user32: Don't regard the clipboard as changed if we don't own it.

I ran into a situation where user32 will call EndClipboardUpdate even though the clipboard hasn't changed. It went something like this: * Program A acquires the clipboard and adds some delay-rendered data. * Program B requests data from the clipboard, causing program A to receive WM_RENDERFORMAT. * Program A calls SetClipboardData to fulfill the request, setting bCBHasChanged to TRUE. * Program C acquires the clipboard. * Program A opens the clipboard to enumerate the formats. When it closes the clipboard, EndClipboardUpdate is called. Signed-off-by: Vincent Povirk <vincent@codeweavers.com> Signed-off-by: Alexandre Julliard <julliard@winehq.org>

user32: Don't regard the clipboard as changed if we don't own it.
b68e03f9 · Vincent Povirk · Alexandre Julliard · 13830123 · b68e03f9
Commit b68e03f9 authored May 18, 2016 by Vincent Povirk Committed by Alexandre Julliard May 21, 2016
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Showing with 14 additions and 3 deletions

clipboard.c dlls/user32/clipboard.c +14 -3

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--- a/dlls/user32/clipboard.c
+++ b/dlls/user32/clipboard.c
@@ -178,6 +178,7 @@ INT WINAPI GetClipboardFormatNameA(UINT wFormat, LPSTR retStr, INT maxlen)
 BOOL WINAPI OpenClipboard( HWND hWnd )
 {
    BOOL bRet;
+    UINT flags;
    TRACE("(%p)...\n", hWnd);
@@ -185,10 +186,16 @@ BOOL WINAPI OpenClipboard( HWND hWnd )
    {
        req->flags = SET_CB_OPEN;
        req->clipboard = wine_server_user_handle( hWnd );
-        bRet = !wine_server_call( req );
+        if ((bRet = !wine_server_call( req )))
+            flags = reply->flags;
    }
    SERVER_END_REQ;
+    if (bRet && !(flags & CB_PROCESS))
+    {
+        bCBHasChanged = FALSE;
+    }
    TRACE(" returning %i\n", bRet);
    return bRet;
@@ -201,6 +208,7 @@ BOOL WINAPI OpenClipboard( HWND hWnd )
 BOOL WINAPI CloseClipboard(void)
 {
    HWND viewer = 0;
+    UINT flags;
    BOOL ret;
    TRACE("() Changed=%d\n", bCBHasChanged);
@@ -210,18 +218,21 @@ BOOL WINAPI CloseClipboard(void)
        req->flags = SET_CB_CLOSE;
        if (bCBHasChanged) req->flags |= SET_CB_SEQNO;
        if ((ret = !wine_server_call_err( req )))
+        {
            viewer = wine_server_ptr_handle( reply->old_viewer );
+            flags = reply->flags;
+        }
    }
    SERVER_END_REQ;
    if (!ret) return FALSE;
-    if (bCBHasChanged)
+    if (bCBHasChanged && (flags & CB_PROCESS))
    {
        USER_Driver->pEndClipboardUpdate();
-        bCBHasChanged = FALSE;
        if (viewer) SendNotifyMessageW(viewer, WM_DRAWCLIPBOARD, (WPARAM) GetClipboardOwner(), 0);
    }
+    bCBHasChanged = FALSE;
    return TRUE;
 }