feat(referrers): push manifest with subject

src/OrasProject.Oras/Registry/Remote/HttpResponseMessageExtensions.cs

@@ -113,7 +113,7 @@ internal static void CheckOciSubjectHeader(this HttpResponseMessage response, Re
         if (repository.ReferrersState == Referrers.ReferrersState.Unknown && response.Headers.Contains("OCI-Subject"))
         {
             // Set it to Supported when the response header contains OCI-Subject
-            repository.ReferrersState = Referrers.ReferrersState.Supported;
+            repository.SetReferrersState(true);
         }
 
         // If the "OCI-Subject" header is NOT set, it means that either the manifest

src/OrasProject.Oras/Registry/Remote/ManifestStore.cs

@@ -29,7 +29,7 @@
 
 public class ManifestStore(Repository repository) : IManifestStore
 {
     public Repository Repository { get; init; } = repository;
 
     /// <summary>
     /// Fetches the content identified by the descriptor.
@@ -248,10 +248,10 @@
                 desc.Annotations = imageManifest.Annotations;
                 break;
             default:
                 return;
         }
 
-        Repository.ReferrersState = Referrers.ReferrersState.NotSupported;
+        Repository.SetReferrersState(false);
         await UpdateReferrersIndex(subject, new Referrers.ReferrerChange(desc, Referrers.ReferrerOperation.Add), cancellationToken).ConfigureAwait(false);
     }
 
@@ -304,7 +304,7 @@
         }
 
         // 4. delete the dangling original referrers index, if applicable
         await DeleteAsync(oldDesc, cancellationToken).ConfigureAwait(false);
     }
 
     /// <summary>
@@ -323,8 +323,8 @@
             var (desc, content) = await FetchAsync(referrersTag, cancellationToken).ConfigureAwait(false);
             var index = JsonSerializer.Deserialize<Index>(content);
             if (index == null)
             {
                 throw new JsonException("null index manifests list");
             }
             return (desc, index.Manifests);
         }

src/OrasProject.Oras/Registry/Remote/Referrers.cs

@@ -70,46 +70,50 @@
                 updateRequired = true;
                 continue;
             }
+
             var basicDesc = oldReferrer.BasicDescriptor;
-            if (updatedReferrersSet.Contains(basicDesc))
+            if (referrerChange.ReferrerOperation == ReferrerOperation.Delete && Equals(basicDesc, referrerChange.Referrer.BasicDescriptor))
             {
-                // Skip any duplicate referrers
                 updateRequired = true;
                 continue;
             }
-            // Update the updatedReferrers list
-            // Add referrer index in the updatedReferrersSet
-            if (referrerChange.ReferrerOperation == ReferrerOperation.Delete && Descriptor.Equals(basicDesc, referrerChange.Referrer.BasicDescriptor))
+
+            if (updatedReferrersSet.Contains(basicDesc))
             {
+                // Skip any duplicate referrers
                 updateRequired = true;
                 continue;
             }
+
+            // Update the updatedReferrers list
+            // Add referrer into the updatedReferrersSet
             updatedReferrers.Add(oldReferrer);
             updatedReferrersSet.Add(basicDesc);
         }
 
-        var basicReferrerDesc = referrerChange.Referrer.BasicDescriptor;
         if (referrerChange.ReferrerOperation == ReferrerOperation.Add)
         {
+            var basicReferrerDesc = referrerChange.Referrer.BasicDescriptor;
             if (!updatedReferrersSet.Contains(basicReferrerDesc))
             {
                 // Add the new referrer only when it has not already existed in the updatedReferrersSet
                 updatedReferrers.Add(referrerChange.Referrer);
                 updatedReferrersSet.Add(basicReferrerDesc);
+                updateRequired = true;
             }
         }
 
         // Skip unnecessary update
-        if (!updateRequired && updatedReferrersSet.Count == oldReferrers.Count)
+        if (!updateRequired)
         {
             // Check for any new referrers in the updatedReferrersSet that are not present in the oldReferrers list
             foreach (var oldReferrer in oldReferrers)
             {
                 var basicDesc = oldReferrer.BasicDescriptor;
                 if (!updatedReferrersSet.Contains(basicDesc))
                 {
                     updateRequired = true;
                     break;
                 }
             }
 
@@ -117,7 +121,7 @@
             {
                 return (updatedReferrers, false);
             }
         }
         return (updatedReferrers, true);
     }
 }

src/OrasProject.Oras/Registry/Remote/Repository.cs

@@ -368,4 +368,9 @@ internal Reference ParseReferenceFromContentReference(string reference)
     /// <returns></returns>
     public async Task MountAsync(Descriptor descriptor, string fromRepository, Func<CancellationToken, Task<Stream>>? getContent = null, CancellationToken cancellationToken = default) 
         => await ((IMounter)Blobs).MountAsync(descriptor, fromRepository, getContent, cancellationToken).ConfigureAwait(false);
+
+    public void SetReferrersState(bool isSupported)
+    {
+        ReferrersState = isSupported ? Referrers.ReferrersState.Supported : Referrers.ReferrersState.NotSupported;
+    }
 }

src/OrasProject.Oras/Registry/Remote/RepositoryOptions.cs

@@ -51,13 +51,15 @@ public struct RepositoryOptions
     /// </summary>
     public int TagListPageSize { get; set; }
 
-    // SkipReferrersGc specifies whether to delete the dangling referrers
-    // index when referrers tag schema is utilized.
-    //  - If false, the old referrers index will be deleted after the new one is successfully uploaded.
-    //  - If true, the old referrers index is kept.
-    // By default, it is disabled (set to false). See also:
-    //  - https://github.com/opencontainers/distribution-spec/blob/v1.1.0/spec.md#referrers-tag-schema
-    //  - https://github.com/opencontainers/distribution-spec/blob/v1.1.0/spec.md#pushing-manifests-with-subject
-    //  - https://github.com/opencontainers/distribution-spec/blob/v1.1.0/spec.md#deleting-manifests
+    /// <summary>
+    /// SkipReferrersGc specifies whether to delete the dangling referrers
+    /// index when referrers tag schema is utilized.
+    ///  - If false, the old referrers index will be deleted after the new one is successfully uploaded.
+    ///  - If true, the old referrers index is kept.
+    /// By default, it is disabled (set to false). See also:
+    ///  - https://github.com/opencontainers/distribution-spec/blob/v1.1.0/spec.md#referrers-tag-schema
+    ///  - https://github.com/opencontainers/distribution-spec/blob/v1.1.0/spec.md#pushing-manifests-with-subject
+    ///  - https://github.com/opencontainers/distribution-spec/blob/v1.1.0/spec.md#deleting-manifests
+    /// </summary>
     public bool SkipReferrersGc { get; set; }
 }