Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,72 @@ | ||
| namespace CasCap.Common.Extensions; | ||
|
|
||
| /// <summary> | ||
| /// Asynchronous locking based on a key | ||
| /// https://www.hanselman.com/blog/EyesWideOpenCorrectCachingIsAlwaysHard.aspx | ||
| /// https://stackoverflow.com/questions/31138179/asynchronous-locking-based-on-a-key | ||
| /// Note: Not an extension class, stored under this namespace temporarily. | ||
| /// </summary> | ||
| public sealed class AsyncDuplicateLock | ||
| { | ||
| sealed class RefCounted<T> | ||
| { | ||
| public RefCounted(T value) | ||
| { | ||
| RefCount = 1; | ||
| Value = value; | ||
| } | ||
|
|
||
| public int RefCount { get; set; } | ||
| public T Value { get; private set; } | ||
| } | ||
|
|
||
| static readonly Dictionary<object, RefCounted<SemaphoreSlim>> SemaphoreSlims = new(); | ||
|
|
||
| static SemaphoreSlim GetOrCreate(object key) | ||
| { | ||
| RefCounted<SemaphoreSlim>? item; | ||
|
Check warning on line 27 in src/CasCap.GooglePhotosCli/Extensions/AsyncDuplicateLock.cs
|
||
| lock (SemaphoreSlims) | ||
| { | ||
| if (SemaphoreSlims.TryGetValue(key, out item)) | ||
| ++item.RefCount; | ||
| else | ||
| { | ||
| item = new RefCounted<SemaphoreSlim>(new SemaphoreSlim(1, 1)); | ||
| SemaphoreSlims[key] = item; | ||
| } | ||
| } | ||
| return item.Value; | ||
| } | ||
|
|
||
| public static IDisposable Lock(object key) | ||
| { | ||
| GetOrCreate(key).Wait(); | ||
| return new Releaser { Key = key }; | ||
| } | ||
|
|
||
| public static async Task<IDisposable> LockAsync(object key) | ||
| { | ||
| await GetOrCreate(key).WaitAsync().ConfigureAwait(false); | ||
| return new Releaser { Key = key }; | ||
| } | ||
|
|
||
| sealed class Releaser : IDisposable | ||
| { | ||
| #pragma warning disable CS8618 // Non-nullable field is uninitialized. Consider declaring as nullable. | ||
| public object Key { get; set; } | ||
| #pragma warning restore CS8618 // Non-nullable field is uninitialized. Consider declaring as nullable. | ||
|
|
||
| public void Dispose() | ||
| { | ||
| RefCounted<SemaphoreSlim> item; | ||
| lock (SemaphoreSlims) | ||
| { | ||
| item = SemaphoreSlims[Key]; | ||
| --item.RefCount; | ||
| if (item.RefCount == 0) | ||
| SemaphoreSlims.Remove(Key); | ||
| } | ||
| item.Value.Release(); | ||
| } | ||
| } | ||
| } | ||
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters