From 8cdc64083823b4ee6e715bb5da8918d5f1448523 Mon Sep 17 00:00:00 2001
From: Marco Thaller <marco.thaller@kdab.com>
Date: Fri, 8 Dec 2023 20:42:38 +0100
Subject: [PATCH] Add signal to indicate destruction of Object
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The 'destroyed' signal is emitted when Object::~Object
is called before any of the Object's children are destroyed.

Change-Id: Ida5783cc515d28efc75d7d9a060b1b3aea4e4cea
Reviewed-on: https://codereview.kdab.com/c/kdab/kdutils/+/135487
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>
Tested-by: Continuous Integration <build@kdab.com>
Reviewed-by: Miłosz Kosobucki <milosz.kosobucki@kdab.com>
---
 src/KDFoundation/object.cpp                 | 2 ++
 src/KDFoundation/object.h                   | 1 +
 tests/auto/foundation/object/tst_object.cpp | 8 ++++++++
 3 files changed, 11 insertions(+)

diff --git a/src/KDFoundation/object.cpp b/src/KDFoundation/object.cpp
index e7ee8af..d8adc0b 100644
--- a/src/KDFoundation/object.cpp
+++ b/src/KDFoundation/object.cpp
@@ -25,6 +25,8 @@ Object::Object()
 
 Object::~Object()
 {
+    destroyed.emit(this);
+
     // Destroy the children in LIFO to be more like the stack
     while (!m_children.empty()) {
         childRemoved.emit(this, m_children.back().get());
diff --git a/src/KDFoundation/object.h b/src/KDFoundation/object.h
index b4f77bf..e75e3ef 100644
--- a/src/KDFoundation/object.h
+++ b/src/KDFoundation/object.h
@@ -97,6 +97,7 @@ class KDFOUNDATION_API Object : public EventReceiver
     KDBindings::Signal<Object *, Object *> parentChanged;
     KDBindings::Signal<Object *, Object *> childAdded;
     KDBindings::Signal<Object *, Object *> childRemoved;
+    KDBindings::Signal<Object *> destroyed;
 
 protected:
     virtual void timerEvent(TimerEvent *ev);
diff --git a/tests/auto/foundation/object/tst_object.cpp b/tests/auto/foundation/object/tst_object.cpp
index ea4fba2..7b77c16 100644
--- a/tests/auto/foundation/object/tst_object.cpp
+++ b/tests/auto/foundation/object/tst_object.cpp
@@ -290,6 +290,14 @@ TEST_CASE("Object destruction")
             REQUIRE(expectedDestructionOrder[i] == destructionOrder[i]);
         }
     }
+
+    SUBCASE("destroyed signal is emitted on object destruction")
+    {
+        auto obj = new Object();
+        SignalSpy objectDestroyedSpy(obj->destroyed);
+        delete obj;
+        REQUIRE(objectDestroyedSpy.count() == 1);
+    }
 }
 
 TEST_CASE("Event delivery")