Struct History 

pub struct History { /* private fields */ }

The engine-owned mutable history.

Implementations

impl History

pub fn from_request_json(json: &str) -> Result<Self, String>

Load a whole history document (a saved part file parses as one). Rolls to the last feature. Ensures a features array exists.

pub fn features(&self) -> &[Value]

The features slice (empty if none).

pub fn len(&self) -> usize

pub fn is_empty(&self) -> bool

pub fn rollback(&self) -> usize

The rolled-to index, clamped to a valid feature (0 when empty).

pub fn set_rollback(&mut self, index: usize)

pub fn feature_type(&self, index: usize) -> Option<String>

pub fn feature_id(&self, index: usize) -> Option<String>

pub fn index_of(&self, id: &str) -> Option<usize>

pub fn feature_params(&self, index: usize) -> Option<Value>

The inputParams document of the feature at index (for the dialog).

pub fn set_feature_params(&mut self, index: usize, params: Value)

pub fn push_feature(&mut self, feature: Value)

pub fn remove_feature(&mut self, index: usize)

pub fn swap(&mut self, a: usize, b: usize)

pub fn next_feature_id(&mut self, base: &str) -> String

Mint the id for a NEW feature: {base}{N} where base is the feature’s shortName and N is this history’s persistent GLOBAL counter, bumped by one on every mint (P.CU → P.CU7, S → S8). GLOBAL across all feature types, MONOTONIC, and NEVER reused — a delete does not free a number and undo does not rewind the counter — and it persists across save/load, so two features can never receive the same id over the document’s whole lifetime.

pub fn prefix_request(&self) -> Value

The stopAtId-truncated request that stops AFTER the rolled-to feature — the roll-to-step request the pipeline runs. Empty history → empty request.

pub fn listing_json(&self) -> String

The tree listing for the UI: { step, features: [{index, type, id}] }.

pub fn request_json(&self) -> String

The whole request document (for persistence / debugging), with the persistent global feature counter folded back in under "featureCounter" so it round-trips through save/load (the twin of Self::from_request_json, which lifts it back out). Written only when non-zero, so a document that has never minted a feature persists byte-for-byte as before (mirrors the metadata field’s “un-annotated model persists unchanged” convention).

pub fn can_undo(&self) -> bool

Whether an undo step is available (for enabling the toolbar button).

pub fn can_redo(&self) -> bool

Whether a redo step is available.

pub fn undo(&mut self) -> bool

Undo the last model mutation: push the current state onto the redo stack and restore the previous document + rolled-to step. Returns whether it changed anything (false when the undo stack is empty).

pub fn redo(&mut self) -> bool

Redo the last undone model mutation (symmetric with Self::undo).

impl History

pub fn expressions(&self) -> String

The history document’s expressions source string (empty when absent or stored as null). The panel’s editor binds to this.

pub fn set_expressions(&mut self, expressions: &str)

Replace the expressions source string. Snapshotted for undo, coalescing a run of keystroke edits into ONE undo entry (like a slider drag) via the shared "expressions" coalesce key, so a distinct add/edit/roll starts a fresh entry. A no-op re-set (same text) still records under the same key.

pub fn configurator(&self) -> Value

The configurator object (typed named inputs), or {} when absent — read-only for the panel’s display (deeper configurator editing deferred).

impl History

pub fn feature_persistent_data(&self, index: usize) -> Option<Value>

The persistentData document of the feature at index (None if the feature or the field is absent) — the read twin of Self::feature_params.

pub fn set_feature_persistent_field( &mut self, index: usize, key: &str, value: Value, )

Set a single key inside the feature-at-index’s persistentData object, creating (or replacing a non-object) persistentData as needed. Snapshotted for undo (a structural edit — never coalesced), like an add/delete.

Trait Implementations

impl Clone for History

fn clone(&self) -> History

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for History

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

Formats the value using the given formatter.

impl Default for History

fn default() -> Self

Returns the “default value” for a type.