Enum SessionOp 

pub enum SessionOp<'a> {
    StoreOutbox {
        packet_id: PacketId,
        qos: QoS,
        topic: &'a Topic,
        payload: &'a [u8],
        retain: bool,
        properties: &'a PublishProperties,
    },
    RemoveOutbox {
        packet_id: PacketId,
    },
    MarkSent {
        packet_id: PacketId,
    },
    StorePubrelPending {
        packet_id: PacketId,
    },
    RemovePubrelPending {
        packet_id: PacketId,
    },
    StoreIncomingQos2 {
        packet_id: PacketId,
    },
    RemoveIncomingQos2 {
        packet_id: PacketId,
    },
    Clear,
    StoreFilter {
        filter: &'a TopicFilter,
        state: FilterState,
    },
    RemoveFilter {
        filter: &'a TopicFilter,
    },
}

A single mutation to session state, in a form that can be serialized and replayed.

Passed to super::SessionState::apply to mutate the session. A persistence backend can also match on it to map each operation onto its own representation (e.g. SQL statements), the same way Property is matched.

The store_* / remove_* constructors build the variants and are handy at call sites; the wire op code is an encoding detail derived from the variant.

Variants

StoreOutbox

Store (or replace) an outgoing publish in the outbox.

Fields

packet_id: PacketId

Packet identifier of the publish.

qos: QoS

Delivery quality of service (QoS 1 or 2).

topic: &'a Topic

Publish topic.

payload: &'a [u8]

Publish payload.

retain: bool

Whether the publish carries the RETAIN flag.

properties: &'a PublishProperties

v5 publish properties.

RemoveOutbox

Remove an outgoing publish from the outbox.

Fields

packet_id: PacketId

Packet identifier of the publish to remove.

MarkSent

Mark a stored outgoing publish as having been written to the wire, so a post-restart retransmit carries DUP=1 as required by MQTT §3.3.1.1 [MQTT-3.3.1-1].

Fields

packet_id: PacketId

Packet identifier of the publish.

StorePubrelPending

Store a QoS 2 entry directly in the awaiting-PUBCOMP (pubrel-pending) state.

Fields

packet_id: PacketId

Packet identifier of the entry.

RemovePubrelPending

Remove a QoS 2 entry from the pubrel-pending set.

Fields

packet_id: PacketId

Packet identifier of the entry.

StoreIncomingQos2

Store an incoming QoS 2 publish in the awaiting-PUBREL state.

Fields

packet_id: PacketId

Packet identifier of the incoming publish.

RemoveIncomingQos2

Remove an incoming QoS 2 publish.

Fields

packet_id: PacketId

Packet identifier of the incoming publish.

Clear

Clear all in-flight state. Confirmed subscriptions are preserved.

StoreFilter

Store (or replace) a filter entry verbatim. Persists the per-filter subscription model: a confirmed subscription, an in-flight SUBSCRIBE, or an in-flight UNSUBSCRIBE. The state carries the subscription options and identifier where they apply.

Fields

filter: &'a TopicFilter

Topic filter.

state: FilterState

Lifecycle state, including options and subscription id where they apply.

RemoveFilter

Remove a filter entry.

Fields

filter: &'a TopicFilter

Topic filter to remove.

Implementations

impl<'a> SessionOp<'a>

pub const fn store_outbox(packet_id: PacketId, entry: &OutboxEntry<'a>) -> Self

Creates an operation to store an outgoing publish from an OutboxEntry, preserving its QoS.

pub const fn remove_outbox(packet_id: PacketId) -> Self

Creates an operation to remove an outgoing publish from the outbox.

Removal is keyed by packet id alone; the entry’s QoS is irrelevant.

pub const fn store_qos2_pubcomp(packet_id: PacketId) -> Self

Creates an operation to store a QoS 2 entry directly in the awaiting-PUBCOMP state.

pub const fn remove_pubrel(packet_id: PacketId) -> Self

Creates an operation to remove a QoS 2 entry from the awaiting-PUBCOMP phase (pubrel-pending set).

pub const fn store_incoming_qos2(packet_id: PacketId) -> Self

Creates an operation to store an incoming QoS 2 publish in the “awaiting PUBREC” phase.

pub const fn remove_incoming_qos2(packet_id: PacketId) -> Self

Creates an operation to remove an incoming QoS 2 publish.

pub const fn clear() -> Self

Creates an operation to clear all in-flight session state.

pub const fn store_filter(filter: &'a TopicFilter, state: FilterState) -> Self

Creates an operation to store (or replace) a filter entry verbatim.

pub const fn remove_filter(filter: &'a TopicFilter) -> Self

Creates an operation to remove a filter entry.

pub const fn mark_sent(packet_id: PacketId) -> Self

Creates an operation that marks a pending QoS 1 or QoS 2 publish as having been written to the wire at least once.

Journaling this ensures that, after a process restart, retransmissions carry DUP=1 as required by MQTT §3.3.1.1 [MQTT-3.3.1-1].

const fn op_code(&self) -> u8

Returns the op code byte for this operation.

pub const fn encoded_len(&self) -> usize

Returns the total length of the encoded operation.

pub fn encode_to_vec(&self, buf: &mut Vec<u8>)

Available on crate feature alloc only.

Encodes this operation into the provided buffer.

pub const fn encode(&self, w: &mut Writer<'_>) -> Result<(), EncodeError>

Encodes this operation into the provided writer.

Errors

Returns EncodeError::InsufficientSpace if the writer does not have enough remaining capacity.

pub fn decode(r: &mut Reader<'a>) -> Result<Self, OpDecodeError>

Decodes an operation from the provided reader.

Errors

Returns OpDecodeError if the reader contains invalid data.

Trait Implementations

impl<'a> Clone for SessionOp<'a>

fn clone(&self) -> SessionOp<'a>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a> Debug for SessionOp<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'a> Copy for SessionOp<'a>