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Remove workaround for compiler bug breaking constrained existential types on iOS 15 release builds 

Closes #178
This commit is contained in:
Shadowfacts 2023-02-05 11:04:11 -05:00
parent 7cadcf1e86
commit 985eb24e88
1 changed files with 16 additions and 31 deletions
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47
Tusker/MultiThreadDictionary.swift
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@ -13,20 +13,24 @@ import os
// to make the lock semantics more clear
@available(iOS, obsoleted: 16.0)
class MultiThreadDictionary<Key: Hashable & Sendable, Value: Sendable> {
private let lock: LockHolder<[AnyHashable: Any]>
private let lock: any Lock<[Key: Value]>
init() {
self.lock = LockHolder(initialState: [:])
if #available(iOS 16.0, *) {
self.lock = OSAllocatedUnfairLock(initialState: [:])
} else {
self.lock = UnfairLock(initialState: [:])
}
}
subscript(key: Key) -> Value? {
get {
return try! lock.withLock { dict in
return lock.withLock { dict in
dict[key]
} as! Value?
}
}
set(value) {
_ = try! lock.withLock { dict in
_ = lock.withLock { dict in
dict[key] = value
}
}
@ -34,40 +38,21 @@ class MultiThreadDictionary<Key: Hashable & Sendable, Value: Sendable> {
/// If the result of this function is unused, it is preferable to use `removeValueWithoutReturning` as it executes asynchronously and doesn't block the calling thread.
func removeValue(forKey key: Key) -> Value? {
return try! lock.withLock { dict in
return lock.withLock { dict in
dict.removeValue(forKey: key)
} as! Value?
}
}
func contains(key: Key) -> Bool {
return try! lock.withLock { dict in
return lock.withLock { dict in
dict.keys.contains(key)
} as! Bool
}
}
// TODO: this should really be throws/rethrows but the stupid type-erased lock makes that not possible
func withLock<R>(_ body: @Sendable (inout [Key: Value]) -> R) -> R where R: Sendable {
return try! lock.withLock { dict in
var downcasted = dict as! [Key: Value]
defer { dict = downcasted }
return body(&downcasted)
} as! R
}
}
// this type erased struct is necessary due to a compiler bug with stored constrained existential types
// see https://github.com/apple/swift/issues/61403
// see #178
fileprivate struct LockHolder<State> {
let withLock: (_ body: @Sendable (inout State) throws -> any Sendable) throws -> any Sendable
init(initialState: State) {
if #available(iOS 16.0, *) {
let lock = OSAllocatedUnfairLock(initialState: initialState)
self.withLock = lock.withLock(_:)
} else {
let lock = UnfairLock(initialState: initialState)
self.withLock = lock.withLock(_:)
func withLock<R>(_ body: @Sendable (inout [Key: Value]) throws -> R) rethrows -> R where R: Sendable {
return try lock.withLock { dict in
return try body(&dict)
}
}
}