Struct StateSpec 

pub struct StateSpec { /* private fields */ }

A validated, shareable SystemState layout.

StateSpec owns an Arc to immutable metadata, making Clone a cheap reference-count increment. Every state derived from a specification shares the exact field order and name lookup table.

Implementations

impl StateSpec

pub fn load(path: impl AsRef<Path>) -> Result<Self, StateError>

Loads and validates a state specification from a JSON template.

The file is read as bytes and parsed directly, avoiding an intermediate UTF-8 String allocation. The returned specification retains the input path for diagnostics and provenance but does not canonicalize it or keep the file open.

Errors

Returns:

• StateError::TemplateRead when the file cannot be read;
• StateError::TemplateParse when JSON syntax or structure is invalid;
• StateError::EmptyFieldName for an empty normalized field name;
• StateError::DuplicateField for repeated normalized names;
• StateError::EmptyTypeTag for an empty normalized type tag.

pub fn empty(&self, time: TimePoint) -> SystemState

Creates an empty SystemState that shares this specification.

Every declared field exists in the returned state’s layout, while every payload slot starts empty. Cloning the specification is constant-time and does not duplicate layout data.

pub fn to_json(&self) -> Result<String, Error>

Converts this specification into a pretty-printed JSON template.

The generated document has the same strict fields structure accepted by StateSpec::load. Runtime-only field indices and the source path are omitted: field indices are reconstructed from array order, and the destination path becomes the source when the JSON is loaded again.

Serialization borrows the immutable field slice and does not clone field names or type tags.

Errors

Returns the underlying serde_json::Error if JSON serialization fails.

pub fn source(&self) -> &Path

Returns the path from which this specification was loaded.

The path is retained exactly as supplied to StateSpec::load. It may be relative and is not guaranteed to remain accessible after loading.

pub fn fields(&self) -> &[FieldSpec]

Returns field definitions in deterministic template order.

pub fn len(&self) -> usize

Returns the number of declared fields.

pub fn is_empty(&self) -> bool

Reports whether the template declares no fields.

Empty templates are structurally valid. They can represent a time-bearing event stream whose payload schema will be extended in a later template revision.

pub fn get(&self, name: &str) -> Option<&FieldSpec>

Looks up a field definition by its normalized name.

pub fn contains(&self, name: &str) -> bool

Reports whether the template declares name.

Trait Implementations

impl Clone for StateSpec

fn clone(&self) -> StateSpec

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StateSpec

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

Formats the value using the given formatter.