq->requestor, pszWndTgtName, xAtomToString(pEvReq->target).c_str());
 
 #ifdef VBOX_WITH_DRAG_AND_DROP_PROMISES
@@ -1400 +1456 @@
 #endif /* VBOX_WITH_DRAG_AND_DROP_PROMISES */
                     /* Get the data format the requestor wants from us. */
-                    RTCString strFormat = xAtomToString(pEvReq->target);
-                    Assert(strFormat.isNotEmpty());
-                    VBClLogInfo("Target window=%#x requested data from host as '%s', rc=%Rrc\n",
-                                pEvReq->requestor, strFormat.c_str(), rc);
+                    VBClLogInfo("Target window %#x ('%s') requested data from host as '%s', rc=%Rrc\n",
+                                pEvReq->requestor, pszWndTgtName, xAtomToString(pEvReq->target).c_str(), rc);
 
                     /* Make a copy of the MIME data to be passed back. The X server will be become
                      * the new owner of that data, so no deletion needed. */
                     /** @todo Do we need to do some more conversion here? XConvertSelection? */
-                    void *pvData = RTMemDup(m_pvSelReqData, m_cbSelReqData);
-                    uint32_t cbData = m_cbSelReqData;
+                    AssertMsgBreakStmt(m_pvSelReqData != NULL, ("Selection request data is NULL\n"),   rc = VERR_INVALID_PARAMETER);
+                    AssertMsgBreakStmt(m_cbSelReqData  > 0,    ("Selection request data size is 0\n"), rc = VERR_INVALID_PARAMETER);
+
+                    void    const *pvData = RTMemDup(m_pvSelReqData, m_cbSelReqData);
+                    AssertMsgBreakStmt(pvData != NULL, ("Duplicating selection request failed\n"), rc = VERR_NO_MEMORY);
+                    uint32_t const cbData = m_cbSelReqData;
 
                     /* Always return the requested property. */
@@ -1419 +1477 @@
                                               reinterpret_cast<const unsigned char*>(pvData), cbData);
 
-                    LogFlowFunc(("Changing property '%s' (target '%s') of window=%RU32: %s\n",
+                    LogFlowFunc(("Changing property '%s' (of type '%s') of window %#x ('%s'): %s\n",
                                  xAtomToString(pEvReq->property).c_str(),
                                  xAtomToString(pEvReq->target).c_str(),
-                                 pEvReq->requestor,
+                                 pEvReq->requestor, pszWndTgtName,
                                  gX11->xErrorToString(xRc).c_str()));
                     RT_NOREF(xRc);
@@ -1433 +1491 @@
             {
                 VBClLogError("Refusing unknown command/format '%s' of wnd=%#x ('%s')\n",
-                             xAtomToString(pEvReq->target).c_str(), pEvReq->requestor, pszWndName);
+                             xAtomToString(pEvReq->target).c_str(), pEvReq->requestor, pszWndTgtName);
                 rc = VERR_NOT_SUPPORTED;
             }
 
-            LogFlowThisFunc(("Offering type '%s', property '%s' to wnd=%#x ...\n",
-                             xAtomToString(pEvReq->target).c_str(),
-                             xAtomToString(pEvReq->property).c_str(), pEvReq->requestor));
+            VBClLogVerbose(1, "Offering type '%s', property '%s' to window %#x ('%s') ...\n",
+                           xAtomToString(pEvReq->target).c_str(),
+                           xAtomToString(pEvReq->property).c_str(), pEvReq->requestor, pszWndTgtName);
 
             int xRc = XSendEvent(pEvReq->display, pEvReq->requestor, True /* Propagate */, 0, &evResp);
             if (xRc == 0)
-                VBClLogError("Error sending SelectionNotify(1) event to wnd=%#x: %s\n",
-                             pEvReq->requestor, gX11->xErrorToString(xRc).c_str());
+                VBClLogError("Error sending SelectionNotify(1) event to window %#x ('%s'): %s\n",
+                             pEvReq->requestor, pszWndTgtName, gX11->xErrorToString(xRc).c_str());
+
             XFlush(pEvReq->display);
-
-            if (pszWndName)
-                RTStrFree(pszWndName);
             break;
         }
@@ -1456 +1512 @@
             break;
     }
+
+    RTStrFree(pszWndTgtName);
+    pszWndTgtName = NULL;
 
     LogFlowThisFunc(("Returning rc=%Rrc\n", rc));
@@ -1726 +1785 @@
         XSetSelectionOwner(m_pDisplay, xAtom(XA_XdndSelection), m_wndProxy.hWnd, CurrentTime);
 
+        if (g_cVerbosity)
+        {
+            RTCString strMsg("Enter: Host -> Guest\n\n");
+            strMsg += RTCStringFmt("Allowed actions: %#x\n", dndListActionsAllowed);
+            strMsg += "Formats:\n";
+            for (size_t i = 0; i < lstActions.size(); i++)
+            {
+                if (i > 0)
+                    strMsg += "\n";
+                strMsg += lstActions.at(i);
+            }
+
+            VBClShowNotify(VBOX_DND_SHOWNOTIFY_HEADER, strMsg.c_str());
+        }
+
         m_enmMode  = HG;
         m_enmState = Dragging;
@@ -1741 +1815 @@
 int DragInstance::hgLeave(void)
 {
+    if (g_cVerbosity)
+        VBClShowNotify(VBOX_DND_SHOWNOTIFY_HEADER, "Leave: Host -> Guest");
+
     if (m_enmMode == HG) /* Only reset if in the right operation mode. */
         reset();
@@ -1774 +1851 @@
     mouseCursorMove(uPosX, uPosY);
 
+    /* Search for the application window below the cursor. */
+    Window wndBelowCursor       = gX11->applicationWindowBelowCursor(m_wndRoot);
+    char *pszWndBelowCursorName = wndX11GetNameA(wndBelowCursor);
+    AssertPtrReturn(pszWndBelowCursorName, VERR_NO_MEMORY);
+
     long newVer = -1; /* This means the current window is _not_ XdndAware. */
 
-    /* Search for the application window below the cursor. */
-    Window wndCursor = gX11->applicationWindowBelowCursor(m_wndRoot);
-    if (wndCursor != None)
+    if (wndBelowCursor != None)
     {
         /* Temp stuff for the XGetWindowProperty call. */
@@ -1788 +1868 @@
         /* Query the XdndAware property from the window. We are interested in
          * the version and if it is XdndAware at all. */
-        xRc = XGetWindowProperty(m_pDisplay, wndCursor, xAtom(XA_XdndAware),
+        xRc = XGetWindowProperty(m_pDisplay, wndBelowCursor, xAtom(XA_XdndAware),
                                  0, 2, False, AnyPropertyType,
                                  &atmTmp, &fmt, &cItems, &cbRemaining, &pcData);
         if (xRc != Success)
         {
-            VBClLogError("Error getting properties of cursor window=%#x: %s\n", wndCursor, gX11->xErrorToString(xRc).c_str());
+            VBClLogError("Error getting properties of cursor window=%#x: %s\n", wndBelowCursor, gX11->xErrorToString(xRc).c_str());
         }
         else
@@ -1801 +1881 @@
                 /** @todo Do we need to deal with this? */
                 VBClLogError("Wrong window properties for window %#x: pcData=%#x, iFmt=%d, cItems=%ul\n",
-                             wndCursor, pcData, fmt, cItems);
+                             wndBelowCursor, pcData, fmt, cItems);
             }
             else
@@ -1813 +1893 @@
     }
 
-#ifdef DEBUG
-    char *pszNameCursor = wndX11GetNameA(wndCursor);
-    AssertPtr(pszNameCursor);
-    char *pszNameCur = wndX11GetNameA(m_wndCur);
-    AssertPtr(pszNameCur);
+    char *pszWndCurName = wndX11GetNameA(m_wndCur);
+    AssertPtrReturn(pszWndCurName, VERR_NO_MEMORY);
 
     LogFlowThisFunc(("wndCursor=%x ('%s', Xdnd version %ld), wndCur=%x ('%s', Xdnd version %ld)\n",
-                     wndCursor, pszNameCursor, newVer, m_wndCur, pszNameCur, m_curVer));
-
-    RTStrFree(pszNameCursor);
-    RTStrFree(pszNameCur);
-#endif
-
-    if (   wndCursor != m_wndCur
-        && m_curVer  != -1)
-    {
-        LogFlowThisFunc(("XA_XdndLeave: window=%#x\n", m_wndCur));
-
-        char *pszWndName = wndX11GetNameA(m_wndCur);
-        AssertPtr(pszWndName);
-        VBClLogInfo("Left old window %#x ('%s'), Xdnd version=%ld\n", m_wndCur, pszWndName, newVer);
-        RTStrFree(pszWndName);
+                     wndBelowCursor, pszWndBelowCursorName, newVer, m_wndCur, pszWndCurName, m_curVer));
+
+    if (   wndBelowCursor != m_wndCur
+        && m_curVer       != -1)
+    {
+        VBClLogInfo("Left old window %#x ('%s'), supported Xdnd version %ld\n", m_wndCur, pszWndCurName, m_curVer);
 
         /* We left the current XdndAware window. Announce this to the current indow. */
@@ -1848 +1916 @@
         xRc = XSendEvent(m_pDisplay, m_wndCur, False, NoEventMask, reinterpret_cast<XEvent*>(&m));
         if (xRc == 0)
-            VBClLogError("Error sending XA_XdndLeave event to old window=%#x: %s\n", m_wndCur, gX11->xErrorToString(xRc).c_str());
+            VBClLogError("Error sending leave event to old window %#x: %s\n", m_wndCur, gX11->xErrorToString(xRc).c_str());
 
         /* Reset our current window. */
@@ -1858 +1926 @@
      * Do we have a new Xdnd-aware window which now is under the cursor?
      */
-    if (   wndCursor != m_wndCur
-        && newVer    != -1)
-    {
-        LogFlowThisFunc(("XA_XdndEnter: window=%#x\n", wndCursor));
-
-        char *pszWndName = wndX11GetNameA(wndCursor);
-        AssertPtr(pszWndName);
-        VBClLogInfo("Entered new window %#x ('%s'), supports Xdnd version=%ld\n", wndCursor, pszWndName, newVer);
-        RTStrFree(pszWndName);
+    if (   wndBelowCursor != m_wndCur
+        && newVer         != -1)
+    {
+        VBClLogInfo("Entered new window %#x ('%s'), supports Xdnd version=%ld\n", wndBelowCursor, pszWndBelowCursorName, newVer);
 
         /*
@@ -1878 +1941 @@
         m.type         = ClientMessage;
         m.display      = m_pDisplay;
-        m.window       = wndCursor;
+        m.window       = wndBelowCursor;
         m.message_type = xAtom(XA_XdndEnter);
         m.format       = 32;
@@ -1893 +1956 @@
         m.data.l[XdndEnterType3]  = m_lstAtomFormats.value(2, None); /* Third data type to use. */
 
-        xRc = XSendEvent(m_pDisplay, wndCursor, False, NoEventMask, reinterpret_cast<XEvent*>(&m));
+        xRc = XSendEvent(m_pDisplay, wndBelowCursor, False, NoEventMask, reinterpret_cast<XEvent*>(&m));
         if (xRc == 0)
-            VBClLogError("Error sending XA_XdndEnter event to window=%#x: %s\n", wndCursor, gX11->xErrorToString(xRc).c_str());
+            VBClLogError("Error sending enter event to window %#x: %s\n", wndBelowCursor, gX11->xErrorToString(xRc).c_str());
     }
 
     if (newVer != -1)
     {
-        Assert(wndCursor != None);
-
-        LogFlowThisFunc(("XA_XdndPosition: xPos=%RU32, yPos=%RU32 to window=%#x\n", uPosX, uPosY, wndCursor));
+        Assert(wndBelowCursor != None);
+
+        Atom atmAction = toAtomAction(dndActionDefault);
+        LogFlowThisFunc(("strAction=%s\n", xAtomToString(atmAction).c_str()));
+
+        VBClLogInfo("Sent position event (%RU32 x %RU32) to window %#x ('%s') with actions '%s'\n",
+                    uPosX, uPosY, wndBelowCursor, pszWndBelowCursorName, xAtomToString(atmAction).c_str());
 
         /*
          * Send a XdndPosition event with the proposed action to the guest.
          */
-        Atom atmAction = toAtomAction(dndActionDefault);
-        LogFlowThisFunc(("strAction=%s\n", xAtomToString(atmAction).c_str()));
-
         XClientMessageEvent m;
         RT_ZERO(m);
         m.type         = ClientMessage;
         m.display      = m_pDisplay;
-        m.window       = wndCursor;
+        m.window       = wndBelowCursor;
         m.message_type = xAtom(XA_XdndPosition);
         m.format       = 32;
@@ -1923 +1987 @@
         m.data.l[XdndPositionAction]    = atmAction;                     /* Actions requested by the user. */
 
-        xRc = XSendEvent(m_pDisplay, wndCursor, False, NoEventMask, reinterpret_cast<XEvent*>(&m));
+        xRc = XSendEvent(m_pDisplay, wndBelowCursor, False, NoEventMask, reinterpret_cast<XEvent*>(&m));
         if (xRc == 0)
-            VBClLogError("Error sending XA_XdndPosition event to current window=%#x: %s\n", wndCursor, gX11->xErrorToString(xRc).c_str());
+            VBClLogError("Error sending position event to current window %#x: %s\n", wndBelowCursor, gX11->xErrorToString(xRc).c_str());
     }
 
@@ -1935 +1999 @@
     else
     {
-        Assert(wndCursor != None);
-
-        m_wndCur = wndCursor;
+        Assert(wndBelowCursor != None);
+
+        m_wndCur = wndBelowCursor;
         m_curVer = newVer;
     }
+
+    RTStrFree(pszWndBelowCursorName);
+    RTStrFree(pszWndCurName);
 
     LogFlowFuncLeaveRC(rc);
@@ -1979 +2046 @@
     int rc = VbglR3DnDHGSendReqData(&m_dndCtx, szFormat);
     VBClLogInfo("Drop event from host resulted in: %Rrc\n", rc);
+
+    if (g_cVerbosity)
+        VBClShowNotify(VBOX_DND_SHOWNOTIFY_HEADER, "Drop: Host -> Guest");
 
     LogFlowFuncLeaveRC(rc);
@@ -2160 +2230 @@
 
         /* Determine the current window which currently has the XdndSelection set. */
-        Window wndSelection = XGetSelectionOwner(m_pDisplay, xAtom(XA_XdndSelection));
-        LogFlowThisFunc(("wndSelection=%#x, wndProxy=%#x, wndCur=%#x\n", wndSelection, m_wndProxy.hWnd, m_wndCur));
+        Window wndSel = XGetSelectionOwner(m_pDisplay, xAtom(XA_XdndSelection));
+        LogFlowThisFunc(("wndSel=%#x, wndProxy=%#x, wndCur=%#x\n", wndSel, m_wndProxy.hWnd, m_wndCur));
 
         /* Is this another window which has a Xdnd selection and not our proxy window? */
         if (   RT_SUCCESS(rc)
-            && wndSelection
-            && wndSelection != m_wndCur)
-        {
-            char *pszWndName = wndX11GetNameA(wndSelection);
-            AssertPtr(pszWndName);
-            VBClLogInfo("New guest source window %#x ('%s')\n", wndSelection, pszWndName);
+            && wndSel
+            && wndSel != m_wndCur)
+        {
+            char *pszWndSelName = wndX11GetNameA(wndSel);
+            AssertPtrReturn(pszWndSelName, VERR_NO_MEMORY);
+            VBClLogInfo("New guest source window %#x ('%s')\n", wndSel, pszWndSelName);
 
             /* Start over. */
@@ -2215 +2285 @@
                     {
                         VBClLogError("Error mapping proxy window to guest source window %#x ('%s'), rc=%Rrc\n",
-                                     wndSelection, pszWndName, rc);
+                                     wndSel, pszWndSelName, rc);
 
                         /* Reset the counter in any case. */
@@ -2223 +2293 @@
             }
 
-            RTStrFree(pszWndName);
+            RTStrFree(pszWndSelName);
         }
         else
@@ -2255 +2325 @@
     if (RT_FAILURE(rc2))
     {
+        switch (rc2)
+        {
+            case VERR_ACCESS_DENIED:
+            {
+                rc = VBClShowNotify(VBOX_DND_SHOWNOTIFY_HEADER,
+                                    "Drag and drop to the host either is not supported or disabled. "
+                                    "Please enable Guest to Host or Bidirectional drag and drop mode "
+                                    "or re-install the VirtualBox Guest Additions.");
+                AssertRC(rc);
+                break;
+            }
+
+            default:
+                break;
+        }
+
         VBClLogError("Error reporting pending drag and drop operation status to host: %Rrc\n", rc2);
         if (RT_SUCCESS(rc))
@@ -3088 +3174 @@
     if (xRc == 0)
     {
-        VBClLogError("Error sending XA_XdndFinished event to source window=%#x: %s\n",
+        VBClLogError("Error sending finished event to source window=%#x: %s\n",
                       hWndSource, gX11->xErrorToString(xRc).c_str());