Clean up ClientInterface locking

3 files changed, 128 insertions, 141 deletions

diff --git a/src/clientiface.h b/src/clientiface.h
index b1591ddb0..1be9c972a 100644
--- a/src/clientiface.h
+++ b/src/clientiface.h
@@ -27,6 +27,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "network/networkprotocol.h"
 #include "network/address.h"
 #include "porting.h"
+#include "threading/mutex_auto_lock.h"
 
 #include <list>
 #include <vector>
@@ -503,9 +504,13 @@ public:
 
 	static std::string state2Name(ClientState state);
 protected:
-	//TODO find way to avoid this functions
-	void lock() { m_clients_mutex.lock(); }
-	void unlock() { m_clients_mutex.unlock(); }
+	class AutoLock {
+	public:
+		AutoLock(ClientInterface &iface): m_lock(iface.m_clients_mutex) {}
+
+	private:
+		RecursiveMutexAutoLock m_lock;
+	};
 
 	RemoteClientMap& getClientList() { return m_clients; }
 
diff --git a/src/network/serverpackethandler.cpp b/src/network/serverpackethandler.cpp
index 12dc24460..a983424ba 100644
--- a/src/network/serverpackethandler.cpp
+++ b/src/network/serverpackethandler.cpp
@@ -452,7 +452,7 @@ void Server::handleCommand_GotBlocks(NetworkPacket* pkt)
 				("GOTBLOCKS length is too short");
 	}
 
-	m_clients.lock();
+	ClientInterface::AutoLock lock(m_clients);
 	RemoteClient *client = m_clients.lockedGetClientNoEx(pkt->getPeerId());
 
 	for (u16 i = 0; i < count; i++) {
@@ -460,7 +460,6 @@ void Server::handleCommand_GotBlocks(NetworkPacket* pkt)
 		*pkt >> p;
 		client->GotBlock(p);
 	}
-	m_clients.unlock();
 }
 
 void Server::process_PlayerPos(RemotePlayer *player, PlayerSAO *playersao,
diff --git a/src/server.cpp b/src/server.cpp
index 23a7dc5a0..df7083b68 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -723,28 +723,29 @@ void Server::AsyncRunStep(bool initial_step)
 		//infostream<<"Server: Checking added and deleted active objects"<<std::endl;
 		MutexAutoLock envlock(m_env_mutex);
 
-		m_clients.lock();
-		const RemoteClientMap &clients = m_clients.getClientList();
-		ScopeProfiler sp(g_profiler, "Server: update objects within range");
+		{
+			ClientInterface::AutoLock clientlock(m_clients);
+			const RemoteClientMap &clients = m_clients.getClientList();
+			ScopeProfiler sp(g_profiler, "Server: update objects within range");
 
-		m_player_gauge->set(clients.size());
-		for (const auto &client_it : clients) {
-			RemoteClient *client = client_it.second;
+			m_player_gauge->set(clients.size());
+			for (const auto &client_it : clients) {
+				RemoteClient *client = client_it.second;
 
-			if (client->getState() < CS_DefinitionsSent)
-				continue;
+				if (client->getState() < CS_DefinitionsSent)
+					continue;
 
-			// This can happen if the client times out somehow
-			if (!m_env->getPlayer(client->peer_id))
-				continue;
+				// This can happen if the client times out somehow
+				if (!m_env->getPlayer(client->peer_id))
+					continue;
 
-			PlayerSAO *playersao = getPlayerSAO(client->peer_id);
-			if (!playersao)
-				continue;
+				PlayerSAO *playersao = getPlayerSAO(client->peer_id);
+				if (!playersao)
+					continue;
 
-			SendActiveObjectRemoveAdd(client, playersao);
+				SendActiveObjectRemoveAdd(client, playersao);
+			}
 		}
-		m_clients.unlock();
 
 		// Write changes to the mod storage
 		m_mod_storage_save_timer -= dtime;
@@ -787,63 +788,64 @@ void Server::AsyncRunStep(bool initial_step)
 
 		m_aom_buffer_counter->increment(aom_count);
 
-		m_clients.lock();
-		const RemoteClientMap &clients = m_clients.getClientList();
-		// Route data to every client
-		std::string reliable_data, unreliable_data;
-		for (const auto &client_it : clients) {
-			reliable_data.clear();
-			unreliable_data.clear();
-			RemoteClient *client = client_it.second;
-			PlayerSAO *player = getPlayerSAO(client->peer_id);
-			// Go through all objects in message buffer
-			for (const auto &buffered_message : buffered_messages) {
-				// If object does not exist or is not known by client, skip it
-				u16 id = buffered_message.first;
-				ServerActiveObject *sao = m_env->getActiveObject(id);
-				if (!sao || client->m_known_objects.find(id) == client->m_known_objects.end())
-					continue;
+		{
+			ClientInterface::AutoLock clientlock(m_clients);
+			const RemoteClientMap &clients = m_clients.getClientList();
+			// Route data to every client
+			std::string reliable_data, unreliable_data;
+			for (const auto &client_it : clients) {
+				reliable_data.clear();
+				unreliable_data.clear();
+				RemoteClient *client = client_it.second;
+				PlayerSAO *player = getPlayerSAO(client->peer_id);
+				// Go through all objects in message buffer
+				for (const auto &buffered_message : buffered_messages) {
+					// If object does not exist or is not known by client, skip it
+					u16 id = buffered_message.first;
+					ServerActiveObject *sao = m_env->getActiveObject(id);
+					if (!sao || client->m_known_objects.find(id) == client->m_known_objects.end())
+						continue;
 
-				// Get message list of object
-				std::vector<ActiveObjectMessage>* list = buffered_message.second;
-				// Go through every message
-				for (const ActiveObjectMessage &aom : *list) {
-					// Send position updates to players who do not see the attachment
-					if (aom.datastring[0] == AO_CMD_UPDATE_POSITION) {
-						if (sao->getId() == player->getId())
-							continue;
-
-						// Do not send position updates for attached players
-						// as long the parent is known to the client
-						ServerActiveObject *parent = sao->getParent();
-						if (parent && client->m_known_objects.find(parent->getId()) !=
-								client->m_known_objects.end())
-							continue;
+					// Get message list of object
+					std::vector<ActiveObjectMessage>* list = buffered_message.second;
+					// Go through every message
+					for (const ActiveObjectMessage &aom : *list) {
+						// Send position updates to players who do not see the attachment
+						if (aom.datastring[0] == AO_CMD_UPDATE_POSITION) {
+							if (sao->getId() == player->getId())
+								continue;
+
+							// Do not send position updates for attached players
+							// as long the parent is known to the client
+							ServerActiveObject *parent = sao->getParent();
+							if (parent && client->m_known_objects.find(parent->getId()) !=
+									client->m_known_objects.end())
+								continue;
+						}
+
+						// Add full new data to appropriate buffer
+						std::string &buffer = aom.reliable ? reliable_data : unreliable_data;
+						char idbuf[2];
+						writeU16((u8*) idbuf, aom.id);
+						// u16 id
+						// std::string data
+						buffer.append(idbuf, sizeof(idbuf));
+						buffer.append(serializeString16(aom.datastring));
 					}
-
-					// Add full new data to appropriate buffer
-					std::string &buffer = aom.reliable ? reliable_data : unreliable_data;
-					char idbuf[2];
-					writeU16((u8*) idbuf, aom.id);
-					// u16 id
-					// std::string data
-					buffer.append(idbuf, sizeof(idbuf));
-					buffer.append(serializeString16(aom.datastring));
 				}
-			}
-			/*
-				reliable_data and unreliable_data are now ready.
-				Send them.
-			*/
-			if (!reliable_data.empty()) {
-				SendActiveObjectMessages(client->peer_id, reliable_data);
-			}
+				/*
+					reliable_data and unreliable_data are now ready.
+					Send them.
+				*/
+				if (!reliable_data.empty()) {
+					SendActiveObjectMessages(client->peer_id, reliable_data);
+				}
 
-			if (!unreliable_data.empty()) {
-				SendActiveObjectMessages(client->peer_id, unreliable_data, false);
+				if (!unreliable_data.empty()) {
+					SendActiveObjectMessages(client->peer_id, unreliable_data, false);
+				}
 			}
 		}
-		m_clients.unlock();
 
 		// Clear buffered_messages
 		for (auto &buffered_message : buffered_messages) {
@@ -1050,18 +1052,14 @@ PlayerSAO* Server::StageTwoClientInit(session_t peer_id)
 {
 	std::string playername;
 	PlayerSAO *playersao = NULL;
-	m_clients.lock();
-	try {
+	{
+		ClientInterface::AutoLock clientlock(m_clients);
 		RemoteClient* client = m_clients.lockedGetClientNoEx(peer_id, CS_InitDone);
 		if (client) {
 			playername = client->getName();
 			playersao = emergePlayer(playername.c_str(), peer_id, client->net_proto_version);
 		}
-	} catch (std::exception &e) {
-		m_clients.unlock();
-		throw;
 	}
-	m_clients.unlock();
 
 	RemotePlayer *player = m_env->getPlayer(playername.c_str());
 
@@ -1233,13 +1231,12 @@ void Server::onMapEditEvent(const MapEditEvent &event)
 void Server::SetBlocksNotSent(std::map<v3s16, MapBlock *>& block)
 {
 	std::vector<session_t> clients = m_clients.getClientIDs();
-	m_clients.lock();
+	ClientInterface::AutoLock clientlock(m_clients);
 	// Set the modified blocks unsent for all the clients
 	for (const session_t client_id : clients) {
 			if (RemoteClient *client = m_clients.lockedGetClientNoEx(client_id))
 				client->SetBlocksNotSent(block);
 	}
-	m_clients.unlock();
 }
 
 void Server::peerAdded(con::Peer *peer)
@@ -1267,13 +1264,11 @@ bool Server::getClientConInfo(session_t peer_id, con::rtt_stat_type type, float*
 
 bool Server::getClientInfo(session_t peer_id, ClientInfo &ret)
 {
-	m_clients.lock();
+	ClientInterface::AutoLock clientlock(m_clients);
 	RemoteClient* client = m_clients.lockedGetClientNoEx(peer_id, CS_Invalid);
 
-	if (!client) {
-		m_clients.unlock();
+	if (!client)
 		return false;
-	}
 
 	ret.state = client->getState();
 	ret.addr = client->getAddress();
@@ -1288,8 +1283,6 @@ bool Server::getClientInfo(session_t peer_id, ClientInfo &ret)
 
 	ret.lang_code = client->getLangCode();
 
-	m_clients.unlock();
-
 	return true;
 }
 
@@ -2218,7 +2211,7 @@ void Server::sendRemoveNode(v3s16 p, std::unordered_set<u16> *far_players,
 	pkt << p;
 
 	std::vector<session_t> clients = m_clients.getClientIDs();
-	m_clients.lock();
+	ClientInterface::AutoLock clientlock(m_clients);
 
 	for (session_t client_id : clients) {
 		RemoteClient *client = m_clients.lockedGetClientNoEx(client_id);
@@ -2241,8 +2234,6 @@ void Server::sendRemoveNode(v3s16 p, std::unordered_set<u16> *far_players,
 		// Send as reliable
 		m_clients.send(client_id, 0, &pkt, true);
 	}
-
-	m_clients.unlock();
 }
 
 void Server::sendAddNode(v3s16 p, MapNode n, std::unordered_set<u16> *far_players,
@@ -2257,7 +2248,7 @@ void Server::sendAddNode(v3s16 p, MapNode n, std::unordered_set<u16> *far_player
 			<< (u8) (remove_metadata ? 0 : 1);
 
 	std::vector<session_t> clients = m_clients.getClientIDs();
-	m_clients.lock();
+	ClientInterface::AutoLock clientlock(m_clients);
 
 	for (session_t client_id : clients) {
 		RemoteClient *client = m_clients.lockedGetClientNoEx(client_id);
@@ -2280,8 +2271,6 @@ void Server::sendAddNode(v3s16 p, MapNode n, std::unordered_set<u16> *far_player
 		// Send as reliable
 		m_clients.send(client_id, 0, &pkt, true);
 	}
-
-	m_clients.unlock();
 }
 
 void Server::sendMetadataChanged(const std::list<v3s16> &meta_updates, float far_d_nodes)
@@ -2290,7 +2279,7 @@ void Server::sendMetadataChanged(const std::list<v3s16> &meta_updates, float far
 	NodeMetadataList meta_updates_list(false);
 	std::vector<session_t> clients = m_clients.getClientIDs();
 
-	m_clients.lock();
+	ClientInterface::AutoLock clientlock(m_clients);
 
 	for (session_t i : clients) {
 		RemoteClient *client = m_clients.lockedGetClientNoEx(i);
@@ -2331,8 +2320,6 @@ void Server::sendMetadataChanged(const std::list<v3s16> &meta_updates, float far
 
 		meta_updates_list.clear();
 	}
-
-	m_clients.unlock();
 }
 
 void Server::SendBlockNoLock(session_t peer_id, MapBlock *block, u8 ver,
@@ -2368,7 +2355,7 @@ void Server::SendBlocks(float dtime)
 
 		std::vector<session_t> clients = m_clients.getClientIDs();
 
-		m_clients.lock();
+		ClientInterface::AutoLock clientlock(m_clients);
 		for (const session_t client_id : clients) {
 			RemoteClient *client = m_clients.lockedGetClientNoEx(client_id, CS_Active);
 
@@ -2378,7 +2365,6 @@ void Server::SendBlocks(float dtime)
 			total_sending += client->getSendingCount();
 			client->GetNextBlocks(m_env,m_emerge, dtime, queue);
 		}
-		m_clients.unlock();
 	}
 
 	// Sort.
@@ -2386,7 +2372,7 @@ void Server::SendBlocks(float dtime)
 	// Lowest is most important.
 	std::sort(queue.begin(), queue.end());
 
-	m_clients.lock();
+	ClientInterface::AutoLock clientlock(m_clients);
 
 	// Maximal total count calculation
 	// The per-client block sends is halved with the maximal online users
@@ -2415,7 +2401,6 @@ void Server::SendBlocks(float dtime)
 		client->SentBlock(block_to_send.pos);
 		total_sending++;
 	}
-	m_clients.unlock();
 }
 
 bool Server::SendBlock(session_t peer_id, const v3s16 &blockpos)
@@ -2424,15 +2409,12 @@ bool Server::SendBlock(session_t peer_id, const v3s16 &blockpos)
 	if (!block)
 		return false;
 
-	m_clients.lock();
+	ClientInterface::AutoLock clientlock(m_clients);
 	RemoteClient *client = m_clients.lockedGetClientNoEx(peer_id, CS_Active);
-	if (!client || client->isBlockSent(blockpos)) {
-		m_clients.unlock();
+	if (!client || client->isBlockSent(blockpos))
 		return false;
-	}
 	SendBlockNoLock(peer_id, block, client->serialization_version,
 			client->net_proto_version);
-	m_clients.unlock();
 
 	return true;
 }
@@ -3534,48 +3516,49 @@ bool Server::dynamicAddMedia(std::string filepath,
 	legacy_pkt.putLongString(filedata);
 
 	std::unordered_set<session_t> delivered, waiting;
-	m_clients.lock();
-	for (auto &pair : m_clients.getClientList()) {
-		if (pair.second->getState() == CS_DefinitionsSent && !ephemeral) {
-			/*
-				If a client is in the DefinitionsSent state it is too late to
-				transfer the file via sendMediaAnnouncement() but at the same
-				time the client cannot accept a media push yet.
-				Short of artificially delaying the joining process there is no
-				way for the server to resolve this so we (currently) opt not to.
-			*/
-			warningstream << "The media \"" << filename << "\" (dynamic) could "
-				"not be delivered to " << pair.second->getName()
-				<< " due to a race condition." << std::endl;
-			continue;
-		}
-		if (pair.second->getState() < CS_Active)
-			continue;
+	{
+		ClientInterface::AutoLock clientlock(m_clients);
+		for (auto &pair : m_clients.getClientList()) {
+			if (pair.second->getState() == CS_DefinitionsSent && !ephemeral) {
+				/*
+					If a client is in the DefinitionsSent state it is too late to
+					transfer the file via sendMediaAnnouncement() but at the same
+					time the client cannot accept a media push yet.
+					Short of artificially delaying the joining process there is no
+					way for the server to resolve this so we (currently) opt not to.
+				*/
+				warningstream << "The media \"" << filename << "\" (dynamic) could "
+					"not be delivered to " << pair.second->getName()
+					<< " due to a race condition." << std::endl;
+				continue;
+			}
+			if (pair.second->getState() < CS_Active)
+				continue;
 
-		const auto proto_ver = pair.second->net_proto_version;
-		if (proto_ver < 39)
-			continue;
+			const auto proto_ver = pair.second->net_proto_version;
+			if (proto_ver < 39)
+				continue;
 
-		const session_t peer_id = pair.second->peer_id;
-		if (!to_player.empty() && getPlayerName(peer_id) != to_player)
-			continue;
+			const session_t peer_id = pair.second->peer_id;
+			if (!to_player.empty() && getPlayerName(peer_id) != to_player)
+				continue;
 
-		if (proto_ver < 40) {
-			delivered.emplace(peer_id);
-			/*
-				The network layer only guarantees ordered delivery inside a channel.
-				Since the very next packet could be one that uses the media, we have
-				to push the media over ALL channels to ensure it is processed before
-				it is used. In practice this means channels 1 and 0.
-			*/
-			m_clients.send(peer_id, 1, &legacy_pkt, true);
-			m_clients.send(peer_id, 0, &legacy_pkt, true);
-		} else {
-			waiting.emplace(peer_id);
-			Send(peer_id, &pkt);
+			if (proto_ver < 40) {
+				delivered.emplace(peer_id);
+				/*
+					The network layer only guarantees ordered delivery inside a channel.
+					Since the very next packet could be one that uses the media, we have
+					to push the media over ALL channels to ensure it is processed before
+					it is used. In practice this means channels 1 and 0.
+				*/
+				m_clients.send(peer_id, 1, &legacy_pkt, true);
+				m_clients.send(peer_id, 0, &legacy_pkt, true);
+			} else {
+				waiting.emplace(peer_id);
+				Send(peer_id, &pkt);
+			}
 		}
 	}
-	m_clients.unlock();
 
 	// Run callback for players that already had the file delivered (legacy-only)
 	for (session_t peer_id : delivered) {