ui: Reimplement :suspend command for remote UIs.

- Remove suspend method from the UI protocol
- Handle `:suspend` by disconnecting the last channel that sent a request to
  nvim.

src/nvim/ex_docmd.c

@@ -71,6 +71,7 @@
 #include "nvim/os/time.h"
 #include "nvim/ex_cmds_defs.h"
 #include "nvim/mouse.h"
+#include "nvim/msgpack_rpc/channel.h"
 
 static int quitmore = 0;
 static int ex_pressedreturn = FALSE;
@@ -5398,10 +5399,16 @@ static void ex_stop(exarg_T *eap)
   /*
    * Disallow suspending for "rvim".
    */
-  if (!check_restricted()
-      ) {
-    if (!eap->forceit)
+  if (!check_restricted()) {
+    if (!eap->forceit) {
       autowrite_all();
+    }
+
+    if (abstract_ui) {
+      channel_close(last_message_source);
+      return;
+    }
+
     windgoto((int)Rows - 1, 0);
     out_char('\n');
     out_flush();

src/nvim/globals.h

@@ -1245,6 +1245,9 @@ EXTERN int curr_tmode INIT(= TMODE_COOK); /* contains current terminal mode */
 EXTERN bool embedded_mode INIT(= false);
 // Using the "abstract_ui" termcap
 EXTERN bool abstract_ui INIT(= false);
+// Id of the last channel sent a message to nvim. Used to determine the target
+// of channel-specific actions such as suspending
+EXTERN uint64_t last_message_source INIT(= 0);
 
 /// Used to track the status of external functions.
 /// Currently only used for iconv().

src/nvim/msgpack_rpc/channel.c

@@ -485,6 +485,7 @@ static void on_request_event(Event event)
 {
   RequestEvent *e = event.data;
   Channel *channel = e->channel;
+  last_message_source = channel->id;
   MsgpackRpcRequestHandler handler = e->handler;
   Array args = e->args;
   uint64_t request_id = e->request_id;

src/nvim/msgpack_rpc/remote_ui.c

@@ -97,7 +97,6 @@ static Object remote_ui_attach(uint64_t channel_id, uint64_t request_id,
   ui->update_fg = remote_ui_update_fg;
   ui->update_bg = remote_ui_update_bg;
   ui->flush = remote_ui_flush;
-  ui->suspend = remote_ui_suspend;
   pmap_put(uint64_t)(connected_uis, channel_id, ui);
   ui_attach(ui);
   return NIL;
@@ -319,9 +318,3 @@ static void remote_ui_flush(UI *ui)
   channel_send_event(data->channel_id, "redraw", data->buffer);
   data->buffer = (Array)ARRAY_DICT_INIT;
 }
-
-static void remote_ui_suspend(UI *ui)
-{
-  UIData *data = ui->data;
-  remote_ui_disconnect(data->channel_id);
-}

src/nvim/ui.c

@@ -117,9 +117,7 @@ void ui_write(uint8_t *s, int len)
  */
 void ui_suspend(void)
 {
-  if (abstract_ui) {
-    UI_CALL(suspend);
-  } else {
+  if (!abstract_ui) {
     mch_suspend();
   }
 }

src/nvim/ui.h

@@ -35,7 +35,6 @@ struct ui_t {
   void (*flush)(UI *ui);
   void (*update_fg)(UI *ui, int fg);
   void (*update_bg)(UI *ui, int bg);
-  void (*suspend)(UI *ui);
 };
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS

test/functional/ui/screen.lua

@@ -99,7 +99,6 @@ function Screen.new(width, height)
     _mouse_enabled = true,
     _bell = false,
     _visual_bell = false,
-    _suspended = true,
     _attrs = {},
     _cursor = {
       enabled = true, row = 1, col = 1
@@ -116,12 +115,10 @@ end
 
 function Screen:attach()
   request('ui_attach', self._width, self._height, true)
-  self._suspended = false
 end
 
 function Screen:detach()
   request('ui_detach')
-  self._suspended = true
 end
 
 function Screen:expect(expected, attr_ids)
@@ -286,10 +283,6 @@ function Screen:_handle_update_bg(bg)
   self._bg = bg
 end
 
-function Screen:_handle_suspend()
-  self._suspended = true
-end
-
 function Screen:_clear_block(top, lines, left, columns)
   for i = top, top + lines - 1 do
     self:_clear_row_section(i, left, left + columns - 1)