feat(tui): builtin UI (TUI) sets client info #30397

Problem:
The default builtin UI client does not declare its client info. This
reduces discoverability and makes it difficult for plugins to identify
the UI.

Solution:
- Call nvim_set_client_info after attaching, as recommended by `:help dev-ui`.
- Also set the "pid" field.
- Also change `ui_active()` to return a count. Not directly relevant to
  this commit, but will be useful later.

src/nvim/api/vim.c

@@ -1586,6 +1586,7 @@ Array nvim_get_api_info(uint64_t channel_id, Arena *arena)
 ///
 /// @param attributes Arbitrary string:string map of informal client properties.
 ///     Suggested keys:
+///     - "pid":     Process id.
 ///     - "website": Client homepage URL (e.g. GitHub repository)
 ///     - "license": License description ("Apache 2", "GPLv3", "MIT", …)
 ///     - "logo":    URI or path to image, preferably small logo or icon.
@@ -1627,7 +1628,7 @@ void nvim_set_client_info(uint64_t channel_id, String name, Dictionary version,
 /// Gets information about a channel.
 ///
 /// @param chan channel_id, or 0 for current channel
-/// @returns Dictionary describing a channel, with these keys:
+/// @returns Channel info dict with these keys:
 ///    - "id"       Channel id.
 ///    - "argv"     (optional) Job arguments list.
 ///    - "stream"   Stream underlying the channel.
@@ -1639,14 +1640,12 @@ void nvim_set_client_info(uint64_t channel_id, String name, Dictionary version,
 ///         - "bytes"      Send and receive raw bytes.
 ///         - "terminal"   |terminal| instance interprets ASCII sequences.
 ///         - "rpc"        |RPC| communication on the channel is active.
-///    -  "pty"     (optional) Name of pseudoterminal. On a POSIX system this
-///                 is a device path like "/dev/pts/1". If the name is unknown,
-///                 the key will still be present if a pty is used (e.g. for
-///                 conpty on Windows).
-///    -  "buffer"  (optional) Buffer with connected |terminal| instance.
-///    -  "client"  (optional) Info about the peer (client on the other end of
-///                 the RPC channel), if provided by it via
-///                 |nvim_set_client_info()|.
+///    -  "pty"     (optional) Name of pseudoterminal. On a POSIX system this is a device path like
+///                 "/dev/pts/1". If unknown, the key will still be present if a pty is used (e.g.
+///                 for conpty on Windows).
+///    -  "buffer"  (optional) Buffer connected to |terminal| instance.
+///    -  "client"  (optional) Info about the peer (client on the other end of the RPC channel),
+///                 which it provided via |nvim_set_client_info()|.
 ///
 Dictionary nvim_get_chan_info(uint64_t channel_id, Integer chan, Arena *arena, Error *err)
   FUNC_API_SINCE(4)

src/nvim/main.c

@@ -351,7 +351,6 @@ int main(int argc, char **argv)
 
   // NORETURN: Start builtin UI client.
   if (ui_client_channel_id) {
-    time_finish();
     ui_client_run(remote_ui);  // NORETURN
   }
   assert(!ui_client_channel_id && !use_builtin_ui);
@@ -1514,7 +1513,7 @@ static void init_startuptime(mparm_T *paramp)
   }
   for (int i = 1; i < paramp->argc - 1; i++) {
     if (STRICMP(paramp->argv[i], "--startuptime") == 0) {
-      time_init(paramp->argv[i + 1], is_embed ? "Embedded" : "Primary/TUI");
+      time_init(paramp->argv[i + 1], is_embed ? "Embedded" : "Primary (or UI client)");
       time_start("--- NVIM STARTING ---");
       break;
     }

src/nvim/tui/input.c

@@ -464,7 +464,7 @@ static void tinput_timer_cb(uv_timer_t *handle)
 {
   TermInput *input = handle->data;
   // If the raw buffer is not empty, process the raw buffer first because it is
-  // processing an incomplete bracketed paster sequence.
+  // processing an incomplete bracketed paste sequence.
   size_t size = rstream_available(&input->read_stream);
   if (size) {
     size_t consumed = handle_raw_buffer(input, true, input->read_stream.read_pos, size);

src/nvim/ui.c

@@ -182,9 +182,10 @@ bool ui_override(void)
   return false;
 }
 
-bool ui_active(void)
+/// Gets the number of UIs connected to this server.
+size_t ui_active(void)
 {
-  return ui_count > 0;
+  return ui_count;
 }
 
 void ui_refresh(void)
@@ -197,7 +198,7 @@ void ui_refresh(void)
   int height = INT_MAX;
   bool ext_widgets[kUIExtCount];
   bool inclusive = ui_override();
-  memset(ext_widgets, ui_active(), ARRAY_SIZE(ext_widgets));
+  memset(ext_widgets, !!ui_active(), ARRAY_SIZE(ext_widgets));
 
   for (size_t i = 0; i < ui_count; i++) {
     RemoteUI *ui = uis[i];

src/nvim/ui_client.c

@@ -24,6 +24,7 @@
 #include "nvim/msgpack_rpc/channel_defs.h"
 #include "nvim/os/os.h"
 #include "nvim/os/os_defs.h"
+#include "nvim/profile.h"
 #include "nvim/tui/tui.h"
 #include "nvim/tui/tui_defs.h"
 #include "nvim/ui.h"
@@ -81,12 +82,15 @@ uint64_t ui_client_start_server(int argc, char **argv)
   return channel->id;
 }
 
+/// Attaches this client to the UI channel, and sets its client info.
 void ui_client_attach(int width, int height, char *term, bool rgb)
 {
+  //
+  // nvim_ui_attach
+  //
   MAXSIZE_TEMP_ARRAY(args, 3);
   ADD_C(args, INTEGER_OBJ(width));
   ADD_C(args, INTEGER_OBJ(height));
-
   MAXSIZE_TEMP_DICT(opts, 9);
   PUT_C(opts, "rgb", BOOLEAN_OBJ(rgb));
   PUT_C(opts, "ext_linegrid", BOOLEAN_OBJ(true));
@@ -94,7 +98,6 @@ void ui_client_attach(int width, int height, char *term, bool rgb)
   if (term) {
     PUT_C(opts, "term_name", CSTR_AS_OBJ(term));
   }
-
   PUT_C(opts, "term_colors", INTEGER_OBJ(t_colors));
   if (!ui_client_is_remote) {
     PUT_C(opts, "stdin_tty", BOOLEAN_OBJ(stdin_isatty));
@@ -108,6 +111,40 @@ void ui_client_attach(int width, int height, char *term, bool rgb)
 
   rpc_send_event(ui_client_channel_id, "nvim_ui_attach", args);
   ui_client_attached = true;
+
+  TIME_MSG("nvim_ui_attach");
+
+  //
+  // nvim_set_client_info
+  //
+  MAXSIZE_TEMP_ARRAY(args2, 5);
+  ADD_C(args2, CSTR_AS_OBJ("nvim-tui"));            // name
+  Object m = api_metadata();
+  Dictionary version = { 0 };
+  assert(m.data.dictionary.size > 0);
+  for (size_t i = 0; i < m.data.dictionary.size; i++) {
+    if (strequal(m.data.dictionary.items[i].key.data, "version")) {
+      version = m.data.dictionary.items[i].value.data.dictionary;
+      break;
+    } else if (i + 1 == m.data.dictionary.size) {
+      abort();
+    }
+  }
+  ADD_C(args2, DICTIONARY_OBJ(version));            // version
+  ADD_C(args2, CSTR_AS_OBJ("ui"));                  // type
+  // We don't send api_metadata.functions as the "methods" because:
+  // 1. it consumes memory.
+  // 2. it is unlikely to be useful, since the peer can just call `nvim_get_api`.
+  // 3. nvim_set_client_info expects a dict instead of an array.
+  ADD_C(args2, ARRAY_OBJ((Array)ARRAY_DICT_INIT));  // methods
+  MAXSIZE_TEMP_DICT(info, 9);                       // attributes
+  PUT_C(info, "website", CSTR_AS_OBJ("https://neovim.io"));
+  PUT_C(info, "license", CSTR_AS_OBJ("Apache 2"));
+  PUT_C(info, "pid", INTEGER_OBJ(os_get_pid()));
+  ADD_C(args2, DICTIONARY_OBJ(info));               // attributes
+  rpc_send_event(ui_client_channel_id, "nvim_set_client_info", args2);
+
+  TIME_MSG("nvim_set_client_info");
 }
 
 void ui_client_detach(void)
@@ -132,6 +169,8 @@ void ui_client_run(bool remote_ui)
     ELOG("test log message");
   }
 
+  time_finish();
+
   // os_exit() will be invoked when the client channel detaches
   while (true) {
     LOOP_PROCESS_EVENTS(&main_loop, resize_events, -1);