Rename Feedser to Concelier

src/StellaOps.Concelier.Exporter.TrivyDb/TrivyDbBlob.cs

@@ -0,0 +1,78 @@
+using System;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace StellaOps.Concelier.Exporter.TrivyDb;
+
+public sealed class TrivyDbBlob
+{
+    private readonly Func<CancellationToken, ValueTask<Stream>> _openReadAsync;
+
+    private TrivyDbBlob(Func<CancellationToken, ValueTask<Stream>> openReadAsync, long length)
+    {
+        _openReadAsync = openReadAsync ?? throw new ArgumentNullException(nameof(openReadAsync));
+        if (length < 0)
+        {
+            throw new ArgumentOutOfRangeException(nameof(length));
+        }
+
+        Length = length;
+    }
+
+    public long Length { get; }
+
+    public ValueTask<Stream> OpenReadAsync(CancellationToken cancellationToken)
+        => _openReadAsync(cancellationToken);
+
+    public static TrivyDbBlob FromBytes(ReadOnlyMemory<byte> payload)
+    {
+        if (payload.IsEmpty)
+        {
+            return new TrivyDbBlob(static _ => ValueTask.FromResult<Stream>(Stream.Null), 0);
+        }
+
+        if (MemoryMarshal.TryGetArray(payload, out ArraySegment<byte> segment) && segment.Array is not null && segment.Offset == 0)
+        {
+            return FromArray(segment.Array);
+        }
+
+        return FromArray(payload.ToArray());
+    }
+
+    public static TrivyDbBlob FromFile(string path, long length)
+    {
+        if (string.IsNullOrWhiteSpace(path))
+        {
+            throw new ArgumentException("File path must be provided.", nameof(path));
+        }
+
+        if (length < 0)
+        {
+            throw new ArgumentOutOfRangeException(nameof(length));
+        }
+
+        return new TrivyDbBlob(
+            cancellationToken => ValueTask.FromResult<Stream>(new FileStream(
+                path,
+                FileMode.Open,
+                FileAccess.Read,
+                FileShare.Read,
+                bufferSize: 81920,
+                options: FileOptions.Asynchronous | FileOptions.SequentialScan)),
+            length);
+    }
+
+    public static TrivyDbBlob FromArray(byte[] buffer)
+    {
+        if (buffer is null)
+        {
+            throw new ArgumentNullException(nameof(buffer));
+        }
+
+        return new TrivyDbBlob(
+            _ => ValueTask.FromResult<Stream>(new MemoryStream(buffer, writable: false)),
+            buffer.LongLength);
+    }
+}