feat: support firefox and other gecko apps

src/lib/apply.sh

@@ -16,6 +16,7 @@ MCA_ROUTES=()
 #   desktop  - no flag file; shadow or edit the desktop entry
 #   steam    - Steam's own two-part treatment
 #   spotify  - the flag goes into spotify-launcher's configuration file
+#   gecko    - a setting in each of the application's profiles
 #   unknown  - cannot tell what engine this is (an AppImage), so nothing is done
 #   off      - detected, but switched off
 #
@@ -27,7 +28,7 @@ MCA_ROUTE=''
 mca_route() {
 	local kind="$1" id="$2" prog="$3" packaging="${4:-native}"
 
-	if [[ $kind == steam || $kind == spotify ]]; then
+	if [[ $kind == steam || $kind == spotify || $kind == gecko ]]; then
 		if mca_config_list_has Skip "$id"; then
 			MCA_ROUTE=off
 		else
@@ -65,6 +66,7 @@ mca_apply() {
 	MCA_CHANGES=0
 	MCA_ROUTES=()
 	MCA_N_ON=0; MCA_N_OFF=0; MCA_N_UNKNOWN=0
+	MCA_GECKO_SEEN=(); MCA_GECKO_WATCH=()
 
 	mca_config_load
 
@@ -116,6 +118,9 @@ mca_apply() {
 				(( spotify_done )) || mca_spotify_apply
 				spotify_done=1
 				;;
+			gecko)
+				mca_gecko_apply "${MCA_PROFILES[i]}" "$packaging" "$prog"
+				;;
 		esac
 	done
 
@@ -178,7 +183,8 @@ MCA_UNIT_SERVICE="middleclick-autoscroll.service"
 # The desktop folder is watched like every other directory an entry can turn up
 # in, but its name is translated and the unit that ships with the package
 # cannot know it. So that one path is written here, into a drop-in, from the
-# name this system actually uses.
+# name this system actually uses. The same goes for where Firefox and its forks
+# keep their profiles, which depends on what is installed.
 MCA_UNIT_DROPIN="${MCA_XDG_CONFIG}/systemd/user/${MCA_UNIT_PATH}.d"
 
 mca_watch_available() {
@@ -196,23 +202,47 @@ mca_watch_enabled() {
 # same reason: the watcher runs after every desktop entry that appears anywhere on
 # the system, and a daemon-reload each time would be absurd.
 _mca_watch_dropin_write() {
-	local dir file="$MCA_UNIT_DROPIN/desktop.conf" content
-
-	dir="$(mca_desktop_folder)"
-	[[ -d $dir ]] || { _mca_watch_dropin_remove; return $?; }
+	local dir path content='' changed=1
 
 	# A per cent sign starts a specifier in a unit file and has to be doubled
 	# to mean itself. Rare in a folder name, fatal when it happens.
-	content="[Path]"$'\n'"PathModified=${dir//%/%%}"$'\n'
+	dir="$(mca_desktop_folder)"
+	[[ -d $dir ]] && content="[Path]"$'\n'"PathModified=${dir//%/%%}"$'\n'
+	_mca_watch_conf desktop.conf "$content" && changed=0
 
-	mca_write_if_changed "$file" "$content"
+	# Filled by the apply that ran just before. A new profile is added there.
+	content=''
+	for path in "${MCA_GECKO_WATCH[@]}"; do
+		content+="PathChanged=${path//%/%%}"$'\n'
+	done
+	[[ -n $content ]] && content="[Path]"$'\n'"$content"
+	_mca_watch_conf profiles.conf "$content" && changed=0
+
+	return "$changed"
+}
+
+# _mca_watch_conf <name> <content>
+# Writes one drop-in, or removes it when the content is empty. Returns 0 when
+# it changed.
+_mca_watch_conf() {
+	local file="$MCA_UNIT_DROPIN/$1"
+
+	if [[ -n $2 ]]; then
+		mca_write_if_changed "$file" "$2"
+		return
+	fi
+
+	[[ -e $file ]] || return 1
+	rm -f -- "$file"
+	rmdir "$MCA_UNIT_DROPIN" 2>/dev/null || true
+	return 0
 }
 
 _mca_watch_dropin_remove() {
-	[[ -e "$MCA_UNIT_DROPIN/desktop.conf" ]] || return 1
-	rm -f -- "$MCA_UNIT_DROPIN/desktop.conf"
-	rmdir "$MCA_UNIT_DROPIN" 2>/dev/null || true
-	return 0
+	local changed=1
+	_mca_watch_conf desktop.conf '' && changed=0
+	_mca_watch_conf profiles.conf '' && changed=0
+	return "$changed"
 }
 
 mca_watch_enable() {
@@ -226,7 +256,8 @@ mca_watch_enable() {
 
 # mca_watch_refresh
 # Keeps a running watcher in step with a desktop folder that has been renamed,
-# which is what a change of session language does to it.
+# which is what a change of session language does to it, and with the Firefox
+# profiles there are now.
 mca_watch_refresh() {
 	mca_watch_available || return 0
 	_mca_watch_dropin_write || return 0
@@ -295,6 +326,7 @@ mca_route_label() {
 		desktop) mca_msg "launcher" ;;
 		steam)   mca_msg "Steam" ;;
 		spotify) printf 'spotify-launcher' ;;
+		gecko)   mca_msg "profile" ;;
 		unknown) mca_msg "cannot tell" ;;
 		*)       mca_msg "off" ;;
 	esac

src/lib/common.sh

@@ -283,11 +283,13 @@ mca_state_write() {
 #   inplace <edited file>               <basename of its backup copy>
 #   flags   <flag file>                 created | appended | merged
 #   kwin    <kwinrc>                    what EnablePrimarySelection said before
+#   gecko   <user.js in a profile>      created | block
 #
 # The kinds differ in how they are undone: a backup is restored wholesale, a
 # flag file only loses the one line that was added to it, and kwinrc gets one
 # key written back. It is a file KDE writes to itself, and putting a whole
-# copy of it back would take everything else settled since with it.
+# copy of it back would take everything else settled since with it. A user.js
+# loses its block, and prefs.js the line Firefox copied out of it.
 
 mca_ledger_add() {
 	local kind="$1" path="$2" detail="${3:-}"

src/lib/detect.sh

@@ -343,7 +343,9 @@ _mca_stat_batch() {
 # taught the hint scan about Discord's launcher, and Discord stayed out of the
 # list anyway, because /usr/bin/discord had not changed and its old "no" was
 # still in here.
-MCA_CACHE_FORMAT="# middleclick-autoscroll detect 2 $MCA_VERSION"
+#
+# 3 adds the gecko verdict.
+MCA_CACHE_FORMAT="# middleclick-autoscroll detect 3 $MCA_VERSION"
 
 _mca_cache_load() {
 	local path stamp verdict first=1
@@ -862,6 +864,8 @@ _mca_appimage_verdict() {
 #   no       - something else
 #   unknown  - an image whose payload could not be read, so neither answer has
 #              been earned and the applications screen offers it as a choice
+#   gecko:<rel> - Firefox or another Gecko application, which keeps its
+#              profiles in <rel>. See gecko.sh.
 #
 # Assigns rather than returns three states through an exit code, and is the one
 # place the memo and the on-disk cache are consulted.
@@ -900,8 +904,11 @@ mca_detect_verdict() {
 	real="$(readlink -f -- "$prog" 2>/dev/null)" || real="$prog"
 
 	MCA_DETECT_UNSURE=0
+	MCA_DETECT_GECKO=''
 	if _mca_detect_uncached "$real"; then
 		MCA_VERDICT=yes
+	elif [[ -n $MCA_DETECT_GECKO ]]; then
+		MCA_VERDICT="gecko:$MCA_DETECT_GECKO"
 	elif (( MCA_DETECT_UNSURE )); then
 		MCA_VERDICT=unknown
 	else
@@ -930,6 +937,10 @@ mca_is_chromium() {
 # was nothing there. Only mca_detect_verdict reads it, straight after the call.
 MCA_DETECT_UNSURE=0
 
+# Set by _mca_detect_uncached to where the profiles are, when the program turned
+# out to be Gecko rather than Chromium.
+MCA_DETECT_GECKO=''
+
 _mca_detect_uncached() {
 	local real="$1" depth="${2:-0}" dir target
 
@@ -943,6 +954,7 @@ _mca_detect_uncached() {
 		if target="$(_mca_script_target "$real")" && [[ -n $target ]]; then
 			_mca_detect_uncached "$(readlink -f -- "$target" 2>/dev/null || printf '%s' "$target")" \
 				$(( depth + 1 )) && return 0
+			[[ -n $MCA_DETECT_GECKO ]] && return 1
 		fi
 		grep -qE "$MCA_SCRIPT_HINTS" -- "$real" 2>/dev/null && return 0
 		return 1
@@ -954,6 +966,14 @@ _mca_detect_uncached() {
 	_mca_has_markers "$dir" && return 0
 	[[ ${dir##*/} == bin ]] && _mca_has_markers "${dir%/*}" && return 0
 
+	# Not Chromium but Gecko, which has autoscroll of its own.
+	if _mca_gecko_rel "$dir" \
+		|| { [[ ${dir##*/} == bin ]] && _mca_gecko_rel "${dir%/*}"; }
+	then
+		MCA_DETECT_GECKO="$MCA_GECKO_REL"
+		return 1
+	fi
+
 	# An AppImage keeps all of that inside a filesystem appended to itself, so
 	# there is nothing next to the binary to find. But the names of everything
 	# in there can be read, and that settles it either way.
@@ -989,8 +1009,9 @@ MCA_IDS=()        # desktop file id, without the .desktop suffix
 MCA_FILES=()      # the desktop entry that is in effect for that id
 MCA_NAMES=()      # display name
 MCA_PROGS=()      # resolved program, or a Flatpak app id or a snap name
-MCA_KINDS=()      # app | browser | steam | spotify | unknown | no
+MCA_KINDS=()      # app | browser | steam | spotify | gecko | unknown | no
 MCA_PACKAGING=()  # native | flatpak | snap
+MCA_PROFILES=()   # where a Gecko application keeps its profiles, see gecko.sh
 
 # A scan reads every desktop entry on the system, so the menu does it once and
 # then redraws from what it found. Applying rescans on its own, so nothing else
@@ -1003,12 +1024,12 @@ mca_scan_once() {
 }
 
 mca_scan() {
-	local dir file id name exec_line prog kind packaging i
+	local dir file id name exec_line prog kind packaging profiles i
 	local -A seen=()
 	local -a c_ids=() c_files=() c_names=() c_progs=() c_browser=() c_stat=()
 
 	MCA_IDS=(); MCA_FILES=(); MCA_NAMES=(); MCA_PROGS=(); MCA_KINDS=()
-	MCA_PACKAGING=()
+	MCA_PACKAGING=(); MCA_PROFILES=()
 
 	# Pass one: read the entries and work out what each of them starts. No
 	# detection yet: that needs a stat per program, and those are collected so
@@ -1073,6 +1094,7 @@ mca_scan() {
 		prog="${c_progs[i]}"
 		kind=no
 		packaging=native
+		profiles=''
 
 		if [[ $prog == flatpak:* ]]; then
 			packaging=flatpak
@@ -1080,6 +1102,8 @@ mca_scan() {
 				kind=steam
 			elif mca_flatpak_is_chromium "${prog#flatpak:}"; then
 				(( c_browser[i] )) && kind=browser || kind=app
+			elif mca_flatpak_gecko "${prog#flatpak:}"; then
+				kind=gecko profiles="$MCA_GECKO_REL"
 			fi
 			prog="${prog#flatpak:}"
 		elif [[ $prog == snap:* ]]; then
@@ -1089,6 +1113,8 @@ mca_scan() {
 				kind=steam
 			elif mca_snap_is_chromium "$prog"; then
 				(( c_browser[i] )) && kind=browser || kind=app
+			elif mca_snap_gecko "$prog"; then
+				kind=gecko profiles="$MCA_GECKO_REL"
 			fi
 		elif mca_prog_is_steam "$prog"; then
 			# Steam is Chromium inside, but nothing about it can be changed
@@ -1103,6 +1129,7 @@ mca_scan() {
 			case "$MCA_VERDICT" in
 				yes)     (( c_browser[i] )) && kind=browser || kind=app ;;
 				unknown) kind=unknown ;;
+				gecko:*) kind=gecko profiles="${MCA_VERDICT#gecko:}" ;;
 			esac
 		fi
 
@@ -1114,6 +1141,7 @@ mca_scan() {
 		MCA_PROGS+=("$prog")
 		MCA_KINDS+=("$kind")
 		MCA_PACKAGING+=("$packaging")
+		MCA_PROFILES+=("$profiles")
 	done
 
 	mca_cache_flush
@@ -1211,16 +1239,14 @@ mca_snap_is_chromium() {
 # Flatpak keeps every application in its own tree, so the marker check works the
 # same way once that tree has been located.
 mca_flatpak_is_chromium() {
-	local id="$1" loc
-	mca_have flatpak || return 1
+	local id="$1"
 
 	if [[ -n ${MCA_DETECT_MEMO[flatpak:$id]+set} ]]; then
 		[[ ${MCA_DETECT_MEMO[flatpak:$id]} == yes ]]
 		return $?
 	fi
 
-	loc="$(flatpak info --show-location "$id" 2>/dev/null)"
-	if [[ -n $loc ]] && _mca_find_markers "$loc/files" 4; then
+	if mca_flatpak_location "$id" && _mca_find_markers "$MCA_FLATPAK_AT/files" 4; then
 		MCA_DETECT_MEMO[flatpak:$id]=yes
 		return 0
 	fi
@@ -1229,6 +1255,25 @@ mca_flatpak_is_chromium() {
 	return 1
 }
 
+# mca_flatpak_location <app id>
+# Where Flatpak keeps the application, in MCA_FLATPAK_AT. Assigned rather than
+# printed so the memo survives: both the Chromium and the Gecko check ask.
+declare -A MCA_FLATPAK_LOC=()
+MCA_FLATPAK_AT=''
+
+mca_flatpak_location() {
+	local id="$1"
+
+	if [[ -z ${MCA_FLATPAK_LOC[$id]+set} ]]; then
+		MCA_FLATPAK_LOC[$id]=''
+		mca_have flatpak \
+			&& MCA_FLATPAK_LOC[$id]="$(flatpak info --show-location "$id" 2>/dev/null)"
+	fi
+
+	MCA_FLATPAK_AT="${MCA_FLATPAK_LOC[$id]}"
+	[[ -n $MCA_FLATPAK_AT ]]
+}
+
 # mca_kind_wanted <kind> <id>
 # Whether this entry should be patched. Skip beats everything, an explicit
 # include beats detection, and detection beats nothing.

src/lib/gecko.sh

@@ -0,0 +1,254 @@
+# shellcheck shell=bash
+#
+# Firefox, and everything else built on Gecko: LibreWolf, Zen, Floorp,
+# Waterfox, Thunderbird.
+#
+# Gecko has autoscroll of its own, off on Linux. There is no command line flag
+# for it, only a setting: general.autoScroll. Settings live in each profile, so
+# the line goes into the profile's user.js, which Gecko reads at every start.
+#
+# Gecko copies what user.js sets into prefs.js. So undoing takes the line out
+# of prefs.js as well. A browser that is still open would write it back when it
+# quits, so for that profile user.js says false instead, and the record stays
+# until the next undo can finish the job.
+
+MCA_GECKO_BEGIN='// >>> middleclick-autoscroll'
+MCA_GECKO_END='// <<< middleclick-autoscroll'
+MCA_GECKO_ON='user_pref("general.autoScroll", true);'
+MCA_GECKO_OFF='user_pref("general.autoScroll", false);'
+
+# The profile folders one apply has done already, and the profiles.ini files
+# the watcher should look at. Both are filled by mca_gecko_apply.
+declare -A MCA_GECKO_SEEN=()
+MCA_GECKO_WATCH=()
+
+# Set by mca_gecko_revert when a profile is still open and has to be undone
+# again later.
+MCA_GECKO_PENDING=0
+
+# _mca_gecko_rel <directory>
+# Whether a Gecko application is installed there. If so, where it keeps its
+# profiles, relative to the home or config folder, in MCA_GECKO_REL. Read from
+# application.ini the way Gecko does it: [App] Profile= when it is set, else
+# Vendor/Name, in lowercase.
+MCA_GECKO_REL=''
+
+_mca_gecko_rel() {
+	local dir="$1" line group='' vendor='' name='' profile='' rel=''
+
+	MCA_GECKO_REL=''
+	[[ -e $dir/libxul.so && -r $dir/application.ini ]] || return 1
+
+	while IFS= read -r line || [[ -n $line ]]; do
+		line="${line%$'\r'}"
+		case "$line" in
+			'['*)      group="$line" ;;
+			Vendor=*)  [[ $group == '[App]' ]] && vendor="${line#*=}" ;;
+			Name=*)    [[ $group == '[App]' ]] && name="${line#*=}" ;;
+			Profile=*) [[ $group == '[App]' ]] && profile="${line#*=}" ;;
+		esac
+	done < "$dir/application.ini"
+
+	if [[ -n $profile ]]; then
+		rel="${profile//\\//}"
+		while [[ $rel == /* ]]; do rel="${rel#/}"; done
+		rel="${rel#.}"
+	elif [[ -n $name ]]; then
+		rel="${vendor:+$vendor/}$name"
+	fi
+
+	# Gecko lowercases in ASCII. A Turkish locale turns I into a dotless ı.
+	rel="${rel,,}"
+	rel="${rel//ı/i}"
+
+	[[ -n $rel && /$rel/ != */../* ]] || return 1
+	MCA_GECKO_REL="$rel"
+}
+
+# _mca_gecko_tree <root> <depth>
+# The same for a Flatpak or a snap, where libxul.so is somewhere in the tree.
+_mca_gecko_tree() {
+	local lib
+
+	MCA_GECKO_REL=''
+	[[ -d $1 ]] || return 1
+	lib="$(find "$1" -maxdepth "$2" -name libxul.so -print -quit 2>/dev/null)"
+	[[ -n $lib ]] && _mca_gecko_rel "${lib%/*}"
+}
+
+# mca_flatpak_gecko <app id> / mca_snap_gecko <snap name>
+# Whether it is Gecko, with the folder in MCA_GECKO_REL. Memoized like the
+# Chromium check, and an empty answer means no.
+declare -A MCA_GECKO_MEMO=()
+
+mca_flatpak_gecko() {
+	local key="flatpak:$1"
+
+	if [[ -z ${MCA_GECKO_MEMO[$key]+set} ]]; then
+		MCA_GECKO_REL=''
+		mca_flatpak_location "$1" && _mca_gecko_tree "$MCA_FLATPAK_AT/files" 4
+		MCA_GECKO_MEMO[$key]="$MCA_GECKO_REL"
+	fi
+
+	MCA_GECKO_REL="${MCA_GECKO_MEMO[$key]}"
+	[[ -n $MCA_GECKO_REL ]]
+}
+
+mca_snap_gecko() {
+	local key="snap:$1" d
+
+	if [[ -z ${MCA_GECKO_MEMO[$key]+set} ]]; then
+		MCA_GECKO_REL=''
+		for d in "${MCA_SNAP_DIRS[@]}"; do
+			_mca_gecko_tree "$d/$1/current" 5 && break
+		done
+		MCA_GECKO_MEMO[$key]="$MCA_GECKO_REL"
+	fi
+
+	MCA_GECKO_REL="${MCA_GECKO_MEMO[$key]}"
+	[[ -n $MCA_GECKO_REL ]]
+}
+
+# mca_gecko_roots <rel> <packaging> <name>
+# Every folder that can hold the application's profiles.ini. An older install
+# uses ~/.<rel>. A new one (Firefox 147 and later) uses $XDG_CONFIG_HOME/<rel>,
+# or ~/<rel> for a fork with a profile name of its own. A Flatpak or a snap has
+# the same inside its own folder.
+mca_gecko_roots() {
+	local rel="$1" packaging="$2" name="$3" d
+
+	case "$packaging" in
+		flatpak)
+			printf '%s\n' "$HOME/.var/app/$name/.$rel" "$HOME/.var/app/$name/config/$rel"
+			;;
+		snap)
+			for d in common current; do
+				printf '%s\n' "$HOME/snap/$name/$d/.$rel" "$HOME/snap/$name/$d/.config/$rel"
+			done
+			;;
+		*)
+			printf '%s\n' "$HOME/.$rel" "$MCA_XDG_CONFIG/$rel"
+			[[ $rel == */* ]] || printf '%s\n' "$HOME/$rel"
+			;;
+	esac
+}
+
+# mca_gecko_profiles <root>
+# Every profile folder that profiles.ini there lists.
+mca_gecko_profiles() {
+	local root="$1" line path='' relative=1 inprofile=0
+
+	[[ -r $root/profiles.ini ]] || return 0
+
+	while IFS= read -r line || [[ -n $line ]]; do
+		line="${line%$'\r'}"
+		case "$line" in
+			'['*)
+				_mca_gecko_profile_emit
+				[[ $line == '[Profile'* ]] && inprofile=1 || inprofile=0
+				path='' relative=1
+				;;
+			Path=*)       path="${line#Path=}" ;;
+			IsRelative=*) relative="${line#IsRelative=}" ;;
+		esac
+	done < "$root/profiles.ini"
+	_mca_gecko_profile_emit
+}
+
+_mca_gecko_profile_emit() {
+	(( inprofile )) && [[ -n $path ]] || return 0
+	[[ $relative == 1 ]] && path="$root/$path"
+	[[ -d $path ]] && printf '%s\n' "$path"
+	return 0
+}
+
+# _mca_gecko_write <user.js> <line>
+# Puts the line into user.js as a marked block, replacing an older block.
+# Returns like mca_write_if_changed.
+_mca_gecko_write() {
+	local file="$1" line="$2" content=''
+
+	[[ -f $file ]] && content="$(_mca_flags_drop_block "$file" "$MCA_GECKO_BEGIN" "$MCA_GECKO_END")"
+	content="${content:+$content$'\n'}$MCA_GECKO_BEGIN"$'\n'"$line"$'\n'"$MCA_GECKO_END"
+	mca_write_if_changed "$file" "$content"$'\n'
+}
+
+# mca_gecko_apply <rel> <packaging> <name>
+# Turns autoscroll on in every profile of the application.
+mca_gecko_apply() {
+	local root profile
+
+	while IFS= read -r root; do
+		[[ -n ${MCA_GECKO_SEEN[$root]+set} ]] && continue
+		MCA_GECKO_SEEN[$root]=1
+
+		# A new profile is written into profiles.ini, so the watcher can pick
+		# it up.
+		MCA_GECKO_WATCH+=("$root/profiles.ini")
+
+		while IFS= read -r profile; do
+			_mca_gecko_profile_apply "$profile"
+		done < <(mca_gecko_profiles "$root")
+	done < <(mca_gecko_roots "$@")
+}
+
+_mca_gecko_profile_apply() {
+	local dir="$1" file="$1/user.js" detail=created
+
+	# A user.js that links somewhere else is part of a setup of its own.
+	[[ -L $file ]] && return 0
+	[[ -f $file ]] && detail=block
+
+	if ! grep -qxF -- "$MCA_GECKO_BEGIN" "$file" 2>/dev/null; then
+		# Set by the user already, in user.js or in the browser's own
+		# settings. Their choice: nothing is written and nothing recorded.
+		grep -qE '^[[:space:]]*user_pref\([[:space:]]*"general\.autoScroll"' \
+			-- "$file" 2>/dev/null && return 0
+		grep -qxF -- "$MCA_GECKO_ON" "$dir/prefs.js" 2>/dev/null && return 0
+	fi
+
+	_mca_gecko_write "$file" "$MCA_GECKO_ON"
+	case $? in
+		0) MCA_CHANGES=$(( MCA_CHANGES + 1 )) ;;
+		2) return 0 ;;
+	esac
+
+	# A file this program created stays one it created.
+	mca_ledger_has "$file" && detail="$(mca_ledger_detail "$file")"
+	mca_ledger_add gecko "$file" "$detail"
+}
+
+# mca_gecko_revert <user.js> <created|block>
+# Returns 0 when something changed. Sets MCA_GECKO_PENDING when the profile is
+# open and the record has to stay.
+mca_gecko_revert() {
+	local file="$1" detail="$2" dir="${1%/*}" prefs content tmp rc=0
+
+	MCA_GECKO_PENDING=0
+	[[ -f $file && ! -L $file ]] || return 1
+	grep -qxF -- "$MCA_GECKO_BEGIN" "$file" 2>/dev/null || return 1
+
+	# The lock link only exists while the profile is open.
+	if [[ -L $dir/lock ]]; then
+		MCA_GECKO_PENDING=1
+		_mca_gecko_write "$file" "$MCA_GECKO_OFF"
+		return
+	fi
+
+	content="$(_mca_flags_drop_block "$file" "$MCA_GECKO_BEGIN" "$MCA_GECKO_END")"
+	if [[ $detail == created && -z ${content//[[:space:]]/} ]]; then
+		rm -f -- "$file"
+	else
+		printf '%s\n' "$content" > "$file"
+	fi
+
+	prefs="$dir/prefs.js"
+	if [[ -f $prefs && ! -L $prefs ]] && grep -qxF -- "$MCA_GECKO_ON" "$prefs"; then
+		tmp="$(mktemp "$prefs.XXXXXX")" || return 0
+		chmod --reference="$prefs" -- "$tmp" 2>/dev/null || chmod 600 -- "$tmp"
+		# grep says 1 when no line is left, which is fine here.
+		grep -vxF -- "$MCA_GECKO_ON" "$prefs" > "$tmp" || rc=$?
+		if (( rc <= 1 )); then mv -f -- "$tmp" "$prefs"; else rm -f -- "$tmp"; fi
+	fi
+	return 0
+}

src/lib/menu.sh

@@ -419,13 +419,14 @@ mca_ui_apps() {
 	# The per-row labels are resolved once, here. Looking them up inside the
 	# drawing loop is a fork per row per keypress, and that is enough to make
 	# the arrow keys feel like the screen is reloading.
-	local l_off l_cannot l_on l_steam l_flagfile l_launcher
+	local l_off l_cannot l_on l_steam l_flagfile l_launcher l_profile
 	mca_msg_into "$locale" "off";         l_off="$MCA_MSG_RESULT"
 	mca_msg_into "$locale" "cannot tell"; l_cannot="$MCA_MSG_RESULT"
 	mca_msg_into "$locale" "on";          l_on="$MCA_MSG_RESULT"
 	mca_msg_into "$locale" "Steam";       l_steam="$MCA_MSG_RESULT"
 	mca_msg_into "$locale" "flag file";   l_flagfile="$MCA_MSG_RESULT"
 	mca_msg_into "$locale" "launcher";    l_launcher="$MCA_MSG_RESULT"
+	mca_msg_into "$locale" "profile";     l_profile="$MCA_MSG_RESULT"
 
 	local s_off="${MCA_C_DIM}${l_off}${MCA_C_RESET}"
 	local s_cannot="${MCA_C_DIM}${l_cannot}${MCA_C_RESET}"
@@ -434,6 +435,7 @@ mca_ui_apps() {
 	local s_flags="${s_on} ${MCA_C_DIM}(${l_flagfile})${MCA_C_RESET}"
 	local s_desktop="${s_on} ${MCA_C_DIM}(${l_launcher})${MCA_C_RESET}"
 	local s_spotify="${s_on} ${MCA_C_DIM}(spotify-launcher)${MCA_C_RESET}"
+	local s_gecko="${s_on} ${MCA_C_DIM}(${l_profile})${MCA_C_RESET}"
 
 	local clearseq
 	clearseq="$(clear 2>/dev/null)" || clearseq=$'\033[H\033[2J'
@@ -444,7 +446,7 @@ mca_ui_apps() {
 	count=${#MCA_IDS[@]}
 
 	if (( count == 0 )); then
-		MCA_UI_MSG="$(mca_msg "No Chromium-based applications found.")"
+		MCA_UI_MSG="$(mca_msg "No supported applications found.")"
 		return 1
 	fi
 
@@ -526,6 +528,7 @@ mca_ui_apps() {
 				steam)   shown="$s_steam" ;;
 				flags)   shown="$s_flags" ;;
 				spotify) shown="$s_spotify" ;;
+				gecko)   shown="$s_gecko" ;;
 				*)       shown="$s_desktop" ;;
 			esac
 			pad=$(( 34 - ${#labels[idx]} ))

src/lib/patch.sh

@@ -260,8 +260,9 @@ _mca_flags_write() {
 	return 0
 }
 
+# _mca_flags_drop_block <file> [begin marker] [end marker]
 _mca_flags_drop_block() {
-	awk -v b="$MCA_MARK_BEGIN" -v e="$MCA_MARK_END" '
+	awk -v b="${2:-$MCA_MARK_BEGIN}" -v e="${3:-$MCA_MARK_END}" '
 		$0 == b { skip = 1; next }
 		$0 == e { skip = 0; next }
 		!skip
@@ -632,6 +633,7 @@ mca_prune_orphans() {
 
 mca_revert_all() {
 	local kind path detail backup
+	local -a keep=()
 
 	[[ -f $MCA_LEDGER ]] || return 0
 
@@ -674,10 +676,17 @@ mca_revert_all() {
 				mca_kde_paste_revert "$path" "$detail" \
 					&& MCA_CHANGES=$(( MCA_CHANGES + 1 ))
 				;;
+			gecko)
+				mca_gecko_revert "$path" "$detail" \
+					&& MCA_CHANGES=$(( MCA_CHANGES + 1 ))
+				# Still open, so not done yet. See gecko.sh.
+				(( MCA_GECKO_PENDING )) && keep+=("$kind"$'\t'"$path"$'\t'"$detail")
+				;;
 		esac
 	done < <(tac "$MCA_LEDGER" 2>/dev/null)
 
 	rm -f -- "$MCA_LEDGER"
+	(( ${#keep[@]} )) && printf '%s\n' "${keep[@]}" > "$MCA_LEDGER"
 	rmdir "$MCA_BACKUPDIR" 2>/dev/null || true
 	return 0
 }

src/middleclick-autoscroll

@@ -1,14 +1,14 @@
 #!/usr/bin/env bash
 #
 # middleclick-autoscroll: middle-click autoscroll for Chromium-based
-# applications on Linux
+# applications and Firefox on Linux
 #
 # Blink has had Windows-style autoscroll for years, behind a runtime flag that
 # is not turned on for Linux because middle click is taken by primary-selection
 # paste there. Turning it on is a matter of one command line argument. The
 # work is finding every application that needs it, putting the argument
 # somewhere it survives an update, and doing the same for the two programs that
-# do not take arguments at all.
+# do not take arguments at all. Firefox has the same feature behind a setting.
 #
 # Copyright (C) 2026 Felitendo
 # SPDX-License-Identifier: GPL-3.0-or-later
@@ -17,7 +17,7 @@ set -uo pipefail
 
 MCA_LIBDIR="${MCA_LIBDIR:-@LIBDIR@}"
 
-for _mod in common config detect patch steam kde apply menu; do
+for _mod in common config detect patch steam gecko kde apply menu; do
 	# shellcheck source=/dev/null
 	if ! source "$MCA_LIBDIR/$_mod.sh"; then
 		printf 'middleclick-autoscroll: cannot load %s/%s.sh\n' "$MCA_LIBDIR" "$_mod" >&2
@@ -144,7 +144,7 @@ mca_do_list() {
 	mca_count_routes
 
 	if (( ${#MCA_IDS[@]} == 0 )); then
-		mca_note "$(mca_msg "No Chromium-based applications found.")"
+		mca_note "$(mca_msg "No supported applications found.")"
 		return 0
 	fi