integrate simple fs in utils

2 files changed, 116 insertions, 0 deletions

diff --git a/lib/Utils/src/Extensions/IoExtensions.cs b/lib/Utils/src/Extensions/IoExtensions.cs
index bcbe810..d727fed 100644
--- a/lib/Utils/src/Extensions/IoExtensions.cs
+++ b/lib/Utils/src/Extensions/IoExtensions.cs
@@ -371,6 +371,7 @@ namespace VNLib.Utils.Extensions
             string fullPath = Path.Combine(dir.FullName, fileName);
             return new FileStream(fullPath, mode, access, share, bufferSize, options);
         }
+       
         /// <summary>
         /// Deletes the speicifed file from the current directory
         /// </summary>
@@ -383,6 +384,7 @@ namespace VNLib.Utils.Extensions
             string fullPath = Path.Combine(dir.FullName, fileName);
             File.Delete(fullPath);
         }
+        
         /// <summary>
         /// Determines if a file exists within the current directory
         /// </summary>
@@ -396,5 +398,47 @@ namespace VNLib.Utils.Extensions
             string fullPath = Path.Combine(dir.FullName, fileName);
             return FileOperations.FileExists(fullPath);
         }
+
+
+        /// <summary>
+        /// Creates a new scope for the given filesystem. All operations will be offset by the given path
+        /// within the parent filesystem.
+        /// </summary>
+        /// <param name="fs"></param>
+        /// <param name="offsetPath">The base path to prepend to all requests</param>
+        /// <returns>A new <see cref="ISimpleFilesystem"/> with a new filesystem directory scope</returns>
+        public static ISimpleFilesystem CreateNewScope(this ISimpleFilesystem fs, string offsetPath) => new FsScope(fs, offsetPath);
+
+        private sealed record class FsScope(ISimpleFilesystem Parent, string OffsetPath) : ISimpleFilesystem
+        {
+
+            ///<inheritdoc/>
+            public Task DeleteFileAsync(string filePath, CancellationToken cancellation)
+            {
+                string path = Path.Combine(OffsetPath, filePath);
+                return Parent.DeleteFileAsync(path, cancellation);
+            }
+
+            ///<inheritdoc/>
+            public string GetExternalFilePath(string filePath)
+            {
+                string path = Path.Combine(OffsetPath, filePath);
+                return Parent.GetExternalFilePath(path);
+            }
+
+            ///<inheritdoc/>
+            public Task<long> ReadFileAsync(string filePath, Stream output, CancellationToken cancellation)
+            {
+                string path = Path.Combine(OffsetPath, filePath);
+                return Parent.ReadFileAsync(path, output, cancellation);
+            }
+
+            ///<inheritdoc/>
+            public Task WriteFileAsync(string filePath, Stream data, string contentType, CancellationToken cancellation)
+            {
+                string path = Path.Combine(OffsetPath, filePath);
+                return Parent.WriteFileAsync(path, data, contentType, cancellation);
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/lib/Utils/src/IO/ISimpleFilesystem.cs b/lib/Utils/src/IO/ISimpleFilesystem.cs
new file mode 100644
index 0000000..f730a46
--- /dev/null
+++ b/lib/Utils/src/IO/ISimpleFilesystem.cs
@@ -0,0 +1,72 @@
+/*
+* Copyright (c) 2023 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: VNLib.Utils
+* File: ISimpleFilesystem.cs 
+*
+* ISimpleFilesystem.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 Affero General Public License as 
+* published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+*
+* You should have received a copy of the GNU Affero General Public License
+* along with this program.  If not, see https://www.gnu.org/licenses/.
+*/
+
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace VNLib.Utils.IO
+{
+
+    /// <summary>
+    /// Represents an opaque storage interface that abstracts simple storage operations
+    /// ignorant of the underlying storage system.
+    /// </summary>
+    public interface ISimpleFilesystem
+    {
+        /// <summary>
+        /// Gets the full public file path for the given relative file path
+        /// </summary>
+        /// <param name="filePath">The relative file path of the item to get the full path for</param>
+        /// <returns>The full relative file path</returns>
+        string GetExternalFilePath(string filePath);
+
+        /// <summary>
+        /// Deletes a file from the storage system asynchronously
+        /// </summary>
+        /// <param name="filePath">The path to the file to delete</param>
+        /// <param name="cancellation">A token to cancel the operation</param>
+        /// <returns>A task that represents and asynchronous work</returns>
+        Task DeleteFileAsync(string filePath, CancellationToken cancellation);
+
+        /// <summary>
+        /// Writes a file from the stream to the given file location
+        /// </summary>
+        /// <param name="filePath">The path to the file to write to</param>
+        /// <param name="data">The file data to stream</param>
+        /// <param name="contentType">The content type of the file to write</param>
+        /// <param name="cancellation">A token to cancel the operation</param>
+        /// <returns>A task that represents and asynchronous work</returns>
+        Task WriteFileAsync(string filePath, Stream data, string contentType, CancellationToken cancellation);
+
+        /// <summary>
+        /// Reads a file from the storage system at the given path asynchronously
+        /// </summary>
+        /// <param name="filePath">The file to read</param>
+        /// <param name="output">The stream to write the file output to</param>
+        /// <param name="cancellation">A token to cancel the operation</param>
+        /// <returns>The number of bytes read, -1 if the operation failed</returns>
+        Task<long> ReadFileAsync(string filePath, Stream output, CancellationToken cancellation);
+    }
+}