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applied a patch to prevent another IsDialogMessage() hang

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@21714 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin 2003-07-06 19:43:14 +00:00
parent 13e4c4d981
commit ae79d31557
1 changed files with 59 additions and 19 deletions
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78
src/msw/window.cpp
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@ -1927,34 +1927,74 @@ bool wxWindowMSW::MSWProcessMessage(WXMSG* pMsg)
// place edit control from being closed with Escape in a dialog
if ( msg->message != WM_KEYDOWN || msg->wParam != VK_ESCAPE )
{
// ::IsDialogMessage() can enter in an infinite loop when the
// currently focused window is disabled or hidden and its parent
// has WS_EX_CONTROLPARENT style, so don't call it in this case
// ::IsDialogMessage() is broken and may sometimes hang the
// application by going into an infinite loop, so we try to detect
// [some of] the situatations when this may happen and not call it
// then
// assume we can call it by default
bool canSafelyCallIsDlgMsg = TRUE;
HWND hwndFocus = ::GetFocus();
while ( hwndFocus )
// if the currently focused window itself has WS_EX_CONTROLPARENT style, ::IsDialogMessage() will also enter
// an infinite loop, because it will recursively check the child
// windows but not the window itself and so if none of the children
// accepts focus it loops forever (as it only stops when it gets
// back to the window it started from)
//
// while it is very unusual that a window with WS_EX_CONTROLPARENT
// style has the focus, it can happen. One such possibility is if
// all windows are either toplevel, wxDialog, wxPanel or static
// controls and no window can actually accept keyboard input.
if ( ::GetWindowLong(hwndFocus, GWL_EXSTYLE) & WS_EX_CONTROLPARENT )
{
if ( !::IsWindowEnabled(hwndFocus) ||
!::IsWindowVisible(hwndFocus) )
// passimistic by default
canSafelyCallIsDlgMsg = FALSE;
for ( wxWindowList::Node *node = GetChildren().GetFirst();
node;
node = node->GetNext() )
{
// it would enter an infinite loop if we do this!
canSafelyCallIsDlgMsg = FALSE;
if ( node->GetData()->AcceptsFocus() )
{
// it shouldn't hang...
canSafelyCallIsDlgMsg = TRUE;
break;
break;
}
}
if ( !(::GetWindowLong(hwndFocus, GWL_STYLE) & WS_CHILD) )
{
// it's a top level window, don't go further -- e.g. even
// if the parent of a dialog is disabled, this doesn't
// break navigation inside the dialog
break;
}
hwndFocus = ::GetParent(hwndFocus);
}
if ( canSafelyCallIsDlgMsg )
{
// ::IsDialogMessage() can enter in an infinite loop when the
// currently focused window is disabled or hidden and its
// parent has WS_EX_CONTROLPARENT style, so don't call it in
// this case
while ( hwndFocus )
{
if ( !::IsWindowEnabled(hwndFocus) ||
!::IsWindowVisible(hwndFocus) )
{
// it would enter an infinite loop if we do this!
canSafelyCallIsDlgMsg = FALSE;
break;
}
if ( !(::GetWindowLong(hwndFocus, GWL_STYLE) & WS_CHILD) )
{
// it's a top level window, don't go further -- e.g. even
// if the parent of a dialog is disabled, this doesn't
// break navigation inside the dialog
break;
}
hwndFocus = ::GetParent(hwndFocus);
}
}
// let IsDialogMessage() have the message if it's safe to call it
if ( canSafelyCallIsDlgMsg && ::IsDialogMessage(GetHwnd(), msg) )
{
// IsDialogMessage() did something...