Push up pushIndex and prepare for reusable copy methods

src/main/java/land/oras/LayoutRef.java

@@ -69,6 +69,34 @@
         return withTag(digest);
     }
 
+    /**
+     * Convert the manifest to a layout ref.
+     * @param layout The OCI layout.
+     * @param manifest The manifest.
+     * @return The layout ref.
+     */
+    public static LayoutRef fromManifest(OCILayout layout, Manifest manifest) {
+        ManifestDescriptor descriptor = manifest.getDescriptor();
+        if (descriptor == null) {
+            throw new OrasException("Manifest descriptor is null");
+        }
+        return new LayoutRef(layout.getPath(), manifest.getDescriptor().getDigest());
+    }
+
+    /**
+     * Convert the manifest to a layout ref.
+     * @param layout The OCI layout.
+     * @param index The manifest.
+     * @return The layout ref.
+     */
+    public static LayoutRef fromIndex(OCILayout layout, Index index) {
+        ManifestDescriptor descriptor = index.getDescriptor();
+        if (descriptor == null) {
+            throw new OrasException("Index descriptor is null");
+        }
+        return new LayoutRef(layout.getPath(), index.getDescriptor().getDigest());
+    }
+
     /**
      * Parse the layout ref with folder and tag.
      * @param name The layout ref.

src/main/java/land/oras/OCI.java

@@ -211,6 +211,14 @@ public abstract Manifest pushArtifact(
      */
     public abstract Manifest pushManifest(T ref, Manifest manifest);
 
+    /**
+     * Push an index
+     * @param ref The ref
+     * @param index The index
+     * @return The index
+     */
+    public abstract Index pushIndex(T ref, Index index);
+
     /**
      * Retrieve an index
      * @param ref The ref

src/main/java/land/oras/OCILayout.java

@@ -152,13 +152,54 @@
         // Write blobs
         try {
             writeManifest(manifest);
-            writeIndex(index);
+            writeOCIIndex(index);
         } catch (IOException e) {
             throw new OrasException("Failed to write manifest", e);
         }
         return manifest;
     }
 
+    @Override
+    public Index pushIndex(LayoutRef layoutRef, Index index) {
+        byte[] indexData = index.getJson() != null
+                ? index.getJson().getBytes()
+                : index.toJson().getBytes();
+
+        String indexDigest = layoutRef
+                .getAlgorithm()
+                .digest(
+                        index.getJson() != null
+                                ? index.getJson().getBytes()
+                                : index.toJson().getBytes());
+
+        ManifestDescriptor indexDescriptor = ManifestDescriptor.of(
+                        Const.DEFAULT_INDEX_MEDIA_TYPE, indexDigest, indexData.length)
+                .withAnnotations(
+                        index.getAnnotations() == null || index.getAnnotations().isEmpty()
+                                ? null
+                                : index.getAnnotations())
+                .withArtifactType(index.getMediaType());
+        if (layoutRef.getTag() != null && !layoutRef.isValidDigest()) {
+            Map<String, String> newAnnotations = new HashMap<>();
+            if (index.getAnnotations() != null) {
+                newAnnotations.putAll(index.getAnnotations());
+            }
+            newAnnotations.put(Const.ANNOTATION_REF, layoutRef.getTag());
+            indexDescriptor = indexDescriptor.withAnnotations(newAnnotations);
+        }
+
+        Index ociIndex = Index.fromPath(getIndexPath()).withNewManifests(indexDescriptor);
+
+        // Write blobs
+        try {
+            writeIndex(index);
+            writeOCIIndex(ociIndex);
+        } catch (IOException e) {
+            throw new OrasException("Failed to write manifest", e);
+        }
+        return index;
+    }
+
     @Override
     public Index getIndex(LayoutRef ref) {
         Path path = getIndexPath();
@@ -348,7 +389,9 @@
 
                 // Write manifest as any blob
                 Manifest manifest = registry.getManifest(containerRef);
-                writeManifest(manifest);
+                String tag = containerRef.getTag();
+                LayoutRef layoutRef = LayoutRef.fromManifest(this, manifest).withTag(tag);
+                pushManifest(layoutRef, manifest);
 
                 if (recursive) {
                     LOG.debug("Recursively copy referrers");
@@ -359,28 +402,25 @@
                     }
                 }
 
-                // Write the index.json containing this manifest
-                Index index = Index.fromManifests(List.of(manifest.getDescriptor()));
-                writeIndex(index);
-
                 // Write config as any blob
                 writeConfig(registry, containerRef, manifest.getConfig());
             }
             // Index
             else if (registry.isIndexMediaType(contentType)) {
 
                 Index index = registry.getIndex(containerRef);
+                String tag = containerRef.getTag();
+                LayoutRef layoutRef = LayoutRef.fromIndex(this, index);
+                pushIndex(layoutRef.withTag(tag), index);
 
                 // Write all manifests and their config
                 for (ManifestDescriptor descriptor : index.getManifests()) {
                     Manifest manifest = registry.getManifest(containerRef.withDigest(descriptor.getDigest()));
-                    writeManifest(manifest.withDescriptor(descriptor));
+                    LayoutRef manifestLayoutRef = LayoutRef.fromManifest(this, manifest);
+                    pushManifest(manifestLayoutRef, manifest.withDescriptor(descriptor));
                     writeConfig(registry, containerRef, manifest.getConfig());
                 }
 
-                // Write the index
-                writeIndex(index);
-
             } else {
                 throw new OrasException("Unsupported content type: %s".formatted(contentType));
             }
@@ -497,7 +537,7 @@
         return getBlobPath().resolve(algorithm.getPrefix());
     }
 
-    private void writeIndex(Index index) throws IOException {
+    private void writeOCIIndex(Index index) throws IOException {
         Path indexFile = getIndexPath();
         Files.writeString(indexFile, index.getJson() != null ? index.getJson() : index.toJson());
         if (index.getJson() != null) {
@@ -528,6 +568,29 @@
         }
     }
 
+    private void writeIndex(Index index) throws IOException {
+        ManifestDescriptor descriptor = index.getDescriptor();
+        Path manifestFile = getBlobPath(descriptor);
+        Path manifestPrefixDirectory =
+                getBlobAlgorithmPath(index.getDescriptor().getDigest());
+
+        if (!Files.exists(manifestPrefixDirectory)) {
+            Files.createDirectory(manifestPrefixDirectory);
+        }
+        // Skip if already exists
+        if (Files.exists(manifestFile)) {
+            LOG.debug("Manifest already exists: {}", manifestFile);
+            return;
+        }
+        if (index.getJson() == null) {
+            LOG.debug("Writing new manifest: {}", manifestFile);
+            Files.writeString(manifestFile, index.toJson());
+        } else {
+            LOG.debug("Writing existing manifest: {}", manifestFile);
+            Files.writeString(manifestFile, index.getJson());
+        }
+    }
+
     private void writeConfig(Registry registry, ContainerRef containerRef, Config config) throws IOException {
         String configDigest = config.getDigest();
         Path configFile = getBlobPath(config);
@@ -576,6 +639,14 @@
         return layout;
     }
 
+    /**
+     * Return the path to the OCI layout
+     * @return The path to the OCI layout
+     */
+    public Path getPath() {
+        return path;
+    }
+
     /**
      * Builder for the registry
      */

src/main/java/land/oras/Registry.java

@@ -205,12 +205,7 @@ public Manifest pushManifest(ContainerRef containerRef, Manifest manifest) {
         return getManifest(containerRef);
     }
 
-    /**
-     * Push a manifest
-     * @param containerRef The container
-     * @param index The index
-     * @return The location
-     */
+    @Override
     public Index pushIndex(ContainerRef containerRef, Index index) {
         URI uri = URI.create("%s://%s".formatted(getScheme(), containerRef.getManifestsPath()));
         OrasHttpClient.ResponseWrapper<String> response = client.put(
@@ -571,7 +566,7 @@ private byte[] ensureDigest(ContainerRef ref, byte[] data) {
         SupportedAlgorithm algorithm = SupportedAlgorithm.fromDigest(ref.getDigest());
         String dataDigest = algorithm.digest(data);
         if (!ref.getDigest().equals(dataDigest)) {
-            throw new OrasException("Digest mismatch: %s != %s".formatted(ref.getTag(), dataDigest));
+            throw new OrasException("Digest mismatch: %s != %s".formatted(ref.getDigest(), dataDigest));
         }
         return data;
     }

src/test/java/land/oras/LayoutRefTest.java

@@ -45,6 +45,16 @@ void shouldParseLayoutWithAllParts() {
         assertFalse(layoutRef.isValidDigest(), "v1 is not a valid digest");
     }
 
+    @Test
+    void shouldCreateLayoutRefFromManifest() {
+        Manifest manifest = Manifest.empty();
+        OCILayout layout = OCILayout.Builder.builder().defaults(tempDir).build();
+        LayoutRef layoutRef = LayoutRef.fromManifest(layout, manifest);
+        assertNotNull(layoutRef);
+        assertEquals(layout.getPath().toString(), layoutRef.getFolder().toString());
+        assertEquals("sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a", layoutRef.getTag());
+    }
+
     @Test
     void shouldParseLayoutWithDigest() {
         String ociLayout = tempDir.resolve("foo").toString();