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Pods/HandyJSON/Source/AnyExtensions.swift 2.7 KB
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  /*
   * Copyright 1999-2101 Alibaba Group.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  //
  //  AnyExtension.swift
  //  HandyJSON
  //
  //  Created by zhouzhuo on 08/01/2017.
  //
  
  protocol AnyExtensions {}
  
  extension AnyExtensions {
  
      public static func isValueTypeOrSubtype(_ value: Any) -> Bool {
          return value is Self
      }
  
      public static func value(from storage: UnsafeRawPointer) -> Any {
          return storage.assumingMemoryBound(to: self).pointee
      }
  
      public static func write(_ value: Any, to storage: UnsafeMutableRawPointer) {
          guard let this = value as? Self else {
              return
          }
          storage.assumingMemoryBound(to: self).pointee = this
      }
  
      public static func takeValue(from anyValue: Any) -> Self? {
          return anyValue as? Self
      }
  }
  
  func extensions(of type: Any.Type) -> AnyExtensions.Type {
      struct Extensions : AnyExtensions {}
      var extensions: AnyExtensions.Type = Extensions.self
      withUnsafePointer(to: &extensions) { pointer in
          UnsafeMutableRawPointer(mutating: pointer).assumingMemoryBound(to: Any.Type.self).pointee = type
      }
      return extensions
  }
  
  func extensions(of value: Any) -> AnyExtensions {
      struct Extensions : AnyExtensions {}
      var extensions: AnyExtensions = Extensions()
      withUnsafePointer(to: &extensions) { pointer in
          UnsafeMutableRawPointer(mutating: pointer).assumingMemoryBound(to: Any.self).pointee = value
      }
      return extensions
  }
  
  /// Tests if `value` is `type` or a subclass of `type`
  func value(_ value: Any, is type: Any.Type) -> Bool {
      return extensions(of: type).isValueTypeOrSubtype(value)
  }
  
  /// Tests equality of any two existential types
  func == (lhs: Any.Type, rhs: Any.Type) -> Bool {
      return Metadata(type: lhs) == Metadata(type: rhs)
  }
  
  // MARK: AnyExtension + Storage
  extension AnyExtensions {
  
      mutating func storage() -> UnsafeRawPointer {
          if type(of: self) is AnyClass {
              let opaquePointer = Unmanaged.passUnretained(self as AnyObject).toOpaque()
              return UnsafeRawPointer(opaquePointer)
          } else {
              return withUnsafePointer(to: &self) { pointer in
                  return UnsafeRawPointer(pointer)
              }
          }
      }
  }