1 files changed, 79 insertions, 0 deletions

diff --git a/Utils/src/Resources/BackedResourceBase.cs b/Utils/src/Resources/BackedResourceBase.cs
new file mode 100644
index 0000000..0a2e1e3
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+++ b/Utils/src/Resources/BackedResourceBase.cs
@@ -0,0 +1,79 @@
+/*
+* Copyright (c) 2022 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: VNLib.Utils
+* File: BackedResourceBase.cs 
+*
+* BackedResourceBase.cs is part of VNLib.Utils which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* VNLib.Utils is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU General Public License as published
+* by the Free Software Foundation, either version 2 of the License,
+* or (at your option) any later version.
+*
+* VNLib.Utils is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+* General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License 
+* along with VNLib.Utils. If not, see http://www.gnu.org/licenses/.
+*/
+
+using System;
+using System.Text.Json;
+using System.Runtime.CompilerServices;
+
+namespace VNLib.Utils.Resources
+{
+    /// <summary>
+    /// A base class for a resource that is backed by an external data store. 
+    /// Implements the <see cref="IResource"/> interfaceS
+    /// </summary>
+    public abstract class BackedResourceBase : IResource
+    {
+        ///<inheritdoc/>
+        public bool IsReleased { get; protected set; }
+
+        /// <summary>
+        /// Optional <see cref="JsonSerializerOptions"/> to be used when serializing
+        /// the resource
+        /// </summary>
+        internal protected virtual JsonSerializerOptions? JSO { get; }
+
+        /// <summary>
+        /// A value indicating whether the instance should be deleted when released
+        /// </summary>
+        protected bool Deleted { get; set; }
+        /// <summary>
+        /// A value indicating whether the instance should be updated when released
+        /// </summary>
+        protected bool Modified { get; set; }
+
+        /// <summary>
+        /// Checks if the resouce has been disposed and raises an exception if it is
+        /// </summary>
+        /// <exception cref="ObjectDisposedException"></exception>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        protected void Check()
+        {
+            if (IsReleased)
+            {
+                throw new ObjectDisposedException("The resource has been disposed");
+            }
+        }
+
+        /// <summary>
+        /// Returns the JSON serializable resource to be updated during an update
+        /// </summary>
+        /// <returns>The resource to update</returns>
+        protected abstract object GetResource();
+
+        /// <summary>
+        /// Marks the resource for deletion from backing store during closing events
+        /// </summary>
+        public virtual void Delete() => Deleted = true;
+    }
+}
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