Changeset 69668 in vbox for trunk/src/VBox/GuestHost/SharedClipboard

Timestamp:

Nov 13, 2017 9:53:03 AM (7 years ago)

Author:

vboxsync

Message:

GuestHost/SharedClipboard/x11: schedule synchronisation mechanism removal.
bugref:9041: clipboard sharing on macOS host is brittle, Guest->Host direction

The GuestHost part of the X11 shared clipboard code contains a synchronisation
mechanism in the form of a flag which is set before an X11 clipboard request
is triggered and cleared when it completes. This is because the Xt toolkit,
which we use for the shared clipboard, does not support multiple clipboard
operations at once. However, we run all X11 clipboard code on a single thread,
and any function which sets the flag also waits for the operation to complete,
so the flag should not be necessary at all. What is more, if there is any
valid use for it it is far from clear that it would actually work as intended.
This change schedules it for removal after 5.2 using conditional compilation.

File:

• trunk/src/VBox/GuestHost/SharedClipboard/x11-clipboard.cpp (modified) (11 diffs)

trunk/src/VBox/GuestHost/SharedClipboard/x11-clipboard.cpp

@@ -49 +49 @@
 
 #include <VBox/log.h>
+#include <VBox/version.h>
 
 #include <VBox/GuestHost/SharedClipboard.h>
 #include <VBox/GuestHost/clipboard-helper.h>
 #include <VBox/HostServices/VBoxClipboardSvc.h>
+
+/* The serialisation mechanism looks like it is not needed (everything using it
+ * runs on one thread, and the flag is always cleared at the end of calls which
+ * use it).  So we will remove it after the 5.2 series. */
+#if (VBOX_VERSION_MAJOR * 100000 + VBOX_VERSION_MINOR * 1000 + VBOX_VERION_BUILD >= 502051)
+# define VBOX_AFTER_5_2
+#endif
 
 class formats;
@@ -215 +223 @@
     /** The first XFixes event number */
     int fixesEventBase;
+#ifndef VBOX_AFTER_5_2
     /** The Xt Intrinsics can only handle one outstanding clipboard operation
      * at a time, so we keep track of whether one is in process. */
@@ -221 +230 @@
      * it for later. */
     bool fUpdateNeeded;
+#endif
 };
 
@@ -530 +540 @@
 {
     LogRel2 (("%s: called\n", __FUNCTION__));
+#ifndef VBOX_AFTER_5_2
     pCtx->fBusy = false;
     if (pCtx->fUpdateNeeded)
@@ -538 +549 @@
         return;
     }
+#endif
     if (pTargets == NULL) {
         /* No data available */
@@ -620 +632 @@
     LogRel2 (("%s: requesting the targets that the X11 clipboard offers\n",
            __PRETTY_FUNCTION__));
+#ifndef VBOX_AFTER_5_2
     if (pCtx->fBusy)
     {
@@ -626 +639 @@
     }
     pCtx->fBusy = true;
+#endif
 #ifndef TESTCASE
     XtGetSelectionValue(pCtx->widget,
@@ -1736 +1750 @@
     Assert(pReq->mFormat != 0);  /* sanity */
     int rc = VINF_SUCCESS;
+#ifndef VBOX_AFTER_5_2
     CLIPBACKEND *pCtx = pReq->mCtx;
+#endif
     void *pvDest = NULL;
     uint32_t cbDest = 0;
 
+#ifndef VBOX_AFTER_5_2
     pCtx->fBusy = false;
     if (pCtx->fUpdateNeeded)
         clipQueryX11CBFormats(pCtx);
+#endif
     if (pvSrc == NULL)
         /* The clipboard selection may have changed before we could get it. */
@@ -1911 +1929 @@
 
     int rc = VINF_SUCCESS;
+#ifndef VBOX_AFTER_5_2
     bool fBusy = pCtx->fBusy;
     pCtx->fBusy = true;
@@ -1916 +1935 @@
         /* If the clipboard is busy just fend off the request. */
         rc = VERR_TRY_AGAIN;
-    else if (pReq->mFormat == VBOX_SHARED_CLIPBOARD_FMT_UNICODETEXT)
+    else
+#endif
+    if (pReq->mFormat == VBOX_SHARED_CLIPBOARD_FMT_UNICODETEXT)
     {
         /*
@@ -1957 +1978 @@
     {
         rc = VERR_NOT_IMPLEMENTED;
+#ifndef VBOX_AFTER_5_2
         pCtx->fBusy = false;
+#endif
     }
     if (RT_FAILURE(rc))