itch::transport::SequenceTracker Class Reference

Tracks per-session sequence numbers across a transport layer and surfaces gaps. More...

#include <sequencing.hpp>

Public Types
using	GapCallback = std::function< void(std::string_view session, std::uint64_t expected, std::uint64_t received)>
	Invoked once per detected gap with the session, the sequence the tracker expected, and the (higher) sequence actually received.

Public Member Functions
auto	observe (std::string_view session, std::uint64_t first_sequence, std::uint64_t count) -> std::uint64_t
	Records that a packet beginning at first_sequence carried count sequenced messages for session.
auto	set_gap_callback (GapCallback callback) -> void
	Installs the gap-notification callback (empty clears it).
auto	set_retransmit_requester (RetransmitRequester *requester) noexcept -> void
	Installs a non-owning retransmission hook (nullptr clears it).
auto	expected_next (std::string_view session) const -> std::optional< std::uint64_t >
	The next sequence number expected for a session, if it has been seen.
auto	gap_count () const noexcept -> std::uint64_t
	Total number of missing messages detected across all sessions.
auto	messages_seen () const noexcept -> std::uint64_t
	Total number of distinct sequenced messages observed.
auto	reset () -> void
	Forgets all per-session state and resets the counters.

Detailed Description

Tracks per-session sequence numbers across a transport layer and surfaces gaps.

Both the MoldUDP64 and SoupBinTCP decoders feed their per-packet sequence information here. The tracker maintains, per session, the next sequence number it expects to see. When an observed packet starts ahead of that expectation it reports a gap (through the gap callback and the optional RetransmitRequester) and resynchronizes. Duplicate or already-seen sequences are ignored so a replayed recovery stream does not double-count.

Definition at line 71 of file sequencing.hpp.

Member Typedef Documentation

GapCallback

using itch::transport::SequenceTracker::GapCallback = std::function< void(std::string_view session, std::uint64_t expected, std::uint64_t received)>

Invoked once per detected gap with the session, the sequence the tracker expected, and the (higher) sequence actually received.

Definition at line 75 of file sequencing.hpp.

Member Function Documentation

observe()

auto itch::transport::SequenceTracker::observe ( std::string_view  session, std::uint64_t  first_sequence, std::uint64_t  count  ) -> std::uint64_t

inline

Records that a packet beginning at first_sequence carried count sequenced messages for session.

Parameters

session	The session identifier the packet belongs to.
first_sequence	The sequence number of the first message in the packet.
count	The number of sequenced messages carried by the packet.

Returns

The number of missing messages detected (0 when in order).

Definition at line 86 of file sequencing.hpp.

set_gap_callback()

auto itch::transport::SequenceTracker::set_gap_callback ( GapCallback  callback ) -> void

inline

Installs the gap-notification callback (empty clears it).

Parameters

callback

Invoked once per detected gap.

Definition at line 123 of file sequencing.hpp.

set_retransmit_requester()

auto itch::transport::SequenceTracker::set_retransmit_requester ( RetransmitRequester *  requester ) -> void

inlinenoexcept

Installs a non-owning retransmission hook (nullptr clears it).

Parameters

requester

Non-owning pointer to the requester to notify on gaps, or nullptr to clear it.

Definition at line 128 of file sequencing.hpp.

expected_next()

auto itch::transport::SequenceTracker::expected_next ( std::string_view  session ) const -> std::optional<std::uint64_t>

inline

The next sequence number expected for a session, if it has been seen.

Parameters

session

The session identifier to look up.

Returns

The next expected sequence number, or std::nullopt if the session has not been observed.

Definition at line 136 of file sequencing.hpp.

gap_count()

auto itch::transport::SequenceTracker::gap_count ( ) const -> std::uint64_t

inlinenoexcept

Total number of missing messages detected across all sessions.

Returns

The total gap count.

Definition at line 147 of file sequencing.hpp.

messages_seen()

auto itch::transport::SequenceTracker::messages_seen ( ) const -> std::uint64_t

inlinenoexcept

Total number of distinct sequenced messages observed.

Returns

The total count of distinct messages observed.

Definition at line 151 of file sequencing.hpp.

reset()

auto itch::transport::SequenceTracker::reset ( ) -> void

inline

Forgets all per-session state and resets the counters.

Definition at line 154 of file sequencing.hpp.

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The documentation for this class was generated from the following file:

• sequencing.hpp