Implement support for overwriting SubsequentRequest property in the Request<> class

Author: Meyn

Requests/IRequest.cs

@@ -58,13 +58,20 @@ public interface IRequest : IDisposable
         public abstract void Start();
 
         /// <summary>
-        /// Puts the <see cref="IRequest"/> on hold.
+        /// Puts the <see cref="IRequest"/> on hold, allowing it to be resumed later.
         /// </summary>
         public abstract void Pause();
 
         /// <summary>
-        /// Tries to set the <see cref="IRequest"/> <see cref="State"/> to idle.
+        /// Attempts to set the <see cref="IRequest"/> <see cref="State"/> to idle.
         /// </summary>
+        /// <returns><c>true</c> if the state was successfully set to idle; otherwise, <c>false</c>.</returns>
         public abstract bool TrySetIdle();
+
+        /// <summary>
+        /// Checks whether the <see cref="IRequest"/> has reached a final state and will no longer change.
+        /// </summary>
+        /// <returns><c>true</c> if the request is in a final state; otherwise, <c>false</c>.</returns>
+        public abstract bool HasCompleted();
     }
 }

Requests/Request.cs

@@ -100,7 +100,7 @@ public virtual RequestState State
         {
             get => _state; protected set
             {
-                if (_state is RequestState.Compleated or RequestState.Failed or RequestState.Cancelled)
+                if (HasCompleted())
                     return;
                 _state = value;
                 SynchronizationContext.Post((o) => StateChanged?.Invoke((IRequest)o!, value), this);
@@ -357,6 +357,25 @@ public bool TrySetIdle()
             return State == RequestState.Idle;
         }
 
+        /// <summary>
+        /// Sets a subsequent <see cref="IRequest"/> if neither the current nor the provided request has completed.
+        /// </summary>
+        /// <param name="request">The subsequent request to set.</param>
+        /// <returns><c>true</c> if the request was set; otherwise, <c>false</c>.</returns>
+        public bool TrySetSubsequentRequest(IRequest request)
+        {
+            if (HasCompleted() || request.HasCompleted())
+                return false;
+            Options.SubsequentRequest = request;
+            return true;
+        }
+
+        /// <summary>
+        /// Checks whether the <see cref="IRequest"/> has reached a final state (e.g., completed, failed, or cancelled) and will no longer change.
+        /// </summary>
+        /// <returns><c>true</c> if the request is in a final state; otherwise, <c>false</c>.</returns>
+        public bool HasCompleted() => State is RequestState.Compleated or RequestState.Failed or RequestState.Cancelled;
+
         /// <summary>
         /// A class that encapsulates the return objects and notifications for <see cref="Request{TOptions, TCompleated, TFailed}"/>.
         /// </summary>

Requests/RequestContainer.cs

@@ -378,5 +378,11 @@ public bool TrySetIdle()
         /// </summary>
         /// <returns>An enumerable of non-null requests.</returns>
         private IEnumerable<TRequest> GetStored() => _requests[.._count].Where(req => req != null)!;
+
+        /// <summary>
+        /// Since the container's state depends on the items it holds, it cannot complete.
+        /// </summary>
+        /// <returns>Always returns <c>false</c></returns>
+        public bool HasCompleted() => false;
     }
 }

Requests/RequestHandler.cs

@@ -301,7 +301,6 @@ private async Task HandleRequests(PriorityItem<IRequest> pair)
             if (request.State is RequestState.Compleated or RequestState.Failed or RequestState.Cancelled)
             {
                 request.Dispose();
-
                 if (request.SubsequentRequest != null)
                     await SubsequentRequest(request);
             }
@@ -360,6 +359,12 @@ public bool TrySetIdle()
             return requests.All(x => x.Item.State == RequestState.Idle);
         }
 
+        /// <summary>
+        /// Checks whether the <see cref="RequestHandler"/> has reached a final state and will process <see cref="IRequest"/> objects.
+        /// </summary>
+        /// <returns><c>true</c> if the hanlder is in a final state; otherwise, <c>false</c>.</returns>
+        public bool HasCompleted() => _requestsChannel.Reader.Completion.IsCompleted;
+
         /// <summary>
         /// Disposes the <see cref="RequestHandler"/> instance and canceling all ongoing tasks.
         /// </summary>
@@ -398,6 +403,7 @@ public override string ToString()
 
             return sb.ToString();
         }
+
         /// <summary>
         /// Attempts to remove the specified requests from the priority channel.
         /// </summary>

Requests/Requests.csproj

@@ -16,12 +16,11 @@
     <PackageTags>async; channel; priority; request; parallel; </PackageTags>
     <RepositoryUrl>https://github.com/TypNull/Requests</RepositoryUrl>
     <PackageIcon>logo.png</PackageIcon>
-    <Version>2.2.0</Version>
+    <Version>2.2.1</Version>
     <PackageRequireLicenseAcceptance>True</PackageRequireLicenseAcceptance>
     <PackageLicenseFile>LICENSE.txt</PackageLicenseFile>
     <PackageId>Shard.Requests</PackageId>
-    <PackageReleaseNotes>Implement SubsequentRequest
-Fix RequestContainer GetRequests issue</PackageReleaseNotes>
+    <PackageReleaseNotes>Implement support for overwriting SubsequentRequest property in the Request&lt;&gt; class</PackageReleaseNotes>
   </PropertyGroup>
 
   <ItemGroup>