link: Create link object payload message

It describes future protocol version's link object payload. Child objects list
will be moved from the header to the payload. This is done due to the header
size restrictions.

Signed-off-by: Pavel Karpy <[email protected]>

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Added
 - Well-known `Version` node attribute (#267)
 - `INIT` split chain object type (#283)
+- Link object payload message (#283)
 
 ### Removed
 - Redundant object system attribute `__NEOFS__UPLOAD_ID` (#271)

link/types.proto

@@ -0,0 +1,20 @@
+syntax = "proto3";
+
+package neo.fs.v2.link;
+
+option go_package = "github.com/nspcc-dev/neofs-api-go/v2/link/grpc;link";
+option csharp_namespace = "Neo.FileStorage.API.Link";
+
+import "refs/types.proto";
+
+// Link is a helper object that contains the full list of the split chain objects'
+// IDs. It is created only after the whole split chain is known and signed. This
+// object is the only object that has access to every "child object" ID. It is NOT
+// required for the original object assembling. It MUST have ALL the "child objects"
+// IDs. IDs MUST be ordered according to the original payload split, meaning the
+// first payload part holder MUST be placed at the first place in the corresponding
+// link object.
+message Link {
+  // Full list of the "child" object IDs.
+  repeated neo.fs.v2.refs.ObjectID children = 1 [json_name = "children"];
+}

proto-docs/link.md

@@ -0,0 +1,66 @@
+# Protocol Documentation
+<a name="top"></a>
+
+## Table of Contents
+
+- [link/types.proto](#link/types.proto)
+
+  - Messages
+    - [Link](#neo.fs.v2.link.Link)
+
+
+- [Scalar Value Types](#scalar-value-types)
+
+
+
+<a name="link/types.proto"></a>
+<p align="right"><a href="#top">Top</a></p>
+
+## link/types.proto
+
+
+ <!-- end services -->
+
+
+<a name="neo.fs.v2.link.Link"></a>
+
+### Message Link
+Link is a helper object that contains the full list of the split chain objects'
+IDs. It is created only after the whole split chain is known and signed. This
+object is the only object that has access to every "child object" ID. It is NOT
+required for the original object assembling. It MUST have ALL the "child objects"
+IDs. IDs MUST be ordered according to the original payload split, meaning the
+first payload part holder MUST be placed at the first place in the corresponding
+link object.
+
+
+| Field | Type | Label | Description |
+| ----- | ---- | ----- | ----------- |
+| children | [neo.fs.v2.refs.ObjectID](#neo.fs.v2.refs.ObjectID) | repeated | Full list of the "child" object IDs. |
+
+ <!-- end messages -->
+
+ <!-- end enums -->
+
+
+
+## Scalar Value Types
+
+| .proto Type | Notes | C++ Type | Java Type | Python Type |
+| ----------- | ----- | -------- | --------- | ----------- |
+| <a name="double" /> double |  | double | double | float |
+| <a name="float" /> float |  | float | float | float |
+| <a name="int32" /> int32 | Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint32 instead. | int32 | int | int |
+| <a name="int64" /> int64 | Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint64 instead. | int64 | long | int/long |
+| <a name="uint32" /> uint32 | Uses variable-length encoding. | uint32 | int | int/long |
+| <a name="uint64" /> uint64 | Uses variable-length encoding. | uint64 | long | int/long |
+| <a name="sint32" /> sint32 | Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int32s. | int32 | int | int |
+| <a name="sint64" /> sint64 | Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int64s. | int64 | long | int/long |
+| <a name="fixed32" /> fixed32 | Always four bytes. More efficient than uint32 if values are often greater than 2^28. | uint32 | int | int |
+| <a name="fixed64" /> fixed64 | Always eight bytes. More efficient than uint64 if values are often greater than 2^56. | uint64 | long | int/long |
+| <a name="sfixed32" /> sfixed32 | Always four bytes. | int32 | int | int |
+| <a name="sfixed64" /> sfixed64 | Always eight bytes. | int64 | long | int/long |
+| <a name="bool" /> bool |  | bool | boolean | boolean |
+| <a name="string" /> string | A string must always contain UTF-8 encoded or 7-bit ASCII text. | string | String | str/unicode |
+| <a name="bytes" /> bytes | May contain any arbitrary sequence of bytes. | string | ByteString | str |
+

proto-docs/object.md

@@ -1038,14 +1038,15 @@ String presentation of object type is the same as definition:
 * TOMBSTONE
 * STORAGE_GROUP
 * LOCK
+* INIT
 
 | Name | Number | Description |
 | ---- | ------ | ----------- |
 | REGULAR | 0 | Just a normal object |
 | TOMBSTONE | 1 | Used internally to identify deleted objects |
 | STORAGE_GROUP | 2 | StorageGroup information |
 | LOCK | 3 | Object lock |
-| INIT | 4 | Initialization part of the regular split object |
+| INIT | 4 | Initialization part of the regular but split object |
 
 
  <!-- end enums -->