Struct Transaction 

pub struct Transaction { /* private fields */ }

A batch of edits, validated together and applied as a unit.

Opened against a model snapshot and carrying that snapshot’s revision, so a commit against a model that has since changed is refused rather than applied to state the caller never saw.

Implementations

impl Transaction

pub fn new(model: &Model) -> Self

Open a transaction against a model.

pub fn revision(&self) -> u64

The model revision this transaction was opened against.

pub fn edits(&self) -> &[Edit]

The staged edits, in the order they were added.

pub fn is_empty(&self) -> bool

Whether anything is staged.

pub fn len(&self) -> usize

Number of staged edits.

pub fn create(&mut self, entity: Entity) -> EntityId

Stage a new entity, returning the id reserved for it.

The id is allocated from the transaction, not the model, so several creates in one batch cannot collide and the caller can reference a newly created entity from another edit in the same transaction before anything is written.

pub fn stage(&mut self, edit: Edit) -> &mut Self

Stage an already-constructed edit.

Transaction::create allocates ids and is what an author should use. This exists for replaying a batch that was built elsewhere – deserialized, or produced by another process – where the edit list is data rather than a sequence of calls. Preflight checks it exactly the same way, so a replayed batch cannot bypass validation.

pub fn set_attribute( &mut self, id: EntityId, slot: usize, value: Value, ) -> &mut Self

Stage an attribute write.

pub fn retype( &mut self, id: EntityId, type_name: impl Into<Arc<str>>, ) -> &mut Self

Stage a type change.

pub fn remove(&mut self, id: EntityId) -> &mut Self

Stage a removal.

pub fn preflight(&self, model: &Model) -> Vec<Conflict>

Check every edit without touching the model.

Returns every conflict found rather than the first: an author fixing a batch wants the whole list, and stopping at the first turns one review into N round trips.

Conflicts are ordered by the edit that produced them, so the report reads in the order the caller wrote the batch.

pub fn commit(self, model: &mut Model) -> Result<Applied, Vec<Conflict>>

Validate and apply, or report every conflict and change nothing.

On Err the model is untouched: preflight runs to completion before the first write, so a rejected transaction cannot leave partial state.

Trait Implementations

impl Clone for Transaction

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Transaction

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

Formats the value using the given formatter.