Add 'meshmc/' from commit 'fad6a1066616b69d7f5fef01178efdf014c59537'

git-subtree-dir: meshmc
git-subtree-mainline: 934382c8a1ce738589dee9ee0f14e1cec812770e
git-subtree-split: fad6a1066616b69d7f5fef01178efdf014c59537

1 files changed, 87 insertions, 0 deletions

diff --git a/meshmc/launcher/Usable.h b/meshmc/launcher/Usable.h
new file mode 100644
index 0000000000..b50b0820ee
--- /dev/null
+++ b/meshmc/launcher/Usable.h
@@ -0,0 +1,87 @@
+/* SPDX-FileCopyrightText: 2026 Project Tick
+ * SPDX-FileContributor: Project Tick
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   MeshMC - A Custom Launcher for Minecraft
+ *   Copyright (C) 2026 Project Tick
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <cstddef>
+#include <memory>
+
+#include "QObjectPtr.h"
+
+class Usable;
+
+/**
+ * Base class for things that can be used by multiple other things and we want
+ * to track the use count.
+ *
+ * @see UseLock
+ */
+class Usable
+{
+	friend class UseLock;
+
+  public:
+	std::size_t useCount() const
+	{
+		return m_useCount;
+	}
+	bool isInUse() const
+	{
+		return m_useCount > 0;
+	}
+
+  protected:
+	virtual void decrementUses()
+	{
+		m_useCount--;
+	}
+	virtual void incrementUses()
+	{
+		m_useCount++;
+	}
+
+  private:
+	std::size_t m_useCount = 0;
+};
+
+/**
+ * Lock class to use for keeping track of uses of other things derived from
+ * Usable
+ *
+ * @see Usable
+ */
+class UseLock
+{
+  public:
+	UseLock(shared_qobject_ptr<Usable> usable) : m_usable(usable)
+	{
+		// this doesn't use shared pointer use count, because that wouldn't be
+		// correct. this count is separate.
+		m_usable->incrementUses();
+	}
+	~UseLock()
+	{
+		m_usable->decrementUses();
+	}
+
+  private:
+	shared_qobject_ptr<Usable> m_usable;
+};