Add PreferenceKeys and update HostPreferencesKey (#35)

* Update gitignore file

* Add PreferenceKeys and update Preference folder structure

* Implement HostPreferencesKey reduce

* Add HostPreferencesKeyTests test case

Author: Kyle-Ye

.gitignore

@@ -10,4 +10,5 @@ Example/.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
 /.build-*
 /Benchmarks/.build
 /Example/.build
-Example/Package.resolved
+Example/Package.resolved
+TODO.md

Sources/OpenSwiftUI/DataAndStorage/Preferences/Internal/AnyPreferenceKey.swift renamed to Sources/OpenSwiftUI/DataAndStorage/Preferences/AnyPreferenceKey.swift

@@ -4,17 +4,15 @@
 //
 //  Created by Kyle on 2023/1/6.
 //  Lastest Version: iOS 15.5
-//  Status: WIP
+//  Status: Complete
 //  ID: 7429200566949B8FB892A77E01A988C8
 
 struct HostPreferencesKey: PreferenceKey {
-    static var defaultValue: PreferenceList {
-        PreferenceList()
-    }
+    private static var nodeId: UInt32 = .zero
 
-    static func reduce(value: inout PreferenceList, nextValue: () -> PreferenceList) {
-        // TODO:
+    @inline(__always)
+    static func makeNodeID() -> UInt32 {
+        defer { nodeId &+= 1 }
+        return nodeId
     }
-    
-    private static var nodeId: UInt32 = .zero
 }

Sources/OpenSwiftUI/DataAndStorage/Preferences/Internal/HostPreferenceKey.swift renamed to Sources/OpenSwiftUI/DataAndStorage/Preferences/HostPreferenceKey.swift

@@ -0,0 +1,73 @@
+//
+//  PreferenceKeys.swift
+//  OpenSwiftUI
+//
+//  Created by Kyle on 2024/2/2.
+//  Lastest Version: iOS 15.5
+//  Status: Complete
+
+struct PreferenceKeys {
+    private var keys: [AnyPreferenceKey.Type]
+    
+    init() {
+        self.keys = []
+    }
+}
+
+extension PreferenceKeys: RandomAccessCollection, MutableCollection {
+    var startIndex: Int { keys.startIndex }
+    var endIndex: Int { keys.endIndex }
+    
+    mutating func add<Key: PreferenceKey>(_: Key.Type) {
+        keys.append(_AnyPreferenceKey<Key>.self)
+    }
+    
+    mutating func add(_ key: AnyPreferenceKey.Type) {
+        keys.append(key)
+    }
+    
+    func contains<Key: PreferenceKey>(_: Key.Type) -> Bool {
+        contains(_AnyPreferenceKey<Key>.self)
+    }
+    
+    func contains(_ key: AnyPreferenceKey.Type) -> Bool {
+        keys.contains { $0 == key }
+    }
+    
+    mutating func remove<Key: PreferenceKey>(_: Key.Type) {
+        remove(_AnyPreferenceKey<Key>.self)
+    }
+    
+    mutating func remove(_ key: AnyPreferenceKey.Type) {
+        for index in keys.indices {
+            if keys[index] == key {
+                keys.remove(at: index)
+                return
+            }
+        }
+    }
+    
+    var isEmpty: Bool { keys.isEmpty }
+
+    subscript(position: Int) -> AnyPreferenceKey.Type {
+        get { keys[position] }
+        set { keys[position] = newValue }
+    }
+}
+
+extension PreferenceKeys: Equatable {
+    static func == (lhs: PreferenceKeys, rhs: PreferenceKeys) -> Bool {
+        guard lhs.keys.count == rhs.keys.count else {
+            return false
+        }
+        guard !lhs.keys.isEmpty else {
+            return true
+        }
+        for index in lhs.indices {
+            guard lhs[index] == rhs[index] else {
+                return false
+            }
+        }
+        return true
+    }
+}

Sources/OpenSwiftUI/DataAndStorage/Preferences/Internal/HostPreferencesKey.swift renamed to Sources/OpenSwiftUI/DataAndStorage/Preferences/HostPreferencesKey.swift

@@ -8,7 +8,7 @@
 //  ID: C1C63C2F6F2B9F3EB30DD747F0605FBD
 
 struct PreferenceList: CustomStringConvertible {
-    private var first: PreferenceNode?
+    fileprivate var first: PreferenceNode?
 
     subscript<Key: PreferenceKey>(_ keyType: Key.Type) -> Value<Key.Value> {
         get {
@@ -174,3 +174,34 @@ private class _PreferenceNode<Key: PreferenceKey>: PreferenceNode {
         "\(Key.self) = \(value)"
     }
 }
+
+extension HostPreferencesKey {
+    static var defaultValue: PreferenceList {
+        PreferenceList()
+    }
+    
+    static func reduce(value: inout PreferenceList, nextValue: () -> PreferenceList) {
+        let newValue = nextValue()
+        guard let newFirst = newValue.first else {
+            return
+        }
+        guard let first = value.first else {
+            value.first = newFirst
+            return
+        }
+        value.first = nil
+        first.forEach { node in
+            if let mergedNode = node.combine(from: newFirst, next: value.first) {
+                value.first = mergedNode
+            } else {
+                value.first = node.copy(next: value.first)
+            }
+        }
+        newFirst.forEach { node in
+            guard node.find(from: first) == nil else {
+                return
+            }
+            value.first = node.copy(next: value.first)
+        }
+    }
+}

Sources/OpenSwiftUI/DataAndStorage/Preferences/Internal/PreferenceKeyVisitor.swift renamed to Sources/OpenSwiftUI/DataAndStorage/Preferences/PreferenceKeyVisitor.swift

@@ -4,7 +4,7 @@
 //
 //  Created by Kyle on 2023/9/24.
 //  Lastest Version: iOS 15.5
-//  Status: WIP
+//  Status: Complete
 
 extension View {
     /// Sets a value for the given preference.