tests: Add a test case for the Object::deleteLater() API, to verify

- the object is deleted from the correct thread
- multiple deleteLater() calls delete the object once only

Signed-off-by: Umang Jain <email@uajain.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

test/object-delete.cpp

@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2020, Google Inc.
+ *
+ * object.cpp - Object deletion tests
+ */
+
+#include <iostream>
+
+#include <libcamera/object.h>
+
+#include "libcamera/internal/thread.h"
+
+#include "test.h"
+
+using namespace std;
+using namespace libcamera;
+
+class TestObject : public Object
+{
+public:
+	TestObject(unsigned int *count)
+		: deleteCount_(count)
+	{
+	}
+
+	~TestObject()
+	{
+		/* Count the deletions from the correct thread. */
+		if (thread() == Thread::current())
+			(*deleteCount_)++;
+	}
+
+	unsigned int *deleteCount_;
+};
+
+class NewThread : public Thread
+{
+public:
+	NewThread(Object *obj)
+		: object_(obj)
+	{
+	}
+
+protected:
+	void run()
+	{
+		object_->deleteLater();
+	}
+
+private:
+	Object *object_;
+};
+
+class ObjectDeleteTest : public Test
+{
+protected:
+	int run()
+	{
+		/*
+		 * Test that deferred deletion is executed from the object's
+		 * thread, not the caller's thread.
+		 */
+		unsigned int count = 0;
+		TestObject *obj = new TestObject(&count);
+
+		NewThread thread(obj);
+		thread.start();
+		thread.wait();
+
+		Thread::current()->dispatchMessages(Message::Type::DeferredDelete);
+
+		if (count != 1) {
+			cout << "Failed to dispatch DeferredDelete (" << count << ")" << endl;
+			return TestFail;
+		}
+
+		/*
+		 * Test that multiple calls to deleteLater() delete the object
+		 * once only.
+		 */
+		count = 0;
+		obj = new TestObject(&count);
+		obj->deleteLater();
+		obj->deleteLater();
+
+		Thread::current()->dispatchMessages(Message::Type::DeferredDelete);
+		if (count != 1) {
+			cout << "Multiple deleteLater() failed (" << count << ")" << endl;
+			return TestFail;
+		}
+
+		return TestPass;
+	}
+};
+
+TEST_REGISTER(ObjectDeleteTest)