Share Deque

Author: BrennanConroy

src/libraries/System.Threading.RateLimiting/src/System/Threading/RateLimiting/Internal/Deque.cs renamed to src/libraries/Common/src/System/Collections/Generic/Deque.cs

@@ -47,18 +47,6 @@ public void EnqueueTail(T item)
         //    _size++;
         //}
 
-        public T PeekHead()
-        {
-            Debug.Assert(!IsEmpty); // caller's responsibility to make sure there are elements remaining
-            return _array[_head];
-        }
-
-        public T PeekTail()
-        {
-            Debug.Assert(!IsEmpty); // caller's responsibility to make sure there are elements remaining
-            return _array[_head];
-        }
-
         public T DequeueHead()
         {
             Debug.Assert(!IsEmpty); // caller's responsibility to make sure there are elements remaining
@@ -75,6 +63,23 @@ public T DequeueHead()
             return item;
         }
 
+        public T PeekHead()
+        {
+            Debug.Assert(!IsEmpty); // caller's responsibility to make sure there are elements remaining
+            return _array[_head];
+        }
+
+        public T PeekTail()
+        {
+            Debug.Assert(!IsEmpty); // caller's responsibility to make sure there are elements remaining
+            var index = _tail - 1;
+            if (index == -1)
+            {
+                index = _array.Length - 1;
+            }
+            return _array[index];
+        }
+
         public T DequeueTail()
         {
             Debug.Assert(!IsEmpty); // caller's responsibility to make sure there are elements remaining

src/libraries/System.Threading.Channels/src/System.Threading.Channels.csproj

@@ -11,7 +11,6 @@ System.Threading.Channel&lt;T&gt;</PackageDescription>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="System\VoidResult.cs" />
-    <Compile Include="System\Collections\Generic\Deque.cs" />
     <Compile Include="System\Threading\Channels\AsyncOperation.cs" />
     <Compile Include="System\Threading\Channels\AsyncOperation.netcoreapp.cs"
              Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp'" />
@@ -40,6 +39,8 @@ System.Threading.Channel&lt;T&gt;</PackageDescription>
              Link="Common\Internal\Padding.cs" />
     <Compile Include="$(CommonPath)System\Collections\Concurrent\SingleProducerConsumerQueue.cs"
              Link="Common\System\Collections\Concurrent\SingleProducerConsumerQueue.cs" />
+    <Compile Include="$(CommonPath)System\Collections\Generic\Deque.cs"
+             Link="Common\System\Collections\Generic\Deque.cs" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp'">
     <Reference Include="System.Collections" />

src/libraries/System.Threading.Channels/src/System/Collections/Generic/Deque.cs

@@ -11,7 +11,6 @@ System.Threading.RateLimiting.TokenBucketRateLimiter
 System.Threading.RateLimiting.RateLimitLease</PackageDescription>
   </PropertyGroup>
   <ItemGroup>
-    <Compile Include="System\Threading\RateLimiting\Internal\Deque.cs" />
     <Compile Include="System\Threading\RateLimiting\ConcurrencyLimiter.cs" />
     <Compile Include="System\Threading\RateLimiting\ConcurrencyLimiterOptions.cs" />
     <Compile Include="System\Threading\RateLimiting\MetadataName.cs" />
@@ -21,6 +20,8 @@ System.Threading.RateLimiting.RateLimitLease</PackageDescription>
     <Compile Include="System\Threading\RateLimiting\RateLimitLease.cs" />
     <Compile Include="System\Threading\RateLimiting\TokenBucketRateLimiter.cs" />
     <Compile Include="System\Threading\RateLimiting\TokenBucketRateLimiterOptions.cs" />
+    <Compile Include="$(CommonPath)System\Collections\Generic\Deque.cs"
+             Link="Common\System\Collections\Generic\Deque.cs" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp'">
     <Reference Include="System.Runtime" />

src/libraries/System.Threading.RateLimiting/src/System.Threading.RateLimiting.csproj

@@ -8,7 +8,7 @@ namespace System.Threading.RateLimiting
 {
     /// <summary>
     /// Abstraction for leases returned by <see cref="RateLimiter"/> implementations.
-    /// A lease represents the success or failure to acquire a resource and any potential metadata that is relevant to the acquisition operation.
+    /// A lease represents the success or failure to acquire a resource and contains potential metadata that is relevant to the acquisition operation.
     /// </summary>
     public abstract class RateLimitLease : IDisposable
     {

src/libraries/System.Threading.RateLimiting/src/System/Threading/RateLimiting/RateLimitLease.cs

@@ -72,11 +72,11 @@ public override async Task CanAcquireResourceAsync_QueuesAndGrabsOldest()
         [Fact]
         public override async Task CanAcquireResourceAsync_QueuesAndGrabsNewest()
         {
-            var limiter = new ConcurrencyLimiter(new ConcurrencyLimiterOptions(1, QueueProcessingOrder.NewestFirst, 2));
-            var lease = await limiter.WaitAsync().DefaultTimeout();
+            var limiter = new ConcurrencyLimiter(new ConcurrencyLimiterOptions(2, QueueProcessingOrder.NewestFirst, 3));
+            var lease = await limiter.WaitAsync(2).DefaultTimeout();
 
             Assert.True(lease.IsAcquired);
-            var wait1 = limiter.WaitAsync();
+            var wait1 = limiter.WaitAsync(2);
             var wait2 = limiter.WaitAsync();
             Assert.False(wait1.IsCompleted);
             Assert.False(wait2.IsCompleted);

src/libraries/System.Threading.RateLimiting/tests/ConcurrencyLimiterTests.cs

@@ -83,12 +83,13 @@ public override async Task CanAcquireResourceAsync_QueuesAndGrabsOldest()
         [Fact]
         public override async Task CanAcquireResourceAsync_QueuesAndGrabsNewest()
         {
-            var limiter = new TokenBucketRateLimiter(new TokenBucketRateLimiterOptions(1, QueueProcessingOrder.NewestFirst, 2,
+            var limiter = new TokenBucketRateLimiter(new TokenBucketRateLimiterOptions(2, QueueProcessingOrder.NewestFirst, 3,
                 TimeSpan.FromMinutes(0), 1, autoReplenishment: false));
-            var lease = await limiter.WaitAsync().DefaultTimeout();
 
+            var lease = await limiter.WaitAsync(2).DefaultTimeout();
             Assert.True(lease.IsAcquired);
-            var wait1 = limiter.WaitAsync();
+
+            var wait1 = limiter.WaitAsync(2);
             var wait2 = limiter.WaitAsync();
             Assert.False(wait1.IsCompleted);
             Assert.False(wait2.IsCompleted);
@@ -104,6 +105,7 @@ public override async Task CanAcquireResourceAsync_QueuesAndGrabsNewest()
             lease.Dispose();
             Assert.Equal(0, limiter.GetAvailablePermits());
             Assert.True(limiter.TryReplenish());
+            Assert.True(limiter.TryReplenish());
 
             lease = await wait1.DefaultTimeout();
             Assert.True(lease.IsAcquired);