Absorbed AccessSet implementation into TypeAccess.

Author: Ratysz

crates/bevy_ecs/src/core/access.rs

@@ -196,87 +196,6 @@ impl QueryAccess {
     }
 }
 
-// TODO consider ditching, see CondensedTypeAccess for comparison
-#[derive(Debug, Eq, PartialEq, Clone)]
-enum AccessSet<T: Hash + Eq + PartialEq> {
-    All,
-    Some(HashSet<T>),
-}
-
-impl<T: Hash + Eq + PartialEq> Default for AccessSet<T> {
-    fn default() -> Self {
-        Self::Some(Default::default())
-    }
-}
-
-impl<T: Hash + Eq + PartialEq + Copy> AccessSet<T> {
-    fn is_disjoint(&self, other: &AccessSet<T>) -> bool {
-        if let (AccessSet::Some(set), AccessSet::Some(other)) = (self, other) {
-            set.is_disjoint(other)
-        } else {
-            false
-        }
-    }
-
-    fn extend(&mut self, other: &AccessSet<T>) {
-        match self {
-            AccessSet::All => (),
-            AccessSet::Some(set) => match other {
-                AccessSet::All => *self = AccessSet::All,
-                AccessSet::Some(other) => set.extend(other),
-            },
-        }
-    }
-
-    fn insert(&mut self, item: T) {
-        match self {
-            AccessSet::All => (),
-            AccessSet::Some(set) => {
-                set.insert(item);
-            }
-        }
-    }
-
-    fn clear(&mut self) {
-        match self {
-            // If a system had full access before, it'll have full access next time either way.
-            AccessSet::All => (),
-            AccessSet::Some(set) => set.clear(),
-        }
-    }
-
-    fn contains(&self, item: &T) -> bool {
-        match self {
-            AccessSet::All => true,
-            AccessSet::Some(set) => set.contains(item),
-        }
-    }
-
-    fn find_conflict<'a>(&'a self, other: &'a AccessSet<T>) -> AccessConflict<'a, T> {
-        match (self, other) {
-            (AccessSet::Some(set), AccessSet::Some(other)) => {
-                if let Some(intersection) = set.intersection(other).next() {
-                    return AccessConflict::Element(intersection);
-                }
-            }
-            (AccessSet::Some(set), AccessSet::All) | (AccessSet::All, AccessSet::Some(set)) => {
-                if let Some(first) = set.iter().next() {
-                    return AccessConflict::Element(first);
-                }
-            }
-            (AccessSet::All, AccessSet::All) => return AccessConflict::All,
-        }
-        AccessConflict::None
-    }
-
-    fn distinct_iterator(&self) -> Option<impl Iterator<Item = &T>> {
-        match self {
-            AccessSet::All => None,
-            AccessSet::Some(set) => Some(set.iter()),
-        }
-    }
-}
-
 pub enum AccessConflict<'a, T> {
     None,
     Element(&'a T),
@@ -286,17 +205,19 @@ pub enum AccessConflict<'a, T> {
 /// Provides information about the types a [System] reads and writes
 #[derive(Debug, Eq, PartialEq, Clone)]
 pub struct TypeAccess<T: Hash + Eq + PartialEq> {
-    reads_and_writes: AccessSet<T>,
-    writes: AccessSet<T>,
-    reads: AccessSet<T>,
+    reads_all: bool,
+    writes_all: bool,
+    reads_and_writes: HashSet<T>,
+    writes: HashSet<T>,
 }
 
 impl<T: Hash + Eq + PartialEq> Default for TypeAccess<T> {
     fn default() -> Self {
         Self {
+            reads_all: false,
+            writes_all: false,
             reads_and_writes: Default::default(),
             writes: Default::default(),
-            reads: Default::default(),
         }
     }
 }
@@ -307,36 +228,72 @@ impl<T: Hash + Eq + PartialEq + Copy> TypeAccess<T> {
         for write in writes {
             type_access.add_write(write);
         }
-
         for read in reads {
             type_access.add_read(read);
         }
-
         type_access
     }
 
     pub fn is_compatible(&self, other: &TypeAccess<T>) -> bool {
-        self.writes.is_disjoint(&other.reads_and_writes)
-            && self.reads_and_writes.is_disjoint(&other.writes)
+        if self.writes_all() {
+            !other.writes_all && !other.reads_all && other.reads_and_writes.is_empty()
+        } else if self.reads_all {
+            !other.writes_all && other.writes.is_empty()
+        } else {
+            self.writes.is_disjoint(&other.reads_and_writes)
+                && self.reads_and_writes.is_disjoint(&other.writes)
+        }
     }
 
     pub fn get_conflict<'a>(&'a self, other: &'a TypeAccess<T>) -> AccessConflict<'a, T> {
-        let conflict = self.writes.find_conflict(&other.reads_and_writes);
-        if let AccessConflict::None = conflict {
-            return self.reads_and_writes.find_conflict(&other.writes);
+        if self.writes_all {
+            if other.writes_all || other.reads_all {
+                AccessConflict::All
+            } else {
+                match other.reads_and_writes.iter().next() {
+                    Some(element) => AccessConflict::Element(element),
+                    None => AccessConflict::None,
+                }
+            }
+        } else if self.reads_all {
+            if other.writes_all {
+                AccessConflict::All
+            } else {
+                match other.writes.iter().next() {
+                    Some(element) => AccessConflict::Element(element),
+                    None => AccessConflict::None,
+                }
+            }
+        } else if other.writes_all {
+            match self.reads_and_writes.iter().next() {
+                Some(element) => AccessConflict::Element(element),
+                None => AccessConflict::None,
+            }
+        } else if other.reads_all {
+            match self.writes.iter().next() {
+                Some(element) => AccessConflict::Element(element),
+                None => AccessConflict::None,
+            }
+        } else {
+            match self.writes.intersection(&other.reads_and_writes).next() {
+                Some(element) => AccessConflict::Element(element),
+                None => match other.writes.intersection(&self.reads_and_writes).next() {
+                    Some(element) => AccessConflict::Element(element),
+                    None => AccessConflict::None,
+                },
+            }
         }
-        conflict
     }
 
     pub fn extend(&mut self, other: &TypeAccess<T>) {
+        self.reads_all = self.reads_all || other.reads_all;
+        self.writes_all = self.writes_all || other.writes_all;
         self.writes.extend(&other.writes);
-        self.reads.extend(&other.reads);
         self.reads_and_writes.extend(&other.reads_and_writes);
     }
 
     pub fn add_read(&mut self, ty: T) {
         self.reads_and_writes.insert(ty);
-        self.reads.insert(ty);
     }
 
     pub fn add_write(&mut self, ty: T) {
@@ -345,51 +302,53 @@ impl<T: Hash + Eq + PartialEq + Copy> TypeAccess<T> {
     }
 
     pub fn read_all(&mut self) {
-        self.reads_and_writes = AccessSet::All;
-        self.reads = AccessSet::All;
+        self.reads_all = true;
     }
 
     pub fn write_all(&mut self) {
-        self.reads_and_writes = AccessSet::All;
-        self.writes = AccessSet::All;
+        self.reads_all = true;
+        self.writes_all = true;
     }
 
-    /// NB: does not reset access sets that have been set to `All`.
     pub fn clear(&mut self) {
+        self.reads_all = false;
+        self.writes_all = false;
         self.reads_and_writes.clear();
-        self.reads.clear();
         self.writes.clear();
     }
 
     pub fn is_read_or_write(&self, ty: &T) -> bool {
-        self.reads_and_writes.contains(ty)
+        self.reads_all || self.writes_all || self.reads_and_writes.contains(ty)
     }
 
     pub fn is_write(&self, ty: &T) -> bool {
-        self.writes.contains(ty)
+        self.writes_all || self.writes.contains(ty)
     }
 
     pub fn reads_all(&self) -> bool {
-        self.reads == AccessSet::All
+        self.reads_all
     }
 
     pub fn writes_all(&self) -> bool {
-        self.writes == AccessSet::All
+        self.writes_all
     }
 
-    /// Returns an iterator of distinct accessed types if neither write nor read access is `All`.
+    /// Returns an iterator of distinct accessed types if only some types are accessed.
     pub fn all_distinct_types(&self) -> Option<impl Iterator<Item = &T>> {
-        self.reads_and_writes.distinct_iterator()
+        if !(self.reads_all || self.writes_all) {
+            return Some(self.reads_and_writes.iter());
+        }
+        None
     }
 
     pub fn condense(&self, all_types: &[T]) -> CondensedTypeAccess {
-        if self.writes_all() {
+        if self.writes_all {
             unreachable!(
                 "Access for systems that exclusively access all of `World`\
                  or `Resources` should never be condensed."
             )
         }
-        if self.reads_all() {
+        if self.reads_all {
             let mut writes = FixedBitSet::with_capacity(all_types.len());
             for (index, access_type) in all_types.iter().enumerate() {
                 if self.writes.contains(access_type) {