Struct GroupAccessScope 

pub struct GroupAccessScope { /* private fields */ }

Subscriber-side group access (Spec §2.2.2.5.2.8/9).

When Presentation.access_scope = GROUP and coherent_access is active, the subscriber MUST guarantee the atomic view across all DataReaders in the subscriber between begin_access and end_access.

Group-access scope with snapshot atomicity: each begin_access increments the snapshot_generation counter; all DataReaders in the subscriber that are read between begin and end see the SAME generation and therefore, per spec, an atomic cut across all topics.

Implementations

impl GroupAccessScope

pub fn new() -> Arc<Self>

New empty scope.

pub fn is_active(&self) -> bool

True if at least one begin_access is currently open.

pub fn current_snapshot(&self) -> u64

Current snapshot generation (see struct docs). 0 means “no snapshot ever opened”.

pub fn begin(&self)

Subscriber::begin_access (Spec §2.2.2.5.2.8). Idempotently nestable — each call raises the counter, each end_access lowers it. On the 0→1 transition the snapshot generation is also incremented (atomic cut begin).

pub fn end(&self) -> Result<()>

Subscriber::end_access (Spec §2.2.2.5.2.9).

Errors

PreconditionNotMet if no begin_access is open (counter would underflow).

Trait Implementations

impl Debug for GroupAccessScope

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

Formats the value using the given formatter.

impl Default for GroupAccessScope

fn default() -> GroupAccessScope

Returns the “default value” for a type.