Noncopyable InoutRef (#446)

Sources/Verge/Library/InoutRef.swift

@@ -30,7 +30,7 @@ import Foundation
  - Warning: Do not retain this object anywhere.
  */
 @dynamicMemberLookup
-public final class InoutRef<Wrapped> {
+public struct InoutRef<Wrapped>: ~Copyable {
 
   // MARK: - Nested types
 
@@ -99,7 +99,7 @@ public final class InoutRef<Wrapped> {
 
   private(set) var nonatomic_hasModified = false
 
-  private lazy var nonatomic_modifiedKeyPaths: Set<PartialKeyPath<Wrapped>> = .init()
+  private var nonatomic_modifiedKeyPaths: Set<PartialKeyPath<Wrapped>> = .init()
 
   private var nonatomic_wasModifiedIndeterminate = false
 
@@ -161,11 +161,11 @@ public final class InoutRef<Wrapped> {
     }
   }
 
-  func append(trace: MutationTrace) {
+  mutating func append(trace: MutationTrace) {
     traces.append(trace)
   }
 
-  func append(traces otherTraces: [MutationTrace]) {
+  mutating func append(traces otherTraces: [MutationTrace]) {
     traces.append(contentsOf: otherTraces)
   }
 
@@ -234,20 +234,20 @@ public final class InoutRef<Wrapped> {
   }
 
   @inline(__always)
-  private func maskAsModified<U>(on keyPath: KeyPath<Wrapped, U>) {
+  private mutating  func maskAsModified<U>(on keyPath: KeyPath<Wrapped, U>) {
     nonatomic_modifiedKeyPaths.insert(keyPath)
     nonatomic_hasModified = true
   }
 
   @inline(__always)
-  private func maskAsModified<U>(on keyPath: KeyPath<Wrapped, U?>) {
+  private mutating func maskAsModified<U>(on keyPath: KeyPath<Wrapped, U?>) {
     nonatomic_modifiedKeyPaths.insert(keyPath)
     nonatomic_hasModified = true
   }
 
   /// Marks as modified
   /// `modification` property becomes to `.indeterminate`.
-  public func markAsModified() {
+  public mutating func markAsModified() {
     nonatomic_hasModified = true
     nonatomic_wasModifiedIndeterminate = true
   }
@@ -258,7 +258,7 @@ public final class InoutRef<Wrapped> {
    We can't overload `=` operator.
    https://docs.swift.org/swift-book/LanguageGuide/AdvancedOperators.html
    */
-  public func replace(with newValue: Wrapped) {
+  public mutating func replace(with newValue: Wrapped) {
     markAsModified()
     pointer.pointee = newValue
   }
@@ -268,15 +268,15 @@ public final class InoutRef<Wrapped> {
   /// Attention: Using this method makes modifition indeterminate.
   @available(*, renamed: "modifyDirectly")
   @discardableResult
-  public func modify<Return>(_ perform: (inout Wrapped) throws -> Return) rethrows -> Return {
+  public mutating func modify<Return>(_ perform: (inout Wrapped) throws -> Return) rethrows -> Return {
     return try modifyDirectly(perform)
   }
 
   /// Modify the wrapped value with native accessing (without KeyPath + DynamicMemberLookup)
   ///
   /// Attention: Using this method makes modifition indeterminate.
   @discardableResult
-  public func modifyDirectly<Return>(_ perform: (inout Wrapped) throws -> Return) rethrows -> Return {
+  public mutating func modifyDirectly<Return>(_ perform: (inout Wrapped) throws -> Return) rethrows -> Return {
     markAsModified()
     return try perform(&pointer.pointee)
   }
@@ -307,15 +307,15 @@ public final class InoutRef<Wrapped> {
 
    - SeeAlso: InoutRef<Wrapped>.Modification
    */
-  public func withType<Return>(_ perform: (Wrapped.Type, InoutRef<Wrapped>) throws -> Return) rethrows -> Return {
-    try perform(Wrapped.self, self)
+  public mutating func withType<Return>(_ perform: (Wrapped.Type, inout InoutRef<Wrapped>) throws -> Return) rethrows -> Return {
+    try perform(Wrapped.self, &self)
   }
 
   /**
    Returns a tantative InoutRef that projects the value specified by KeyPath.
    That InoutRef must be used only in the given perform closure.
    */
-  public func map<U, Result>(keyPath: WritableKeyPath<Wrapped, U>, perform: (inout InoutRef<U>) throws -> Result) rethrows -> Result {
+  public mutating func map<U, Result>(keyPath: WritableKeyPath<Wrapped, U>, perform: (inout InoutRef<U>) throws -> Result) rethrows -> Result {
     try withUnsafeMutablePointer(to: &pointer.pointee[keyPath: keyPath]) { (pointer) in
       var ref = InoutRef<U>.init(pointer)
       defer {
@@ -336,15 +336,14 @@ public final class InoutRef<Wrapped> {
    Returns a tantative InoutRef that projects the value specified by KeyPath.
    That InoutRef must be used only in the given perform closure.
    */
-  public func map<U, Result>(keyPath: WritableKeyPath<Wrapped, U?>, perform: (inout InoutRef<U>?) throws -> Result) rethrows -> Result {
+  public mutating func map<U, Result>(keyPath: WritableKeyPath<Wrapped, U?>, perform: (inout InoutRef<U>) throws -> Result) rethrows -> Result? {
 
     guard pointer.pointee[keyPath: keyPath] != nil else {
-      var _nil: InoutRef<U>! = .none
-      return try perform(&_nil)
+      return nil
     }
 
     return try withUnsafeMutablePointer(to: &pointer.pointee[keyPath: keyPath]!) { (pointer) in
-      var ref: InoutRef<U>! = InoutRef<U>.init(pointer)
+      var ref: InoutRef<U> = InoutRef<U>.init(pointer)
       defer {
         self.nonatomic_hasModified = ref.nonatomic_hasModified
         self.nonatomic_wasModifiedIndeterminate = ref.nonatomic_wasModifiedIndeterminate

Sources/Verge/Store/Store.swift

@@ -175,9 +175,12 @@ open class Store<State: Equatable, Activity>: EventEmitter<_StoreEvent<State, Ac
 
     // making reduced state
     var _initialState = initialState
-    var inoutRef = InoutRef<State>.init(&_initialState)
-    State.reduce(modifying: &inoutRef, current: .init(old: nil, new: initialState))
-    let reduced = inoutRef.wrapped
+
+    let reduced = withUnsafeMutablePointer(to: &_initialState) { pointer in
+      var inoutRef = InoutRef<State>.init(pointer)
+      State.reduce(modifying: &inoutRef, current: .init(old: nil, new: initialState))
+      return inoutRef.wrapped
+    }
 
     self.nonatomicValue = .init(old: nil, new: reduced)
     self._lock = storeOperation

Tests/VergeTests/InoutRefTests.swift

@@ -86,7 +86,7 @@ final class InoutTests: XCTestCase {
 
     withUnsafeMutablePointer(to: &state) { pointer in
 
-      let ref1 = InoutRef(pointer)
+      var ref1 = InoutRef(pointer)
       let ref2 = InoutRef(pointer)
 
       XCTAssertEqual(ref1.count, ref2.count)
@@ -142,7 +142,7 @@ final class InoutTests: XCTestCase {
     })
 
     withUnsafeMutablePointer(to: &value) { (pointer) -> Void in
-      let proxy = InoutRef.init(pointer)
+      var proxy = InoutRef.init(pointer)
 
       proxy.wrappedValue = 1
 
@@ -178,7 +178,7 @@ final class InoutTests: XCTestCase {
     var value = DemoState()
 
     let modification = withUnsafeMutablePointer(to: &value) { (pointer) -> InoutRef<DemoState>.Modification? in
-      let proxy = InoutRef.init(pointer)
+      var proxy = InoutRef.init(pointer)
       proxy.count += 1
 
       XCTAssert(proxy.hasModified(\.self))
@@ -203,7 +203,7 @@ final class InoutTests: XCTestCase {
     var value = DemoState()
 
     let modification = withUnsafeMutablePointer(to: &value) { (pointer) -> InoutRef<DemoState>.Modification? in
-      let proxy = InoutRef.init(pointer)
+      var proxy = InoutRef.init(pointer)
       proxy.count += 1
       proxy.map(keyPath: \.inner) { (inner) in
         inner.name = UUID().uuidString
@@ -228,7 +228,7 @@ final class InoutTests: XCTestCase {
     var value = DemoState()
 
     let modification = withUnsafeMutablePointer(to: &value) { (pointer) -> InoutRef<DemoState>.Modification? in
-      let proxy = InoutRef.init(pointer)
+      var proxy = InoutRef.init(pointer)
       proxy.modify {
         $0.count += 1
       }
@@ -251,7 +251,7 @@ final class InoutTests: XCTestCase {
     var value = DemoState()
 
     let modification = withUnsafeMutablePointer(to: &value) { (pointer) -> InoutRef<DemoState>.Modification? in
-      let proxy = InoutRef.init(pointer)
+      var proxy = InoutRef.init(pointer)
       proxy.modify {
         $0.count += 1
       }
@@ -266,7 +266,7 @@ final class InoutTests: XCTestCase {
     var value = DemoState()
 
     let modification = withUnsafeMutablePointer(to: &value) { (pointer) -> InoutRef<DemoState>.Modification? in
-      let proxy = InoutRef.init(pointer)
+      var proxy = InoutRef.init(pointer)
       proxy.wrapped.updateFromItself()
       return proxy.modification
     }

Tests/VergeTests/VergeStoreTests.swift

@@ -121,17 +121,16 @@ final class VergeStoreTests: XCTestCase {
 
       let _: Changes<State.NestedState> = _detached.state
 
-      _detached.commit { state in
-        let _: InoutRef<State.NestedState> = state
-
+      _detached.commit { (state: inout InoutRef<State.NestedState>) in
+
       }
 
       let optionalNestedTarget = detached(from: \.optionalNested)
 
       let _: Changes<State.OptionalNestedState?> = optionalNestedTarget.state
 
-      optionalNestedTarget.commit { state in
-        let _: InoutRef<State.OptionalNestedState?> = state
+      optionalNestedTarget.commit { (state: inout InoutRef<State.OptionalNestedState?>) in
+
       }
 
     }
@@ -154,16 +153,16 @@ final class VergeStoreTests: XCTestCase {
 
       let _: Changes<Edge<_State.TreeA>> = state
 
-      commit { state in
-        let _: InoutRef<Edge<_State.TreeA>> = state
+      commit { (state: inout InoutRef<Edge<_State.TreeA>>) in
+
       }
 
       let treeB = detached(from: \.$treeB)
 
       let _: Changes<Edge<_State.TreeB>> = treeB.state
 
-      treeB.commit { state in
-        let _: InoutRef<Edge<_State.TreeB>> = state
+      treeB.commit { (state: inout InoutRef<Edge<_State.TreeB>>) in
+
       }
 
     }