5 files changed, 52 insertions, 12 deletions
diff --git a/src/nvim/api/private/defs.h b/src/nvim/api/private/defs.h
index 5fb95a163f..a6710193ff 100644
--- a/src/nvim/api/private/defs.h
+++ b/src/nvim/api/private/defs.h
@@ -9,13 +9,15 @@
 #define STRING_INIT {.data = NULL, .size = 0}
 #define OBJECT_INIT { .type = kObjectTypeNil }
 #define ERROR_INIT { .set = false }
-#define REMOTE_TYPE(type) typedef uint64_t type
+#define REMOTE_TYPE(type) typedef handle_T type
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # define ArrayOf(...) Array
 # define DictionaryOf(...) Dictionary
 #endif
 
+typedef int handle_T;
+
 // Basic types
 typedef enum {
   kErrorTypeException,
@@ -31,6 +33,9 @@ typedef enum {
 /// Used as the message ID of notifications.
 #define NO_RESPONSE UINT64_MAX
 
+/// Used as channel_id when the call is local
+#define INVALID_CHANNEL UINT64_MAX
+
 typedef struct {
   ErrorType type;
   char msg[1024];
diff --git a/src/nvim/api/private/dispatch.h b/src/nvim/api/private/dispatch.h
new file mode 100644
index 0000000000..d91456c306
--- /dev/null
+++ b/src/nvim/api/private/dispatch.h
@@ -0,0 +1,23 @@
+#ifndef NVIM_API_PRIVATE_DISPATCH_H
+#define NVIM_API_PRIVATE_DISPATCH_H
+
+#include "nvim/api/private/defs.h"
+
+typedef Object (*ApiDispatchWrapper)(uint64_t channel_id,
+                                     uint64_t request_id,
+                                     Array args,
+                                     Error *error);
+
+/// The rpc_method_handlers table, used in msgpack_rpc_dispatch(), stores
+/// functions of this type.
+typedef struct {
+  ApiDispatchWrapper fn;
+  bool async;  // function is always safe to run immediately instead of being
+               // put in a request queue for handling when nvim waits for input.
+} MsgpackRpcRequestHandler;
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "api/private/dispatch.h.generated.h"
+#endif
+
+#endif  // NVIM_API_PRIVATE_DISPATCH_H
diff --git a/src/nvim/api/private/handle.c b/src/nvim/api/private/handle.c
index 69df7294ad..acb0fb332a 100644
--- a/src/nvim/api/private/handle.c
+++ b/src/nvim/api/private/handle.c
@@ -5,30 +5,26 @@
 #include "nvim/map.h"
 #include "nvim/api/private/handle.h"
 
-#define HANDLE_INIT(name) name##_handles = pmap_new(uint64_t)()
+#define HANDLE_INIT(name) name##_handles = pmap_new(handle_T)()
 
 #define HANDLE_IMPL(type, name) \
-  static PMap(uint64_t) *name##_handles = NULL; \
+  static PMap(handle_T) *name##_handles = NULL; /* NOLINT */ \
   \
-  type *handle_get_##name(uint64_t handle) \
+  type *handle_get_##name(handle_T handle) \
   { \
-    return pmap_get(uint64_t)(name##_handles, handle); \
+    return pmap_get(handle_T)(name##_handles, handle); \
   } \
   \
   void handle_register_##name(type *name) \
   { \
-    assert(!name->handle); \
-    name->handle = next_handle++; \
-    pmap_put(uint64_t)(name##_handles, name->handle, name); \
+    pmap_put(handle_T)(name##_handles, name->handle, name); \
   } \
   \
   void handle_unregister_##name(type *name) \
   { \
-    pmap_del(uint64_t)(name##_handles, name->handle); \
+    pmap_del(handle_T)(name##_handles, name->handle); \
   }
 
-static uint64_t next_handle = 1;
-
 HANDLE_IMPL(buf_T, buffer)
 HANDLE_IMPL(win_T, window)
 HANDLE_IMPL(tabpage_T, tabpage)
diff --git a/src/nvim/api/private/handle.h b/src/nvim/api/private/handle.h
index 804e266dc3..30bbfbee1b 100644
--- a/src/nvim/api/private/handle.h
+++ b/src/nvim/api/private/handle.h
@@ -3,9 +3,10 @@
 
 #include "nvim/vim.h"
 #include "nvim/buffer_defs.h"
+#include "nvim/api/private/defs.h"
 
 #define HANDLE_DECLS(type, name) \
-  type *handle_get_##name(uint64_t handle); \
+  type *handle_get_##name(handle_T handle); \
   void handle_register_##name(type *name); \
   void handle_unregister_##name(type *name);
 
diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index c88bf2127a..7df2079d93 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -507,6 +507,10 @@ Object vim_to_object(typval_T *obj)
 
 buf_T *find_buffer_by_handle(Buffer buffer, Error *err)
 {
+  if (buffer == 0) {
+    return curbuf;
+  }
+
   buf_T *rv = handle_get_buffer(buffer);
 
   if (!rv) {
@@ -518,6 +522,10 @@ buf_T *find_buffer_by_handle(Buffer buffer, Error *err)
 
 win_T * find_window_by_handle(Window window, Error *err)
 {
+  if (window == 0) {
+    return curwin;
+  }
+
   win_T *rv = handle_get_window(window);
 
   if (!rv) {
@@ -529,6 +537,10 @@ win_T * find_window_by_handle(Window window, Error *err)
 
 tabpage_T * find_tab_by_handle(Tabpage tabpage, Error *err)
 {
+  if (tabpage == 0) {
+    return curtab;
+  }
+
   tabpage_T *rv = handle_get_tabpage(tabpage);
 
   if (!rv) {
@@ -764,12 +776,15 @@ static void init_type_metadata(Dictionary *metadata)
 
   Dictionary buffer_metadata = ARRAY_DICT_INIT;
   PUT(buffer_metadata, "id", INTEGER_OBJ(kObjectTypeBuffer));
+  PUT(buffer_metadata, "prefix", STRING_OBJ(cstr_to_string("nvim_buf_")));
 
   Dictionary window_metadata = ARRAY_DICT_INIT;
   PUT(window_metadata, "id", INTEGER_OBJ(kObjectTypeWindow));
+  PUT(window_metadata, "prefix", STRING_OBJ(cstr_to_string("nvim_win_")));
 
   Dictionary tabpage_metadata = ARRAY_DICT_INIT;
   PUT(tabpage_metadata, "id", INTEGER_OBJ(kObjectTypeTabpage));
+  PUT(tabpage_metadata, "prefix", STRING_OBJ(cstr_to_string("nvim_tabpage_")));
 
   PUT(types, "Buffer", DICTIONARY_OBJ(buffer_metadata));
   PUT(types, "Window", DICTIONARY_OBJ(window_metadata));