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nitpicker: fix corner case in view stack operation 

This patch addresses the corner case that the specified neighbor view
is the first view of the view stack. If this is the case when inserting
the view in front of the neighbor (behind == false), the target position
within the view stack must be a null pointer, not the first view.

Because the conditions have become rather complicated, both cases
of 'behind' are handled separately now.
This commit is contained in:
Norman Feske 2015-11-11 19:30:04 +01:00 committed by Christian Helmuth
parent 909c4c9ffc
commit a1c0c99045
1 changed files with 19 additions and 15 deletions
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34
repos/os/src/server/nitpicker/view_stack.cc
View File

@ -61,28 +61,32 @@ Rect View_stack::_outline(View const &view) const
View const *View_stack::_target_stack_position(View const *neighbor, bool behind)
{
View const *cv = _first_view();
if (behind) {
for (; cv; cv = _next_view(*cv)) {
if (!neighbor)
return nullptr;
/* bring view to front? */
if (behind && !neighbor)
break;
/* find target position behind neighbor */
for (View const *cv = _first_view(); cv; cv = _next_view(*cv))
if (cv == neighbor)
return cv;
/* insert view after cv? */
if (behind && (cv == neighbor))
break;
} else {
/* insert view in front of cv? */
if (!behind && (_next_view(*cv) == neighbor))
break;
if (neighbor == _first_view())
return nullptr;
/* insert view in front of the background? */
if (!behind && !neighbor && _next_view(*cv)->background())
break;
/* find target position in front of neighbor */
for (View const *cv = _first_view(), *next = nullptr; cv; cv = next) {
next = _next_view(*cv);
if (!next || next == neighbor || next->background())
return cv;
}
}
return cv ? cv : _first_view();
/* we should never reach this point */
return nullptr;
}