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Codechange: make Window destruction not rely on undefined behavior.

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This commit is contained in:
frosch
2021-05-09 17:12:34 +02:00
committed by frosch
parent f96f113951
commit f6d5c0136e
2 changed files with 63 additions and 140 deletions
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136
src/window.cpp
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@@ -53,10 +53,8 @@ static Point _drag_delta; ///< delta between mouse cursor and upper left corner
static Window *_mouseover_last_w = nullptr; ///< Window of the last OnMouseOver event.
static Window *_last_scroll_window = nullptr; ///< Window of the last scroll event.
/** List of windows opened at the screen sorted from the front. */
Window *_z_front_window = nullptr;
/** List of windows opened at the screen sorted from the back. */
Window *_z_back_window = nullptr;
/** List of windows opened at the screen sorted from the front to back. */
WindowList _z_windows;
/** If false, highlight is white, otherwise the by the widget defined colour. */
bool _window_highlight_colour = false;
@@ -1109,16 +1107,7 @@ Window::~Window()
free(this->nested_array); // Contents is released through deletion of #nested_root.
delete this->nested_root;
/*
* Make fairly sure that this is written, and not "optimized" away.
* The delete operator is overwritten to not delete it; the deletion
* happens at a later moment in time after the window has been
* removed from the list of windows to prevent issues with items
* being removed during the iteration as not one but more windows
* may be removed by a single call to ~Window by means of the
* DeleteChildWindows function.
*/
const_cast<volatile WindowClass &>(this->window_class) = WC_INVALID;
*this->z_position = nullptr;
}
/**
@@ -1231,7 +1220,7 @@ void ChangeWindowOwner(Owner old_owner, Owner new_owner)
}
}
static void BringWindowToFront(Window *w);
static void BringWindowToFront(Window *w, bool dirty = true);
/**
* Find a window and make it the relative top-window on the screen.
@@ -1351,90 +1340,23 @@ static uint GetWindowZPriority(WindowClass wc)
}
}
/**
* Adds a window to the z-ordering, according to its z-priority.
* @param w Window to add
*/
static void AddWindowToZOrdering(Window *w)
{
assert(w->z_front == nullptr && w->z_back == nullptr);
if (_z_front_window == nullptr) {
/* It's the only window. */
_z_front_window = _z_back_window = w;
w->z_front = w->z_back = nullptr;
} else {
/* Search down the z-ordering for its location. */
Window *v = _z_front_window;
uint last_z_priority = UINT_MAX;
(void)last_z_priority; // Unused without asserts
while (v != nullptr && (v->window_class == WC_INVALID || GetWindowZPriority(v->window_class) > GetWindowZPriority(w->window_class))) {
if (v->window_class != WC_INVALID) {
/* Sanity check z-ordering, while we're at it. */
assert(last_z_priority >= GetWindowZPriority(v->window_class));
last_z_priority = GetWindowZPriority(v->window_class);
}
v = v->z_back;
}
if (v == nullptr) {
/* It's the new back window. */
w->z_front = _z_back_window;
w->z_back = nullptr;
_z_back_window->z_back = w;
_z_back_window = w;
} else if (v == _z_front_window) {
/* It's the new front window. */
w->z_front = nullptr;
w->z_back = _z_front_window;
_z_front_window->z_front = w;
_z_front_window = w;
} else {
/* It's somewhere else in the z-ordering. */
w->z_front = v->z_front;
w->z_back = v;
v->z_front->z_back = w;
v->z_front = w;
}
}
}
/**
* Removes a window from the z-ordering.
* @param w Window to remove
*/
static void RemoveWindowFromZOrdering(Window *w)
{
if (w->z_front == nullptr) {
assert(_z_front_window == w);
_z_front_window = w->z_back;
} else {
w->z_front->z_back = w->z_back;
}
if (w->z_back == nullptr) {
assert(_z_back_window == w);
_z_back_window = w->z_front;
} else {
w->z_back->z_front = w->z_front;
}
w->z_front = w->z_back = nullptr;
}
/**
* On clicking on a window, make it the frontmost window of all windows with an equal
* or lower z-priority. The window is marked dirty for a repaint
* @param w window that is put into the relative foreground
* @param dirty whether to mark the window dirty
*/
static void BringWindowToFront(Window *w)
static void BringWindowToFront(Window *w, bool dirty)
{
RemoveWindowFromZOrdering(w);
AddWindowToZOrdering(w);
auto priority = GetWindowZPriority(w->window_class);
WindowList::iterator dest = _z_windows.begin();
while (dest != _z_windows.end() && (*dest == nullptr || GetWindowZPriority((*dest)->window_class) <= priority)) ++dest;
w->SetDirty();
if (dest != w->z_position) {
_z_windows.splice(dest, _z_windows, w->z_position);
}
if (dirty) w->SetDirty();
}
/**
@@ -1476,7 +1398,7 @@ void Window::InitializeData(WindowNumber window_number)
if (!EditBoxInGlobalFocus() || this->nested_root->GetWidgetOfType(WWT_EDITBOX) != nullptr) SetFocusedWindow(this);
/* Insert the window into the correct location in the z-ordering. */
AddWindowToZOrdering(this);
BringWindowToFront(this, false);
}
/**
@@ -1848,6 +1770,7 @@ void Window::InitNested(WindowNumber window_number)
*/
Window::Window(WindowDesc *desc) : window_desc(desc), mouse_capture_widget(-1)
{
this->z_position = _z_windows.insert(_z_windows.end(), this);
}
/**
@@ -1875,8 +1798,6 @@ void InitWindowSystem()
{
IConsoleClose();
_z_back_window = nullptr;
_z_front_window = nullptr;
_focused_window = nullptr;
_mouseover_last_w = nullptr;
_last_scroll_window = nullptr;
@@ -1898,14 +1819,7 @@ void UnInitWindowSystem()
for (Window *w : Window::Iterate()) delete w;
for (Window *w = _z_front_window; w != nullptr; /* nothing */) {
Window *to_del = w;
w = w->z_back;
free(to_del);
}
_z_front_window = nullptr;
_z_back_window = nullptr;
_z_windows.clear();
}
/**
@@ -3068,15 +2982,13 @@ void InputLoop()
CheckSoftLimit();
/* Do the actual free of the deleted windows. */
for (Window *v = _z_front_window; v != nullptr; /* nothing */) {
Window *w = v;
v = v->z_back;
if (w->window_class != WC_INVALID) continue;
RemoveWindowFromZOrdering(w);
free(w);
/* Remove dead entries from the window list */
for (auto it = _z_windows.begin(); it != _z_windows.end(); ) {
if (*it == nullptr) {
it = _z_windows.erase(it);
} else {
++it;
}
}
if (_input_events_this_tick != 0) {