https://github.com/somerandomiosdev/readwritelock
A Swifty Read/Write lock for iOS, macOS, tvOS, and watchOS
https://github.com/somerandomiosdev/readwritelock
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Last synced: 15 days ago
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A Swifty Read/Write lock for iOS, macOS, tvOS, and watchOS
- Host: GitHub
- URL: https://github.com/somerandomiosdev/readwritelock
- Owner: SomeRandomiOSDev
- License: mit
- Created: 2019-06-06T12:03:41.000Z (over 6 years ago)
- Default Branch: main
- Last Pushed: 2021-10-25T16:36:30.000Z (about 4 years ago)
- Last Synced: 2025-10-21T08:57:34.539Z (15 days ago)
- Topics: hacktoberfest
- Language: Shell
- Homepage:
- Size: 43.9 KB
- Stars: 7
- Watchers: 0
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# ReadWriteLock
[](https://app.codacy.com/app/SomeRandomiOSDev/ReadWriteLock?utm_source=github.com&utm_medium=referral&utm_content=SomeRandomiOSDev/ReadWriteLock&utm_campaign=Badge_Grade_Dashboard)
[](https://cocoapods.org/pods/ReadWriteLock)
[](https://cocoapods.org/pods/ReadWriteLock)
[](https://github.com/Carthage/Carthage)
[](https://cocoapods.org/pods/ReadWriteLock)
[](https://codecov.io/gh/SomeRandomiOSDev/ReadWriteLock)
**ReadWriteLock** is a lightweight framework of a safe an easy implementation of a read-write lock for iOS, macOS, tvOS, and watchOS.
## Installation
**ReadWriteLock** is available through [CocoaPods](https://cocoapods.org), [Carthage](https://github.com/Carthage/Carthage) and the [Swift Package Manager](https://swift.org/package-manager/).
To install via CocoaPods, simply add the following line to your Podfile:
```ruby
pod 'ReadWriteLock'
```
To install via Carthage, simply add the following line to your Cartfile:
```ruby
github "SomeRandomiOSDev/ReadWriteLock"
```
To install via the Swift Package Manager add the following line to your `Package.swift` file's `dependencies`:
```swift
.package(url: "https://github.com/SomeRandomiOSDev/ReadWriteLock.git", from: "1.0.0")
```
## Usage
First import **ReadWriteLock** at the top of your Swift file:
```swift
import ReadWriteLock
```
After importing simply instantiate a `ReadWriteLock` instance and start acquiring locks:
```swift
let lock = ReadWriteLock()
var protectedResource = ...
DispatchQueue.global(qos: .background).async {
...
lock.acquireWriteLock {
protectedResource = ...
}
}
...
DispatchQueue.global(qos: .background).async {
...
lock.acquireReadLock {
process(protectedResource)
}
}
```
Or you can conditionally attempt to acquire a lock. Acquiring a lock in this way will not block if the lock has already been claimed:
```swift
...
lock.attemptAcquireReadLock { isLockAcquired in
if isLockAcquired {
process(protectedResource)
} else {
// `lock` is currently locked for writing.
}
}
```
Acquiring locks uses Swift closures to scope the lifetime of the read/write lock. This prevents lingering locks when the `ReadWriteLock` object is deallocated and helps prevent deadlocks. Note that if you attempt to acquire a write lock from inside of the scope of an already acquired read or write lock, or acquiring a read lock from inside of the scope of an already acquired write lock, the thread will deadlock:
```swift
// All of these code blocks will deadlock
lock.acquireWriteLock {
...
lock.acquireWriteLock {
// deadlock
}
}
lock.acquireReadLock {
...
lock.acquireWriteLock {
// deadlock
}
}
lock.attemptAcquireWriteLock { isLockAcquired in
...
if isLockAcquired {
lock.acquireWriteLock {
// deadlock
}
}
}
...
```
The benefit of read/write locks over traditional locks is that you may have (virtually) unlimited read locks, even nested read locks, without deadlocking:
```swift
lock.acquireReadLock {
...
lock.acquireReadLock {
// won't deadlock
}
lock.attemptAcquireReadLock { isLockAcquired in
// isLockAcquired is `true`
}
}
```
Read/write locks are ideal for synchronizing access to properties:
```swift
struct SynchronizedValue {
private var lock = ReadWriteLock()
private var _value: T
var value: T {
get {
return lock.acquireReadLock { _value }
}
set {
lock.acquireWriteLock { _value = newValue }
}
}
}
```
## Contributing
If you have need for a specific feature or you encounter a bug, please open an issue. If you extend the functionality of **ReadWriteLock** yourself or you feel like fixing a bug yourself, please submit a pull request.
## Author
Joe Newton, somerandomiosdev@gmail.com
## License
**ReadWriteLock** is available under the MIT license. See the `LICENSE` file for more info.