From c56d7fe0eba7905b0a63c4a1cfe909988653c23d Mon Sep 17 00:00:00 2001
From: kwolekr <kwolekr@minetest.net>
Date: Tue, 27 Oct 2015 02:51:43 -0400
Subject: [PATCH] Add DISABLE_CLASS_COPY macro (and use it)

Use this macro to disallow copying of an object using the assignment
operator or copy constructor.  This catches otherwise silent-but-deadly
mistakes such as "ServerMap map = env->getMap();" at compile time.

If so desired, it is still possible to copy a class, but it now requires
an explicit call to memcpy or std::copy.
---
 src/basicmacros.h         | 8 ++++++++
 src/client.h              | 2 ++
 src/emerge.h              | 2 ++
 src/environment.h         | 1 +
 src/map.h                 | 2 ++
 src/mapgen.h              | 3 +++
 src/objdef.h              | 3 +++
 src/server.h              | 2 ++
 src/threading/mutex.h     | 3 +++
 src/threading/semaphore.h | 3 +++
 src/threading/thread.h    | 1 +
 11 files changed, 30 insertions(+)

diff --git a/src/basicmacros.h b/src/basicmacros.h
index 05987e32..cebf0604 100644
--- a/src/basicmacros.h
+++ b/src/basicmacros.h
@@ -30,4 +30,12 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #define CONTAINS(c, v) (std::find((c).begin(), (c).end(), (v)) != (c).end())
 
+// To disable copy constructors and assignment operations for some class
+// 'Foobar', add the macro DISABLE_CLASS_COPY(Foobar) as a private member.
+// Note this also disables copying for any classes derived from 'Foobar' as well
+// as classes having a 'Foobar' member.
+#define DISABLE_CLASS_COPY(C) \
+	C(const C &);             \
+	C &operator=(const C &)
+
 #endif
diff --git a/src/client.h b/src/client.h
index 5b57aa52..07fb79dc 100644
--- a/src/client.h
+++ b/src/client.h
@@ -682,6 +682,8 @@ private:
 	// TODO: Add callback to update these when g_settings changes
 	bool m_cache_smooth_lighting;
 	bool m_cache_enable_shaders;
+
+	DISABLE_CLASS_COPY(Client);
 };
 
 #endif // !CLIENT_HEADER
diff --git a/src/emerge.h b/src/emerge.h
index 47ff218b..a143b660 100644
--- a/src/emerge.h
+++ b/src/emerge.h
@@ -164,6 +164,8 @@ private:
 	bool popBlockEmergeData(v3s16 pos, BlockEmergeData *bedata);
 
 	friend class EmergeThread;
+
+	DISABLE_CLASS_COPY(EmergeManager);
 };
 
 #endif
diff --git a/src/environment.h b/src/environment.h
index 1984cf40..cb8be71b 100644
--- a/src/environment.h
+++ b/src/environment.h
@@ -137,6 +137,7 @@ protected:
 private:
 	Mutex m_time_lock;
 
+	DISABLE_CLASS_COPY(Environment);
 };
 
 /*
diff --git a/src/map.h b/src/map.h
index 78af8c8d..78614d22 100644
--- a/src/map.h
+++ b/src/map.h
@@ -365,6 +365,8 @@ private:
 	u32 m_unprocessed_count;
 	u32 m_inc_trending_up_start_time; // milliseconds
 	bool m_queue_size_timer_started;
+
+	DISABLE_CLASS_COPY(Map);
 };
 
 /*
diff --git a/src/mapgen.h b/src/mapgen.h
index 0561ddf9..57e99584 100644
--- a/src/mapgen.h
+++ b/src/mapgen.h
@@ -182,6 +182,9 @@ public:
 
 	virtual void makeChunk(BlockMakeData *data) {}
 	virtual int getGroundLevelAtPoint(v2s16 p) { return 0; }
+
+private:
+	DISABLE_CLASS_COPY(Mapgen);
 };
 
 struct MapgenFactory {
diff --git a/src/objdef.h b/src/objdef.h
index 65e5c017..e7e956e5 100644
--- a/src/objdef.h
+++ b/src/objdef.h
@@ -90,6 +90,9 @@ protected:
 	INodeDefManager *m_ndef;
 	std::vector<ObjDef *> m_objects;
 	ObjDefType m_objtype;
+
+private:
+	DISABLE_CLASS_COPY(ObjDefManager);
 };
 
 #endif
diff --git a/src/server.h b/src/server.h
index fa732010..a4be7d3f 100644
--- a/src/server.h
+++ b/src/server.h
@@ -649,6 +649,8 @@ private:
 		Particles
 	*/
 	std::vector<u32> m_particlespawner_ids;
+
+	DISABLE_CLASS_COPY(Server);
 };
 
 /*
diff --git a/src/threading/mutex.h b/src/threading/mutex.h
index 4c9af71b..f1a4882b 100644
--- a/src/threading/mutex.h
+++ b/src/threading/mutex.h
@@ -44,6 +44,7 @@ DEALINGS IN THE SOFTWARE.
 	#include <pthread.h>
 #endif
 
+#include "basicmacros.h"
 
 class Mutex
 {
@@ -59,6 +60,8 @@ private:
 #else // pthread
 	pthread_mutex_t mutex;
 #endif
+
+	DISABLE_CLASS_COPY(Mutex);
 };
 
 #endif  // C++11
diff --git a/src/threading/semaphore.h b/src/threading/semaphore.h
index 58d758f2..736f2bc7 100644
--- a/src/threading/semaphore.h
+++ b/src/threading/semaphore.h
@@ -28,6 +28,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 	#include <semaphore.h>
 #endif
 
+#include "basicmacros.h"
 
 class Semaphore {
 public:
@@ -46,6 +47,8 @@ private:
 #else
 	sem_t semaphore;
 #endif
+
+	DISABLE_CLASS_COPY(Semaphore);
 };
 
 #endif
diff --git a/src/threading/thread.h b/src/threading/thread.h
index 3d85e0eb..83ca785c 100644
--- a/src/threading/thread.h
+++ b/src/threading/thread.h
@@ -161,6 +161,7 @@ private:
 	std::thread *m_thread_obj;
 #endif
 
+	DISABLE_CLASS_COPY(Thread);
 };
 
 #endif