rework refresh queue

MediaBrowser.Providers/Manager/IPriorityQueue.cs

@@ -0,0 +1,59 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Priority_Queue
+{
+    /// <summary>
+    /// Credit: https://github.com/BlueRaja/High-Speed-Priority-Queue-for-C-Sharp
+    /// The IPriorityQueue interface.  This is mainly here for purists, and in case I decide to add more implementations later.
+    /// For speed purposes, it is actually recommended that you *don't* access the priority queue through this interface, since the JIT can
+    /// (theoretically?) optimize method calls from concrete-types slightly better.
+    /// </summary>
+    public interface IPriorityQueue<TItem, in TPriority> : IEnumerable<TItem>
+        where TPriority : IComparable<TPriority>
+    {
+        /// <summary>
+        /// Enqueue a node to the priority queue.  Lower values are placed in front. Ties are broken by first-in-first-out.
+        /// See implementation for how duplicates are handled.
+        /// </summary>
+        void Enqueue(TItem node, TPriority priority);
+
+        /// <summary>
+        /// Removes the head of the queue (node with minimum priority; ties are broken by order of insertion), and returns it.
+        /// </summary>
+        TItem Dequeue();
+
+        /// <summary>
+        /// Removes every node from the queue.
+        /// </summary>
+        void Clear();
+
+        /// <summary>
+        /// Returns whether the given node is in the queue.
+        /// </summary>
+        bool Contains(TItem node);
+
+        /// <summary>
+        /// Removes a node from the queue.  The node does not need to be the head of the queue.  
+        /// </summary>
+        void Remove(TItem node);
+
+        /// <summary>
+        /// Call this method to change the priority of a node.  
+        /// </summary>
+        void UpdatePriority(TItem node, TPriority priority);
+
+        /// <summary>
+        /// Returns the head of the queue, without removing it (use Dequeue() for that).
+        /// </summary>
+        TItem First { get; }
+
+        /// <summary>
+        /// Returns the number of nodes in the queue.
+        /// </summary>
+        int Count { get; }
+    }
+}