chore(storage): implement ListObjectACLs

storage/acl.go

@@ -67,6 +67,8 @@ type ProjectTeam struct {
 }
 
 // ACLHandle provides operations on an access control list for a Google Cloud Storage bucket or object.
+// ACLHandle on an object operates on the latest generation of that object by default.
+// Selecting a specific generation of an object is not currently supported by the client.
 type ACLHandle struct {
 	c           *Client
 	bucket      string

storage/client_test.go

@@ -652,6 +652,38 @@ func TestDeleteDefaultObjectACLEmulated(t *testing.T) {
 	})
 }
 
+func TestListObjectACLsEmulated(t *testing.T) {
+	transportClientTest(t, func(t *testing.T, project, bucket string, client storageClient) {
+		// Populate test object.
+		ctx := context.Background()
+		_, err := client.CreateBucket(ctx, project, &BucketAttrs{
+			Name: bucket,
+		})
+		if err != nil {
+			t.Fatalf("client.CreateBucket: %v", err)
+		}
+		want := ObjectAttrs{
+			Bucket: bucket,
+			Name:   fmt.Sprintf("testObject-%d", time.Now().Nanosecond()),
+		}
+		w := veneerClient.Bucket(bucket).Object(want.Name).NewWriter(context.Background())
+		if _, err := w.Write(randomBytesToWrite); err != nil {
+			t.Fatalf("failed to populate test object: %v", err)
+		}
+		if err := w.Close(); err != nil {
+			t.Fatalf("closing object: %v", err)
+		}
+		acls, err := client.ListObjectACLs(ctx, bucket, want.Name)
+		if err != nil {
+			t.Fatalf("client.ListObjectACLs: %v", err)
+		}
+		// Assert there are 4 ObjectACL entities, including object owner and project owners/editors/viewers.
+		if got, want := len(acls), 4; want != got {
+			t.Errorf("ListObjectACLs: got %v, want %v items", acls, want)
+		}
+	})
+}
+
 func TestOpenReaderEmulated(t *testing.T) {
 	transportClientTest(t, func(t *testing.T, project, bucket string, client storageClient) {
 		// Populate test data.

storage/grpc_client.go

@@ -611,9 +611,17 @@ func (c *grpcStorageClient) UpdateBucketACL(ctx context.Context, bucket string,
 func (c *grpcStorageClient) DeleteObjectACL(ctx context.Context, bucket, object string, entity ACLEntity, opts ...storageOption) error {
 	return errMethodNotSupported
 }
+
+// ListObjectACLs retrieves object ACL entries. By default, it operates on the latest generation of this object.
+// Selecting a specific generation of this object is not currently supported by the client.
 func (c *grpcStorageClient) ListObjectACLs(ctx context.Context, bucket, object string, opts ...storageOption) ([]ACLRule, error) {
-	return nil, errMethodNotSupported
+	o, err := c.GetObject(ctx, bucket, object, defaultGen, nil, nil, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return o.ACL, nil
 }
+
 func (c *grpcStorageClient) UpdateObjectACL(ctx context.Context, bucket, object string, entity ACLEntity, role ACLRole, opts ...storageOption) (*ACLRule, error) {
 	return nil, errMethodNotSupported
 }

storage/http_client.go

@@ -614,9 +614,25 @@ func configureACLCall(ctx context.Context, userProject string, call interface{ H
 func (c *httpStorageClient) DeleteObjectACL(ctx context.Context, bucket, object string, entity ACLEntity, opts ...storageOption) error {
 	return errMethodNotSupported
 }
+
+// ListObjectACLs retrieves object ACL entries. By default, it operates on the latest generation of this object.
+// Selecting a specific generation of this object is not currently supported by the client.
 func (c *httpStorageClient) ListObjectACLs(ctx context.Context, bucket, object string, opts ...storageOption) ([]ACLRule, error) {
-	return nil, errMethodNotSupported
+	s := callSettings(c.settings, opts...)
+	var acls *raw.ObjectAccessControls
+	var err error
+	req := c.raw.ObjectAccessControls.List(bucket, object)
+	configureACLCall(ctx, s.userProject, req)
+	err = run(ctx, func() error {
+		acls, err = req.Do()
+		return err
+	}, s.retry, s.idempotent, setRetryHeaderHTTP(req))
+	if err != nil {
+		return nil, err
+	}
+	return toObjectACLRules(acls.Items), nil
 }
+
 func (c *httpStorageClient) UpdateObjectACL(ctx context.Context, bucket, object string, entity ACLEntity, role ACLRole, opts ...storageOption) (*ACLRule, error) {
 	return nil, errMethodNotSupported
 }