flewkey/cuberite-2a
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Clarify cClientHandle, cPlayer ownership semantics

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+ A cPlayer, once created, has a strong pointer to the cClientHandle. The player ticks the clienthandle. If he finds the handle destroyed, he destroys himself in turn. Nothing else can kill the player.
* The client handle has a pointer to the player. Once a player is created, the client handle never outlasts the player, nor does it manage the player's lifetime. The pointer is always safe to use after FinishAuthenticate, which is also the point where cProtocol is put into the Game state that allows player manipulation.
+ Entities are once again never lost by constructing a chunk when they try to move into one that doesn't exist.
* Fixed a forgotten Super invocation in cPlayer::OnRemoveFromWorld.
* Fix SaveToDisk usage in destructor by only saving things cPlayer owns, instead of accessing cWorld.
This commit is contained in:
Tiger Wang
2021-01-06 00:35:42 +00:00
parent 9328afe65c
commit 054a89dd9e
21 changed files with 505 additions and 1126 deletions
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75
src/ChunkSender.cpp
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@@ -104,13 +104,13 @@ void cChunkSender::QueueSendChunkTo(int a_ChunkX, int a_ChunkZ, Priority a_Prior
m_SendChunks.push(sChunkQueue{a_Priority, Chunk});
info.m_Priority = a_Priority;
}
info.m_Clients.insert(a_Client);
info.m_Clients.insert(a_Client->shared_from_this());
}
else
{
m_SendChunks.push(sChunkQueue{a_Priority, Chunk});
auto info = sSendChunk{Chunk, a_Priority};
info.m_Clients.insert(a_Client);
info.m_Clients.insert(a_Client->shared_from_this());
m_ChunkInfo.emplace(Chunk, info);
}
}
@@ -135,13 +135,19 @@ void cChunkSender::QueueSendChunkTo(int a_ChunkX, int a_ChunkZ, Priority a_Prior
m_SendChunks.push(sChunkQueue{a_Priority, Chunk});
info.m_Priority = a_Priority;
}
info.m_Clients.insert(a_Clients.begin(), a_Clients.end());
for (const auto & Client : a_Clients)
{
info.m_Clients.insert(Client->shared_from_this());
}
}
else
{
m_SendChunks.push(sChunkQueue{a_Priority, Chunk});
auto info = sSendChunk{Chunk, a_Priority};
info.m_Clients.insert(a_Clients.begin(), a_Clients.end());
for (const auto & Client : a_Clients)
{
info.m_Clients.insert(Client->shared_from_this());
}
m_ChunkInfo.emplace(Chunk, info);
}
}
@@ -152,24 +158,6 @@ void cChunkSender::QueueSendChunkTo(int a_ChunkX, int a_ChunkZ, Priority a_Prior
void cChunkSender::RemoveClient(cClientHandle * a_Client)
{
{
cCSLock Lock(m_CS);
for (auto && pair : m_ChunkInfo)
{
auto && clients = pair.second.m_Clients;
clients.erase(a_Client); // nop for sets that do not contain a_Client
}
}
m_evtQueue.Set();
m_evtRemoved.Wait(); // Wait for all remaining instances of a_Client to be processed (Execute() makes a copy of m_ChunkInfo)
}
void cChunkSender::Execute(void)
{
while (!m_ShouldTerminate)
@@ -189,16 +177,13 @@ void cChunkSender::Execute(void)
continue;
}
std::unordered_set<cClientHandle *> clients;
std::swap(itr->second.m_Clients, clients);
auto clients = std::move(itr->second.m_Clients);
m_ChunkInfo.erase(itr);
cCSUnlock Unlock(Lock);
SendChunk(Chunk.m_ChunkX, Chunk.m_ChunkZ, clients);
}
}
m_evtRemoved.SetAll(); // Notify all waiting threads that all clients are processed and thus safe to destroy
} // while (!m_ShouldTerminate)
}
@@ -206,21 +191,27 @@ void cChunkSender::Execute(void)
void cChunkSender::SendChunk(int a_ChunkX, int a_ChunkZ, std::unordered_set<cClientHandle *> a_Clients)
void cChunkSender::SendChunk(int a_ChunkX, int a_ChunkZ, const WeakClients & a_Clients)
{
// Contains strong pointers to clienthandles.
std::vector<std::shared_ptr<cClientHandle>> Clients;
// Ask the client if it still wants the chunk:
for (auto itr = a_Clients.begin(); itr != a_Clients.end();)
for (const auto & WeakClient : a_Clients)
{
if (!(*itr)->WantsSendChunk(a_ChunkX, a_ChunkZ))
auto Client = WeakClient.lock();
if ((Client != nullptr) && Client->WantsSendChunk(a_ChunkX, a_ChunkZ))
{
itr = a_Clients.erase(itr);
}
else
{
itr++;
Clients.push_back(std::move(Client));
}
}
// Bail early if every requester disconnected:
if (Clients.empty())
{
return;
}
// If the chunk has no clients, no need to packetize it:
if (!m_World.HasChunkAnyClients(a_ChunkX, a_ChunkZ))
{
@@ -247,9 +238,9 @@ void cChunkSender::SendChunk(int a_ChunkX, int a_ChunkZ, std::unordered_set<cCli
}
// Send:
m_Serializer.SendToClients(a_ChunkX, a_ChunkZ, m_Data, m_BiomeMap, a_Clients);
m_Serializer.SendToClients(a_ChunkX, a_ChunkZ, m_Data, m_BiomeMap, Clients);
for (const auto Client : a_Clients)
for (const auto & Client : Clients)
{
// Send block-entity packets:
for (const auto & Pos : m_BlockEntities)
@@ -270,7 +261,17 @@ void cChunkSender::SendChunk(int a_ChunkX, int a_ChunkZ, std::unordered_set<cCli
Client->GetUsername().c_str()
);
*/
a_Entity.SpawnOn(*Client);
/* This check looks highly suspect.
Its purpose is to check the client still has a valid player object associated,
since the player destroys itself when the client is destroyed.
It's done within the world lock to ensure correctness.
A better way involves fixing chunk sending (GH #3696) to obviate calling SpawnOn from this thread in the first place. */
if (!Client->IsDestroyed())
{
a_Entity.SpawnOn(*Client);
}
return true;
});
}