From 5c5844cedb938c38ea595957b172c48a67c502fc Mon Sep 17 00:00:00 2001
From: Even Oscar Andersen <even.oscar.andersen@qt.io>
Date: Sat, 21 Dec 2024 10:36:30 +0100
Subject: [PATCH] Make QWasmScreen::allWindows return all (wasm) windows
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It seems that findChildren does not return every window if called
at an inconvenient time.

This causes not all windows to be returned, and later the
QWasmCompositor will not detect a valid window to compose,
and therefor goes to disabled.

Fixes: QTBUG-132414
Pick-to: 6.9
Change-Id: I6c872071751d5a2fbdeea36fb8f4c7e9677fd7d0
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
---
 src/plugins/platforms/wasm/qwasmscreen.cpp | 29 +++++++++++++---------
 src/plugins/platforms/wasm/qwasmscreen.h   |  2 +-
 2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/src/plugins/platforms/wasm/qwasmscreen.cpp b/src/plugins/platforms/wasm/qwasmscreen.cpp
index 1ec7d758395..badc5468c8b 100644
--- a/src/plugins/platforms/wasm/qwasmscreen.cpp
+++ b/src/plugins/platforms/wasm/qwasmscreen.cpp
@@ -330,21 +330,26 @@ QWasmWindowTreeNode *QWasmScreen::parentNode()
     return nullptr;
 }
 
-QList<QWasmWindow *> QWasmScreen::allWindows()
+QList<QWasmWindow *> QWasmScreen::allWindows() const
 {
-    QList<QWasmWindow *> windows;
-    for (auto *child : childStack()) {
-        const QWindowList list = child->window()->findChildren<QWindow *>(Qt::FindChildrenRecursively);
-        for (auto child : list) {
-            auto handle = child->handle();
-            if (handle) {
-                auto wnd = static_cast<QWasmWindow *>(handle);
-                windows.push_back(wnd);
-            }
+    QList<QWasmWindow *> currentChildren;
+    QList<QWasmWindow *> result;
+
+    for (auto *w : childStack())
+        currentChildren << w;
+
+    while (!currentChildren.empty()) {
+        result << currentChildren;
+
+        QList<QWasmWindow *> toIterate;
+        currentChildren.swap(toIterate);
+
+        for (auto child : toIterate) {
+            for (auto *w : child->childStack())
+                currentChildren << w;
         }
-        windows.push_back(child);
     }
-    return windows;
+    return result;
 }
 
 QT_END_NAMESPACE
diff --git a/src/plugins/platforms/wasm/qwasmscreen.h b/src/plugins/platforms/wasm/qwasmscreen.h
index cf9916b9075..66e7e39d008 100644
--- a/src/plugins/platforms/wasm/qwasmscreen.h
+++ b/src/plugins/platforms/wasm/qwasmscreen.h
@@ -43,7 +43,7 @@ public:
     QWasmCompositor *compositor();
     QWasmDeadKeySupport *deadKeySupport() { return m_deadKeySupport.get(); }
 
-    QList<QWasmWindow *> allWindows();
+    QList<QWasmWindow *> allWindows() const;
 
     QRect geometry() const override;
     int depth() const override;