Files
livevue-rs/src/context.rs
T
2026-03-08 20:10:15 +01:00

222 lines
7.5 KiB
Rust

use crate::signal::{Signal, SignalOpts, SignalStore};
use crate::query::{CacheKey, Query};
use crate::store::Store;
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::sync::Arc;
use uuid::Uuid;
// ---------------------------------------------------------------------------
// Component tree
// ---------------------------------------------------------------------------
/// Describes which dynamic components are mounted, parsed from the `tree`
/// signal.
///
/// Static children (always rendered by their parent) do NOT appear here —
/// only dynamic/conditional slots. `page` resolves the root component;
/// `children` is the seam for nested dynamic components.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ComponentTree {
/// The root page component name, e.g. `"TodoList"`.
pub page: String,
/// Dynamic child slots. Key is the slot name, value describes the child.
#[serde(default)]
pub children: HashMap<String, ComponentNode>,
}
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ComponentNode {
pub component: String,
#[serde(default)]
pub key: Option<String>,
}
impl Default for ComponentTree {
fn default() -> Self {
Self {
page: String::new(),
children: HashMap::new(),
}
}
}
// ---------------------------------------------------------------------------
// RenderContext
// ---------------------------------------------------------------------------
/// The component's window into the framework.
///
/// Passed as `&mut cx` to every component function. Provides access to
/// signals, DB queries, KV reads, and subscription key collection.
///
/// After rendering, call `take_subscription_keys()` to flush subscriptions
/// to the `SubscriptionRegistry` for this connection.
pub struct RenderContext {
/// This connection's UUID.
pub connection_id: Uuid,
/// Signal values populated from `last_signals_json` (or initial defaults
/// on first render).
pub signals: SignalStore,
/// Parsed component tree from the `tree` signal.
pub tree: ComponentTree,
/// Access to DB, KV store, and the broadcast event channel.
pub store: Arc<Store>,
/// Subscription keys accumulated during this render.
pub(crate) subscription_keys: Vec<CacheKey>,
/// Signal names touched during this render (for demangling tracking).
pub(crate) touched_signals: Vec<String>,
}
impl RenderContext {
pub fn new(
connection_id: Uuid,
signals: SignalStore,
tree: ComponentTree,
store: Arc<Store>,
) -> Self {
Self {
connection_id,
signals,
tree,
store,
subscription_keys: Vec::new(),
touched_signals: Vec::new(),
}
}
// -----------------------------------------------------------------------
// Signals
// -----------------------------------------------------------------------
/// Create a signal reference with the given name and scoping options.
///
/// Records the signal as "touched" for demangling tracking.
///
/// ```ignore
/// let open = cx.signal("open", mangle(card.id));
/// let val: bool = open.read_or(&cx.signals, false);
/// ```
pub fn signal(&mut self, name: &str, opts: SignalOpts) -> Signal {
let mangled = opts.apply(name);
self.touched_signals.push(mangled.clone());
Signal::new(mangled)
}
// -----------------------------------------------------------------------
// DB Queries
// -----------------------------------------------------------------------
/// Execute a single DB query, collecting its subscription key.
///
/// ```ignore
/// let todos = cx.run(ListTodos).await?;
/// ```
pub async fn run<Q: Query>(&mut self, query: Q) -> anyhow::Result<Q::Output> {
let key = query.cache_key();
if key != CacheKey::None {
self.subscription_keys.push(key);
}
query.execute(&self.store.db).await
}
/// Execute two DB queries concurrently, collecting both subscription keys.
///
/// ```ignore
/// let (board, columns) = cx.run_all(
/// GetBoard { id: 1 },
/// ListColumns { board_id: 1 },
/// ).await?;
/// ```
pub async fn run_all<A: Query, B: Query>(
&mut self,
a: A,
b: B,
) -> anyhow::Result<(A::Output, B::Output)> {
let key_a = a.cache_key();
let key_b = b.cache_key();
if key_a != CacheKey::None {
self.subscription_keys.push(key_a);
}
if key_b != CacheKey::None {
self.subscription_keys.push(key_b);
}
let db = self.store.db.clone();
let (ra, rb) = tokio::try_join!(a.execute(&db), b.execute(&db))?;
Ok((ra, rb))
}
/// Three-query concurrent variant.
pub async fn run_all3<A: Query, B: Query, C: Query>(
&mut self,
a: A,
b: B,
c: C,
) -> anyhow::Result<(A::Output, B::Output, C::Output)> {
let key_a = a.cache_key();
let key_b = b.cache_key();
let key_c = c.cache_key();
if key_a != CacheKey::None {
self.subscription_keys.push(key_a);
}
if key_b != CacheKey::None {
self.subscription_keys.push(key_b);
}
if key_c != CacheKey::None {
self.subscription_keys.push(key_c);
}
let db = self.store.db.clone();
let (ra, rb, rc) = tokio::try_join!(a.execute(&db), b.execute(&db), c.execute(&db))?;
Ok((ra, rb, rc))
}
// -----------------------------------------------------------------------
// KV / Channel queries
// -----------------------------------------------------------------------
/// Read a value from the KV store and register a subscription to its key.
///
/// When `store.kv.set(key, ...)` is called (or `store.publish(...)` for
/// that key), all connections that called `kv_run` with that key during
/// their last render will be scheduled for rerender.
///
/// Returns `None` if the key has not been set yet.
///
/// ```ignore
/// let tick: Option<serde_json::Value> = cx.kv_run("clock").await;
/// ```
pub async fn kv_run(&mut self, key: impl Into<String>) -> Option<serde_json::Value> {
let key = key.into();
self.subscription_keys
.push(CacheKey::Channel { key: key.clone() });
self.store.kv.get(&key)
}
// -----------------------------------------------------------------------
// Post-render access
// -----------------------------------------------------------------------
/// Take the subscription keys accumulated during this render.
///
/// Call this at the top of the component call stack before returning from
/// `render_fn`. The returned `Vec<CacheKey>` is the second element of the
/// `(String, Vec<CacheKey>)` tuple — the framework uses it to update the
/// `SubscriptionRegistry` for this connection after each successful render.
///
/// Keys accumulate naturally as the call stack unwinds: each `cx.run()`
/// and `cx.kv_run()` call pushes its key, so the top-level collect gets
/// the full set from the entire render.
pub fn take_subscription_keys(&mut self) -> Vec<CacheKey> {
std::mem::take(&mut self.subscription_keys)
}
/// Take the touched signal names.
pub fn take_touched_signals(&mut self) -> Vec<String> {
std::mem::take(&mut self.touched_signals)
}
}