Rewritten chunk status to specify whether the chunk is in queue.

This fixes #1370.

src/Chunk.cpp

@@ -71,7 +71,7 @@ cChunk::cChunk(
 	cChunk * a_NeighborXM, cChunk * a_NeighborXP, cChunk * a_NeighborZM, cChunk * a_NeighborZP,
 	cAllocationPool<cChunkData::sChunkSection> & a_Pool
 ) :
-	m_IsValid(false),
+	m_Presence(cpInvalid),
 	m_IsLightValid(false),
 	m_IsDirty(false),
 	m_IsSaving(false),
@@ -165,11 +165,22 @@ cChunk::~cChunk()
 
 
 
-void cChunk::SetValid(void)
+void cChunk::SetPresence(cChunk::ePresence a_Presence)
 {
-	m_IsValid = true;
-	
-	m_World->GetChunkMap()->ChunkValidated();
+	m_Presence = a_Presence;
+	if (a_Presence == cpPresent)
+	{
+		m_World->GetChunkMap()->ChunkValidated();
+	}
+}
+
+
+
+
+
+void cChunk::SetShouldGenerateIfLoadFailed(bool a_ShouldGenerateIfLoadFailed)
+{
+	m_ShouldGenerateIfLoadFailed = a_ShouldGenerateIfLoadFailed;
 }
 
 
@@ -178,6 +189,9 @@ void cChunk::SetValid(void)
 
 void cChunk::MarkRegenerating(void)
 {
+	// Set as queued again:
+	SetPresence(cpQueued);
+
 	// Tell all clients attached to this chunk that they want this chunk:
 	for (cClientHandleList::iterator itr = m_LoadedByClient.begin(); itr != m_LoadedByClient.end(); ++itr)
 	{
@@ -191,7 +205,11 @@ void cChunk::MarkRegenerating(void)
 
 bool cChunk::CanUnload(void)
 {
-	return m_LoadedByClient.empty() && !m_IsDirty && (m_StayCount == 0);
+	return
+		m_LoadedByClient.empty() &&  // The chunk is not used by any client
+		!m_IsDirty &&                // The chunk has been saved properly or hasn't been touched since the load / gen
+		(m_StayCount == 0) &&        // The chunk is not in a ChunkStay
+		(m_Presence != cpQueued) ;   // The chunk is not queued for loading / generating (otherwise multi-load / multi-gen could occur)
 }
 
 
@@ -223,7 +241,7 @@ void cChunk::MarkSaved(void)
 void cChunk::MarkLoaded(void)
 {
 	m_IsDirty = false;
-	SetValid();
+	SetPresence(cpPresent);
 }
 
 
@@ -232,12 +250,17 @@ void cChunk::MarkLoaded(void)
 
 void cChunk::MarkLoadFailed(void)
 {
-	if (m_IsValid)
+	ASSERT(m_Presence == cpQueued);
+
+	// If the chunk is marked as needed, generate it:
+	if (m_ShouldGenerateIfLoadFailed)
 	{
-		return;
+		m_World->GetGenerator().QueueGenerateChunk(m_PosX, m_PosZ, false);
+	}
+	else
+	{
+		m_Presence = cpInvalid;
 	}
-	
-	m_HasLoadFailed = true;
 }
 
 
@@ -246,6 +269,8 @@ void cChunk::MarkLoadFailed(void)
 
 void cChunk::GetAllData(cChunkDataCallback & a_Callback)
 {
+	ASSERT(m_Presence == cpPresent);
+
 	a_Callback.HeightMap(&m_HeightMap);
 	a_Callback.BiomeData(&m_BiomeMap);
 
@@ -272,6 +297,7 @@ void cChunk::SetAllData(cSetChunkData & a_SetChunkData)
 {
 	ASSERT(a_SetChunkData.IsHeightMapValid());
 	ASSERT(a_SetChunkData.AreBiomesValid());
+	ASSERT(IsQueued());
 	
 	memcpy(m_BiomeMap, a_SetChunkData.GetBiomes(), sizeof(m_BiomeMap));
 	memcpy(m_HeightMap, a_SetChunkData.GetHeightMap(), sizeof(m_HeightMap));
@@ -317,7 +343,7 @@ void cChunk::SetAllData(cSetChunkData & a_SetChunkData)
 	CreateBlockEntities();
 	
 	// Set the chunk data as valid. This may be needed for some simulators that perform actions upon block adding (Vaporize)
-	SetValid();
+	SetPresence(cpPresent);
 	
 	// Wake up all simulators for their respective blocks:
 	WakeUpSimulators();