Merge pull request #14717 from notomo/add-win-call-api

api: add nvim_win_call

2 files changed, 65 insertions, 0 deletions

diff --git a/src/nvim/api/window.c b/src/nvim/api/window.c
index a26213af98..178375d7f1 100644
--- a/src/nvim/api/window.c
+++ b/src/nvim/api/window.c
@@ -11,6 +11,7 @@
 #include "nvim/api/window.h"
 #include "nvim/api/private/defs.h"
 #include "nvim/api/private/helpers.h"
+#include "nvim/lua/executor.h"
 #include "nvim/ex_docmd.h"
 #include "nvim/vim.h"
 #include "nvim/buffer.h"
@@ -524,3 +525,39 @@ void nvim_win_close(Window window, Boolean force, Error *err)
   ex_win_close(force, win, tabpage == curtab ? NULL : tabpage);
   vim_ignored = try_leave(&tstate, err);
 }
+
+/// Calls a function with window as temporary current window.
+///
+/// @see |win_execute()|
+/// @see |nvim_buf_call()|
+///
+/// @param window     Window handle, or 0 for current window
+/// @param fun        Function to call inside the window (currently lua callable
+///                   only)
+/// @param[out] err   Error details, if any
+/// @return           Return value of function. NB: will deepcopy lua values
+///                   currently, use upvalues to send lua references in and out.
+Object nvim_win_call(Window window, LuaRef fun, Error *err)
+  FUNC_API_SINCE(7)
+  FUNC_API_LUA_ONLY
+{
+  win_T *win = find_window_by_handle(window, err);
+  if (!win) {
+    return NIL;
+  }
+  tabpage_T *tabpage = win_find_tabpage(win);
+
+  win_T *save_curwin;
+  tabpage_T *save_curtab;
+
+  try_start();
+  Object res = OBJECT_INIT;
+  if (switch_win_noblock(&save_curwin, &save_curtab, win, tabpage, true) ==
+      OK) {
+    Array args = ARRAY_DICT_INIT;
+    res = nlua_call_ref(fun, NULL, args, true, err);
+  }
+  restore_win_noblock(save_curwin, save_curtab, true);
+  try_end(err);
+  return res;
+}
diff --git a/test/functional/lua/vim_spec.lua b/test/functional/lua/vim_spec.lua
index 08a0552a38..836f514433 100644
--- a/test/functional/lua/vim_spec.lua
+++ b/test/functional/lua/vim_spec.lua
@@ -1931,6 +1931,34 @@ describe('lua stdlib', function()
       eq(buf2, val)
     end)
   end)
+
+  describe('vim.api.nvim_win_call', function()
+    it('can access window options', function()
+      command('vsplit')
+      local win1 = meths.get_current_win()
+      command('wincmd w')
+      local win2 = exec_lua [[
+        win2 = vim.api.nvim_get_current_win()
+        return win2
+      ]]
+      command('wincmd p')
+
+      eq('', meths.win_get_option(win1, 'winhighlight'))
+      eq('', meths.win_get_option(win2, 'winhighlight'))
+
+      local val = exec_lua [[
+        return vim.api.nvim_win_call(win2, function()
+          vim.cmd "setlocal winhighlight=Normal:Normal"
+          return vim.api.nvim_get_current_win()
+        end)
+      ]]
+
+      eq('', meths.win_get_option(win1, 'winhighlight'))
+      eq('Normal:Normal', meths.win_get_option(win2, 'winhighlight'))
+      eq(win1, meths.get_current_win())
+      eq(win2, val)
+    end)
+  end)
 end)
 
 describe('lua: require("mod") from packages', function()