BridgeStorage.swift

//===--- BridgeStorage.swift - Discriminated storage for bridged types ----===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// Types that are bridged to Objective-C need to manage an object
// that may be either some native class or the @objc Cocoa
// equivalent. _BridgeStorage discriminates between these two
// possibilities and stores a single extra bit when the stored type is
// native. It is assumed that the @objc class instance may in fact
// be a tagged pointer, and thus no extra bits may be available.
//
//===----------------------------------------------------------------------===//
import SwiftShims

@frozen
@usableFromInline
internalstruct_BridgeStorage<NativeClass:AnyObject>{
@usableFromInline
internaltypealiasNative=NativeClass

@usableFromInline
internaltypealiasObjC=AnyObject

 // rawValue is passed inout to _isUnique. Although its value
 // is unchanged, it must appear mutable to the optimizer.
@usableFromInline
internalvarrawValue:Builtin.BridgeObject

@inlinable
@inline(__always)
internalinit(native:Native, isFlagged flag:Bool){
 // Note: Some platforms provide more than one spare bit, but the minimum is
 // a single bit.

_internalInvariant(_usesNativeSwiftReferenceCounting(NativeClass.self))

 rawValue =_makeNativeBridgeObject(
 native,
 flag ?(1asUInt) << _objectPointerLowSpareBitShift :0)
}

@inlinable
@inline(__always)
internalinit(objC:ObjC){
_internalInvariant(_usesNativeSwiftReferenceCounting(NativeClass.self))
 rawValue =_makeObjCBridgeObject(objC)
}

@inlinable
@inline(__always)
internalinit(native:Native){
_internalInvariant(_usesNativeSwiftReferenceCounting(NativeClass.self))
 rawValue =Builtin.reinterpretCast(native)
}

#if !(arch(i386) || arch(arm) || arch(wasm32))
@inlinable
@inline(__always)
internalinit(taggedPayload:UInt){
 rawValue =_bridgeObject(taggingPayload: taggedPayload)
}
#endif

@inlinable
@inline(__always)
internalmutatingfunc isUniquelyReferencedNative()->Bool{
return_isUnique(&rawValue)
}

@_alwaysEmitIntoClient
@inline(__always)
internalmutatingfunc beginCOWMutationNative()->Bool{
returnBool(Builtin.beginCOWMutation(&rawValue))
}

@inlinable
internalvarisNative:Bool{
@inline(__always)get{
letresult=Builtin.classifyBridgeObject(rawValue)
return !Bool(Builtin.or_Int1(result.isObjCObject,
 result.isObjCTaggedPointer))
}
}

@inlinable
staticvarflagMask:UInt{
@inline(__always)get{
return(1asUInt) << _objectPointerLowSpareBitShift
}
}

@inlinable
internalvarisUnflaggedNative:Bool{
@inline(__always)get{
return(_bitPattern(rawValue)&
(_bridgeObjectTaggedPointerBits | _objCTaggedPointerBits |
 _objectPointerIsObjCBit | _BridgeStorage.flagMask))==0
}
}

@inlinable
internalvarisObjC:Bool{
@inline(__always)get{
return !isNative
}
}

@inlinable
internalvarnativeInstance:Native{
@inline(__always)get{
_internalInvariant(isNative)
returnBuiltin.castReferenceFromBridgeObject(rawValue)
}
}

@inlinable
internalvarunflaggedNativeInstance:Native{
@inline(__always)get{
_internalInvariant(isNative)
_internalInvariant(_nonPointerBits(rawValue)==0)
returnBuiltin.reinterpretCast(rawValue)
}
}

@inlinable
@inline(__always)
internalmutatingfunc isUniquelyReferencedUnflaggedNative()->Bool{
_internalInvariant(isNative)
return_isUnique_native(&rawValue)
}

@_alwaysEmitIntoClient
@inline(__always)
internalmutatingfunc beginCOWMutationUnflaggedNative()->Bool{
_internalInvariant(isNative)
returnBool(Builtin.beginCOWMutation_native(&rawValue))
}

@_alwaysEmitIntoClient
@inline(__always)
internalmutatingfunc endCOWMutation(){
_internalInvariant(isNative)
Builtin.endCOWMutation(&rawValue)
}

@inlinable
internalvarobjCInstance:ObjC{
@inline(__always)get{
_internalInvariant(isObjC)
returnBuiltin.castReferenceFromBridgeObject(rawValue)
}
}
}