[#194] object: Add status returns related to LOCKs

Add `status.Object` section for object failures. Add `LOCKED` and
`LOCK_NON_REGULAR_OBJECT` codes to it. Return these codes from `Put` and
`Delete` RPCs of `ObjectService`.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

object/service.proto

@@ -35,7 +35,13 @@ service ObjectService {
   // Statuses:
   // - **OK** (0, SECTION_SUCCESS):
   // object has been successfully saved in the container;
-  // - Common failures (SECTION_FAILURE_COMMON).
+  // - Common failures (SECTION_FAILURE_COMMON);
+  // - **LOCKED** (2048, SECTION_OBJECT):
+  // placement of an object of type TOMBSTONE that includes at least one locked
+  // object is prohibited;
+  // - **LOCK_NON_REGULAR_OBJECT** (2049, SECTION_OBJECT):
+  // placement of an object of type LOCK that includes at least one object of
+  // type other than REGULAR is prohibited.
   rpc Put(stream PutRequest) returns (PutResponse);
 
   // Delete the object from a container. There is no immediate removal
@@ -44,7 +50,9 @@ service ObjectService {
   // Statuses:
   // - **OK** (0, SECTION_SUCCESS):
   // object has been successfully marked to be removed from the container;
-  // - Common failures (SECTION_FAILURE_COMMON).
+  // - Common failures (SECTION_FAILURE_COMMON);
+  // - **LOCKED** (2048, SECTION_OBJECT):
+  // deleting a locked object is prohibited.
   rpc Delete(DeleteRequest) returns (DeleteResponse);
 
   // Returns the object Headers without data payload. By default full header is

status/types.proto

@@ -103,8 +103,15 @@ enum Object {
     // Details:
     // - [**0**] Human-readable description.
     ACCESS_DENIED = 0;
+
     // [**2049**] Object not found.
     OBJECT_NOT_FOUND = 1;
+
+    // [**2050**] Operation rejected by the object lock.
+    LOCKED = 2;
+
+    // [**2051**] Locking an object with a non-REGULAR type rejected.
+    LOCK_NON_REGULAR_OBJECT = 3;
 }
 
 // Section of statuses for container-related operations.
@@ -117,6 +124,7 @@ enum Container {
 enum Session {
     // [**4096**] Token not found.
     TOKEN_NOT_FOUND = 0;
+
     // [**4097**] Token has expired.
     TOKEN_EXPIRED = 1;
 }