Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/salsa/src/input.rs')
| -rw-r--r-- | crates/salsa/src/input.rs | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/crates/salsa/src/input.rs b/crates/salsa/src/input.rs new file mode 100644 index 0000000000..f6188d4a84 --- /dev/null +++ b/crates/salsa/src/input.rs @@ -0,0 +1,240 @@ +//! +use crate::debug::TableEntry; +use crate::durability::Durability; +use crate::hash::FxIndexMap; +use crate::plumbing::CycleRecoveryStrategy; +use crate::plumbing::InputQueryStorageOps; +use crate::plumbing::QueryStorageMassOps; +use crate::plumbing::QueryStorageOps; +use crate::revision::Revision; +use crate::runtime::StampedValue; +use crate::Database; +use crate::Query; +use crate::Runtime; +use crate::{DatabaseKeyIndex, QueryDb}; +use indexmap::map::Entry; +use parking_lot::RwLock; +use std::convert::TryFrom; +use tracing::debug; + +/// Input queries store the result plus a list of the other queries +/// that they invoked. This means we can avoid recomputing them when +/// none of those inputs have changed. +pub struct InputStorage<Q> +where + Q: Query, +{ + group_index: u16, + slots: RwLock<FxIndexMap<Q::Key, Slot<Q>>>, +} + +struct Slot<Q> +where + Q: Query, +{ + database_key_index: DatabaseKeyIndex, + stamped_value: RwLock<StampedValue<Q::Value>>, +} + +impl<Q> std::panic::RefUnwindSafe for InputStorage<Q> +where + Q: Query, + Q::Key: std::panic::RefUnwindSafe, + Q::Value: std::panic::RefUnwindSafe, +{ +} + +impl<Q> QueryStorageOps<Q> for InputStorage<Q> +where + Q: Query, +{ + const CYCLE_STRATEGY: crate::plumbing::CycleRecoveryStrategy = CycleRecoveryStrategy::Panic; + + fn new(group_index: u16) -> Self { + InputStorage { group_index, slots: Default::default() } + } + + fn fmt_index( + &self, + _db: &<Q as QueryDb<'_>>::DynDb, + index: DatabaseKeyIndex, + fmt: &mut std::fmt::Formatter<'_>, + ) -> std::fmt::Result { + assert_eq!(index.group_index, self.group_index); + assert_eq!(index.query_index, Q::QUERY_INDEX); + let slot_map = self.slots.read(); + let key = slot_map.get_index(index.key_index as usize).unwrap().0; + write!(fmt, "{}({:?})", Q::QUERY_NAME, key) + } + + fn maybe_changed_after( + &self, + db: &<Q as QueryDb<'_>>::DynDb, + input: DatabaseKeyIndex, + revision: Revision, + ) -> bool { + assert_eq!(input.group_index, self.group_index); + assert_eq!(input.query_index, Q::QUERY_INDEX); + debug_assert!(revision < db.salsa_runtime().current_revision()); + let slots = &self.slots.read(); + let slot = slots.get_index(input.key_index as usize).unwrap().1; + slot.maybe_changed_after(db, revision) + } + + fn fetch(&self, db: &<Q as QueryDb<'_>>::DynDb, key: &Q::Key) -> Q::Value { + db.unwind_if_cancelled(); + + let slots = &self.slots.read(); + let slot = slots + .get(key) + .unwrap_or_else(|| panic!("no value set for {:?}({:?})", Q::default(), key)); + + let StampedValue { value, durability, changed_at } = slot.stamped_value.read().clone(); + + db.salsa_runtime().report_query_read_and_unwind_if_cycle_resulted( + slot.database_key_index, + durability, + changed_at, + ); + + value + } + + fn durability(&self, _db: &<Q as QueryDb<'_>>::DynDb, key: &Q::Key) -> Durability { + match self.slots.read().get(key) { + Some(slot) => slot.stamped_value.read().durability, + None => panic!("no value set for {:?}({:?})", Q::default(), key), + } + } + + fn entries<C>(&self, _db: &<Q as QueryDb<'_>>::DynDb) -> C + where + C: std::iter::FromIterator<TableEntry<Q::Key, Q::Value>>, + { + let slots = self.slots.read(); + slots + .iter() + .map(|(key, slot)| { + TableEntry::new(key.clone(), Some(slot.stamped_value.read().value.clone())) + }) + .collect() + } +} + +impl<Q> Slot<Q> +where + Q: Query, +{ + fn maybe_changed_after(&self, _db: &<Q as QueryDb<'_>>::DynDb, revision: Revision) -> bool { + debug!("maybe_changed_after(slot={:?}, revision={:?})", self, revision,); + + let changed_at = self.stamped_value.read().changed_at; + + debug!("maybe_changed_after: changed_at = {:?}", changed_at); + + changed_at > revision + } +} + +impl<Q> QueryStorageMassOps for InputStorage<Q> +where + Q: Query, +{ + fn purge(&self) { + *self.slots.write() = Default::default(); + } +} + +impl<Q> InputQueryStorageOps<Q> for InputStorage<Q> +where + Q: Query, +{ + fn set(&self, runtime: &mut Runtime, key: &Q::Key, value: Q::Value, durability: Durability) { + tracing::debug!("{:?}({:?}) = {:?} ({:?})", Q::default(), key, value, durability); + + // The value is changing, so we need a new revision (*). We also + // need to update the 'last changed' revision by invoking + // `guard.mark_durability_as_changed`. + // + // CAREFUL: This will block until the global revision lock can + // be acquired. If there are still queries executing, they may + // need to read from this input. Therefore, we wait to acquire + // the lock on `map` until we also hold the global query write + // lock. + // + // (*) Technically, since you can't presently access an input + // for a non-existent key, and you can't enumerate the set of + // keys, we only need a new revision if the key used to + // exist. But we may add such methods in the future and this + // case doesn't generally seem worth optimizing for. + runtime.with_incremented_revision(|next_revision| { + let mut slots = self.slots.write(); + + // Do this *after* we acquire the lock, so that we are not + // racing with somebody else to modify this same cell. + // (Otherwise, someone else might write a *newer* revision + // into the same cell while we block on the lock.) + let stamped_value = StampedValue { value, durability, changed_at: next_revision }; + + match slots.entry(key.clone()) { + Entry::Occupied(entry) => { + let mut slot_stamped_value = entry.get().stamped_value.write(); + let old_durability = slot_stamped_value.durability; + *slot_stamped_value = stamped_value; + Some(old_durability) + } + + Entry::Vacant(entry) => { + let key_index = u32::try_from(entry.index()).unwrap(); + let database_key_index = DatabaseKeyIndex { + group_index: self.group_index, + query_index: Q::QUERY_INDEX, + key_index, + }; + entry.insert(Slot { + database_key_index, + stamped_value: RwLock::new(stamped_value), + }); + None + } + } + }); + } +} + +/// Check that `Slot<Q, MP>: Send + Sync` as long as +/// `DB::DatabaseData: Send + Sync`, which in turn implies that +/// `Q::Key: Send + Sync`, `Q::Value: Send + Sync`. +#[allow(dead_code)] +fn check_send_sync<Q>() +where + Q: Query, + Q::Key: Send + Sync, + Q::Value: Send + Sync, +{ + fn is_send_sync<T: Send + Sync>() {} + is_send_sync::<Slot<Q>>(); +} + +/// Check that `Slot<Q, MP>: 'static` as long as +/// `DB::DatabaseData: 'static`, which in turn implies that +/// `Q::Key: 'static`, `Q::Value: 'static`. +#[allow(dead_code)] +fn check_static<Q>() +where + Q: Query + 'static, + Q::Key: 'static, + Q::Value: 'static, +{ + fn is_static<T: 'static>() {} + is_static::<Slot<Q>>(); +} + +impl<Q> std::fmt::Debug for Slot<Q> +where + Q: Query, +{ + fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + write!(fmt, "{:?}", Q::default()) + } +} |