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use std::sync::LazyLock;
use re_entity_db::EntityDb;
use re_log_types::{ApplicationId, StoreId};
use crate::{Cache, CacheEntryAccess, StoreCache, ViewClassRegistry};
/// The current Blueprint and Recording being displayed by the viewer
pub struct ActiveStoreContext<'a> {
/// The current active blueprint.
pub blueprint: &'a EntityDb,
/// The default blueprint (i.e. the one logged from code), if any.
pub default_blueprint: Option<&'a EntityDb>,
/// The current active recording.
///
/// If none is active, this will point to a dummy empty recording.
pub recording: &'a EntityDb,
/// Per-recording caches.
pub caches: &'a StoreCache,
/// Should we enable the heuristics during this frame?
pub should_enable_heuristics: bool,
}
impl ActiveStoreContext<'_> {
pub fn is_active(&self, store_id: &StoreId) -> bool {
self.recording.store_id() == store_id || self.blueprint.store_id() == store_id
}
pub fn application_id(&self) -> &ApplicationId {
self.recording.application_id()
}
pub fn recording_store_id(&self) -> &StoreId {
self.recording.store_id()
}
/// Accesses a memoization cache for reading and writing.
///
/// Shorthand for `self.caches.memoizer(f)`.
pub fn memoizer<C: Cache + Default, R>(&self, f: impl FnOnce(&mut C) -> R) -> R {
self.caches.memoizer(f)
}
/// Accesses an existing memoization cache for reading.
///
/// Shorthand for `self.caches.memoizer_read(f)`.
pub fn memoizer_read<C: Cache, R>(&self, f: impl FnOnce(&C) -> R) -> Option<R> {
self.caches.memoizer_read(f)
}
/// Tries to read an existing memoization cache entry, then computes it through mutable access on miss.
///
/// Use this if you're working with init-only cache entries, expect your cache entry to be usually present
/// and want to avoid the overhead of a write lock.
/// Note that this _adds_ overhead for the miss path compared to `memoizer`, so don't use this if you expect many misses!
/// (UI code typically doesn't need to care about this optimization, since it's usually single-threaded already.)
///
/// Shorthand for `self.caches.memoizer_read_or_compute(key)`.
pub fn memoizer_read_or_compute<C, Key, Value>(&self, key: &Key) -> Value
where
C: CacheEntryAccess<Key, Value> + Default,
{
self.caches.memoizer_read_or_compute::<C, Key, Value>(key)
}
}
impl ActiveStoreContext<'static> {
/// A sentinel "empty" store context, backed by static empty stores.
///
/// Useful as a last-resort fallback for code paths that require a
/// non-optional [`ActiveStoreContext`] but can be reached while no
/// recording/blueprint is active (e.g. Redap catalog browsing). Prefer
/// propagating `Option<ActiveStoreContext>` upwards when possible.
// TODO(RR-3033): should not be needed, instead we the application should handle absence of an active store context explicitly.
pub fn empty() -> Self {
static EMPTY_RECORDING: LazyLock<EntityDb> =
LazyLock::new(|| EntityDb::new(StoreId::empty_recording()));
static EMPTY_BLUEPRINT: LazyLock<EntityDb> = LazyLock::new(|| {
EntityDb::new(StoreId::default_blueprint(
StoreId::empty_recording().application_id().clone(),
))
});
static EMPTY_CACHES: LazyLock<StoreCache> = LazyLock::new(|| {
StoreCache::empty(&ViewClassRegistry::default(), StoreId::empty_recording())
});
Self {
blueprint: &EMPTY_BLUEPRINT,
default_blueprint: None,
recording: &EMPTY_RECORDING,
caches: &EMPTY_CACHES,
should_enable_heuristics: false,
}
}
}