Add Logger typealias and Logging wrapper (#11)

Sources/Cache/Cache/ExpiringCache.swift

@@ -11,7 +11,7 @@ import Foundation
  */
 public class ExpiringCache<Key: Hashable, Value>: Cacheable {
     /// `Error` that reports expired values
-    public struct ExpiriedValueError<Key: Hashable>: LocalizedError {
+    public struct ExpiriedValueError: LocalizedError {
         /// Expired key
         public let key: Key
 

Sources/Cache/Global/Global+loggers.swift

@@ -0,0 +1,13 @@
+#if canImport(OSLog)
+import OSLog
+
+/// Typealias for `os.Logger`
+@available(macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+public typealias Logger = os.Logger
+
+@available(macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+extension Global {
+    /// The global cache for Loggers
+    public static var loggers: RequiredKeysCache<AnyHashable, Logger> = RequiredKeysCache()
+}
+#endif

Sources/Cache/PropertyWrappers/Logging.swift

@@ -0,0 +1,52 @@
+#if canImport(OSLog)
+@available(macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+@propertyWrapper public struct Logging<Key: Hashable> {
+    /// The key associated with the Logger in the cache.
+    public let key: Key
+
+    /// The `RequiredKeysCache` instance to resolve the dependency from.
+    public let cache: RequiredKeysCache<Key, Logger>
+
+    /// The wrapped value that can be accessed and mutated by the property wrapper.
+    public var wrappedValue: Logger {
+        get {
+            cache.resolve(requiredKey: key, as: Logger.self)
+        }
+        set {
+            cache.set(value: newValue, forKey: key)
+        }
+    }
+
+    #if !os(Windows)
+    /// Initializes the `Logging` property wrapper.
+    ///
+    /// - Parameters:
+    ///   - key: The key associated with the Logger in the cache.
+    ///   - cache: The `RequiredKeysCache` instance to resolve the dependency from.
+    public init(
+        key: Key,
+        using cache: RequiredKeysCache<Key, Logger> = Global.loggers
+    ) {
+        self.key = key
+        self.cache = cache
+
+        _ = self.cache.requiredKeys.insert(key)
+    }
+    #else
+    /// Initializes the `Logging` property wrapper.
+    ///
+    /// - Parameters:
+    ///   - key: The key associated with the Logger in the cache.
+    ///   - cache: The `RequiredKeysCache` instance to resolve the dependency from.
+    public init(
+        key: Key,
+        using cache: RequiredKeysCache<Key, Any>
+    ) {
+        self.key = key
+        self.cache = cache
+
+        _ = self.cache.requiredKeys.insert(key)
+    }
+    #endif
+}
+#endif

Sources/Cache/PropertyWrappers/Resolved.swift

@@ -31,8 +31,6 @@
             cache.set(value: newValue, forKey: key)
         }
     }
-
-
 
     #if !os(Windows)
     /**

Tests/CacheTests/LoggingTests.swift

@@ -0,0 +1,48 @@
+import XCTest
+@testable import Cache
+
+#if canImport(OSLog)
+@available(macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0, *)
+final class LoggingTests: XCTestCase {
+    func testLogging() {
+        struct CachedValueObject {
+            enum Key {
+                case pi
+                case value
+            }
+
+            static let cache = RequiredKeysCache<Key, Logger>()
+
+            @Logging(key: Key.value, using: cache)
+            var someValue: Logger
+        }
+
+        CachedValueObject.cache.set(value: Logger(subsystem: "subsystem", category: "category"), forKey: .value)
+
+        let object = CachedValueObject()
+
+        object.someValue.log("Success")
+    }
+
+    func testGloballyLogger() {
+        struct CachedValueObject {
+            enum Key {
+                case pi
+                case value
+            }
+
+            @Logging(key: Key.value, using: Global.loggers)
+            var someValue: Logger
+        }
+
+        Global.loggers.set(
+            value: Logger(subsystem: "subsystem", category: "category"),
+            forKey: CachedValueObject.Key.value
+        )
+
+        let object = CachedValueObject()
+
+        object.someValue.log("Success")
+    }
+}
+#endif