Add core.compare_block_status function (#11247)

Makes it possible to check the status of the mapblock in a future-extensible way.

9 files changed, 76 insertions, 4 deletions

diff --git a/src/emerge.cpp b/src/emerge.cpp
index 32e7d9f24..3a2244d7e 100644
--- a/src/emerge.cpp
+++ b/src/emerge.cpp
@@ -358,6 +358,13 @@ bool EmergeManager::enqueueBlockEmergeEx(
 }
 
 
+bool EmergeManager::isBlockInQueue(v3s16 pos)
+{
+	MutexAutoLock queuelock(m_queue_mutex);
+	return m_blocks_enqueued.find(pos) != m_blocks_enqueued.end();
+}
+
+
 //
 // Mapgen-related helper functions
 //
diff --git a/src/emerge.h b/src/emerge.h
index aac3e7dd3..b060226f8 100644
--- a/src/emerge.h
+++ b/src/emerge.h
@@ -174,6 +174,8 @@ public:
 		EmergeCompletionCallback callback,
 		void *callback_param);
 
+	bool isBlockInQueue(v3s16 pos);
+
 	v3s16 getContainingChunk(v3s16 blockpos);
 
 	Mapgen *getCurrentMapgen();
diff --git a/src/map.cpp b/src/map.cpp
index 7c59edbaa..641287c3d 100644
--- a/src/map.cpp
+++ b/src/map.cpp
@@ -1549,6 +1549,11 @@ MapBlock *ServerMap::getBlockOrEmerge(v3s16 p3d)
 	return block;
 }
 
+bool ServerMap::isBlockInQueue(v3s16 pos)
+{
+	return m_emerge && m_emerge->isBlockInQueue(pos);
+}
+
 // N.B.  This requires no synchronization, since data will not be modified unless
 // the VoxelManipulator being updated belongs to the same thread.
 void ServerMap::updateVManip(v3s16 pos)
diff --git a/src/map.h b/src/map.h
index e68795c4a..8d20c4a44 100644
--- a/src/map.h
+++ b/src/map.h
@@ -365,6 +365,8 @@ public:
 	*/
 	MapBlock *getBlockOrEmerge(v3s16 p3d);
 
+	bool isBlockInQueue(v3s16 pos);
+
 	/*
 		Database functions
 	*/
diff --git a/src/mapblock.h b/src/mapblock.h
index 7b82301e9..2e3eb0d76 100644
--- a/src/mapblock.h
+++ b/src/mapblock.h
@@ -140,7 +140,7 @@ public:
 	//// Flags
 	////
 
-	inline bool isDummy()
+	inline bool isDummy() const
 	{
 		return !data;
 	}
diff --git a/src/script/lua_api/l_env.cpp b/src/script/lua_api/l_env.cpp
index 39c229ee4..98f8861fa 100644
--- a/src/script/lua_api/l_env.cpp
+++ b/src/script/lua_api/l_env.cpp
@@ -46,13 +46,22 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "client/client.h"
 #endif
 
-struct EnumString ModApiEnvMod::es_ClearObjectsMode[] =
+const EnumString ModApiEnvMod::es_ClearObjectsMode[] =
 {
 	{CLEAR_OBJECTS_MODE_FULL,  "full"},
 	{CLEAR_OBJECTS_MODE_QUICK, "quick"},
 	{0, NULL},
 };
 
+const EnumString ModApiEnvMod::es_BlockStatusType[] =
+{
+	{ServerEnvironment::BS_UNKNOWN, "unknown"},
+	{ServerEnvironment::BS_EMERGING, "emerging"},
+	{ServerEnvironment::BS_LOADED,  "loaded"},
+	{ServerEnvironment::BS_ACTIVE,  "active"},
+	{0, NULL},
+};
+
 ///////////////////////////////////////////////////////////////////////////////
 
 
@@ -1389,6 +1398,24 @@ int ModApiEnvMod::l_forceload_block(lua_State *L)
 	return 0;
 }
 
+// compare_block_status(nodepos)
+int ModApiEnvMod::l_compare_block_status(lua_State *L)
+{
+	GET_ENV_PTR;
+
+	v3s16 nodepos = check_v3s16(L, 1);
+	std::string condition_s = luaL_checkstring(L, 2);
+	auto status = env->getBlockStatus(getNodeBlockPos(nodepos));
+	
+	int condition_i = -1;
+	if (!string_to_enum(es_BlockStatusType, condition_i, condition_s))
+		return 0; // Unsupported
+
+	lua_pushboolean(L, status >= condition_i);
+	return 1;
+}
+
+
 // forceload_free_block(blockpos)
 // blockpos = {x=num, y=num, z=num}
 int ModApiEnvMod::l_forceload_free_block(lua_State *L)
@@ -1462,6 +1489,7 @@ void ModApiEnvMod::Initialize(lua_State *L, int top)
 	API_FCT(transforming_liquid_add);
 	API_FCT(forceload_block);
 	API_FCT(forceload_free_block);
+	API_FCT(compare_block_status);
 	API_FCT(get_translated_string);
 }
 
diff --git a/src/script/lua_api/l_env.h b/src/script/lua_api/l_env.h
index 42c2d64f8..979b13c40 100644
--- a/src/script/lua_api/l_env.h
+++ b/src/script/lua_api/l_env.h
@@ -195,6 +195,9 @@ private:
 	// stops forceloading a position
 	static int l_forceload_free_block(lua_State *L);
 
+	// compare_block_status(nodepos)
+	static int l_compare_block_status(lua_State *L);
+
 	// Get a string translated server side
 	static int l_get_translated_string(lua_State * L);
 
@@ -207,7 +210,8 @@ public:
 	static void Initialize(lua_State *L, int top);
 	static void InitializeClient(lua_State *L, int top);
 
-	static struct EnumString es_ClearObjectsMode[];
+	static const EnumString es_ClearObjectsMode[];
+	static const EnumString es_BlockStatusType[];
 };
 
 class LuaABM : public ActiveBlockModifier {
diff --git a/src/serverenvironment.cpp b/src/serverenvironment.cpp
index 3d9ba132b..413a785e6 100644
--- a/src/serverenvironment.cpp
+++ b/src/serverenvironment.cpp
@@ -1542,6 +1542,21 @@ void ServerEnvironment::step(float dtime)
 	m_server->sendDetachedInventories(PEER_ID_INEXISTENT, true);
 }
 
+ServerEnvironment::BlockStatus ServerEnvironment::getBlockStatus(v3s16 blockpos)
+{
+	if (m_active_blocks.contains(blockpos))
+		return BS_ACTIVE;
+
+	const MapBlock *block = m_map->getBlockNoCreateNoEx(blockpos);
+	if (block && !block->isDummy())
+		return BS_LOADED;
+
+	if (m_map->isBlockInQueue(blockpos))
+		return BS_EMERGING;
+
+	return BS_UNKNOWN;
+}
+
 u32 ServerEnvironment::addParticleSpawner(float exptime)
 {
 	// Timers with lifetime 0 do not expire
diff --git a/src/serverenvironment.h b/src/serverenvironment.h
index a11c814ed..c5ca463ee 100644
--- a/src/serverenvironment.h
+++ b/src/serverenvironment.h
@@ -342,7 +342,16 @@ public:
 	void reportMaxLagEstimate(float f) { m_max_lag_estimate = f; }
 	float getMaxLagEstimate() { return m_max_lag_estimate; }
 
-	std::set<v3s16>* getForceloadedBlocks() { return &m_active_blocks.m_forceloaded_list; };
+	std::set<v3s16>* getForceloadedBlocks() { return &m_active_blocks.m_forceloaded_list; }
+
+	// Sorted by how ready a mapblock is
+	enum BlockStatus {
+		BS_UNKNOWN,
+		BS_EMERGING,
+		BS_LOADED,
+		BS_ACTIVE // always highest value
+	};
+	BlockStatus getBlockStatus(v3s16 blockpos);
 
 	// Sets the static object status all the active objects in the specified block
 	// This is only really needed for deleting blocks from the map