framework: fix race in ToolBarManager creation

ToolbarLayoutManager::createToolbar() may be called concurrently on
different threads, and then it can happen that both threads want to
create the same toolbar URL, see that it does not exist in line 457,
then both release the SolarMutex and create a new ToolBarManager
and the first inserts it and then the second overwrites it on line 514
without disposing the first one.

The non-disposed extra ToolBarManager is kept alive because it is
registered as a listener on the Frame.  When the Frame::close() is
called, the ToolbarLayoutManager is disposed, and that disposes all the
ToolBarManagers it knows about, but not the extra one, which is
then un-ref'd and then has a live VclPtr m_pToolBar, which asserts
because the SolarMutex is not locked since commit
e794ce1eef6730e5a46d5fb0aa6db2895ede85e7.

(This commit is thanks to rr, which recorded the
JunitTest_framework_complex execution and allowed debugging this.)

Change-Id: I8f5333e8e36ac8ea347ef545e014ffc10501aebb

2 files changed, 9 insertions, 7 deletions

diff --git a/framework/source/layoutmanager/toolbarlayoutmanager.cxx b/framework/source/layoutmanager/toolbarlayoutmanager.cxx
index 4db5ca56b30b..385fcd4dcc21 100644
--- a/framework/source/layoutmanager/toolbarlayoutmanager.cxx
+++ b/framework/source/layoutmanager/toolbarlayoutmanager.cxx
@@ -508,12 +508,14 @@ bool ToolbarLayoutManager::createToolbar( const OUString& rResourceURL )
             UIElement& rElement = impl_findToolbar( rResourceURL );
             if ( !rElement.m_aName.isEmpty() )
             {
-                // Reuse a local entry so we are able to use the latest
-                // UI changes for this document.
-                implts_setElementData( rElement, xDockWindow );
-                rElement.m_xUIElement = xUIElement;
-                bVisible = rElement.m_bVisible;
-                bFloating = rElement.m_bFloating;
+                // somebody else must have created it while we released
+                // the SolarMutex - just dispose our new instance and
+                // do nothing. (We have to dispose either the new or the
+                // existing m_xUIElement.)
+                aWriteLock.clear();
+                uno::Reference<lang::XComponent> const xC(xUIElement, uno::UNO_QUERY);
+                xC->dispose();
+                return false;
             }
             else
             {
diff --git a/framework/source/uielement/toolbarmanager.cxx b/framework/source/uielement/toolbarmanager.cxx
index 4c330b3e64ce..489ad878715a 100644
--- a/framework/source/uielement/toolbarmanager.cxx
+++ b/framework/source/uielement/toolbarmanager.cxx
@@ -200,7 +200,7 @@ ToolBarManager::ToolBarManager( const Reference< XComponentContext >& rxContext,
 ToolBarManager::~ToolBarManager()
 {
     assert(!m_aAsyncUpdateControllersTimer.IsActive());
-    OSL_ASSERT( !m_pToolBar );
+    assert(!m_pToolBar); // must be disposed by ToolbarLayoutManager
     OSL_ASSERT( !m_bAddedToTaskPaneList );
 }