Files
komp_ac/canvas/src/computed/state.rs
2025-08-18 21:10:06 +02:00

88 lines
2.9 KiB
Rust

// src/computed/state.rs
//! Computed field state: caching and dependency graph.
//!
//! This module holds the internal state necessary to track which fields are
//! computed, their dependencies, and cached computed values. It is used by the
//! editor to avoid unnecessary recomputation and to present computed fields as
//! read-only.
use std::collections::{HashMap, HashSet};
/// Internal state for computed field management
#[derive(Debug, Clone)]
pub struct ComputedState {
/// Cached computed values (field_index -> computed_value)
computed_values: HashMap<usize, String>,
/// Field dependency graph (field_index -> depends_on_fields)
dependencies: HashMap<usize, Vec<usize>>,
/// Track which fields are computed (display-only)
computed_fields: HashSet<usize>,
}
impl ComputedState {
/// Create a new, empty computed state
pub fn new() -> Self {
Self {
computed_values: HashMap::new(),
dependencies: HashMap::new(),
computed_fields: HashSet::new(),
}
}
/// Register a field as computed with its dependencies
///
/// - `field_index`: the field that is computed (display-only)
/// - `dependencies`: indices of fields this computed field depends on
pub fn register_computed_field(&mut self, field_index: usize, mut dependencies: Vec<usize>) {
// Deduplicate dependencies to keep graph lean
dependencies.sort_unstable();
dependencies.dedup();
self.computed_fields.insert(field_index);
self.dependencies.insert(field_index, dependencies);
}
/// Check if a field is computed (read-only, skip editing/navigation)
pub fn is_computed_field(&self, field_index: usize) -> bool {
self.computed_fields.contains(&field_index)
}
/// Get cached computed value for a field, if available
pub fn get_computed_value(&self, field_index: usize) -> Option<&String> {
self.computed_values.get(&field_index)
}
/// Update cached computed value for a field
pub fn set_computed_value(&mut self, field_index: usize, value: String) {
self.computed_values.insert(field_index, value);
}
/// Get fields that should be recomputed when `changed_field` changed
///
/// This scans the dependency graph and returns all computed fields
/// that list `changed_field` as a dependency.
pub fn fields_to_recompute(&self, changed_field: usize) -> Vec<usize> {
self.dependencies
.iter()
.filter_map(|(field, deps)| {
if deps.contains(&changed_field) {
Some(*field)
} else {
None
}
})
.collect()
}
/// Iterator over all computed field indices
pub fn computed_fields(&self) -> impl Iterator<Item = usize> + '_ {
self.computed_fields.iter().copied()
}
}
impl Default for ComputedState {
fn default() -> Self {
Self::new()
}
}