Removing SubscribeSessionFactory and SubscriptionConfiguration (#162)

refactor(subscribe): removing SubscribeSessionFactory with SubscriptionConfiguration
refactor(subscribe): making SubscriptionSession class an internal

.swiftformat

@@ -1,11 +1,24 @@
-# format options
+# Format options
 --indent 2
 --commas inline
 
 --disable wrapMultilineStatementBraces
+--wraparguments before-first
+--wrapparameters before-first
+--maxwidth 130
+--disable wrapSingleLineComments
+--voidtype void
+--redundanttype inferred
+--self remove
 
-# file options
+--enable spaceAroundBrackets,spaceAroundComments,spaceAroundGenerics,spaceAroundParens,spaceInsideBraces
+--enable spaceInsideBrackets,spaceInsideComments,spaceInsideGenerics,spaceInsideParens,trailingclosures,trailingCommas
+--enable wrapConditionalBodies, wrapEnumCases, wrapLoopBodies
+--enable redundantLetError,redundantParens,redundantSelf,redundantReturn,redundantBreak
+--enable duplicateImports
+
+# File options
 --exclude .build
 
 # Swift Version
---swiftversion 5.0
+--swiftversion 5.8

.swiftlint.yml

@@ -1,4 +1,5 @@
 line_length:
+  warning: 130
   ignores_comments: true
 disabled_rules:
   - identifier_name
@@ -11,6 +12,7 @@ excluded:
   - .bundle
   - fastlane
   - Tests
+  - Pods
 opt_in_rules:
   - force_unwrapping
   - overridden_super_call

Sources/PubNub/DependencyContainer/DependencyContainer.swift

@@ -0,0 +1,338 @@
+//
+//  DependencyContainer.swift
+//
+//  Copyright (c) PubNub Inc.
+//  All rights reserved.
+//
+//  This source code is licensed under the license found in the
+//  LICENSE file in the root directory of this source tree.
+//
+
+import Foundation
+
+// A protocol that represents a unique key for each dependency. Each type conforming to `DependencyKey`
+// represents a distinct dependency.
+protocol DependencyKey {
+  // A value associated with a given `DependencyKey`
+  associatedtype Value
+  // Creates a value of the type Value for a given `DependencyKey` if no existing dependency
+  // is found in the `DependencyContainer`. The `container` parameter is used in case of
+  // nested dependencies, i.e., when the dependency being created depends on other objects in the `DependencyContainer`.
+  static func value(from container: DependencyContainer) -> Value
+}
+
+// The class that serves as a registry for dependencies. Each dependency is associated with a unique key
+// conforming to the `DependencyKey` protocol.
+class DependencyContainer {
+  private var resolvedValues: [ObjectIdentifier: any Wrappable] = [:]
+  private var registeredKeys: [ObjectIdentifier: (key: any DependencyKey.Type, scope: Scope)] = [:]
+
+  // Defines the lifecycle of the given dependency
+  enum Scope {
+    // The dependency is owned by the container. It lives as long as the container itself lives.
+    // The dependency is strongly referenced by the container.
+    case container
+    // The container does not own the dependency. The dependency could be deallocated even if the container
+    // is still alive, if there are no more strong references to it.
+    case weak
+    // Indicates that the DependencyContainer doesn't keep any reference (neither strong nor weak) to the dependency.
+    // Each time the dependency is requested, a new instance is created and returned
+    case transient
+  }
+
+  init(instanceID: UUID = UUID(), configuration: PubNubConfiguration) {
+    register(value: configuration, forKey: PubNubConfigurationDependencyKey.self)
+    register(value: instanceID, forKey: PubNubInstanceIDDependencyKey.self)
+    register(key: FileURLSessionDependencyKey.self, scope: .weak)
+    register(key: DefaultHTTPSessionDependencyKey.self, scope: .weak)
+    register(key: HTTPSubscribeSessionDependencyKey.self, scope: .weak)
+    register(key: HTTPPresenceSessionDependencyKey.self, scope: .weak)
+    register(key: HTTPSubscribeSessionQueueDependencyKey.self, scope: .weak)
+    register(key: PresenceStateContainerDependencyKey.self, scope: .weak)
+    register(key: SubscribeEventEngineDependencyKey.self, scope: .weak)
+    register(key: PresenceEventEngineDependencyKey.self, scope: .weak)
+    register(key: SubscriptionSessionDependencyKey.self, scope: .weak)
+  }
+
+  subscript<K>(key: K.Type) -> K.Value where K: DependencyKey {
+    guard let underlyingKey = registeredKeys[ObjectIdentifier(key)] else {
+      preconditionFailure("Cannot find \(key). Ensure this key was registered before")
+    }
+    if underlyingKey.scope == .transient {
+      if let value = underlyingKey.key.value(from: self) as? K.Value {
+        return value
+      } else {
+        preconditionFailure("Cannot create value for key \(key)")
+      }
+    }
+    if let valueWrapper = resolvedValues[ObjectIdentifier(key)] {
+      if let underlyingValue = valueWrapper.value as? K.Value {
+        return underlyingValue
+      }
+    }
+    if let value = underlyingKey.key.value(from: self) as? K.Value {
+      if Mirror(reflecting: value).displayStyle == .class && underlyingKey.scope == .weak {
+        resolvedValues[ObjectIdentifier(key)] = WeakWrapper(value as AnyObject)
+      } else {
+        resolvedValues[ObjectIdentifier(key)] = ValueWrapper(value)
+      }
+      return value
+    }
+    preconditionFailure("Cannot create value for key \(key)")
+  }
+
+  func register<K: DependencyKey>(key: K.Type, scope: Scope = .container) {
+    registeredKeys[ObjectIdentifier(key)] = (key: key, scope: scope)
+  }
+
+  @discardableResult
+  func register<K: DependencyKey>(value: K.Value?, forKey key: K.Type, in scope: Scope = .container) -> DependencyContainer {
+    guard let value = value else {
+      return self
+    }
+    registeredKeys[ObjectIdentifier(key)] = (key: key, scope: scope)
+
+    if Mirror(reflecting: value).displayStyle == .class && scope == .weak {
+      resolvedValues[ObjectIdentifier(key)] = WeakWrapper(value as AnyObject)
+    } else {
+      resolvedValues[ObjectIdentifier(key)] = ValueWrapper(value)
+    }
+
+    return self
+  }
+}
+
+typealias SubscribeEngine = EventEngine<any SubscribeState, Subscribe.Event, Subscribe.Invocation, Subscribe.Dependencies>
+typealias PresenceEngine = EventEngine<any PresenceState, Presence.Event, Presence.Invocation, Presence.Dependencies>
+
+extension DependencyContainer {
+  var configuration: PubNubConfiguration {
+    self[PubNubConfigurationDependencyKey.self]
+  }
+
+  var instanceID: UUID {
+    self[PubNubInstanceIDDependencyKey.self]
+  }
+
+  var fileURLSession: URLSessionReplaceable {
+    self[FileURLSessionDependencyKey.self]
+  }
+
+  var subscriptionSession: SubscriptionSession {
+    self[SubscriptionSessionDependencyKey.self]
+  }
+
+  var presenceStateContainer: PubNubPresenceStateContainer {
+    self[PresenceStateContainerDependencyKey.self]
+  }
+
+  var defaultHTTPSession: SessionReplaceable {
+    resolveSession(
+      session: self[DefaultHTTPSessionDependencyKey.self],
+      with: [automaticRetry].compactMap { $0 }
+    )
+  }
+
+  fileprivate var httpSubscribeSession: SessionReplaceable {
+    resolveSession(
+      session: self[HTTPSubscribeSessionDependencyKey.self],
+      with: [instanceIDOperator].compactMap { $0 }
+    )
+  }
+
+  fileprivate var httpPresenceSession: SessionReplaceable {
+    resolveSession(
+      session: self[HTTPPresenceSessionDependencyKey.self],
+      with: [instanceIDOperator].compactMap { $0 }
+    )
+  }
+
+  fileprivate var automaticRetry: RequestOperator? {
+    configuration.automaticRetry
+  }
+
+  fileprivate var instanceIDOperator: RequestOperator? {
+    configuration.useInstanceId ? InstanceIdOperator(instanceID: instanceID.uuidString) : nil
+  }
+
+  fileprivate var httpSubscribeSessionQueue: DispatchQueue {
+    self[HTTPSubscribeSessionQueueDependencyKey.self]
+  }
+
+  fileprivate var subscribeEngine: SubscribeEngine {
+    self[SubscribeEventEngineDependencyKey.self]
+  }
+
+  fileprivate var presenceEngine: PresenceEngine {
+    self[PresenceEventEngineDependencyKey.self]
+  }
+}
+
+private extension DependencyContainer {
+  func resolveSession(session: SessionReplaceable, with operators: [RequestOperator]) -> SessionReplaceable {
+    session.defaultRequestOperator == nil ? session.usingDefault(requestOperator: MultiplexRequestOperator(
+      operators: operators
+    )) : session.usingDefault(requestOperator: session.defaultRequestOperator?.merge(
+      operators: operators
+    ))
+  }
+}
+
+// - MARK: PubNubConfiguration
+
+struct PubNubConfigurationDependencyKey: DependencyKey {
+  static func value(from container: DependencyContainer) -> PubNubConfiguration {
+    container.configuration
+  }
+}
+
+struct PubNubInstanceIDDependencyKey: DependencyKey {
+  static func value(from container: DependencyContainer) -> UUID {
+    container.instanceID
+  }
+}
+
+// MARK: - HTTPSessions
+
+struct DefaultHTTPSessionDependencyKey: DependencyKey {
+  static func value(from container: DependencyContainer) -> SessionReplaceable {
+    HTTPSession(configuration: .pubnub)
+  }
+}
+
+struct HTTPSubscribeSessionDependencyKey: DependencyKey {
+  static func value(from container: DependencyContainer) -> SessionReplaceable {
+    HTTPSession(
+      configuration: .subscription,
+      sessionQueue: container.httpSubscribeSessionQueue,
+      sessionStream: SessionListener(queue: container.httpSubscribeSessionQueue)
+    )
+  }
+}
+
+struct HTTPSubscribeSessionQueueDependencyKey: DependencyKey {
+  static func value(from container: DependencyContainer) -> DispatchQueue {
+    DispatchQueue(label: "Subscribe Response Queue")
+  }
+}
+
+struct HTTPPresenceSessionDependencyKey: DependencyKey {
+  static func value(from container: DependencyContainer) -> HTTPSession {
+    HTTPSession(
+      configuration: .pubnub,
+      sessionQueue: container.httpSubscribeSessionQueue,
+      sessionStream: SessionListener(queue: container.httpSubscribeSessionQueue)
+    )
+  }
+}
+
+// MARK: - FileURLSession
+
+struct FileURLSessionDependencyKey: DependencyKey {
+  static func value(from container: DependencyContainer) -> URLSessionReplaceable {
+    URLSession(
+      configuration: .pubnubBackground,
+      delegate: FileSessionManager(),
+      delegateQueue: .main
+    )
+  }
+}
+
+// MARK: - PresenceStateContainer
+
+struct PresenceStateContainerDependencyKey: DependencyKey {
+  static func value(from container: DependencyContainer) -> PubNubPresenceStateContainer {
+    PubNubPresenceStateContainer.shared
+  }
+}
+
+// MARK: SubscribeEventEngine
+
+struct SubscribeEventEngineDependencyKey: DependencyKey {
+  static func value(from container: DependencyContainer) -> SubscribeEngine {
+    let effectHandlerFactory = SubscribeEffectFactory(
+      session: container.httpSubscribeSession,
+      presenceStateContainer: container.presenceStateContainer
+    )
+    let subscribeEngine = SubscribeEngine(
+      state: Subscribe.UnsubscribedState(),
+      transition: SubscribeTransition(),
+      dispatcher: EffectDispatcher(factory: effectHandlerFactory),
+      dependencies: EventEngineDependencies(value: Subscribe.Dependencies(configuration: container.configuration))
+    )
+    return subscribeEngine
+  }
+}
+
+// MARK: PresenceEventEngine
+
+struct PresenceEventEngineDependencyKey: DependencyKey {
+  static func value(from container: DependencyContainer) -> PresenceEngine {
+    let effectHandlerFactory = PresenceEffectFactory(
+      session: container.httpPresenceSession,
+      presenceStateContainer: container.presenceStateContainer
+    )
+    let presenceEngine = PresenceEngine(
+      state: Presence.HeartbeatInactive(),
+      transition: PresenceTransition(configuration: container.configuration),
+      dispatcher: EffectDispatcher(factory: effectHandlerFactory),
+      dependencies: EventEngineDependencies(value: Presence.Dependencies(configuration: container.configuration))
+    )
+    return presenceEngine
+  }
+}
+
+// MARK: - SubscriptionSession
+
+struct SubscriptionSessionDependencyKey: DependencyKey {
+  static func value(from container: DependencyContainer) -> SubscriptionSession {
+    if container.configuration.enableEventEngine {
+      return SubscriptionSession(
+        strategy: EventEngineSubscriptionSessionStrategy(
+          configuration: container.configuration,
+          subscribeEngine: container.subscribeEngine,
+          presenceEngine: container.presenceEngine,
+          presenceStateContainer: container.presenceStateContainer
+        )
+      )
+    } else {
+      return SubscriptionSession(
+        strategy: LegacySubscriptionSessionStrategy(
+          configuration: container.configuration,
+          network: container.httpSubscribeSession,
+          presenceSession: container.httpPresenceSession
+        )
+      )
+    }
+  }
+}
+
+// Provides a standard interface for objects that wrap or encapsulate other objects in a dependency container context.
+protocol Wrappable<T> {
+  associatedtype T
+  var value: T? { get }
+}
+
+// A concrete implementation of the `Wrappable` protocol, designed to hold a weak reference to the object it wraps.
+// It only accepts classes (reference types) as its generic parameter, because weak references
+// can only be made to reference types.
+private class WeakWrapper<T: AnyObject>: Wrappable {
+  private weak var optionalValue: T?
+
+  var value: T? {
+    optionalValue
+  }
+
+  init(_ value: T) {
+    self.optionalValue = value
+  }
+}
+
+// Holds a strong reference to the object it wraps
+private class ValueWrapper<T>: Wrappable {
+  let value: T?
+
+  init(_ value: T) {
+    self.value = value
+  }
+}