From 54d732ccd0277a278539b2ab97da1e966c81aeb1 Mon Sep 17 00:00:00 2001
From: Anairkoen Schno <aaron.cirr.com@gmail.com>
Date: Tue, 3 Dec 2019 22:54:32 -0600
Subject: [PATCH] Added some synchronization helpers

---
 IPA.Loader/IPA.Loader.csproj            |   5 +
 IPA.Loader/Utilities/Synchronization.cs | 173 ++++++++++++++++++++++++
 2 files changed, 178 insertions(+)
 create mode 100644 IPA.Loader/Utilities/Synchronization.cs

diff --git a/IPA.Loader/IPA.Loader.csproj b/IPA.Loader/IPA.Loader.csproj
index b689ce82..da6512b1 100644
--- a/IPA.Loader/IPA.Loader.csproj
+++ b/IPA.Loader/IPA.Loader.csproj
@@ -87,6 +87,7 @@
     <Compile Include="Config\Config.cs" />
     <Compile Include="Config\ConfigProviders\JsonConfigProvider.cs" />
     <Compile Include="Config\IConfigProvider.cs" />
+    <Compile Include="Config\IConfigStore.cs" />
     <Compile Include="Config\SelfConfig.cs" />
     <Compile Include="JsonConverters\AlmostVersionConverter.cs" />
     <Compile Include="JsonConverters\MultilineStringConverter.cs" />
@@ -138,6 +139,7 @@
     <Compile Include="Updating\BeatMods\ApiEndpoint.cs" />
     <Compile Include="Updating\BeatMods\Updater.cs" />
     <Compile Include="Utilities\Extensions.cs" />
+    <Compile Include="Utilities\Synchronization.cs" />
     <Compile Include="Utilities\Utils.cs" />
     <Compile Include="Utilities\Win32.cs" />
   </ItemGroup>
@@ -172,5 +174,8 @@
   <ItemGroup>
     <None Include="icon_black.png" />
   </ItemGroup>
+  <ItemGroup>
+    <Folder Include="Utilities\Async\" />
+  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
 </Project>
\ No newline at end of file
diff --git a/IPA.Loader/Utilities/Synchronization.cs b/IPA.Loader/Utilities/Synchronization.cs
new file mode 100644
index 00000000..f321b6bc
--- /dev/null
+++ b/IPA.Loader/Utilities/Synchronization.cs
@@ -0,0 +1,173 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace IPA.Utilities
+{
+    /// <summary>
+    /// Utilities for inter-thread synchronization. All Locker method acquire their object immediately.
+    /// </summary>
+    public static class Synchronization
+    {
+        #region Public types
+        /// <summary>
+        /// A synchronization state locker that releases its state when its <see cref="IDisposable.Dispose"/>
+        /// method is called. ALWAYS use with a <see langword="using"/> block or statement. Otherwise, the locker
+        /// may not release the object be released properly.
+        /// </summary>
+        public interface ISyncStateLocker : IDisposable { }
+
+        /// <summary>
+        /// A locker type for <see cref="ReaderWriterLockSlim"/> locks. 
+        /// ALWAYS use with a <see langword="using"/> block or statement. Otherwise, the locker
+        /// may not release the object be released properly.
+        /// </summary>
+        public interface IReadWriteLocker : ISyncStateLocker { }
+
+        /// <summary>
+        /// An upgradable locker type for <see cref="ReaderWriterLockSlim"/>. 
+        /// ALWAYS use with a <see langword="using"/> block or statement. Otherwise, the locker
+        /// may not release the object be released properly.
+        /// </summary>
+        public interface IUpgradableLocker : IReadWriteLocker
+        {
+            /// <summary>
+            /// Upgrades the locker and gives a new locker to manage the upgraded lock.
+            /// </summary>
+            /// <returns>the locker to use with <see langword="using"/> to manage the write lock</returns>
+            IReadWriteLocker Upgrade();
+        }
+        #endregion
+
+        #region Implementations
+        private sealed class MutexLocker : ISyncStateLocker
+        {
+            private readonly Mutex mutex;
+
+            public MutexLocker(Mutex mutex)
+            {
+                this.mutex = mutex;
+                mutex.WaitOne(); // wait and acquire mutex
+            }
+
+            public void Dispose() => mutex.ReleaseMutex(); // release mutex
+        }
+
+        private sealed class SemaphoreLocker : ISyncStateLocker
+        {
+            private readonly Semaphore sem;
+
+            public SemaphoreLocker(Semaphore sem)
+            {
+                this.sem = sem;
+                sem.WaitOne();
+            }
+
+            public void Dispose() => sem.Release();
+        }
+
+        private sealed class SemaphoreSlimLocker : ISyncStateLocker
+        {
+            private readonly SemaphoreSlim sem;
+
+            public SemaphoreSlimLocker(SemaphoreSlim sem)
+            {
+                this.sem = sem;
+                sem.Wait();
+            }
+
+            public void Dispose() => sem.Release();
+        }
+
+        private sealed class ReaderWriterLockSlimWriteLocker : IReadWriteLocker
+        {
+            private readonly ReaderWriterLockSlim rwl;
+
+            public ReaderWriterLockSlimWriteLocker(ReaderWriterLockSlim lck)
+            {
+                rwl = lck;
+                rwl.EnterWriteLock();
+            }
+
+            public void Dispose() => rwl.ExitWriteLock();
+        }
+
+        private sealed class ReaderWriterLockSlimReadLocker : IReadWriteLocker
+        {
+            private readonly ReaderWriterLockSlim rwl;
+
+            public ReaderWriterLockSlimReadLocker(ReaderWriterLockSlim lck)
+            {
+                rwl = lck;
+                rwl.EnterReadLock();
+            }
+
+            public void Dispose() => rwl.ExitReadLock();
+        }
+
+        private sealed class ReaderWriterLockSlimUpgradableReadLocker : IUpgradableLocker
+        {
+            private readonly ReaderWriterLockSlim rwl;
+
+            public ReaderWriterLockSlimUpgradableReadLocker(ReaderWriterLockSlim lck)
+            {
+                rwl = lck;
+                rwl.EnterUpgradeableReadLock();
+            }
+
+            public IReadWriteLocker Upgrade() => new ReaderWriterLockSlimWriteLocker(rwl);
+
+            public void Dispose() => rwl.ExitUpgradeableReadLock();
+        }
+        #endregion
+
+        #region Accessors
+        // TODO: add async fun stuff to this
+
+        /// <summary>
+        /// Creates an <see cref="ISyncStateLocker"/> for a mutex.
+        /// </summary>
+        /// <param name="mut">the mutex to acquire</param>
+        /// <returns>the locker to use with <see langword="using"/></returns>
+        public static ISyncStateLocker Locker(Mutex mut) => new MutexLocker(mut);
+
+        /// <summary>
+        /// Creates an <see cref="ISyncStateLocker"/> for a semaphore.
+        /// </summary>
+        /// <param name="sem">the semaphore to acquire</param>
+        /// <returns>the locker to use with <see langword="using"/></returns>
+        public static ISyncStateLocker Locker(Semaphore sem) => new SemaphoreLocker(sem);
+
+        /// <summary>
+        /// Creates an <see cref="ISyncStateLocker"/> for a slim semaphore.
+        /// </summary>
+        /// <param name="sem">the slim semaphore to acquire</param>
+        /// <returns>the locker to use with <see langword="using"/></returns>
+        public static ISyncStateLocker Locker(SemaphoreSlim sem) => new SemaphoreSlimLocker(sem);
+
+        /// <summary>
+        /// Creates an <see cref="IReadWriteLocker"/> for a <see cref="ReaderWriterLockSlim"/>.
+        /// </summary>
+        /// <param name="rwl">the lock to acquire in write mode</param>
+        /// <returns>the locker to use with <see langword="using"/></returns>
+        public static IReadWriteLocker LockWrite(ReaderWriterLockSlim rwl) => new ReaderWriterLockSlimWriteLocker(rwl);
+
+        /// <summary>
+        /// Creates an <see cref="IReadWriteLocker"/> for a <see cref="ReaderWriterLockSlim"/>.
+        /// </summary>
+        /// <param name="rwl">the lock to acquire in read mode</param>
+        /// <returns>the locker to use with <see langword="using"/></returns>
+        public static IReadWriteLocker LockRead(ReaderWriterLockSlim rwl) => new ReaderWriterLockSlimReadLocker(rwl);
+
+        /// <summary>
+        /// Creates an <see cref="IUpgradableLocker"/> for a <see cref="ReaderWriterLockSlim"/>.
+        /// </summary>
+        /// <param name="rwl">the lock to acquire in upgradable read mode</param>
+        /// <returns>the locker to use with <see langword="using"/></returns>
+        public static IUpgradableLocker LockReadUpgradable(ReaderWriterLockSlim rwl) => new ReaderWriterLockSlimUpgradableReadLocker(rwl);
+        #endregion
+    }
+}