TM-SGNL-iOS/SignalServiceKit/Util/Atomics.swift
TeleMessage developers dde0620daf initial commit
2025-05-03 12:28:28 -07:00

442 lines
9.6 KiB
Swift

//
// Copyright 2019 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
//
public enum AtomicError: Error {
case invalidTransition
}
// MARK: -
extension UnfairLock {
// The default lock shared by _all_ atomics.
public static let sharedGlobal = UnfairLock()
}
// MARK: -
public final class AtomicBool: Sendable {
private let value: AtomicValue<Bool>
public init(_ value: Bool, lock: UnfairLock) {
self.value = AtomicValue(value, lock: lock)
}
public func get() -> Bool {
value.get()
}
public func set(_ value: Bool) {
self.value.set(value)
}
public func swap(_ value: Bool) -> Bool {
self.value.swap(value)
}
// Sets value to "toValue" IFF it currently has "fromValue",
// otherwise throws.
private func transition(from fromValue: Bool, to toValue: Bool) throws {
try value.transition(from: fromValue, to: toValue)
}
public func tryToSetFlag() -> Bool {
do {
try transition(from: false, to: true)
return true
} catch {
return false
}
}
public func tryToClearFlag() -> Bool {
do {
try transition(from: true, to: false)
return true
} catch {
return false
}
}
}
// MARK: -
public final class AtomicUInt: Sendable {
private let value: AtomicValue<UInt>
public init(_ value: UInt = 0, lock: UnfairLock) {
self.value = AtomicValue(value, lock: lock)
}
public func get() -> UInt {
value.get()
}
public func set(_ value: UInt) {
self.value.set(value)
}
public func swap(_ value: UInt) -> UInt {
self.value.swap(value)
}
@discardableResult
public func increment() -> UInt {
value.map { $0 + 1 }
}
@discardableResult
public func decrementOrZero() -> UInt {
value.map { max($0, 1) - 1 }
}
@discardableResult
public func add(_ delta: UInt) -> UInt {
value.map { $0 + delta }
}
}
// MARK: -
public final class AtomicValue<T>: Sendable {
private let lock: UnfairLock
nonisolated(unsafe) private var value: T
public init(_ value: T, lock: UnfairLock) {
self.value = value
self.lock = lock
}
public func get() -> T {
lock.withLock {
self.value
}
}
public func set(_ value: T) {
lock.withLock {
self.value = value
}
}
// Returns the old value.
public func swap(_ value: T) -> T {
lock.withLock {
let oldValue = self.value
self.value = value
return oldValue
}
}
// Transform the current value using a block.
@discardableResult
public func map(_ block: (T) -> T) -> T {
lock.withLock {
let newValue = block(self.value)
self.value = newValue
return newValue
}
}
@discardableResult
public func update<Result>(block: (inout T) throws -> Result) rethrows -> Result {
try lock.withLock { try block(&self.value) }
}
}
// MARK: -
extension AtomicValue where T: Equatable {
// Sets value to "toValue" IFF it currently has "fromValue",
// otherwise throws.
public func transition(from fromValue: T, to toValue: T) throws {
try lock.withLock {
guard self.value == fromValue else {
throw AtomicError.invalidTransition
}
self.value = toValue
}
}
}
// MARK: -
public final class AtomicOptional<T>: Sendable {
fileprivate let value: AtomicValue<T?>
public init(_ value: T?, lock: UnfairLock) {
self.value = AtomicValue(value, lock: lock)
}
public func get() -> T? {
value.get()
}
public func set(_ value: T?) {
self.value.set(value)
}
// Returns the old value.
public func swap(_ value: T?) -> T? {
self.value.swap(value)
}
public func map(_ block: (T?) -> T?) -> T? {
value.map(block)
}
}
extension AtomicOptional where T: Equatable {
// Sets value to "toValue" IFF it currently has "fromValue",
// otherwise throws.
public func transition(from fromValue: T?, to toValue: T?) throws {
try value.transition(from: fromValue, to: toValue)
}
public func setIfNil(_ newValue: T) throws {
try value.transition(from: nil, to: newValue)
}
public func tryToSetIfNil(_ newValue: T) -> Bool {
do {
try setIfNil(newValue)
return true
} catch {
return false
}
}
public func clearIfEqual(_ oldValue: T) throws {
try value.transition(from: oldValue, to: nil)
}
public func tryToClearIfEqual(_ oldValue: T) -> Bool {
do {
try clearIfEqual(oldValue)
return true
} catch {
return false
}
}
}
// MARK: -
public final class AtomicArray<T>: Sendable {
private let lock: UnfairLock
nonisolated(unsafe) private var values: [T]
public init(_ values: [T] = [], lock: UnfairLock) {
self.values = values
self.lock = lock
}
public func get() -> [T] {
lock.withLock {
values
}
}
public func set(_ values: [T]) {
lock.withLock {
self.values = values
}
}
public func append(_ value: T) {
lock.withLock {
values.append(value)
}
}
public func append(contentsOf newElements: some Sequence<T>) {
lock.withLock {
values.append(contentsOf: newElements)
}
}
public var first: T? {
lock.withLock {
values.first
}
}
public func popHead() -> T? {
lock.withLock {
guard !values.isEmpty else {
return nil
}
return values.removeFirst()
}
}
public func popTail() -> T? {
lock.withLock {
guard !values.isEmpty else {
return nil
}
return values.removeLast()
}
}
public func pushTail(_ value: T) {
append(value)
}
public func pushHead(_ value: T) {
lock.withLock {
self.values.insert(value, at: 0)
}
}
public var count: Int {
lock.withLock { values.count }
}
@discardableResult
public func removeAll() -> [T] {
lock.withLock {
let oldValues = values
values = []
return oldValues
}
}
}
extension AtomicArray where T: Equatable {
public func remove(_ valueToRemove: T) {
lock.withLock {
self.values = self.values.filter { (value: T) -> Bool in
valueToRemove != value
}
}
}
}
// MARK: -
public final class AtomicDictionary<Key: Hashable, Value>: Sendable {
private let lock: UnfairLock
nonisolated(unsafe) private var values: [Key: Value]
public init(_ values: [Key: Value] = [:], lock: UnfairLock) {
self.values = values
self.lock = lock
}
public subscript(_ key: Key) -> Value? {
get { lock.withLock { self.values[key] } }
set { lock.withLock { self.values[key] = newValue } }
}
public func pop(_ key: Key) -> Value? {
lock.withLock {
guard let value = self.values[key] else { return nil }
self.values[key] = nil
return value
}
}
public func get() -> [Key: Value] {
lock.withLock { self.values }
}
public func set(_ values: [Key: Value]) {
lock.withLock { self.values = values }
}
public var isEmpty: Bool {
lock.withLock { values.isEmpty }
}
@discardableResult
public func removeValue(forKey key: Key) -> Value? {
lock.withLock {
values.removeValue(forKey: key)
}
}
@discardableResult
public func removeAllValues() -> [Value] {
lock.withLock {
let result = Array(values.values)
values.removeAll()
return result
}
}
public var count: Int {
lock.withLock { values.count }
}
public var allValues: [Value] {
lock.withLock { Array(values.values) }
}
}
// MARK: -
public final class AtomicSet<T: Hashable>: Sendable {
private let lock: UnfairLock
nonisolated(unsafe) private var values = Set<T>()
public init(lock: UnfairLock) {
self.lock = lock
}
public func insert(_ value: T) {
lock.withLock { _ = self.values.insert(value) }
}
public func contains(_ value: T) -> Bool {
lock.withLock { self.values.contains(value) }
}
@discardableResult
public func remove(_ value: T) -> Bool {
lock.withLock { () -> Bool in
self.values.remove(value) != nil
}
}
public var isEmpty: Bool {
lock.withLock { values.isEmpty }
}
public var count: Int {
lock.withLock { values.count }
}
public var allValues: Set<T> {
lock.withLock { values }
}
@discardableResult
public func removeAllValues() -> Set<T> {
lock.withLock {
let result = values
values.removeAll()
return result
}
}
}
@propertyWrapper
public struct Atomic<Value>: Sendable {
private let value: AtomicValue<Value>
public init(wrappedValue value: Value) {
self.value = AtomicValue(value, lock: UnfairLock())
}
public var wrappedValue: Value {
get {
value.get()
}
nonmutating set {
value.set(newValue)
}
}
}