added random access read stream

Azure/InedoExtension/FileSystems/AzureFileSystem.cs

@@ -66,7 +66,11 @@ public override async Task<Stream> OpenReadAsync(string fileName, FileAccessHint
 
             var file = await this.Container.GetBlobReferenceFromServerAsync(path, cancellationToken).ConfigureAwait(false);
             await file.FetchAttributesAsync(cancellationToken).ConfigureAwait(false);
-            return new PositionStream(await file.OpenReadAsync(cancellationToken).ConfigureAwait(false), file.Properties.Length);
+
+            if (hints.HasFlag(FileAccessHints.RandomAccess))
+                return new BufferedStream(new RandomAccessBlobStream(file), 32 * 1024);
+            else
+                return new PositionStream(await file.OpenReadAsync(cancellationToken).ConfigureAwait(false), file.Properties.Length);
         }
         public override async Task<Stream> CreateFileAsync(string fileName, FileAccessHints hints = FileAccessHints.Default, CancellationToken cancellationToken = default)
         {

Azure/InedoExtension/FileSystems/RandomAccessBlobStream.cs

@@ -0,0 +1,77 @@
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Azure.Storage.Blob;
+
+namespace Inedo.ProGet.Extensions.Azure.PackageStores
+{
+    internal sealed class RandomAccessBlobStream : Stream
+    {
+        private readonly ICloudBlob blob;
+
+        public RandomAccessBlobStream(ICloudBlob blob)
+        {
+            this.blob = blob;
+            this.Length = blob.Properties.Length;
+        }
+
+        public override bool CanRead => true;
+        public override bool CanSeek => true;
+        public override bool CanWrite => false;
+        public override long Length { get; }
+        public override long Position { get; set; }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            if (buffer == null)
+                throw new ArgumentNullException(nameof(buffer));
+            if (offset < 0)
+                throw new ArgumentOutOfRangeException(nameof(offset));
+            if (count < 0)
+                throw new ArgumentOutOfRangeException(nameof(count));
+
+            int bytesToRead = (int)Math.Min(count, this.Length - this.Position);
+            if (bytesToRead <= 0)
+                return 0;
+
+            return this.blob.DownloadRangeToByteArray(buffer, offset, this.Position, bytesToRead);
+        }
+        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        {
+            if (buffer == null)
+                throw new ArgumentNullException(nameof(buffer));
+            if (offset < 0)
+                throw new ArgumentOutOfRangeException(nameof(offset));
+            if (count < 0)
+                throw new ArgumentOutOfRangeException(nameof(count));
+
+            int bytesToRead = (int)Math.Min(count, this.Length - this.Position);
+            if (bytesToRead <= 0)
+                return 0;
+
+            return await this.blob.DownloadRangeToByteArrayAsync(buffer, offset, this.Position, bytesToRead, cancellationToken).ConfigureAwait(false);
+        }
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            return this.Position = origin switch
+            {
+                SeekOrigin.Begin => offset,
+                SeekOrigin.Current => this.Position + offset,
+                SeekOrigin.End => this.Length + offset,
+                _ => throw new ArgumentOutOfRangeException(nameof(origin))
+            };
+        }
+        public override void Flush()
+        {
+        }
+        public override void SetLength(long value)
+        {
+            throw new NotSupportedException();
+        }
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            throw new NotSupportedException();
+        }
+    }
+}

Azure/InedoExtension/InedoExtension.csproj

@@ -8,8 +8,8 @@
     <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.Azure.Storage.Blob" Version="11.2.2" />
-    <PackageReference Include="Inedo.SDK" Version="1.11.0">
+    <PackageReference Include="Microsoft.Azure.Storage.Blob" Version="11.2.3" />
+    <PackageReference Include="Inedo.SDK" Version="1.13.0-ci.4">
       <ExcludeAssets>runtime</ExcludeAssets>
     </PackageReference>
   </ItemGroup>