src/util/numeric.{cpp,h}: Fix FacePositionCache data race

src/util/numeric.cpp

@@ -23,13 +23,17 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "log.h"
 #include "../constants.h" // BS, MAP_BLOCKSIZE
 #include "../noise.h" // PseudoRandom, PcgRandom
+#include "../jthread/jmutexautolock.h"
 #include <string.h>
 #include <iostream>
 
 std::map<u16, std::vector<v3s16> > FacePositionCache::m_cache;
+JMutex FacePositionCache::m_cache_mutex;
 // Calculate the borders of a "d-radius" cube
+// TODO: Make it work without mutex and data races, probably thread-local
 std::vector<v3s16> FacePositionCache::getFacePositions(u16 d)
 {
+	JMutexAutoLock cachelock(m_cache_mutex);
 	if (m_cache.find(d) != m_cache.end())
 		return m_cache[d];
 

src/util/numeric.h

@@ -24,6 +24,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "../irr_v2d.h"
 #include "../irr_v3d.h"
 #include "../irr_aabb3d.h"
+#include "../jthread/jmutex.h"
 #include <list>
 #include <map>
 #include <vector>
@@ -41,6 +42,7 @@ class FacePositionCache
 private:
 	static void generateFacePosition(u16 d);
 	static std::map<u16, std::vector<v3s16> > m_cache;
+	static JMutex m_cache_mutex;
 };
 
 class IndentationRaiser