From a45c1c45a29cbf9416bb03f77c99b383db43e7a0 Mon Sep 17 00:00:00 2001
From: Eli Zaretskii <eliz@gnu.org>
Date: Mon, 18 Apr 2022 21:04:57 +0300
Subject: [PATCH] Minor improvements in 'restart-emacs' on MS-Windows

* src/w32.c (w32_reexec_emacs): Explicitly request a new console
for the restarted Emacs -nw, and specify its dimensions.  Specify
NULL instead of security attributes, per examples on the Internet.
* src/w32console.c (initialize_w32_display): Check errors in call
to GetConsoleCursorInfo.
---
 src/w32.c        | 51 ++++++++++++++++++++++++++----------------------
 src/w32console.c | 12 +++++++++---
 2 files changed, 37 insertions(+), 26 deletions(-)

diff --git a/src/w32.c b/src/w32.c
index e4237579d84..74923ffece9 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -10628,41 +10628,46 @@ int
 w32_reexec_emacs (char *cmd_line, const char *wdir)
 {
   STARTUPINFO si;
-  SECURITY_ATTRIBUTES sec_attrs;
   BOOL status;
   PROCESS_INFORMATION proc_info;
+  DWORD dwCreationFlags = NORMAL_PRIORITY_CLASS;
 
   GetStartupInfo (&si);		/* Use the same startup info as the caller.  */
-  sec_attrs.nLength = sizeof (sec_attrs);
-  sec_attrs.lpSecurityDescriptor = NULL;
-  sec_attrs.bInheritHandle = FALSE;
-
-  /* Make sure we are in the original directory, in case the command
-     line specifies the program as a relative file name.  */
-  chdir (wdir);
-
-  /* This is a kludge: it causes the restarted "emacs -nw" to have a
-     new console window created for it, and that new window might have
-     different (default) properties, not the ones of the parent
-     process's console window.  But without this, restarting Emacs in
-     the -nw mode simply doesn't work.  FIXME!  */
   if (inhibit_window_system)
     {
-      if (!FreeConsole ())
+      HANDLE screen_handle;
+      CONSOLE_SCREEN_BUFFER_INFO screen_info;
+
+      screen_handle = GetStdHandle (STD_OUTPUT_HANDLE);
+      if (screen_handle != INVALID_HANDLE_VALUE
+	  && GetConsoleScreenBufferInfo (screen_handle, &screen_info))
 	{
-	  errno = ENOEXEC;
-	  return -1;
+	  /* Make the restarted Emacs's console window the same
+	     dimensions as ours.  FIXME: for some reason this doesn't
+	     seem to work!  */
+	  si.dwFlags |= STARTF_USECOUNTCHARS;
+	  si.dwXCountChars = screen_info.dwSize.X;
+	  si.dwYCountChars = screen_info.dwSize.Y;
 	}
+      /* This is a kludge: it causes the restarted "emacs -nw" to have
+	 a new console window created for it, and that new window
+	 might have different (default) properties, not the ones of
+	 the parent process's console window.  But without this,
+	 restarting Emacs in the -nw mode simply doesn't work.
+	 FIXME!  */
+      dwCreationFlags = CREATE_NEW_CONSOLE;
     }
 
-  status = CreateProcess (NULL,		/* program */
+  /* Make sure we are in the original directory, in case the command
+     line specifies the program as a relative file name.  */
+  chdir (wdir);
+
+  status = CreateProcess (NULL,		/* no program, take from command line */
 			  cmd_line,	/* command line */
-			  &sec_attrs,	/* process attributes */
+			  NULL,
 			  NULL,		/* thread attributes */
-			  TRUE,		/* inherit handles? */
-			  inhibit_window_system
-			  ? 0		/* inherit parent's console */
-			  : NORMAL_PRIORITY_CLASS,
+			  FALSE,	/* unherit handles? */
+			  dwCreationFlags,
 			  NULL,		/* environment */
 			  wdir,		/* initial directory */
 			  &si,		/* startup info */
diff --git a/src/w32console.c b/src/w32console.c
index 12e1f397894..09749126e03 100644
--- a/src/w32console.c
+++ b/src/w32console.c
@@ -716,10 +716,10 @@ initialize_w32_display (struct terminal *term, int *width, int *height)
 
   if (cur_screen == INVALID_HANDLE_VALUE)
     {
-      printf ("CreateConsoleScreenBuffer failed in ResetTerm\n");
+      printf ("CreateConsoleScreenBuffer failed in initialize_w32_display\n");
       printf ("LastError = 0x%lx\n", GetLastError ());
       fflush (stdout);
-      exit (0);
+      exit (1);
     }
 #else
   cur_screen = prev_screen;
@@ -760,7 +760,13 @@ initialize_w32_display (struct terminal *term, int *width, int *height)
       }
   }
 
-  GetConsoleScreenBufferInfo (cur_screen, &info);
+  if (!GetConsoleScreenBufferInfo (cur_screen, &info))
+    {
+      printf ("GetConsoleScreenBufferInfo failed in initialize_w32_display\n");
+      printf ("LastError = 0x%lx\n", GetLastError ());
+      fflush (stdout);
+      exit (1);
+    }
 
   char_attr_normal = info.wAttributes;
 
-- 
2.39.2