bug#20481: 24.5; Newlines in message-box output don't work on Windows

bug#20481: 24.5; Newlines in message-box output don't work on Windows

[Adam Connor]

[-- Attachment #1: Type: text/plain, Size: 4778 bytes --]

If I display a message using message-box, newlines seem to be ignored.
For example
    (message-box "secret\nmessage")

will show the message "secretmessage". I have also tried \r\n with the
same result.

Not a huge problem but annoying...



In GNU Emacs 24.5.1 (x86_64-w64-mingw32)
 of 2015-04-11 on KAEL
Windowing system distributor `Microsoft Corp.', version 6.3.9600
Configured using:
 `configure --prefix=/z/emacs --host=x86_64-w64-mingw32
 --target=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --with-wide-int
 --with-jpeg --with-xpm --with-png --with-tiff --with-rsvg --with-xml2
 --with-gnutls --with-sound=yes --with-file-notification=yes
 --without-dbus --without-imagemagick 'CFLAGS=-Ofast
 -fomit-frame-pointer -funroll-loops -g0 -pipe' 'LDFLAGS=-static-libgcc
 -static-libstdc++ -static -s -Wl,-s''

Important settings:
  value of $LANG: ENU
  locale-coding-system: utf-8

Major mode: Emacs-Lisp

Minor modes in effect:
  my-keys-minor-mode: t
  tabbar-mwheel-mode: t
  tabbar-mode: t
  global-nlinum-mode: t
  nlinum-mode: t
  diff-auto-refine-mode: t
  global-undo-tree-mode: t
  undo-tree-mode: t
  recentf-mode: t
  desktop-save-mode: t
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
Auto-saving...
Quit
Saving file c:/Users/Adam/.emacs.d/elisp/file-utils.el...
Wrote c:/Users/Adam/.emacs.d/elisp/file-utils.el
file-older-than
Quit
Saving file c:/Users/Adam/.emacs.d/elisp/file-utils.el...
Wrote c:/Users/Adam/.emacs.d/elisp/file-utils.el
file-older-than
Wrote c:/Users/Adam/.emacs.d/packages-updated.txt
nil

Load-path shadows:
~/.emacs.d/lib/tabbar-master/revive hides ~/.emacs.d/lib/revive
c:/Users/Adam/.emacs.d/elpa/dash-2.10.0/dash hides ~/.emacs.d/lib/dash
~/.emacs.d/lib/indent hides
c:/dev/emacs-w64-24.5/share/emacs/24.5/lisp/indent

Features:
(shadow sort mail-extr emacsbug sendmail debug eieio-opt speedbar
sb-image ezimage dframe find-func geiser-mode geiser-xref geiser-chicken
geiser-racket geiser-guile geiser-repl geiser-image geiser-compile
geiser-debug geiser-company geiser-doc geiser-menu geiser-autodoc eldoc
info-look geiser geiser-edit etags geiser-completion geiser-eval
geiser-connection tq geiser-syntax rx geiser-log geiser-popup view
geiser-impl geiser-custom geiser-base tar-mode thingatpt cmuscheme
scheme tabify autoload misearch multi-isearch lisp-mnt help-mode
mule-util gnutls mm-archive network-stream starttls url-cache
url-handlers finder-inf vc-git tabbar revbufs fill-column-indicator
nlinum linum virtualenvwrapper dash vc-svn psvn derived log-edit message
format-spec rfc822 mml mml-sec mailabbrev mail-utils gmm-utils
mailheader pcvs-util add-log diff-mode pp elp ediff-merg ediff-wind
ediff-diff ediff-mult ediff-help ediff-init ediff-util dired rdp-utils
web-mode flymake compile python json comint ring ansi-color util
undo-tree soap-client mm-decode mm-bodies mm-encode url-http tls
url-auth mail-parse rfc2231 rfc2047 rfc2045 ietf-drums url-gw url
url-proxy url-privacy url-expand url-methods url-history url-cookie
url-domsuf url-util url-parse auth-source eieio byte-opt bytecomp
byte-compile cl-extra cconv eieio-core gnus-util mm-util mail-prsvr
password-cache url-vars mailcap warnings xml easy-mmode virtualenv-utils
env-utils proj-utils cl-macs s cl gv ido edmacro kmacro ibuffer
framemove advice help-fns ehelp editorconfig file-utils recentf
tree-widget wid-edit desktop frameset cl-loaddefs cl-lib info easymenu
package epg-config misterioso-theme library-utils time-date tooltip
electric uniquify ediff-hook vc-hooks lisp-float-type mwheel dos-w32
ls-lisp w32-common-fns disp-table w32-win w32-vars tool-bar dnd fontset
image regexp-opt fringe tabulated-list newcomment lisp-mode prog-mode
register page menu-bar rfn-eshadow timer select scroll-bar mouse
jit-lock font-lock syntax facemenu font-core frame cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev
minibuffer nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
w32notify w32 multi-tty emacs)

Memory information:
((conses 16 699525 109272)
 (symbols 56 35736 0)
 (miscs 48 3413 2679)
 (strings 32 87577 14382)
 (string-bytes 1 2273331)
 (vectors 16 37061)
 (vector-slots 8 1409654 155048)
 (floats 8 159 939)
 (intervals 56 66830 766)
 (buffers 960 23))

[-- Attachment #2: Type: text/html, Size: 5260 bytes --]

bug#20481: 24.5; Newlines in message-box output don't work on Windows

[Eli Zaretskii]

> From: Adam Connor <adamc55@gmail.com>
> Date: Thu, 30 Apr 2015 22:18:13 -0500
> 
> If I display a message using message-box, newlines seem to be ignored.
> For example
> (message-box "secret\nmessage")
> 
> will show the message "secretmessage". I have also tried \r\n with the
> same result.
> 
> Not a huge problem but annoying...

Emacs on Windows doesn't really support message boxes (a.k.a. "dialog
boxes"), except for simple Yes/No questions popped up by yes-or-no-p.
For other messages, such as this one, Emacs on Windows emulates dialog
boxes by menus, and in a menu an item cannot contain a newline.

In this case, we faithfully pass the original string with a newline to
the MS-Windows menu API, and I believe it is dropped by Windows when
it displays the menu.

IOW, this is a missing feature: dialog boxes are not fully supported
on MS-Windows.

bug#20481: 24.5; Newlines in message-box output don't work on Windows

[Eli Zaretskii]

> From: Adam Connor <adamc55@gmail.com>
> Date: Fri, 1 May 2015 15:22:29 -0500
> 
> Thanks for explaining. That's unfortunate.

Patches to have Emacs on Windows support dialog boxes are welcome.
There's already code there, currently ifdef'ed away, which is
incomplete and "needs work".

bug#20481: 24.5; , Newlines in message-box output don't work on Windows

[Cecilio Pardo]

[-- Attachment #1: Type: text/plain, Size: 88 bytes --]

This patch adds support on Windows Vista an later for dialog boxes using 
TaskDialog.



[-- Attachment #2: patch.diff --]
[-- Type: text/plain, Size: 4868 bytes --]

diff --git a/src/w32menu.c b/src/w32menu.c
index cea4f4892a4..029e4bbf805 100644
--- a/src/w32menu.c
+++ b/src/w32menu.c
@@ -52,6 +52,9 @@
 
 #include "w32common.h"	/* for osinfo_cache */
 
+#include "commctrl.h"
+
+/* This only applies to OS versions prior to Vista. */
 #undef HAVE_DIALOGS /* TODO: Implement native dialogs.  */
 
 #ifndef TRUE
@@ -101,14 +104,148 @@ #define FALSE 0
 
 void w32_free_menu_strings (HWND);
 
+
+#define TASK_DIALOG_MAX_BUTTONS = 10;
+
+static HRESULT
+task_dialog_callback(HWND hwnd, UINT msg, WPARAM wParam,
+		     LPARAM lParam, LONG_PTR callback_data)
+{
+  switch (msg)
+    {
+    case TDN_CREATED:
+      /* Disable all buttons with ID >= 2000 */
+      for (int i = 0; i < TASK_DIALOG_MAX_BUTTONS; i++)
+	SendMessage( hwnd, TDM_ENABLE_BUTTON, 2000 + i, FALSE );
+      break;
+    }
+  return S_OK;
+}
+
 Lisp_Object
 w32_popup_dialog (struct frame *f, Lisp_Object header, Lisp_Object contents)
 {
-
   check_window_system (f);
 
-#ifndef HAVE_DIALOGS
+  void *task_dialog_indirect =
+    get_proc_addr (GetModuleHandle ("comctl32.dll"), "TaskDialogIndirect");
+
+  if (task_dialog_indirect)
+    {
+      /* Get the title as a UTF-16 string. */
+      CHECK_STRING (XCAR (contents));
+      char *title =  SSDATA (XCAR (contents));
+      int wide_length = sizeof(WCHAR) *
+	pMultiByteToWideChar (CP_UTF8, 0, title, -1, NULL, 0);
+      WCHAR *title_text_wide = alloca (wide_length);
+      pMultiByteToWideChar (CP_UTF8, 0, title, -1,
+			    title_text_wide, wide_length);
+
+      /* Prepare the struct with the dialog's buttons. */
+      TASKDIALOG_BUTTON buttons[TASK_DIALOG_MAX_BUTTONS];
+      Lisp_Object button_values[TASK_DIALOG_MAX_BUTTONS];
+      int button_count = 0;
+      Lisp_Object b = XCDR (contents);
+
+      while ( !NILP (b) ) {
+	if ( button_count >= TASK_DIALOG_MAX_BUTTONS )
+	  {
+	    /* We have too many buttons. We ignore the rest. */
+	    break;
+	  }
+
+	Lisp_Object item = XCAR(b);
+
+	if (Fconsp (item))
+	  {
+	    /* A normal item (text . value) */
+	    Lisp_Object item_name = XCAR (item);
+	    Lisp_Object item_value = XCDR (item);
+
+	    CHECK_STRING (item_name);
+
+	    int wide_length = sizeof(WCHAR) *
+	      pMultiByteToWideChar (CP_UTF8, 0, SSDATA (item_name), -1,
+				    NULL, 0);
+	    buttons[button_count].pszButtonText = alloca (wide_length);
+	    pMultiByteToWideChar (CP_UTF8, 0, SSDATA (item_name), -1,
+				  (LPWSTR)
+				  buttons[button_count].pszButtonText,
+				  wide_length);
+	    buttons[button_count].nButtonID = 1000 + button_count;
+	    button_values[button_count++] = item_value;
+	  }
+	else if (NILP (item))
+	  {
+	    /* A nil item means to put all following items on the
+	       right. We ignore this. */
+	  }
+	else if (STRINGP(item))
+	  {
+	    /* A string item means an unselectable button. We add a
+	       button, an then need to disable it on the callback.
+	       We use ids based on 2000 to mark these buttons */
+	    int wide_length = sizeof(WCHAR) *
+	      pMultiByteToWideChar (CP_UTF8, 0, SSDATA (item), -1, NULL, 0);
+	    buttons[button_count].pszButtonText = alloca (wide_length);
+	    pMultiByteToWideChar (CP_UTF8, 0, SSDATA (item), -1,
+				  (LPWSTR)
+				  buttons[button_count].pszButtonText,
+				  wide_length);
+	    buttons[button_count].nButtonID = 2000 + button_count;
+	    button_values[button_count++] = Qnil;
+	  }
+
+	b = XCDR (b);
+      }
+
+      int pressed_button = 0;
+
+      TASKDIALOGCONFIG config = { };
+      config.hwndParent = FRAME_W32_WINDOW (f);
+      config.cbSize = sizeof(config);
+      config.hInstance = hinst;
+      config.dwFlags = TDF_ALLOW_DIALOG_CANCELLATION;
+      config.pfCallback = task_dialog_callback;
+
+      config.pszWindowTitle = L"Question";
+      if (!NILP (header))
+	{
+	  config.pszWindowTitle = L"Information";
+	  config.pszMainIcon = TD_INFORMATION_ICON;
+	}
 
+      config.pszMainInstruction = title_text_wide;
+      config.pButtons = buttons;
+      config.cButtons = button_count;
+
+      if (!SUCCEEDED (TaskDialogIndirect (&config, &pressed_button,
+					  NULL, NULL)))
+	return quit ();
+
+
+      switch (pressed_button)
+	{
+	case IDOK:
+	  /* This can only happen if no buttons where
+	     provided. An OK button is automatically added. */
+	  return Qt;
+	case IDCANCEL:
+	  /* The user closed the dialog without using the buttons */
+	  return quit();
+	default:
+	  /* One of the specified buttons. */
+	  int button_index = pressed_button - 1000;
+	  if ( button_index >= 0 && button_index < button_count )
+	    return button_values[button_index];
+	  return quit();
+	}
+    }
+
+  /* If we get here, TaskDialog is not supported. Use MessageBox/Menu. */
+
+
+#ifndef HAVE_DIALOGS
   /* Handle simple Yes/No choices as MessageBox popups.  */
   if (is_simple_dialog (contents))
     return simple_dialog_show (f, contents, header);

bug#20481: 24.5; , Newlines in message-box output don't work on Windows

[Eli Zaretskii]

> Date: Mon, 19 Aug 2024 18:13:31 +0200
> From: Cecilio Pardo <cpardo@imayhem.com>
> 
> This patch adds support on Windows Vista an later for dialog boxes using 
> TaskDialog.

Thanks.

First, to accept a contribution of this size we'll need a
copyright-assignment paperwork from you.  Should I send you the form
to fill with instructions to go with it, so you could start the
paperwork rolling?

A few comments about the patch:

> +  void *task_dialog_indirect =
> +    get_proc_addr (GetModuleHandle ("comctl32.dll"), "TaskDialogIndirect");
> +
> +  if (task_dialog_indirect)

A minor optimization is to call get_proc_addr only once and save the
result in a static variable.  We use this technique in many places in
Emacs, and I see no reason not to do that here.

> +      /* Get the title as a UTF-16 string. */
> +      CHECK_STRING (XCAR (contents));
> +      char *title =  SSDATA (XCAR (contents));
> +      int wide_length = sizeof(WCHAR) *
> +	pMultiByteToWideChar (CP_UTF8, 0, title, -1, NULL, 0);
> +      WCHAR *title_text_wide = alloca (wide_length);
> +      pMultiByteToWideChar (CP_UTF8, 0, title, -1,
> +			    title_text_wide, wide_length);

The text of Lisp strings is stored by Emacs in a super-set of UTF-8,
so it cannot be safely passed to MultiByteToWideChar.  You need to
encode it in UTF-8 first (use ENCODE_UTF_8).

> +	    CHECK_STRING (item_name);
> +
> +	    int wide_length = sizeof(WCHAR) *
> +	      pMultiByteToWideChar (CP_UTF8, 0, SSDATA (item_name), -1,
> +				    NULL, 0);
> +	    buttons[button_count].pszButtonText = alloca (wide_length);
> +	    pMultiByteToWideChar (CP_UTF8, 0, SSDATA (item_name), -1,
> +				  (LPWSTR)
> +				  buttons[button_count].pszButtonText,
> +				  wide_length);

Same here.

> +	else if (NILP (item))
> +	  {
> +	    /* A nil item means to put all following items on the
> +	       right. We ignore this. */
                    ^^              ^^
Our convention is to leave two spaces between sentences in
documentation, comments, and strings.  We also leave two spaces at the
end of C comments, before the closing "*/" (here and elsewhere in the
patch).

> +	else if (STRINGP(item))
                       ^^
Another stylistic nit: please leave one space between the name of a
function/macro and the opening parenthesis that follows it (here and
elsewhere in the patch).

> +	    /* A string item means an unselectable button. We add a
> +	       button, an then need to disable it on the callback.
> +	       We use ids based on 2000 to mark these buttons */
> +	    int wide_length = sizeof(WCHAR) *
> +	      pMultiByteToWideChar (CP_UTF8, 0, SSDATA (item), -1, NULL, 0);
> +	    buttons[button_count].pszButtonText = alloca (wide_length);
> +	    pMultiByteToWideChar (CP_UTF8, 0, SSDATA (item), -1,
> +				  (LPWSTR)
> +				  buttons[button_count].pszButtonText,
> +				  wide_length);

UTF-8 encoding again.

bug#20481: 24.5; , Newlines in message-box output don't work on Windows

[Cecilio Pardo]

On 19/08/2024 19:44, Eli Zaretskii wrote:
>> Date: Mon, 19 Aug 2024 18:13:31 +0200
>> From: Cecilio Pardo <cpardo@imayhem.com>
>>
>> This patch adds support on Windows Vista an later for dialog boxes using
>> TaskDialog.
> Thanks.
>
> First, to accept a contribution of this size we'll need a
> copyright-assignment paperwork from you.  Should I send you the form
> to fill with instructions to go with it, so you could start the
> paperwork rolling?

Yes, please.

Thanks for your comments.