channel/msgpack_rpc: Refactor API dispatching

This is how API dispatching worked before this commit:

- The generated `msgpack_rpc_dispatch` function receives a the `msgpack_packer`
  argument.
- The response is incrementally built while validating/calling the API.
- Return values/errors are also packed into the `msgpack_packer` while the
  final response is being calculated.

Now the `msgpack_packer` argument is no longer provided, and the
`msgpack_rpc_dispatch` function returns `Object`/`Error` values to
`msgpack_rpc_call`, which will use those values to build the response in a
single pass.

This was done because the new `channel_send_call` function created the
possibility of having recursive API invocations, and this wasn't possible when
sharing a single `msgpack_sbuffer` across call frames(it was shared implicitly
through the `msgpack_packer` instance).

Since we only start to build the response when the necessary information has
been computed, it's now safe to share a single `msgpack_sbuffer` instance
across all channels and API invocations.

Some other changes also had to be performed:

- Handling of the metadata discover was moved to `msgpack_rpc_call`
- Expose more types as subtypes of `Object`, this was required to forward the
  return value from `msgpack_rpc_dispatch` to `msgpack_rpc_call`
- Added more helper macros for casting API types to `Object`
  any

1 files changed, 52 insertions, 3 deletions

diff --git a/src/nvim/os/msgpack_rpc_helpers.c b/src/nvim/os/msgpack_rpc_helpers.c
index 3af6794169..e2c277abe4 100644
--- a/src/nvim/os/msgpack_rpc_helpers.c
+++ b/src/nvim/os/msgpack_rpc_helpers.c
@@ -231,12 +231,41 @@ void msgpack_rpc_from_object(Object result, msgpack_packer *res)
       msgpack_rpc_from_array(result.data.array, res);
       break;
 
+    case kObjectTypePosition:
+      msgpack_rpc_from_position(result.data.position, res);
+      break;
+
+    case kObjectTypeBuffer:
+      msgpack_rpc_from_buffer(result.data.buffer, res);
+      break;
+
+    case kObjectTypeWindow:
+      msgpack_rpc_from_window(result.data.window, res);
+      break;
+
+    case kObjectTypeTabpage:
+      msgpack_rpc_from_tabpage(result.data.tabpage, res);
+      break;
+
+    case kObjectTypeStringArray:
+      msgpack_rpc_from_stringarray(result.data.stringarray, res);
+      break;
+
+    case kObjectTypeBufferArray:
+      msgpack_rpc_from_bufferarray(result.data.bufferarray, res);
+      break;
+
+    case kObjectTypeWindowArray:
+      msgpack_rpc_from_windowarray(result.data.windowarray, res);
+      break;
+
+    case kObjectTypeTabpageArray:
+      msgpack_rpc_from_tabpagearray(result.data.tabpagearray, res);
+      break;
+
     case kObjectTypeDictionary:
       msgpack_rpc_from_dictionary(result.data.dictionary, res);
       break;
-
-    default:
-      abort();
   }
 }
 
@@ -282,6 +311,10 @@ void msgpack_rpc_free_object(Object value)
     case kObjectTypeBoolean:
     case kObjectTypeInteger:
     case kObjectTypeFloat:
+    case kObjectTypePosition:
+    case kObjectTypeBuffer:
+    case kObjectTypeWindow:
+    case kObjectTypeTabpage:
       break;
 
     case kObjectTypeString:
@@ -292,6 +325,22 @@ void msgpack_rpc_free_object(Object value)
       msgpack_rpc_free_array(value.data.array);
       break;
 
+    case kObjectTypeStringArray:
+      msgpack_rpc_free_stringarray(value.data.stringarray);
+      break;
+
+    case kObjectTypeBufferArray:
+      msgpack_rpc_free_bufferarray(value.data.bufferarray);
+      break;
+
+    case kObjectTypeWindowArray:
+      msgpack_rpc_free_windowarray(value.data.windowarray);
+      break;
+
+    case kObjectTypeTabpageArray:
+      msgpack_rpc_free_tabpagearray(value.data.tabpagearray);
+      break;
+
     case kObjectTypeDictionary:
       msgpack_rpc_free_dictionary(value.data.dictionary);
       break;