FeatureRequest: Add handlers for selectors

Package.swift

@@ -9,7 +9,18 @@ let package = Package(
     ],
     dependencies: [],
     targets: [
-        .target(name: "CombineCocoa", dependencies: ["Runtime"]),
-        .target(name: "Runtime", dependencies: [])
+        .target(
+			name: "CombineCocoa",
+			dependencies: [
+				"CombineCocoaInterception",
+				"CombineCocoaRuntime"
+			]),
+		.target(
+			name: "CombineCocoaInterception",
+			dependencies: [
+				.target(name: "CombineCocoaRuntime")
+			]
+		),
+        .target(name: "CombineCocoaRuntime")
     ]
 )

Sources/CombineCocoa/DelegateProxy/DelegateProxy.swift

@@ -10,8 +10,8 @@
 import Foundation
 import Combine
 
-#if canImport(Runtime)
-import Runtime
+#if canImport(CombineCocoaRuntime)
+import CombineCocoaRuntime
 #endif
 
 @available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)

Sources/CombineCocoa/Exports.swift

@@ -0,0 +1,8 @@
+//
+//  Exports.swift
+//  
+//
+//  Created by Benjamin Deckys on 2023/07/27.
+//
+
+@_exported import CombineCocoaInterception

Sources/CombineCocoaInterception/NSObject+Association.swift

@@ -0,0 +1,167 @@
+//
+//  NSObject+Association.swift
+//  CombineCocoa
+//
+//  Created by Maxim Krouk on 22.06.21.
+//  Copyright © 2020 Combine Community. All rights reserved.
+//
+
+import Foundation
+
+#if canImport(CombineCocoaRuntime)
+  import CombineCocoaRuntime
+#endif
+
+internal struct AssociationKey<Value> {
+  fileprivate let address: UnsafeRawPointer
+  fileprivate let `default`: Value!
+
+  /// Create an ObjC association key.
+  ///
+  /// - warning: The key must be uniqued.
+  ///
+  /// - parameters:
+  ///   - default: The default value, or `nil` to trap on undefined value. It is
+  ///              ignored if `Value` is an optional.
+  init(default: Value? = nil) {
+    self.address = UnsafeRawPointer(
+      UnsafeMutablePointer<UInt8>.allocate(capacity: 1)
+    )
+    self.default = `default`
+  }
+
+  /// Create an ObjC association key from a `StaticString`.
+  ///
+  /// - precondition: `key` has a pointer representation.
+  ///
+  /// - parameters:
+  ///   - default: The default value, or `nil` to trap on undefined value. It is
+  ///              ignored if `Value` is an optional.
+  init(_ key: StaticString, default: Value? = nil) {
+    assert(key.hasPointerRepresentation)
+    self.address = UnsafeRawPointer(key.utf8Start)
+    self.default = `default`
+  }
+
+  /// Create an ObjC association key from a `Selector`.
+  ///
+  /// - parameters:
+  ///   - default: The default value, or `nil` to trap on undefined value. It is
+  ///              ignored if `Value` is an optional.
+  init(_ key: Selector, default: Value? = nil) {
+    self.address = UnsafeRawPointer(key.utf8Start)
+    self.default = `default`
+  }
+}
+
+internal struct Associations<Base: AnyObject> {
+  fileprivate let base: Base
+
+  init(_ base: Base) {
+    self.base = base
+  }
+}
+
+extension NSObjectProtocol {
+  /// Retrieve the associated value for the specified key. If the value does not
+  /// exist, `initial` would be called and the returned value would be
+  /// associated subsequently.
+  ///
+  /// - parameters:
+  ///   - key: An optional key to differentiate different values.
+  ///   - initial: The action that supples an initial value.
+  ///
+  /// - returns: The associated value for the specified key.
+  internal func associatedValue<T>(
+    forKey key: StaticString = #function,
+    initial: (Self) -> T
+  ) -> T {
+    let key = AssociationKey<T?>(key)
+
+    if let value = associations.value(forKey: key) {
+      return value
+    }
+
+    let value = initial(self)
+    associations.setValue(value, forKey: key)
+
+    return value
+  }
+}
+
+extension NSObjectProtocol {
+  @nonobjc internal var associations: Associations<Self> {
+    return Associations(self)
+  }
+}
+
+extension Associations {
+  /// Retrieve the associated value for the specified key.
+  ///
+  /// - parameters:
+  ///   - key: The key.
+  ///
+  /// - returns: The associated value, or the default value if no value has been
+  ///            associated with the key.
+  internal func value<Value>(
+    forKey key: AssociationKey<Value>
+  ) -> Value {
+    return (objc_getAssociatedObject(base, key.address) as! Value?) ?? key.default
+  }
+
+  /// Retrieve the associated value for the specified key.
+  ///
+  /// - parameters:
+  ///   - key: The key.
+  ///
+  /// - returns: The associated value, or `nil` if no value is associated with
+  ///            the key.
+  internal func value<Value>(
+    forKey key: AssociationKey<Value?>
+  ) -> Value? {
+    return objc_getAssociatedObject(base, key.address) as! Value?
+  }
+
+  /// Set the associated value for the specified key.
+  ///
+  /// - parameters:
+  ///   - value: The value to be associated.
+  ///   - key: The key.
+  internal func setValue<Value>(
+    _ value: Value,
+    forKey key: AssociationKey<Value>
+  ) {
+    objc_setAssociatedObject(base, key.address, value, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
+  }
+
+  /// Set the associated value for the specified key.
+  ///
+  /// - parameters:
+  ///   - value: The value to be associated.
+  ///   - key: The key.
+  internal func setValue<Value>(
+    _ value: Value?,
+    forKey key: AssociationKey<Value?>
+  ) {
+    objc_setAssociatedObject(base, key.address, value, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
+  }
+}
+
+/// Set the associated value for the specified key.
+///
+/// - parameters:
+///   - value: The value to be associated.
+///   - key: The key.
+///   - address: The address of the object.
+internal func unsafeSetAssociatedValue<Value>(
+  _ value: Value?,
+  forKey key: AssociationKey<Value>,
+  forObjectAt address: UnsafeRawPointer
+) {
+  _combinecocoa_objc_setAssociatedObject(
+    address,
+    key.address,
+    value,
+    .OBJC_ASSOCIATION_RETAIN_NONATOMIC
+  )
+}