Add and integrate sdn-open

Originally I thought that not supporting %cd would be an issue,
making this kind of utility unclean.

It turns out the desire to launch xdg-open quickly is stronger.

CMakeLists.txt

@@ -33,9 +33,9 @@ include (GNUInstallDirs)
 # sdn-mc-ext should be in libexec, but we prefer it in PATH.
 install (TARGETS sdn sdn-mc-ext
 	DESTINATION ${CMAKE_INSTALL_BINDIR})
-install (PROGRAMS sdn-install sdn-view
+install (PROGRAMS sdn-install sdn-open sdn-view
 	DESTINATION ${CMAKE_INSTALL_BINDIR})
-install (FILES sdn.1 sdn-install.1 sdn-view.1
+install (FILES sdn.1 sdn-install.1 sdn-open.1 sdn-view.1
 	DESTINATION ${CMAKE_INSTALL_MANDIR}/man1)
 install (FILES LICENSE DESTINATION ${CMAKE_INSTALL_DOCDIR})
 

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2017 - 2024, Přemysl Eric Janouch <p@janouch.name>
+Copyright (c) 2017 - 2025, Přemysl Eric Janouch <p@janouch.name>
 
 Permission to use, copy, modify, and/or distribute this software for any
 purpose with or without fee is hereby granted.

NEWS

@@ -5,7 +5,7 @@ Unreleased
     - + and - adjust the selection using shell globs;
     - t and T insert the selection into the external command line
       in relative or absolute form, respectively;
-	- Enter is like t but enters directories, and M-Enter is synonymous to t;
+    - Enter is like t but enters directories;
     - C-g or Escape clear the selection, similarly to the editor.
 
  * Added an sdn-view script that can process Midnight Commander mc.ext.ini files
@@ -13,6 +13,9 @@ Unreleased
    while the original direct pager invocation has been moved to F13 (which also
    reflects Midnight Commander)
 
+ * Added an sdn-open script which does the same kind of processing as above
+   on top of xdg-open.  This is what is now executed by M-Enter.
+
 
 1.0.0 (2024-12-21)
 

sdn-open

@@ -0,0 +1,52 @@
+#!/bin/sh -e
+# sdn-open: an opener for sdn that makes use of Midnight Commander configuration
+# to make more kinds of files directly openable
+
+if [ "$#" -ne 1 ]
+then
+	echo "Usage: $0 FILE" >&2
+	exit 2
+fi
+
+# This handles both MC_DATADIR and odd installation locations.
+datadir=
+if command -v mc >/dev/null
+then datadir=$(mc --datadir | sed 's/ (.*)$//')
+fi
+
+config=
+for dir in "$HOME"/.config/mc "$datadir" /etc/mc
+do
+	if [ -n "$dir" -a -f "$dir/mc.ext.ini" ]
+	then
+		config=$dir/mc.ext.ini
+		break
+	fi
+done
+
+# This is often used in %env{} expansion, so let's be on the same page.
+export PAGER=${PAGER:-less}
+
+export MC_EXT_FILENAME=$(realpath "$1")
+export MC_EXT_BASENAME=$(basename "$1")
+export MC_EXT_CURRENTDIR=$(dirname "$MC_EXT_FILENAME")
+output=$(sdn-mc-ext <"$config" "$(file -Lbz "$1")" \
+	"$MC_EXT_FILENAME" "$MC_EXT_BASENAME" "$MC_EXT_CURRENTDIR" Open || :)
+kind=$(echo "$output" | sed -n 1p)
+command=$(echo "$output" | sed -n 2p)
+
+case "$kind" in
+cd)
+	# These mostly enter virtual filesystems, which we do not understand.
+	xdg-open "$MC_EXT_FILENAME"
+	;;
+'')
+	if [ -n "$command" ]
+	then eval "$command"
+	else xdg-open "$MC_EXT_FILENAME"
+	fi
+	;;
+*)
+	echo "Unsupported: $kind" >&2
+	exit 1
+esac

sdn-open.1

@@ -0,0 +1,23 @@
+.Dd November 20, 2025
+.Dt SDN-OPEN 1
+.Os
+.Sh NAME
+.Nm sdn-open
+.Nd run Midnight Commander open configuration externally
+.Sh SYNOPSIS
+.Nm sdn-open
+.Ar path
+.Sh DESCRIPTION
+.Nm
+invokes
+.Xr xdg-open 1
+on the passed filename.
+.Pp
+If it succeeds in finding a
+.Xr mc 1
+.Pa mc.ext.ini
+file, it will first process it, and run any matching command instead.
+.Sh REPORTING BUGS
+Use
+.Lk https://git.janouch.name/p/sdn
+to report bugs, request features, or submit pull requests.

sdn.cpp

@@ -1,7 +1,7 @@
 //
 // sdn: simple directory navigator
 //
-// Copyright (c) 2017 - 2024, Přemysl Eric Janouch <p@janouch.name>
+// Copyright (c) 2017 - 2025, Přemysl Eric Janouch <p@janouch.name>
 //
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted.
@@ -430,8 +430,8 @@ enum { ALT = 1 << 24, SYM = 1 << 25 };  // Outside the range of Unicode
 #define CTRL(char) ((char) == '?' ? 0x7f : (char) & 0x1f)
 
 #define ACTIONS(XX) XX(NONE) XX(HELP) XX(QUIT) XX(QUIT_NO_CHDIR) \
-	XX(ENTER) XX(CHOOSE) XX(CHOOSE_FULL) XX(VIEW_RAW) XX(VIEW) XX(EDIT) \
+	XX(ENTER) XX(OPEN) XX(CHOOSE) XX(CHOOSE_FULL) \
-	XX(SORT_LEFT) XX(SORT_RIGHT) \
+	XX(VIEW_RAW) XX(VIEW) XX(EDIT) XX(SORT_LEFT) XX(SORT_RIGHT) \
 	XX(SELECT) XX(DESELECT) XX(SELECT_TOGGLE) XX(SELECT_ABORT) \
 	XX(UP) XX(DOWN) XX(TOP) XX(BOTTOM) XX(HIGH) XX(MIDDLE) XX(LOW) \
 	XX(PAGE_PREVIOUS) XX(PAGE_NEXT) XX(SCROLL_UP) XX(SCROLL_DOWN) XX(CENTER) \
@@ -453,7 +453,7 @@ static const char *g_action_names[] = {ACTIONS(XX)};
 
 static map<wint_t, action> g_normal_actions {
 	{'\r', ACTION_ENTER}, {KEY (ENTER), ACTION_ENTER},
-	{ALT | '\r', ACTION_CHOOSE}, {ALT | KEY (ENTER), ACTION_CHOOSE},
+	{ALT | '\r', ACTION_OPEN}, {ALT | KEY (ENTER), ACTION_OPEN},
 	{'t', ACTION_CHOOSE}, {'T', ACTION_CHOOSE_FULL},
 	{KEY (F (1)), ACTION_HELP}, {'h', ACTION_HELP},
 	{KEY (F (3)), ACTION_VIEW}, {KEY (F (13)), ACTION_VIEW_RAW},
@@ -1056,13 +1056,18 @@ fun run_program (initializer_list<const char *> list, const string &filename) {
 	update ();
 }
 
+fun sdn_open (const string &filename) {
+	run_program ({(const char *) getenv ("SDN_OPENER"), "sdn-open", "xdg-open"},
+		filename);
+}
+
 fun view_raw (const string &filename) {
 	// XXX: we cannot realistically detect that the pager hasn't made a pause
 	// at the end of the file, so we can't ensure all contents have been seen
 	run_program ({(const char *) getenv ("PAGER"), "less", "cat"}, filename);
 }
 
-fun view (const string &filename) {
+fun sdn_view (const string &filename) {
 	run_program ({(const char *) getenv ("SDN_VIEWER"), "sdn-view",
 		(const char *) getenv ("PAGER"), "less", "cat"}, filename);
 }
@@ -1525,12 +1530,15 @@ fun handle (wint_t c) -> bool {
 	case ACTION_ENTER:
 		enter (current);
 		break;
+	case ACTION_OPEN:
+		sdn_open (current.filename);
+		break;
 	case ACTION_VIEW_RAW:
 		// Mimic mc, it does not seem sensible to page directories
 		(is_directory ? change_dir : view_raw) (current.filename);
 		break;
 	case ACTION_VIEW:
-		(is_directory ? change_dir : view) (current.filename);
+		(is_directory ? change_dir : sdn_view) (current.filename);
 		break;
 	case ACTION_EDIT:
 		edit (current.filename);