nnn/plugins/preview-tui
2021-05-15 23:02:01 +05:30

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#!/usr/bin/env sh
# Description: Terminal based file previewer
#
# Note: This plugin needs a "NNN_FIFO" to work. See man.
# For a more extended version of this script with additional optional dependencies, see preview-tui-ext.
#
# Dependencies:
# - Supports 4 independent methods to preview with:
# - tmux (>=3.0), or
# - kitty with allow_remote_control and listen_on set in kitty.conf, or
# - QuickLook on WSL (https://github.com/QL-Win/QuickLook)
# - $TERMINAL set to a terminal (it's xterm by default).
# - less or $PAGER
# - tree or exa or ls
# - mediainfo or file
# - mktemp
# - unzip
# - tar
# - man
# - optional: bat for code syntax highlighting
# - optional: ueberzug, kitty terminal, viu or catimg for images.
# - optional: scope.sh file viewer from ranger.
# 1. drop scope.sh executable in $PATH
# 2. set/export $USE_SCOPE as 1
# - optional: pistol file viewer (https://github.com/doronbehar/pistol).
# 1. install pistol
# 2. set/export $USE_PISTOL as 1
#
# Usage:
# You need to set a NNN_FIFO path and a key for the plugin with NNN_PLUG,
# then start `nnn`:
#
# $ nnn -a
#
# or
#
# $ NNN_FIFO=/tmp/nnn.fifo nnn
#
# Then launch the `preview-tui` plugin in `nnn`.
#
# If you provide the same NNN_FIFO to all nnn instances, there will be a
# single common preview window. If you provide different FIFO path (e.g.
# with -a), they will be independent.
#
# The previews will be shown in a tmux split. If that isn't possible, it
# will try to use a kitty terminal split. And as a final fallback, a
# different terminal window will be used ($TERMINAL).
#
# Tmux and kitty users can configure $SPLIT to either "h" or "v" to set a
# 'h'orizontal split or a 'v'ertical split (as in, the line that splits the
# windows will be horizontal or vertical).
#
# Kitty users need `allow_remote_control` set to `yes`, and `listen_on` set
# to e.g. "$TMPDIR/kitty". To customize the window split, `enabled_layouts`
# has to be set to `all` or `splits` (the former is the default value).
# This terminal is also able to show images without extra dependencies.
#
# Shell: POSIX compliant
# Authors: Todd Yamakawa, Léo Villeveygoux, @Recidiviste, Mario Ortiz Manero, Luuk van Baal
SPLIT="$SPLIT" # you can set a permanent split here
TERMINAL="$TERMINAL" # same goes for the terminal
USE_SCOPE="${USE_SCOPE:-0}"
USE_PISTOL="${USE_PISTOL:-0}"
PAGER="${PAGER:-less -P?n -R}"
TMPDIR="${TMPDIR:-/tmp}"
startpreview() {
NUMPREVIEWTUI="$(($(find "$TMPDIR" -maxdepth 1 -name 'nnn-preview-tui-pagerpid*' 2>/dev/null | wc -l) + 1))"
PAGERPID="$TMPDIR/nnn-preview-tui-pagerpid.$NUMPREVIEWTUI"
IMGPID="$TMPDIR/nnn-preview-tui-gifpid.$NUMPREVIEWTUI"
CURSEL="$TMPDIR/nnn-preview-tui-selection.$NUMPREVIEWTUI"
FIFO_UEBERZUG="$TMPDIR/nnn-preview-tui-ueberzug-fifo.$NUMPREVIEWTUI"
[ "$PAGER" = "most" ] && PAGER="less -R"
if [ -e "${TMUX%%,*}" ] && tmux -V | grep -q '[ -][3456789]\.'; then
TERMINAL=tmux
elif [ -n "$KITTY_LISTEN_ON" ]; then
TERMINAL=kitty
else
TERMINAL="${TERMINAL:-xterm}"
fi
if [ -z "$SPLIT" ] && [ $(($(tput lines) * 2)) -gt "$(tput cols)" ]; then
SPLIT='h'
elif [ "$SPLIT" != 'h' ]; then
SPLIT='v'
fi
if [ "$TERMINAL" = "tmux" ]; then
# tmux splits are inverted
if [ "$SPLIT" = "v" ]; then SPLIT="h"; else SPLIT="v"; fi
tmux split-window -e "NNN_FIFO=$NNN_FIFO" -e "PREVIEW_MODE=1" -e "PAGER=$PAGER" \
-e "USE_SCOPE=$USE_SCOPE" -e "SPLIT=$SPLIT" -e "USE_PISTOL=$USE_PISTOL" \
-e "BAT_STYLE=${BAT_STYLE:-numbers}" -e "PAGERPID=$PAGERPID" \
-e "IMGPID=$IMGPID" -e "CURSEL=$CURSEL" -e "TMPDIR=$TMPDIR" \
-e "FIFO_UEBERZUG=$FIFO_UEBERZUG" -e "QLPATH=$QLPATH" -d"$SPLIT" "$0" "$1"
elif [ "$TERMINAL" = "kitty" ]; then
# Setting the layout for the new window. It will be restored after the
# script ends.
kitty @ goto-layout splits >/dev/null
# Trying to use kitty's integrated window management as the split window.
# All environmental variables that will be used in the new window must
# be explicitly passed.
kitty @ launch --no-response --title "nnn preview" --keep-focus \
--cwd "$PWD" --env "PATH=$PATH" --env "NNN_FIFO=$NNN_FIFO" \
--env "PREVIEW_MODE=1" --env "PAGER=$PAGER" --env "TMPDIR=$TMPDIR" \
--env "USE_SCOPE=$USE_SCOPE" --env "SPLIT=$SPLIT" --env "TERMINAL=$TERMINAL"\
--env "USE_PISTOL=$USE_PISTOL" --env "BAT_STYLE=${BAT_STYLE:-numbers}" \
--env "PAGERPID=$PAGERPID" --env "IMGPID=$IMGPID" --env "FIFO_UEBERZUG=$FIFO_UEBERZUG" \
--env "CURSEL=$CURSEL" --location "${SPLIT}split" "$0" "$1" >/dev/null
elif [ -n "$2" ]; then
QUICKLOOK=1 QLPATH="$2" PREVIEW_MODE=1 "$0" "$1" >/dev/null &
else
PAGERPID="$PAGERPID" IMGPID="$IMGPID" CURSEL="$CURSEL" PREVIEW_MODE=1 \
FIFO_UEBERZUG="$FIFO_UEBERZUG" $TERMINAL -e "$0" "$1" 2>/dev/null &
fi
}
togglepreview() {
if exists QuickLook.exe; then
QLPATH="QuickLook.exe"
elif exists Bridge.exe; then
QLPATH="Bridge.exe"
fi
if pkill -fx "cat $NNN_FIFO" >/dev/null; then
if [ -n "$QLPATH" ] && stat "$1" >/dev/null 2>&1; then
f="$(wslpath -w "$1" 2>&1)" && "$QLPATH" "$f" &
fi
else
startpreview "$1" "$QLPATH"
fi
}
exists() {
type "$1" >/dev/null 2>&1
}
fifo_pager() {
cmd="$1"
shift
# We use a FIFO to access $PAGER PID in jobs control
tmpfifopath="$TMPDIR/nnn-preview-tui-fifo.$$"
mkfifo "$tmpfifopath" || return
$PAGER < "$tmpfifopath" &
printf "%s" "$!" > "$PAGERPID"
(
exec > "$tmpfifopath"
if [ "$cmd" = "pager" ]; then
if exists bat; then
bat --terminal-width="$(tput cols)" --decorations=always --color=always \
--paging=never --style="${BAT_STYLE:-numbers}" "$@" 2>/dev/null &
else
$PAGER "$@" &
fi
else
"$cmd" "$@" &
fi
)
rm "$tmpfifopath"
}
# Binary file: show file info inside the pager
print_bin_info() {
printf -- "-------- \033[1;31mBinary file\033[0m --------\n"
if exists mediainfo; then
mediainfo "$1" 2>/dev/null
else
file -b "$1"
fi
}
handle_mime() {
case "$2" in
image/*) image_preview "$cols" "$lines" "$1" ;;
application/zip) fifo_pager unzip -l "$1" ;;
text/troff)
if exists man; then
fifo_pager man -Pcat -l "$1"
else
fifo_pager pager "$1"
fi ;;
*) handle_ext "$1" "$3" "$4" ;;
esac
}
handle_ext() {
case "$2" in
gz|bz2) fifo_pager tar -tvf "$1" ;;
*) if [ "$3" = "bin" ]; then
fifo_pager print_bin_info "$1"
else
fifo_pager pager "$1"
fi ;;
esac
}
preview_file () {
clear
# Trying to use pistol if it's available.
if [ "$USE_PISTOL" -ne 0 ] && exists pistol; then
fifo_pager pistol "$1"
return
fi
# Trying to use scope.sh if it's available.
if [ "$USE_SCOPE" -ne 0 ] && exists scope.sh; then
fifo_pager scope.sh "$1" "$cols" "$lines" "$(mktemp -d)" \
"True" 2>/dev/null
return
fi
# Use QuickLook if it's available.
if [ -n "$QUICKLOOK" ]; then
stat "$1" >/dev/null 2>&1 && f="$(wslpath -w "$1" 2>&1)" && "$QLPATH" "$f" &
return
fi
# Detecting the exact type of the file: the encoding, mime type, and
# extension in lowercase.
encoding="$(file -bL --mime-encoding -- "$1")"
mimetype="$(file -bL --mime-type -- "$1")"
ext="${1##*.}"
if [ -n "$ext" ]; then
ext="$(printf "%s" "${ext}" | tr '[:upper:]' '[:lower:]')"
fi
lines=$(tput lines)
cols=$(tput cols)
# Otherwise, falling back to the defaults.
if [ -d "$1" ]; then
cd "$1" || return
if exists tree; then
fifo_pager tree --filelimit "$(find . -maxdepth 1 | wc -l)" -L 3 -C -F --dirsfirst --noreport
elif exists exa; then
exa -G --colour=always 2>/dev/null
else
fifo_pager ls -F --directories-first --color=always
fi
elif [ "${encoding#*)}" = "binary" ]; then
handle_mime "$1" "$mimetype" "$ext" "bin"
else
handle_mime "$1" "$mimetype" "$ext"
fi
}
image_preview() {
if [ "$TERMINAL" = "kitty" ]; then
# Kitty terminal users can use the native image preview method although one might consider
# installing ueberzug and moving the ueberzug clause to the top since it performs alot better.
kitty +kitten icat --silent --place "$1"x"$2"@0x0 --transfer-mode=stream --stdin=no "$3" &
printf "%s" "$!" > "$IMGPID"
elif [ -n "$QLPATH" ] && stat "$3" >/dev/null 2>&1; then
f="$(wslpath -w "$3" 2>&1)" && "$QLPATH" "$f" &
elif exists ueberzug; then
ueberzug_layer "$1" "$2" "$3"
elif exists catimg; then
catimg "$3" &
printf "%s" "$!" > "$IMGPID"
elif exists viu; then
viu -t "$3" &
printf "%s" "$!" > "$IMGPID"
else
fifo_pager print_bin_info "$3"
fi
}
ueberzug_layer() {
printf '{"action": "add", "identifier": "nnn_ueberzug", "x": 0, "y": 0, "width": "%s", "height": "%s", "scaler": "fit_contain", "path": "%s"}\n' "$1" "$2" "$3" > "$FIFO_UEBERZUG"
}
ueberzug_remove() {
printf '{"action": "remove", "identifier": "nnn_ueberzug"}\n' > "$FIFO_UEBERZUG"
}
ueberzug_refresh() {
clear
kill "$(cat "$IMGPID" 2>/dev/null)" >/dev/null 2>&1
pkill -P "$$" >/dev/null 2>&1
pkill -f -n preview-tui-ext >/dev/null 2>&1
tail --follow "$FIFO_UEBERZUG" | ueberzug layer --silent --parser json &
printf "\n" > "$NNN_FIFO"
preview_fifo 2>/dev/null &
preview_file "$(cat "$CURSEL")"
wait
}
preview_fifo() {
# use cat instead of 'exec <' to avoid issues with dash shell
# shellcheck disable=SC2002
cat "$NNN_FIFO" |\
while read -r selection; do
kill "$(cat "$IMGPID" 2>/dev/null)" >/dev/null 2>&1
kill "$(cat "$PAGERPID" 2>/dev/null)" >/dev/null 2>&1
[ "$TERMINAL" != "kitty" ] && exists ueberzug && ueberzug_remove
preview_file "$selection"
printf "%s" "$selection" > "$CURSEL"
done
kill "$(cat "$IMGPID" 2>/dev/null)" >/dev/null 2>&1
kill "$(cat "$PAGERPID" 2>/dev/null)" >/dev/null 2>&1
[ "$TERMINAL" != "kitty" ] && exists ueberzug && ueberzug_remove
rm "$PAGERPID" "$IMGPID" "$CURSEL" "$FIFO_UEBERZUG" >/dev/null 2>&1
pkill -P "$$" >/dev/null 2>&1
}
if [ "$PREVIEW_MODE" ]; then
if [ "$TERMINAL" != "kitty" ] && exists ueberzug; then
mkfifo "$FIFO_UEBERZUG"
trap 'ueberzug_refresh; rm "$FIFO_UEBERZUG"' WINCH
tail --follow "$FIFO_UEBERZUG" | ueberzug layer --silent --parser json &
fi
trap 'rm "$PAGERPID" "$IMGPID" "$CURSEL" "$FIFO_UEBERZUG" 2>/dev/null' INT HUP EXIT
preview_file "$PWD/$1"
printf "%s" "$PWD/$1" > "$CURSEL" &
preview_fifo 2>/dev/null &
wait
else
if [ ! -r "$NNN_FIFO" ]; then
clear
printf "No FIFO available! (\$NNN_FIFO='%s')\nPlease read Usage in preview-tui." "$NNN_FIFO"
cfg=$(stty -g); stty raw -echo; head -c 1; stty "$cfg"
elif [ "$KITTY_WINDOW_ID" ] && [ -z "$KITTY_LISTEN_ON" ]; then
clear
printf "\$KITTY_LISTEN_ON not set!\nPlease read Usage in preview-tui."
cfg=$(stty -g); stty raw -echo; head -c 1; stty "$cfg"
else
togglepreview "$1" &
fi
fi