AnyExtensions.swift
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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)
}
}
}
}