winex11.drv: Handle clipboard on an auxiliary thread for windowless apps (try 4)

[Yuri Khan]

Fixes clipboard copying in applications that don't handle window
messages. Per Alexandre Julliard's suggestions, no thread is started
if the application passes a non-null window handle to OpenClipboard,
so in the majority of cases the behavior is the same as previously.
The file-local functions are now static, parameter to thread proc
renamed 'unused', unused local variable removed (thanks Dmitry
Timoshkov).
-------------- next part --------------
diff --git a/dlls/winex11.drv/clipboard.c b/dlls/winex11.drv/clipboard.c
index 3806080..82928a2 100644
--- a/dlls/winex11.drv/clipboard.c
+++ b/dlls/winex11.drv/clipboard.c
@@ -2504,6 +2504,52 @@ INT CDECL X11DRV_GetClipboardFormatName(UINT wFormat, LPWSTR retStr, INT maxlen)
     return strlenW(retStr);
 }
 
+static void selection_acquire(void)
+{
+    Window owner;
+    Display *display;
+
+    owner = thread_selection_wnd();
+    display = thread_display();
+
+    wine_tsx11_lock();
+
+    selectionAcquired = 0;
+    selectionWindow = 0;
+
+    /* Grab PRIMARY selection if not owned */
+    if (use_primary_selection)
+        XSetSelectionOwner(display, XA_PRIMARY, owner, CurrentTime);
+
+    /* Grab CLIPBOARD selection if not owned */
+    XSetSelectionOwner(display, x11drv_atom(CLIPBOARD), owner, CurrentTime);
+
+    if (use_primary_selection && XGetSelectionOwner(display, XA_PRIMARY) == owner)
+        selectionAcquired |= S_PRIMARY;
+
+    if (XGetSelectionOwner(display,x11drv_atom(CLIPBOARD)) == owner)
+        selectionAcquired |= S_CLIPBOARD;
+
+    wine_tsx11_unlock();
+
+    if (selectionAcquired)
+    {
+        selectionWindow = owner;
+        TRACE("Grabbed X selection, owner=(%08x)\n", (unsigned) owner);
+    }
+}
+
+static DWORD WINAPI selection_thread_proc(LPVOID unused)
+{
+    selection_acquire();
+
+    while (selectionAcquired)
+    {
+        MsgWaitForMultipleObjectsEx(0, NULL, INFINITE, QS_SENDMESSAGE, 0);
+    }
+
+    return 0;
+}
 
 /**************************************************************************
  *		AcquireClipboard (X11DRV.@)
@@ -2511,8 +2557,7 @@ INT CDECL X11DRV_GetClipboardFormatName(UINT wFormat, LPWSTR retStr, INT maxlen)
 int CDECL X11DRV_AcquireClipboard(HWND hWndClipWindow)
 {
     DWORD procid;
-    Window owner;
-    Display *display;
+    HANDLE selectionThread;
 
     TRACE(" %p\n", hWndClipWindow);
 
@@ -2540,33 +2585,21 @@ int CDECL X11DRV_AcquireClipboard(HWND hWndClipWindow)
         }
     }
 
-    owner = thread_selection_wnd();
-    display = thread_display();
-
-    wine_tsx11_lock();
-
-    selectionAcquired = 0;
-    selectionWindow = 0;
-
-    /* Grab PRIMARY selection if not owned */
-    if (use_primary_selection)
-        XSetSelectionOwner(display, XA_PRIMARY, owner, CurrentTime);
-
-    /* Grab CLIPBOARD selection if not owned */
-    XSetSelectionOwner(display, x11drv_atom(CLIPBOARD), owner, CurrentTime);
-
-    if (use_primary_selection && XGetSelectionOwner(display, XA_PRIMARY) == owner)
-        selectionAcquired |= S_PRIMARY;
-
-    if (XGetSelectionOwner(display,x11drv_atom(CLIPBOARD)) == owner)
-        selectionAcquired |= S_CLIPBOARD;
+    if (hWndClipWindow)
+    {
+        selection_acquire();
+    }
+    else
+    {
+        selectionThread = CreateThread(NULL, 0, &selection_thread_proc, NULL, 0, NULL);
 
-    wine_tsx11_unlock();
+        if (!selectionThread)
+        {
+            WARN("Could not start clipboard thread\n");
+            return 0;
+        }
 
-    if (selectionAcquired)
-    {
-        selectionWindow = owner;
-        TRACE("Grabbed X selection, owner=(%08x)\n", (unsigned) owner);
+        CloseHandle(selectionThread);
     }
 
     return 1;