Add ObjectInstances.findQuickWindow and passive-instrumenter exampleHEADmaster

This is a means of instrumenting any pure-QML application to generate an
object diagram showing the items and related objects belonging to the
first top-level window that can be found.

Using a Timer for that is kindof crude; perhaps we should rather
have a separate WindowFinder object that can emit a signal when a
new top-level window is discovered, or something like that. Or use
a Shortcut to trigger it manually. But it works well enough for now.

Change-Id: Ib2d82dfd6fbd4da4b46fbaadb08de2c5e649ffe6
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 29 insertions, 0 deletions

diff --git a/examples/objectInstancesTimer.qml b/examples/objectInstancesTimer.qml
new file mode 100644
index 0000000..28a336a
--- /dev/null
+++ b/examples/objectInstancesTimer.qml
@@ -0,0 +1,29 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+import QtQml
+import Qt.labs.UmlQuick.Generators
+
+/*
+    This is a means of instrumenting any pure-QML application to generate an
+    object diagram showing the items and related objects belonging to
+    the first top-level window that can be found. Run it like this,
+    and it will write out a .dot file after 2 seconds:
+
+    qml objectInstancesTimer.qml testApplication.qml
+*/
+ObjectInstances {
+    id: oi
+    outputPrefix: "objects-"
+
+    property var timer: Timer {
+        interval: 2000
+        running: true
+        onTriggered: {
+            // TODO use some separate WindowFinder object instead of an invokable function;
+            // somehow that should avoid the need for a Timer
+            oi.root = findQuickWindow()
+            oi.generate()
+        }
+    }
+}