fill client holes (lockstep)

include/server/state/GameStateHandler.h

@@ -19,6 +19,7 @@ class GameStateHandler : public protocol::PacketHandler {
 
 	virtual void Handle(const protocol::packets::SpawnTroopPacket& a_Packet) override;
 	virtual void Handle(const protocol::packets::PlaceTowerPacket& a_Packet) override;
+	virtual void Handle(const protocol::packets::LockStepRequestPacket& a_Packet) override;
 };
 
 }  // namespace server

include/td/protocol/packet/PacketData.h

@@ -110,6 +110,14 @@ struct PlaceTower {
 	TowerCoords m_Position;
 };
 
+struct LockStepRequest {
+	std::vector<StepTime> m_Missing;
+};
+
+struct LockStepResponse {
+	std::map<StepTime, LockStep> m_Steps;
+};
+
 }  // namespace pdata
 }  // namespace protocol
 }  // namespace td

include/td/protocol/packet/Packets.h

@@ -22,6 +22,8 @@ enum class PacketID : std::uint8_t {
 	BeginGame,
 	Disconnect,
 	KeepAlive,
+	LockStepRequest,
+	LockStepResponse,
 	LockSteps,
 	LoggingSuccess,
 	PlaceTower,
@@ -49,6 +51,8 @@ using BeginGamePacket = PacketMessage<pdata::BeginGame, PacketID::BeginGame>;
 using ChatMessagePacket = PacketMessage<pdata::ChatMessage, PacketID::ChatMessage>;
 using DisconnectPacket = PacketMessage<pdata::Disconnect, PacketID::Disconnect>;
 using KeepAlivePacket = PacketMessage<pdata::KeepAlive, PacketID::KeepAlive>;
+using LockStepRequestPacket = PacketMessage<pdata::LockStepRequest, PacketID::LockStepRequest>;
+using LockStepResponsePacket = PacketMessage<pdata::LockStepResponse, PacketID::LockStepResponse>;
 using LockStepsPacket = PacketMessage<pdata::LockSteps, PacketID::LockSteps>;
 using LoggingSuccessPacket = PacketMessage<pdata::LoggingSuccess, PacketID::LoggingSuccess>;
 using PlaceTowerPacket = PacketMessage<pdata::PlaceTower, PacketID::PlaceTower>;
@@ -63,7 +67,7 @@ using WorldDataPacket = PacketMessage<pdata::WorldData, PacketID::WorldData>;
 }  // namespace packets
 
 using AllPackets = std::tuple<packets::BeginGamePacket, packets::ChatMessagePacket, packets::DisconnectPacket,
-	packets::KeepAlivePacket, packets::LockStepsPacket, packets::LoggingSuccessPacket, packets::PlaceTowerPacket,
+	packets::KeepAlivePacket, packets::LockStepRequestPacket, packets::LockStepResponsePacket, packets::LockStepsPacket, packets::LoggingSuccessPacket, packets::PlaceTowerPacket,
 	packets::PlayerJoinPacket, packets::PlayerLeavePacket, packets::PlayerLoginPacket, packets::PredictCommandPacket,
 	packets::SpawnTroopPacket, packets::WorldHeaderPacket, packets::WorldDataPacket>;
 

include/td/simulation/ClientSimulation.h

@@ -2,6 +2,7 @@
 
 #include <td/game/World.h>
 #include <optional>
+#include <td/misc/Signal.h>
 
 namespace td {
 namespace sim {
@@ -17,16 +18,18 @@ class ClientSimulation : public protocol::PacketHandler {
 	GameBuffer m_History;
 	std::uint64_t m_CurrentTime;
 	std::uint64_t m_LastTime;
-	std::size_t m_CurrentStep;
+	StepTime m_CurrentStep;
 
 	std::shared_ptr<WorldSnapshot> m_LastSnapshot;
-	std::uint64_t m_LastValidStep;
+	StepTime m_LastValidStep;
 
 	static const protocol::LockStep EMPTY_LOCKSTEP;
 
 	using protocol::PacketHandler::Handle;
 
   public:
+	utils::Signal<const std::vector<StepTime>&> OnMissingLockSteps;
+
 	/**
 	 * \brief Replay constructor
 	 * \param a_StepTime in ms
@@ -45,15 +48,18 @@ class ClientSimulation : public protocol::PacketHandler {
 	float Update();
 
 	virtual void Handle(const protocol::packets::LockStepsPacket& a_LockSteps) override;
-	virtual void Handle(const protocol::packets::PredictCommandPacket& a_Predict) override;
+	virtual void Handle(const protocol::packets::LockStepResponsePacket& a_LockSteps) override;
 
   private:
-	void Step();
+	/**
+	 * \returns false if the empty lockstep was used
+	 */
+	bool Step();
 
 	/**
 	 * \brief Ticks a_Count times
 	 */
-	void FastForward(std::size_t a_Count);
+	std::size_t FastForward(std::size_t a_Count);
 
 	/**
 	 * \brief Tries to recompute simulation if needed (for example in late command receival)

include/td/simulation/ServerSimulation.h

@@ -31,6 +31,8 @@ class ServerSimulation : public protocol::CommandHandler {
 
 	virtual void Handle(const protocol::commands::SpawnTroopCommand& a_SpawnTroop) override;
 	virtual void Handle(const protocol::commands::PlaceTowerCommand& a_PlaceTower) override;
+
+	protocol::packets::LockStepResponsePacket GetResponse(const protocol::packets::LockStepRequestPacket& a_Missing) const;
 };
 
 }  // namespace sim