Add completion for `ip`

This is quite ugly because the syntax is ugly, the documentation both
under- and overspecified at the same time (a BNF that isn't...) and it
has a lot of functionality.

But the completion works half-decent for `ip address`, so let's ship it.

1 files changed, 344 insertions, 0 deletions

diff --git a/share/completions/ip.fish b/share/completions/ip.fish
new file mode 100644
index 00000000..b7ded602
--- /dev/null
+++ b/share/completions/ip.fish
@@ -0,0 +1,344 @@
+# ip(8) completion for fish
+
+# The difficulty here is that ip allows abbreviating options, so we need to complete "ip a" like "ip address", but not "ip m" like "ip mroute"
+# Also the manpage and even the grammar it accepts is utter shite (options can only be before commands, some things are only in the BNF, others only in the text)
+# It also quite likes the word "dev", even though it needs it less than the BNF specifies
+
+set -l ip_commands link address addrlabel route rule neigh ntable tunnel tuntap maddr mroute mrule monitor xfrm netns l2tp tcp_metrics
+set -l ip_addr a ad add addr addre addres address
+set -l ip_link l li lin link
+set -l ip_all_commands $ip_commands $ip_addr $ip_link
+
+function __fish_ip_commandwords
+	set -l skip 0
+	set -l cmd (commandline -opc)
+	# HACK: Handle and/or/not specially because they have hardcoded completion behavior
+	# that doesn't remove them from the commandline
+	if contains -- $cmd[1] and or not
+		set -e cmd[1]
+	end
+	# Remove the first word because it's "ip" or an alias for it
+	set -e cmd[1]
+	set -l have_command 0
+	for word in $cmd
+		switch $word
+			# Normalize the commands to their full form - `ip a` is `ip address`
+			# This can't be just an unambiguity check because there's also `ip addrlabel`
+			case a ad add addr addre addres address
+				# "addr add" is a thing, so we can only echo "address" if it's actually the command
+				if test $have_command = 0
+					set have_command 1
+					echo address
+				else
+					echo $word
+				end
+			case l li lin link
+				if test $have_command = 0
+					set have_command 1
+					echo link
+				else
+					echo $word
+				end
+			case "addrl*"
+				if test $have_command = 0
+					set have_command 1
+					echo addrlabel
+				else
+					echo $word
+				end
+			case r ro rou rout route
+				if test $have_command = 0
+					set have_command 1
+					echo route
+				else
+					echo $word
+				end
+			case "ru*"
+				if test $have_command = 0
+					set have_command 1
+					echo rule
+				else
+					echo $word
+				end
+			case n ne nei neig neigh
+				if test $have_command = 0
+					set have_command 1
+					echo neigh
+				else
+					echo $word
+				end
+			case nt
+				if test $have_command = 0
+					set have_command 1
+					echo ntable
+				else
+					echo $word
+				end
+			case t tu tun tunn tunne tunnel
+				if test $have_command = 0
+					set have_command 1
+					echo tunnel
+				else
+					echo $word
+				end
+			case "tunt*"
+				if test $have_command = 0
+					set have_command 1
+					echo tuntap
+				else
+					echo $word
+				end
+			case m ma mad madd maddr maddre maddres maddress
+				if test $have_command = 0
+					set have_command 1
+					echo maddress
+				else
+					echo $word
+				end
+			case mr "mro*"
+				if test $have_command = 0
+					set have_command 1
+					echo mroute
+				else
+					echo $word
+				end
+			case "mru*"
+				if test $have_command = 0
+					set have_command 1
+					echo mrule
+				else
+					echo $word
+				end
+			case "mo*"
+				if test $have_command = 0
+					set have_command 1
+					echo monitor
+				else
+					echo $word
+				end
+			case "x*"
+				if test $have_command = 0
+					set have_command 1
+					echo xfrm
+				else
+					echo $word
+				end
+			case "net*"
+				if test $have_command = 0
+					set have_command 1
+					echo netns
+				else
+					echo $word
+				end
+			case "l*"
+				if test $have_command = 0
+					set have_command 1
+					echo l2tp
+				else
+					echo $word
+				end
+			case "tc*"
+				if test $have_command = 0
+					set have_command 1
+					echo tcp_metrics
+				else
+					echo $word
+				end
+			case "to*"
+				if test $have_command = 0
+					set have_command 1
+					echo token
+				else
+					echo $word
+				end
+			case '-n' '-netns' '--netns'
+				if test $have_command = 0
+					set skip 1
+				else
+					echo $word
+				end
+			case '-*'
+				test $have_command = 0; and continue
+				echo $word
+			case '*'
+				if test $skip = 1
+					set skip 0
+					continue
+				end
+				echo $word
+		end
+	end
+	# Print an empty line if the current token is empty, so we know that the one before it is finished
+	# TODO: For some reason it is necessary to always print the current token - why doesn't the above loop catch it?
+	set -l token (commandline -ct)
+	echo $token
+end
+
+function __fish_ip_device
+	ip -o link show | while read a b c
+		printf '%s\t%s\n' (string replace ':' '' -- $b) "Device"
+	end
+end
+
+function __fish_ip_scope
+	if test -r /etc/iproute2/rt_scopes
+		string replace -r '#.*' '' < /etc/iproute2/rt_scopes \
+		| string match -v '^\s*$' \
+		| string replace -r '(\S+)\s*(\S+)' '$1\t$2\n$2\t$1' \
+		| string match -rv '^(global|link|host).*' # Ignore scopes with better descriptions
+	end
+	# Predefined scopes
+	printf '%s\t%s\n' global "Address is globally valid" \
+	link "Address is link-local, only valid on this device" \
+	host "Address is only valid on this host"
+end
+
+function __fish_complete_ip
+	set -l cmd (__fish_ip_commandwords)
+	set -l count (count $cmd)
+	switch "$cmd[1]"
+		case address
+			# We're still _on_ the second word, which is the subcommand
+			if not set -q cmd[3]
+				printf '%s\t%s\n' add "Add new protocol address" \
+				delete "Delete protocol address" \
+				show "Look at protocol addresses" \
+				flush "Flush protocol addresses"
+			else
+				switch $cmd[2]
+					# Change and replace are undocumented (apart from mentions in the BNF)
+					case add change replace
+						switch $count
+							case 3
+								# __fish_ip_complete_ip
+							case '*'
+								switch $cmd[-2]
+									case dev
+										__fish_ip_device
+									case scope
+										__fish_ip_scope
+									# TODO: Figure out how to complete these
+									case label
+										# Prefix
+									case local peer broadcast
+										# Address
+									case valid_lft preferred_lft
+										# Lifetime
+									case '*'
+										printf '%s\t%s\n' forever "Keep address valid forever" \
+										home "(Ipv6 only) Designate address as home adress" \
+										nodad "(Ipv6 only) Don't perform duplicate address detection" \
+										dev "Add address to specified device" \
+										scope "Set scope of address" \
+										label "Tag address with label"
+								end
+						end
+					case delete
+						switch $count
+							case 3
+								ip -o addr show | while read a b c d e
+									echo $d
+								end
+							case 4
+								# A dev argument is mandatory, but contrary to the BNF, other things (like "scope") are also valid here
+								# And yes, unlike e.g. show, this _needs_ the "dev" before the device
+								# Otherwise it barfs and says "??? prefix is expected"
+								# Anyway, try to steer the user towards supplying a device
+								echo dev
+							case 5
+								switch $cmd[-2]
+									case dev
+										ip -o addr show | string match "*$cmd[3]*" | while read a b c
+											echo $b
+										end
+								# TODO: Moar
+						end
+					case show save flush # These take the same args
+						switch $cmd[-2]
+							case dev
+								__fish_ip_device
+							case scope
+								__fish_ip_scope
+							case to
+								# Prefix
+							case label
+								# Label-pattern
+							case '*'
+								printf '%s\t%s\n' up "Only active devices" \
+								dev "Limit to a certain device" \
+								scope "Limit scope" \
+								to "Limit prefix" \
+								label "Limit by label" \
+								dynamic "(Ipv6 only) Limit to dynamic addresses" \
+								permanent "(Ipv6 only) Limit to permanent addresses"
+								__fish_ip_device
+								# TODO: Moar
+						end
+					end
+				end
+			end
+		case link
+			if not set -q cmd[3]
+				printf '%s\t%s\n' add "Add virtual link" \
+				delete "Delete virtual link" \
+				set "Change device attributes" \
+				show "Display device attributes" \
+				help "Display help"
+			else
+				# TODO: Add moar
+				switch $cmd[2]
+					case add
+						switch $cmd[-2]
+							case link
+								__fish_ip_device
+							case name
+							case type
+								printf '%s\t%s\n' \
+								macvtap "Virtual interface based on link layer address (MAC) and TAP." \
+								vcan "Virtual Controller Area Network interface" \
+								veth "Virtual ethernet interface" \
+								vlan "802.1q tagged virtual LAN interface" \
+								vxlan "Virtual eXtended LAN" \
+								ip6tnl "Virtual tunnel interface IPv4|IPv6 over IPv6" \
+								ipip "Virtual tunnel interface IPv4 over IPv4" \
+								sit "Virtual tunnel interface IPv6 over IPv4" \
+								gre "Virtual tunnel interface GRE over IPv4" \
+								gretap "Virtual L2 tunnel interface GRE over IPv4" \
+								ip6gre "Virtual tunnel interface GRE over IPv6" \
+								ip6gretap "Virtual L2 tunnel interface GRE over IPv6" \
+								vti "Virtual tunnel interface" \
+								nlmon "Netlink monitoring device" \
+								ipvlan "Interface for L3 (IPv6/IPv4) based VLANs" \
+								lowpan "Interface for 6LoWPAN (IPv6) over IEEE 802.15.4 / Bluetooth" \
+								geneve "GEneric NEtwork Virtualization Encapsulation"
+						end
+					case delete
+					case set
+					case show
+					case help
+				end
+			end
+	end
+end
+			
+complete -f -c ip
+complete -f -c ip -a '(__fish_complete_ip)'
+complete -f -c ip -n "not __fish_seen_subcommand_from $ip_all_commands" -a "$ip_commands"
+# Yes, ip only takes options before "objects"
+complete -c ip -s b -l batch -d "Read commands from file or stdin" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -l force -d "Don't terminate on errors in batch mode" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -s V -l Version -d "Print the version" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s s -l stats -d "Output more information" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s d -l details -d "Output more detailed information" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s l -l loops -d "Specify maximum number of loops for 'ip addr flush'" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s f -l family -d "The protocol family to use" -a "inet inet6 bridge ipx dnet link any" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s 4 -d "Short for --family inet" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s 6 -d "Short for --family inet6" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s B -d "Short for --family bridge" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s D -d "Short for --family decnet" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s I -d "Short for --family ipx" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s O -d "Short for --family link" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s o -l oneline -d "Output on one line" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s r -l resolve -d "Resolve names and print them instead of addresses" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s n -l net -l netns -d "Use specified network namespace" -n "not __fish_seen_subcommand_from $ip_commands"
+complete -c ip -f -s a -l all -d "Execute command for all objects" -n "not __fish_seen_subcommand_from $ip_commands"