Cleanups and small refactorings

Sources/FirebladeECS/Component.swift

@@ -6,18 +6,13 @@
 //
 
 public protocol Component: class, TypeIdentifiable {}
+public typealias ComponentIdentifier = ObjectIdentifier
 
 extension Component {
 	public var identifier: ComponentIdentifier { return typeObjectIdentifier }
 	public static var identifier: ComponentIdentifier { return typeObjectIdentifier }
 }
 
-// MARK: - activatable protocol
-extension Component {
-	public func activate() { /* default does nothing */ }
-	public func deactivate() { /* default does nothing */ }
-}
-
 // MARK: - entity component hashable
 extension Component {
 
@@ -39,3 +34,20 @@ extension Component {
 		return Self.hashValue(using: entityIdx)
 	}
 }
+
+// MARK: - component identifier hashable
+extension ComponentIdentifier {
+
+	/// Provides XOR hash value from component identifier (aka type) and entity index.
+	/// Is only stable for app runtime.
+	///
+	/// - Parameter entityIdx: entity index
+	/// - Returns: combinded entity component hash
+	func hashValue(using entityIdx: EntityIndex) -> EntityComponentHash {
+		return hashValue(using: entityIdx.identifier)
+	}
+
+	func hashValue(using entityId: EntityIdentifier) -> EntityComponentHash {
+		return EntityComponentHash.compose(entityId: entityId, componentTypeHash: hashValue)
+	}
+}

Sources/FirebladeECS/ComponentIdentifier.swift

@@ -1,24 +0,0 @@
-//
-//  ComponentIdentifier.swift
-//  FirebladeECS
-//
-//  Created by Christian Treffs on 08.10.17.
-//
-
-public typealias ComponentIdentifier = ObjectIdentifier
-
-extension ComponentIdentifier {
-
-	/// Provides XOR hash value from component identifier (aka type) and entity index.
-	/// Is only stable for app runtime.
-	///
-	/// - Parameter entityIdx: entity index
-	/// - Returns: combinded entity component hash
-	func hashValue(using entityIdx: EntityIndex) -> EntityComponentHash {
-		return hashValue(using: entityIdx.identifier)
-	}
-
-	func hashValue(using entityId: EntityIdentifier) -> EntityComponentHash {
-		return EntityComponentHash.compose(entityId: entityId, componentTypeHash: hashValue)
-	}
-}

Sources/FirebladeECS/Entity.swift

@@ -6,18 +6,14 @@
 //
 
 public final class Entity: UniqueEntityIdentifiable {
-
 	internal(set) public var identifier: EntityIdentifier = EntityIdentifier.invalid
 	public var name: String?
-
 	unowned let nexus: Nexus
-
 	init(nexus: Nexus, id: EntityIdentifier, name: String? = nil) {
 		self.nexus = nexus
 		self.identifier = id
 		self.name = name
 	}
-
 }
 
 // MARK: - Invalidate
@@ -52,8 +48,8 @@ public extension Entity {
 		return has(type.identifier)
 	}
 
-	public final func has(_ uct: ComponentIdentifier) -> Bool {
-		return nexus.has(componentId: uct, entityIdx: identifier.index)
+	public final func has(_ compId: ComponentIdentifier) -> Bool {
+		return nexus.has(componentId: compId, entityIdx: identifier.index)
 	}
 
 	public final var hasComponents: Bool {
@@ -105,13 +101,13 @@ public extension Entity {
 	}
 
 	@discardableResult
-	public final func remove<C>(_ componentType: C.Type) -> Entity where C: Component {
-		return remove(componentType.identifier)
+	public final func remove<C>(_ compType: C.Type) -> Entity where C: Component {
+		return remove(compType.identifier)
 	}
 
 	@discardableResult
-	public final func remove(_ uct: ComponentIdentifier) -> Entity {
-		nexus.remove(component: uct, from: identifier)
+	public final func remove(_ compId: ComponentIdentifier) -> Entity {
+		nexus.remove(component: compId, from: identifier)
 		return self
 	}
 

Sources/FirebladeECS/Events.swift

@@ -4,43 +4,43 @@
 //
 //  Created by Christian Treffs on 08.10.17.
 //
-protocol Event { }
-public struct EntityCreated: Event {
+public protocol ECSEvent {}
+public struct EntityCreated: ECSEvent {
 	let entityId: EntityIdentifier
 }
 
-public struct EntityDestroyed: Event {
+public struct EntityDestroyed: ECSEvent {
 	let entityId: EntityIdentifier
 }
 
-public struct ComponentAdded: Event {
+public struct ComponentAdded: ECSEvent {
 	let component: ComponentIdentifier
 	let to: EntityIdentifier
 }
 
-public struct ComponentUpdated: Event {
+public struct ComponentUpdated: ECSEvent {
 	let at: EntityIdentifier
 }
 
-public struct ComponentRemoved: Event {
+public struct ComponentRemoved: ECSEvent {
 	let component: ComponentIdentifier
 	let from: EntityIdentifier
 }
 
-struct FamilyMemberAdded: Event {
+struct FamilyMemberAdded: ECSEvent {
 	let member: EntityIdentifier
 	let to: FamilyTraitSet
 }
 
-struct FamilyMemberRemoved: Event {
+struct FamilyMemberRemoved: ECSEvent {
 	let member: EntityIdentifier
 	let from: FamilyTraitSet
 }
 
-struct FamilyCreated: Event {
+struct FamilyCreated: ECSEvent {
 	let family: FamilyTraitSet
 }
 
-struct FamilyDestroyed: Event {
+struct FamilyDestroyed: ECSEvent {
 	let family: FamilyTraitSet
 }

Sources/FirebladeECS/Family+Members.swift

@@ -6,19 +6,16 @@
 //
 
 extension Family {
-	public func iterateMembers(_ apply: @escaping (EntityIdentifier) -> Void) {
+	public func iterate(entities apply: @escaping (EntityIdentifier) -> Void) {
 		for entityId in memberIds {
 			apply(entityId)
 		}
 	}
-}
-
-extension Family {
 
 	public func iterate<A>(components _: A.Type, _ apply: @escaping (EntityIdentifier, A?) -> Void)
 		where A: Component {
 			for entityId in memberIds {
-				let a: A? = self.nexus?.get(for: entityId)
+				let a: A? = nexus?.get(for: entityId)
 				apply(entityId, a)
 			}
 	}
@@ -26,8 +23,8 @@ extension Family {
 	public func iterate<A, B>(components _: A.Type, _: B.Type, _ apply: @escaping (EntityIdentifier, A?, B?) -> Void)
 		where A: Component, B: Component {
 			for entityId in memberIds {
-				let a: A? = self.nexus?.get(for: entityId)
-				let b: B? = self.nexus?.get(for: entityId)
+				let a: A? = nexus?.get(for: entityId)
+				let b: B? = nexus?.get(for: entityId)
 				apply(entityId, a, b)
 			}
 	}
@@ -35,9 +32,9 @@ extension Family {
 	public func iterate<A, B, C>(components _: A.Type, _: B.Type, _: C.Type, _ apply: @escaping (EntityIdentifier, A?, B?, C?) -> Void)
 		where A: Component, B: Component, C: Component {
 			for entityId in memberIds {
-				let a: A? = self.nexus?.get(for: entityId)
-				let b: B? = self.nexus?.get(for: entityId)
-				let c: C? = self.nexus?.get(for: entityId)
+				let a: A? = nexus?.get(for: entityId)
+				let b: B? = nexus?.get(for: entityId)
+				let c: C? = nexus?.get(for: entityId)
 				apply(entityId, a, b, c)
 			}
 	}
@@ -45,21 +42,21 @@ extension Family {
 	public func iterate<A, B, C, D>(components _: A.Type, _: B.Type, _: C.Type, _: D.Type, _ apply: @escaping (EntityIdentifier, A?, B?, C?, D?) -> Void)
 		where A: Component, B: Component, C: Component, D: Component {
 			for entityId in memberIds {
-				let a: A? = self.nexus?.get(for: entityId)
-				let b: B? = self.nexus?.get(for: entityId)
-				let c: C? = self.nexus?.get(for: entityId)
-				let d: D? = self.nexus?.get(for: entityId)
+				let a: A? = nexus?.get(for: entityId)
+				let b: B? = nexus?.get(for: entityId)
+				let c: C? = nexus?.get(for: entityId)
+				let d: D? = nexus?.get(for: entityId)
 				apply(entityId, a, b, c, d)
 			}
 	}
 	public func iterate<A, B, C, D, E>(components _: A.Type, _: B.Type, _: C.Type, _: D.Type, _: E.Type, _ apply: @escaping (EntityIdentifier, A?, B?, C?, D?, E?) -> Void)
 		where A: Component, B: Component, C: Component, D: Component, E: Component {
 			for entityId in memberIds {
-				let a: A? = self.nexus?.get(for: entityId)
-				let b: B? = self.nexus?.get(for: entityId)
-				let c: C? = self.nexus?.get(for: entityId)
-				let d: D? = self.nexus?.get(for: entityId)
-				let e: E? = self.nexus?.get(for: entityId)
+				let a: A? = nexus?.get(for: entityId)
+				let b: B? = nexus?.get(for: entityId)
+				let c: C? = nexus?.get(for: entityId)
+				let d: D? = nexus?.get(for: entityId)
+				let e: E? = nexus?.get(for: entityId)
 				apply(entityId, a, b, c, d, e)
 			}
 	}
@@ -68,12 +65,12 @@ extension Family {
 										  _ apply: @escaping (EntityIdentifier, A?, B?, C?, D?, E?, F?) -> Void)
 		where A: Component, B: Component, C: Component, D: Component, E: Component, F: Component {
 			for entityId in memberIds {
-				let a: A? = self.nexus?.get(for: entityId)
-				let b: B? = self.nexus?.get(for: entityId)
-				let c: C? = self.nexus?.get(for: entityId)
-				let d: D? = self.nexus?.get(for: entityId)
-				let e: E? = self.nexus?.get(for: entityId)
-				let f: F? = self.nexus?.get(for: entityId)
+				let a: A? = nexus?.get(for: entityId)
+				let b: B? = nexus?.get(for: entityId)
+				let c: C? = nexus?.get(for: entityId)
+				let d: D? = nexus?.get(for: entityId)
+				let e: E? = nexus?.get(for: entityId)
+				let f: F? = nexus?.get(for: entityId)
 				apply(entityId, a, b, c, d, e, f)
 			}
 	}

Sources/FirebladeECS/Family.swift

@@ -15,7 +15,7 @@ public final class Family {
 		self.nexus = nexus
 		self.traits = traits
 		defer {
-			nexus.onFamilyInit(family: self)
+			self.nexus?.onFamilyInit(family: self)
 		}
 	}
 

Sources/FirebladeECS/FamilyTraitSet.swift

@@ -10,7 +10,7 @@ public struct FamilyTraitSet {
 	fileprivate let requiresAll: ComponentSet
 	fileprivate let excludesAll: ComponentSet
 	fileprivate let needsAtLeastOne: ComponentSet
-	fileprivate let _hash: Int
+	fileprivate let setHash: Int
 	fileprivate let isEmptyAny: Bool
 
 	public init(requiresAll: [Component.Type], excludesAll: [Component.Type], needsAtLeastOne: [Component.Type] = []) {
@@ -24,7 +24,7 @@ public struct FamilyTraitSet {
 
 		isEmptyAny = one.isEmpty
 
-		_hash = hash(combine: [all, one, none])
+		setHash = hash(combine: [all, one, none])
 
 		self.requiresAll = all
 		self.needsAtLeastOne = one
@@ -72,13 +72,13 @@ extension FamilyTraitSet {
 // MARK: - Equatable
 extension FamilyTraitSet: Equatable {
 	public static func ==(lhs: FamilyTraitSet, rhs: FamilyTraitSet) -> Bool {
-		return lhs._hash == rhs._hash
+		return lhs.setHash == rhs.setHash
 	}
 }
 
 // MARK: - Hashable
 extension FamilyTraitSet: Hashable {
 	public var hashValue: Int {
-		return _hash
+		return setHash
 	}
 }

Sources/FirebladeECS/Hashable.swift

@@ -52,6 +52,6 @@ extension TypeHashable where Self: InstanceHashable {
 			lhs.instanceObjectIdentifier == rhs.instanceObjectIdentifier
 	}
 	public var hashValue: Int {
-		return typeObjectIdentifier.hashValue ^ instanceObjectIdentifier.hashValue // TODO: this might not be best - use hash combine?
+		return  hash(combine: typeObjectIdentifier.hashValue, instanceObjectIdentifier.hashValue)
 	}
 }

Sources/FirebladeECS/ManagedContiguousArray.swift

@@ -19,7 +19,6 @@ public protocol UniformStorage: class {
 
 public class ManagedContiguousArray: UniformStorage {
 	public static var chunkSize: Int = 4096
-
 	public typealias Index = Int
 	public typealias Element = Any
 	var _size: Int = 0

Sources/FirebladeECS/Nexus+Component.swift

@@ -8,11 +8,7 @@
 extension Nexus {
 
 	public var numComponents: Int {
-		var count = 0
-		for (_, uniformComps) in componentsByType {
-			count += uniformComps.count
-		}
-		return count
+		return componentsByType.reduce(0) { return $0 + $1.value.count }
 	}
 
 	public func has(componentId: ComponentIdentifier, entityIdx: EntityIndex) -> Bool {
@@ -35,8 +31,11 @@ extension Nexus {
 		let hash: EntityComponentHash = componentId.hashValue(using: entityIdx)
 		/// test if component is already assigned
 		guard !has(componentId: componentId, entityIdx: entityIdx) else {
+			// FIXME: this is still open to debate
+			// a) we replace the component
+			// b) we copy the properties
+			// c) we assert fail
 			report("ComponentAdd collision: \(entityIdx) already has a component \(component)")
-			// TODO: replace component?! copy properties?!
 			return
 		}
 		if componentsByType[componentId] == nil {
@@ -54,7 +53,7 @@ extension Nexus {
 			componentIdsByEntityLookup[hash] = 0
 		}
 
-		// FIXME: this is costly for many families
+		// FIXME: iterating all families is costly for many families
 		let entityId: EntityIdentifier = entity.identifier
 		for (_, family) in familiesByTraitHash {
 			update(membership: family, for: entityId)
@@ -91,10 +90,10 @@ extension Nexus {
 		let entityIdx: EntityIndex = entityId.index
 		let hash: EntityComponentHash = componentId.hashValue(using: entityIdx)
 
-		// MARK: delete component instance
+		// delete component instance
 		componentsByType[componentId]?.remove(at: entityIdx)
 
-		// MARK: unassign component
+		// unassign component
 		guard let removeIndex: ComponentIdsByEntityIndex = componentIdsByEntityLookup.removeValue(forKey: hash) else {
 			report("ComponentRemove failure: no component found to be removed")
 			return false
@@ -108,7 +107,8 @@ extension Nexus {
 
 		// relocate remaining indices pointing in the componentsByEntity map
 		if let remainingComponents: ComponentIdentifiers = componentIdsByEntity[entityIdx] {
-			// FIXME: may be expensive but is cheap for small entities -> may be fixed with a sparse set?!
+			// FIXME: enumerated iteration of remaning components is costly
+			// solution: we fix it by using a sparse set for components per entity
 			for (index, compId) in remainingComponents.enumerated() {
 				let cHash: EntityComponentHash = compId.hashValue(using: entityIdx)
 				assert(cHash != hash)
@@ -116,7 +116,7 @@ extension Nexus {
 			}
 		}
 
-		// FIXME: this is costly for many families
+		// FIXME: iterating all families is costly for many families
 		for (_, family) in familiesByTraitHash {
 			update(membership: family, for: entityId)
 		}

Sources/FirebladeECS/Nexus+Entity.swift

@@ -8,6 +8,7 @@
 extension Nexus {
 
 	public var entities: [Entity] {
+		// FIXME: we do not want this kind of access to the underlying entity store
 		return entityStorage.filter { isValid(entity: $0.identifier) }
 	}
 
@@ -62,6 +63,7 @@ extension Nexus {
 	@discardableResult
 	public func destroy(entity: Entity) -> Bool {
 		let entityId: EntityIdentifier = entity.identifier
+		// FIXME: we can make this cheaper by eliminating the need to ask if entity is present
 		guard has(entity: entityId) else {
 			report("EntityRemove failure: no entity \(entityId) to remove")
 			return false
@@ -78,6 +80,7 @@ extension Nexus {
 
 		freeEntities.append(entityId)
 
+		// FIXME: iterating all families is costly for many families
 		for (_, family) in familiesByTraitHash {
 			update(membership: family, for: entityId)
 		}

Sources/FirebladeECS/Nexus.swift

@@ -21,8 +21,15 @@ public typealias TraitEntityIdHash = Int
 public typealias EntityIdInFamilyIndex = Int
 public typealias TraitEntityIdHashSet = [TraitEntityIdHash: EntityIdInFamilyIndex]
 
+public protocol NexusDelegate: class {
+	func nexusEventOccurred(_ event: ECSEvent)
+	func nexusRecoverableErrorOccurred(_ message: String)
+}
+
 public class Nexus {
 
+	weak var delegate: NexusDelegate?
+
 	/// - Index: index value matching entity identifier shifted to Int
 	/// - Value: each element is a entity instance
 	var entityStorage: Entities
@@ -80,15 +87,14 @@ public class Nexus {
 
 }
 
+// MARK: - nexus delegate
 extension Nexus {
 
-	func notify(_ event: Event) {
-		//Log.debug(event)
-		// TODO: implement
-
+	func notify(_ event: ECSEvent) {
+		delegate?.nexusEventOccurred(event)
 	}
 
 	func report(_ message: String) {
-		// TODO: implement
+		delegate?.nexusRecoverableErrorOccurred(message)
 	}
 }

Sources/FirebladeECS/SparseSet.swift

@@ -65,18 +65,12 @@ public class SparseSet<Element>: UniformStorage, Sequence {
 		sparse.removeAll(keepingCapacity: keepingCapacity)
 	}
 
-	public func makeIterator() -> SparseIterator<Element> {
-		return SparseIterator<Element>(self)
-		/*
-		// NOTE: was optimized by using a dedicated iterator implementation
-		var iter = dense.makeIterator()
-		return AnyIterator<Element>.init {
-		guard let next: Pair = iter.next() as? Pair else { return nil }
-		return next.value
-		}*/
+	public func makeIterator() -> SparseSetIterator<Element> {
+		return SparseSetIterator<Element>(self)
 	}
 
-	public struct SparseIterator<Element>: IteratorProtocol {
+	// MARK: - SparseIterator
+	public struct SparseSetIterator<Element>: IteratorProtocol {
 		private let sparseSet: SparseSet<Element>
 		private var iterator: IndexingIterator<ContiguousArray<(key: Index, value: Element)?>>
 		init(_ sparseSet: SparseSet<Element>) {
@@ -92,6 +86,8 @@ public class SparseSet<Element>: UniformStorage, Sequence {
 	}
 }
 
+// MARK: - specialized sparse sets
+
 public class SparseComponentSet: SparseSet<Component> {
 	public typealias Index = EntityIndex
 

Tests/FirebladeECSTests/FamilyTests.swift

@@ -77,7 +77,7 @@ class FamilyTests: XCTestCase {
 		XCTAssert(nexus.numEntities == number)
 
 		measure {
-			family.iterateMembers({ (entityId) in
+			family.iterate(entities: { (entityId) in
 				_ = entityId
 			})
 		}