nnn/plugins/preview-tabbed

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#!/usr/bin/env bash
# Description: tabbed/xembed based file previewer
#
# Dependencies:
# - tabbed (https://tools.suckless.org/tabbed): xembed host
# - xterm (or urxvt or st or alacritty) : xembed client for text-based preview
# - mpv (https://mpv.io): xembed client for video/audio
# - sxiv (https://github.com/muennich/sxiv) or,
# - nsxiv (https://codeberg.org/nsxiv/nsxiv) : xembed client for images
# - zathura (https://pwmt.org/projects/zathura): xembed client for PDF
# - nnn's nuke plugin for text preview and fallback
# nuke is a fallback for 'mpv', 'sxiv'/'nsxiv', and 'zathura', but has its
# own dependencies, see the script for more information
# - vim (or any editor/pager really)
# - file
# - mktemp
# - xdotool (optional, to keep main window focused)
#
# Usage:
# - Install the dependencies. Then set a NNN_FIFO
# and set a key for the plugin, then start `nnn`:
# $ NNN_FIFO=/tmp/nnn.fifo nnn
# - Launch the plugin with the designated key from nnn
#
# Notes:
# 1. This plugin needs a "NNN_FIFO" to work. See man.
# 2. If the same NNN_FIFO is used in multiple nnn instances, there will be one
# common preview window. With different FIFO paths, they will be independent.
# 3. This plugin only works on X, not on Wayland.
#
# How it works:
# We use `tabbed` [1] as a xembed [2] host, to have a single window
# owning each previewer window. So each previewer must be a xembed client.
# For text previewers, this is not an issue, as there are a lot of
# xembed-able terminal emulator (we default to `xterm`, but examples are
# provided for `urxvt` and `st`). For graphic preview this can be trickier,
# but a few popular viewers are xembed-able, we use:
# - `mpv`: multimedia player, for video/audio preview
# - `sxiv`/`nsxiv`: image viewer
# - `zathura`: PDF viewer
# - but we always fallback to `nuke` plugin
#
# [1]: https://tools.suckless.org/tabbed/
# [2]: https://specifications.freedesktop.org/xembed-spec/xembed-spec-latest.html
#
# Shell: Bash (job control is weakly specified in POSIX)
# Author: Léo Villeveygoux
XDOTOOL_TIMEOUT=2
PAGER=${PAGER:-"vim -R"}
NUKE="${XDG_CONFIG_HOME:-$HOME/.config}/nnn/plugins/nuke"
if [ -n "$WAYLAND_DISPLAY" ] ; then
echo "Wayland is not supported in preview-tabbed, this plugin could freeze your session!" >&2
exit 1
fi
if type xterm >/dev/null 2>&1 ; then
TERMINAL="xterm -into"
elif type urxvt >/dev/null 2>&1 ; then
TERMINAL="urxvt -embed"
elif type st >/dev/null 2>&1 ; then
TERMINAL="st -w"
elif type alacritty >/dev/null 2>&1 ; then
TERMINAL="alacritty --embed"
else
echo "No xembed term found" >&2
fi
term_nuke () {
# $1 -> $XID, $2 -> $FILE
$TERMINAL "$1" -e "$NUKE" "$2" &
}
start_tabbed () {
FIFO="$(mktemp -u)"
mkfifo "$FIFO"
tabbed > "$FIFO" &
jobs # Get rid of the "Completed" entries
TABBEDPID="$(jobs -p %%)"
if [ -z "$TABBEDPID" ] ; then
echo "Can't start tabbed"
exit 1
fi
read -r XID < "$FIFO"
rm -- "$FIFO"
}
get_viewer_pid () {
VIEWERPID="$(jobs -p %%)"
}
kill_viewer () {
if [ -n "$VIEWERPID" ] && jobs -p | grep "$VIEWERPID" ; then
kill "$VIEWERPID"
fi
}
sigint_kill () {
kill_viewer
kill "$TABBEDPID"
exit 0
}
previewer_loop () {
unset -v NNN_FIFO
# mute from now
exec >/dev/null 2>&1
MAINWINDOW="$(xdotool getactivewindow)"
start_tabbed
trap sigint_kill SIGINT
xdotool windowactivate "$MAINWINDOW"
# Bruteforce focus stealing prevention method,
# works well in floating window managers like XFCE
# but make interaction with the preview window harder
# (uncomment to use):
#xdotool behave "$XID" focus windowactivate "$MAINWINDOW" &
while read -r FILE ; do
jobs # Get rid of the "Completed" entries
if ! jobs | grep tabbed ; then
break
fi
if [ ! -e "$FILE" ] ; then
continue
fi
kill_viewer
MIME="$(file -bL --mime-type "$FILE")"
case "$MIME" in
video/*)
if type mpv >/dev/null 2>&1 ; then
mpv --force-window=immediate --loop-file --wid="$XID" "$FILE" &
else
term_nuke "$XID" "$FILE"
fi
;;
audio/*)
if type mpv >/dev/null 2>&1 ; then
mpv --force-window=immediate --loop-file --wid="$XID" "$FILE" &
else
term_nuke "$XID" "$FILE"
fi
;;
image/*)
if type sxiv >/dev/null 2>&1 ; then
sxiv -ae "$XID" "$FILE" &
elif type nsxiv >/dev/null 2>&1 ; then
nsxiv -ae "$XID" "$FILE" &
else
term_nuke "$XID" "$FILE"
fi
;;
application/pdf)
if type zathura >/dev/null 2>&1 ; then
zathura -e "$XID" "$FILE" &
else
term_nuke "$XID" "$FILE"
fi
;;
inode/directory)
$TERMINAL "$XID" -e nnn "$FILE" &
;;
text/*)
if [ -x "$NUKE" ] ; then
term_nuke "$XID" "$FILE"
else
# shellcheck disable=SC2086
$TERMINAL "$XID" -e $PAGER "$FILE" &
fi
;;
*)
if [ -x "$NUKE" ] ; then
term_nuke "$XID" "$FILE"
else
$TERMINAL "$XID" -e sh -c "file '$FILE' | $PAGER -" &
fi
;;
esac
get_viewer_pid
# following lines are not needed with the bruteforce xdotool method
ACTIVE_XID="$(xdotool getactivewindow)"
if [ $((ACTIVE_XID == XID)) -ne 0 ] ; then
xdotool windowactivate "$MAINWINDOW"
else
timeout "$XDOTOOL_TIMEOUT" xdotool behave "$XID" focus windowactivate "$MAINWINDOW" &
fi
done
kill "$TABBEDPID"
kill_viewer
}
if [ ! -r "$NNN_FIFO" ] ; then
echo "Can't read \$NNN_FIFO ('$NNN_FIFO')"
exit 1
fi
previewer_loop < "$NNN_FIFO" &
disown