[WIP] No More Collection View

ListableUI/Sources/CollectionView/CollectionView.swift

@@ -0,0 +1,133 @@
+//
+//  CollectionView.swift
+//  ListableUI
+//
+//  Created by Kyle Van Essen on 11/29/23.
+//
+
+import Foundation
+
+
+final class LSTCollectionView : UIScrollView {
+
+    private let queue : ListChangesQueue
+
+    private(set) var content : Content
+
+    private var reuseCache : ReusableViewCache
+
+    private let view : ContentView
+
+    // MARK: Initialization
+
+    override init(frame: CGRect) {
+
+        self.queue = .init()
+        self.content = .empty
+        self.reuseCache = .init()
+        self.view = .init(frame: .init(origin: .zero, size: frame.size))
+
+        super.init(frame: frame)
+
+        self.addSubview(self.view)
+    }
+
+    // MARK: UIScrollView
+
+    override func setContentOffset(_ contentOffset: CGPoint, animated: Bool) {
+        super.setContentOffset(contentOffset, animated: animated)
+    }
+
+    // MARK: UIView
+
+    override func layoutSubviews() {
+        super.layoutSubviews()
+
+        self.view.frame = bounds
+    }
+
+    required init?(coder: NSCoder) { fatalError() }
+
+    func set(
+        content : Content,
+        changes: SectionedDiff<Section,
+        AnyIdentifier,
+        AnyItem,
+        AnyIdentifier>,
+        completion : @escaping () -> ()
+    ) {
+        queue.add {
+
+        }
+    }
+
+}
+
+extension LSTCollectionView {
+    final class ContentView : UIScrollView {
+
+    }
+}
+
+open class LSTCollectionReusableView : UIView {
+
+}
+
+open class LSTCollectionSupplementaryView : LSTCollectionReusableView {
+
+}
+
+open class LSTCollectionItemView : LSTCollectionReusableView {
+
+}
+
+
+extension LSTCollectionView {
+
+    struct Content {
+
+        static var empty : Self {
+            fatalError()
+        }
+
+        var supplementaries : Supplementaries
+
+        var sections : [Section]
+    }
+
+    struct Section {
+        var supplementaries : Supplementaries
+
+        var items : [Item]
+    }
+
+    struct Item {
+        var value : AnyItem
+
+        var state : State
+
+        final class State {
+
+        }
+    }
+
+    struct Supplementaries {
+
+        private var byType : [ObjectIdentifier:Supplementary]
+
+    }
+
+    struct Supplementary {
+        var value : AnyHeaderFooter
+
+        var state : State
+
+        final class State {
+
+        }
+    }
+}
+
+protocol SupplementaryTypeKey {
+
+}

ListableUI/Sources/Internal/ReusableViewCache.swift

@@ -10,34 +10,32 @@ import Foundation
 
 final class ReusableViewCache
 {
-    private var views : [String:[AnyObject]] = [:]
-
-    init() {}
+    private var views : [AnyHashable:[AnyObject]] = [:]
 
     func count<Content>(for reuseIdentifier : ReuseIdentifier<Content>) -> Int
     {
-        let views = self.views[reuseIdentifier.stringValue, default: []]
+        let views = self.views[reuseIdentifier, default: []]
 
         return views.count
     }
 
     func push<Content,View:AnyObject>(_ view : View, with reuseIdentifier: ReuseIdentifier<Content>)
     {
-        var views = self.views[reuseIdentifier.stringValue, default: []]
+        var views = self.views[reuseIdentifier, default: []]
 
         listableInternalPrecondition(views.contains { $0 === view } == false, "Cannot push a view which is already in the cache.")
 
         views.append(view)
 
-        self.views[reuseIdentifier.stringValue] = views
+        self.views[reuseIdentifier] = views
     }
 
     func pop<Content,View:AnyObject>(with reuseIdentifier: ReuseIdentifier<Content>, _ create : () -> View) -> View
     {
-        var views = self.views[reuseIdentifier.stringValue, default: []]
+        var views = self.views[reuseIdentifier, default: []]
 
         if let view = views.popLast() {
-            self.views[reuseIdentifier.stringValue] = views
+            self.views[reuseIdentifier] = views
             return view as! View
         } else {
             return create()
@@ -46,7 +44,7 @@ final class ReusableViewCache
 
     func use<Content,View:AnyObject, Result>(with reuseIdentifier: ReuseIdentifier<Content>, create : () -> View, _ use : (View) -> Result) -> Result
     {
-        let views = self.views[reuseIdentifier.stringValue, default: []]
+        let views = self.views[reuseIdentifier, default: []]
 
         if let view = views.last {
             // Fast path: Already in the cache, just reference it here.

ListableUI/Sources/ListView/ListView.swift

@@ -221,6 +221,34 @@ public final class ListView : UIView
         self.updateCollectionViewWithCurrentLayoutProperties()
     }
 
+    //
+    // MARK: Replace UICollectionView Feature Flag
+    //
+
+    public static var isNewBackingViewEnabled : Bool {
+        get {
+            UserDefaults.standard.bool(forKey: "Listable.isNewBackingViewEnabled")
+        }
+
+        set {
+            UserDefaults.standard.setValue(newValue, forKey: "Listable.isNewBackingViewEnabled")
+        }
+    }
+
+    public let isNewBackingViewEnabled : Bool = ListView.isNewBackingViewEnabled
+
+    public func ifNew<Output>(
+        _ ifNew : () throws -> Output,
+        ifOld : () throws -> Output
+    ) rethrows -> Output {
+
+        if Self.isNewBackingViewEnabled {
+            try ifNew()
+        } else {
+            try ifOld()
+        }
+    }
+
     //
     // MARK: Layout
     //