add: NSObject Publisher

CombineCocoa.xcodeproj/xcshareddata/xcschemes/CombineCocoa-Package.xcscheme

@@ -1,32 +1,73 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<Scheme LastUpgradeVersion = "9999" version = "1.3">
-  <BuildAction parallelizeBuildables = "YES" buildImplicitDependencies = "YES">
-    <BuildActionEntries>
-      <BuildActionEntry buildForTesting = "YES" buildForRunning = "YES" buildForProfiling = "YES" buildForArchiving = "YES" buildForAnalyzing = "YES">
-        <BuildableReference
-          BuildableIdentifier = "primary"
-          BuildableName = "'lib$(TARGET_NAME)'"
-          BlueprintName = "Runtime"
-          ReferencedContainer = "container:CombineCocoa.xcodeproj">
-        </BuildableReference>
-      </BuildActionEntry>
-      <BuildActionEntry buildForTesting = "YES" buildForRunning = "YES" buildForProfiling = "YES" buildForArchiving = "YES" buildForAnalyzing = "YES">
-        <BuildableReference
-          BuildableIdentifier = "primary"
-          BuildableName = "'lib$(TARGET_NAME)'"
-          BlueprintName = "CombineCocoa"
-          ReferencedContainer = "container:CombineCocoa.xcodeproj">
-        </BuildableReference>
-      </BuildActionEntry>
-    </BuildActionEntries>
-  </BuildAction>
-  <TestAction
-    buildConfiguration = "Debug"
-    selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
-    selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-    shouldUseLaunchSchemeArgsEnv = "YES"
-    codeCoverageEnabled = "YES">
-    <Testables>
-    </Testables>
-  </TestAction>
+<Scheme
+   LastUpgradeVersion = "9999"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "CombineCocoa::Runtime"
+               BuildableName = "Runtime.framework"
+               BlueprintName = "Runtime"
+               ReferencedContainer = "container:CombineCocoa.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "CombineCocoa::CombineCocoa"
+               BuildableName = "CombineCocoa.framework"
+               BlueprintName = "CombineCocoa"
+               ReferencedContainer = "container:CombineCocoa.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      codeCoverageEnabled = "YES">
+      <Testables>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
 </Scheme>

Sources/CombineCocoa/Interception/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(Runtime)
+  import Runtime
+#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
+  )
+}