feat(oci): oci helm support [r8s-361] (#787)

pkg/liboras/generic_listrepo_client.go

@@ -0,0 +1,47 @@
+package liboras
+
+import (
+	"context"
+	"errors"
+
+	portainer "github.com/portainer/portainer/api"
+	"oras.land/oras-go/v2/registry/remote"
+)
+
+// GenericListRepoClient implements RepositoryListClient for standard OCI registries
+// This client handles repository listing for registries that follow the standard OCI distribution spec
+type GenericListRepoClient struct {
+	registry       *portainer.Registry
+	registryClient *remote.Registry
+}
+
+// NewGenericListRepoClient creates a new generic repository listing client
+func NewGenericListRepoClient(registry *portainer.Registry) *GenericListRepoClient {
+	return &GenericListRepoClient{
+		registry: registry,
+		// registryClient will be set when needed
+	}
+}
+
+// SetRegistryClient sets the ORAS registry client for repository listing operations
+func (c *GenericListRepoClient) SetRegistryClient(registryClient *remote.Registry) {
+	c.registryClient = registryClient
+}
+
+// ListRepositories fetches repositories from a standard OCI registry using ORAS
+func (c *GenericListRepoClient) ListRepositories(ctx context.Context) ([]string, error) {
+	if c.registryClient == nil {
+		return nil, errors.New("registry client not initialized for repository listing")
+	}
+
+	var repositories []string
+	err := c.registryClient.Repositories(ctx, "", func(repos []string) error {
+		repositories = append(repositories, repos...)
+		return nil
+	})
+	if err != nil {
+		return nil, errors.New("failed to list repositories")
+	}
+
+	return repositories, nil
+}