Merge pull request #151 from eerhardt/SHAOneShot

Use SHA256 OneShot APIs

Author: baronfel

Microsoft.NET.Build.Containers/Image.cs

@@ -152,8 +152,8 @@ public string GetDigest(JsonNode json)
 
     public static string GetSha(JsonNode json)
     {
-        using SHA256 mySHA256 = SHA256.Create();
-        byte[] hash = mySHA256.ComputeHash(Encoding.UTF8.GetBytes(json.ToJsonString()));
+        Span<byte> hash = stackalloc byte[SHA256.HashSizeInBytes];
+        SHA256.HashData(Encoding.UTF8.GetBytes(json.ToJsonString()), hash);
 
         return Convert.ToHexString(hash).ToLowerInvariant();
     }

Microsoft.NET.Build.Containers/Layer.cs

@@ -25,7 +25,7 @@ public static Layer FromDirectory(string directory, string containerPath)
     public static Layer FromFiles(IEnumerable<(string path, string containerPath)> fileList)
     {
         long fileSize;
-        byte[] hash;
+        Span<byte> hash = stackalloc byte[SHA256.HashSizeInBytes];
 
         string tempTarballPath = ContentStore.GetTempFile();
         using (FileStream fs = File.Create(tempTarballPath))
@@ -47,8 +47,7 @@ public static Layer FromFiles(IEnumerable<(string path, string containerPath)> f
 
             fs.Position = 0;
 
-            using SHA256 mySHA256 = SHA256.Create();
-            hash = mySHA256.ComputeHash(fs);
+            SHA256.HashData(fs, hash);
         }
 
         string contentHash = Convert.ToHexString(hash).ToLowerInvariant();

Test.Microsoft.NET.Build.Containers.Filesystem/LayerEndToEnd.cs

@@ -28,10 +28,9 @@ public void SingleFileInFolder()
 
         byte[] hashBytes;
 
-        using (SHA256 hasher = SHA256.Create())
         using (FileStream fs = File.OpenRead(l.BackingFile))
         {
-            hashBytes = hasher.ComputeHash(fs);
+            hashBytes = SHA256.HashData(fs);
         }
 
         Assert.AreEqual(Convert.ToHexString(hashBytes), l.Descriptor.Digest.Substring("sha256:".Length), ignoreCase: true);
@@ -67,10 +66,9 @@ public void TwoFilesInTwoFolders()
 
         byte[] hashBytes;
 
-        using (SHA256 hasher = SHA256.Create())
         using (FileStream fs = File.OpenRead(l.BackingFile))
         {
-            hashBytes = hasher.ComputeHash(fs);
+            hashBytes = SHA256.HashData(fs);
         }
 
         Assert.AreEqual(Convert.ToHexString(hashBytes), l.Descriptor.Digest.Substring("sha256:".Length), ignoreCase: true);