Compute SHA256s for blazor.boot.json in parallel (#21021)

* Compute SHA256s for blazor.boot.json in parallel

2 files changed, 139 insertions, 2 deletions

diff --git a/src/Components/WebAssembly/Build/src/Tasks/BlazorGetFileHash.cs b/src/Components/WebAssembly/Build/src/Tasks/BlazorGetFileHash.cs
new file mode 100644
index 0000000000..f10f53a748
--- /dev/null
+++ b/src/Components/WebAssembly/Build/src/Tasks/BlazorGetFileHash.cs
@@ -0,0 +1,135 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Security.Cryptography;
+using Microsoft.Build.Framework;
+using Microsoft.Build.Utilities;
+
+namespace Microsoft.Build.Tasks
+{
+    /// <summary>
+    /// Computes the checksum for a single file.
+    /// </summary>
+    public sealed class BlazorGetFileHash : Task
+    {
+        internal const string _defaultFileHashAlgorithm = "SHA256";
+        internal const string _hashEncodingBase64 = "base64";
+
+        /// <summary>
+        /// The files to be hashed.
+        /// </summary>
+        [Required]
+        public ITaskItem[] Files { get; set; }
+
+        /// <summary>
+        /// The algorithm. Allowed values: SHA256, SHA384, SHA512. Default = SHA256.
+        /// </summary>
+        public string Algorithm { get; set; } = _defaultFileHashAlgorithm;
+
+        /// <summary>
+        /// The metadata name where the hash is stored in each item. Defaults to "FileHash".
+        /// </summary>
+        public string MetadataName { get; set; } = "FileHash";
+
+        /// <summary>
+        /// The encoding to use for generated hashs. Defaults to "hex". Allowed values = "base64".
+        /// </summary>
+        public string HashEncoding { get; set; } = _hashEncodingBase64;
+
+        /// <summary>
+        /// The hash of the file. This is only set if there was one item group passed in.
+        /// </summary>
+        [Output]
+        public string Hash { get; set; }
+
+        /// <summary>
+        /// The input files with additional metadata set to include the file hash.
+        /// </summary>
+        [Output]
+        public ITaskItem[] Items { get; set; }
+
+        public override bool Execute()
+        {
+            if (!SupportsAlgorithm(Algorithm))
+            {
+                Log.LogError("Unrecognized HashAlgorithm {0}", Algorithm);
+                return false;
+            }
+
+            System.Threading.Tasks.Parallel.ForEach(Files, file =>
+            {
+                if (!File.Exists(file.ItemSpec))
+                {
+                    Log.LogError("File not found '{0}", file.ItemSpec);
+                }
+            });
+
+            if (Log.HasLoggedErrors)
+            {
+                return false;
+            }
+
+            System.Threading.Tasks.Parallel.ForEach(Files, file =>
+            {
+                var hash = ComputeHash(Algorithm, file.ItemSpec);
+                file.SetMetadata("FileHashAlgorithm", Algorithm);
+                file.SetMetadata(MetadataName, EncodeHash(hash));
+            });
+
+            Items = Files;
+
+            if (Files.Length == 1)
+            {
+                Hash = Files[0].GetMetadata(MetadataName);
+            }
+
+            return !Log.HasLoggedErrors;
+        }
+
+        internal static string EncodeHash(byte[] hash)
+        {
+           return Convert.ToBase64String(hash);
+        }
+
+        internal static bool SupportsAlgorithm(string algorithmName)
+            => _supportedAlgorithms.Contains(algorithmName);
+
+        internal static byte[] ComputeHash(string algorithmName, string filePath)
+        {
+            using (var stream = File.OpenRead(filePath))
+            using (var algorithm = CreateAlgorithm(algorithmName))
+            {
+                return algorithm.ComputeHash(stream);
+            }
+        }
+
+        private static readonly HashSet<string> _supportedAlgorithms
+            = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
+            {
+                "SHA256",
+                "SHA384",
+                "SHA512",
+            };
+
+        private static HashAlgorithm CreateAlgorithm(string algorithmName)
+        {
+            if (string.Equals(algorithmName, "SHA256", StringComparison.OrdinalIgnoreCase))
+            {
+                return SHA256.Create();
+            }
+            else if (string.Equals(algorithmName, "SHA384", StringComparison.OrdinalIgnoreCase))
+            {
+                return SHA384.Create();
+            }
+            else if (string.Equals(algorithmName, "SHA512", StringComparison.OrdinalIgnoreCase))
+            {
+                return SHA512.Create();
+            }
+
+            throw new ArgumentOutOfRangeException();
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Components/WebAssembly/Build/src/targets/Blazor.MonoRuntime.targets b/src/Components/WebAssembly/Build/src/targets/Blazor.MonoRuntime.targets
index 8c16457068..1b7614bbae 100644
--- a/src/Components/WebAssembly/Build/src/targets/Blazor.MonoRuntime.targets
+++ b/src/Components/WebAssembly/Build/src/targets/Blazor.MonoRuntime.targets
@@ -1,4 +1,6 @@
 <Project>
+  <UsingTask TaskName="BlazorGetFileHash" AssemblyFile="$(_BlazorTasksPath)" />
+
   <PropertyGroup>
     <BlazorWebAssemblyEnableLinking Condition="'$(BlazorWebAssemblyEnableLinking)' == '' AND '$(Configuration)' != 'Debug'">true</BlazorWebAssemblyEnableLinking>
     <BlazorWebAssemblyEnableLinking Condition="'$(BlazorWebAssemblyEnableLinking)' == ''">false</BlazorWebAssemblyEnableLinking>
@@ -153,9 +155,9 @@
       <_ExistingBlazorOutputWithTargetPath Include="@(_BlazorOutputWithTargetPath)" Condition="Exists('%(FullPath)')" />
     </ItemGroup>
 
-    <GetFileHash Files="@(_ExistingBlazorOutputWithTargetPath)" Algorithm="SHA256" HashEncoding="base64">
+    <BlazorGetFileHash Files="@(_ExistingBlazorOutputWithTargetPath)" Algorithm="SHA256" HashEncoding="base64">
       <Output TaskParameter="Items" ItemName="_BlazorOutputWithHash" />
-    </GetFileHash>
+    </BlazorGetFileHash>
 
     <ItemGroup>
       <_BlazorOutputWithIntegrity Include="@(_BlazorOutputWithHash)">