diff --git a/scripts/bash/snap_completer.sh b/scripts/bash/snap_completer.sh new file mode 100755 index 000000000000..828e9fa47c5e --- /dev/null +++ b/scripts/bash/snap_completer.sh @@ -0,0 +1,333 @@ +# shellcheck shell=bash + +# Derived from: https://github.com/spf13/cobra/blob/main/bash_completionsV2.go +# Modifications made by Canonical Ltd, 2024 +# Original work is licensed under the Apache License, Version 2.0 + +# bash completion V2 for lxc +# This script provides bash completions for the LXD Snap. Snap completions are achieved by a marshalling script in snapd. Completion requests are intercepted and scanned before serialization by complete.sh, sent to etelpmoc.sh for de-serialization and processing, and finally, results are serialized. See https://github.com/canonical/snapd/blob/master/data/completion/bash/etelpmoc.sh and https://github.com/canonical/snapd/blob/master/data/completion/bash/complete.sh for detailed descriptions on the snapd bash completion process. + +__lxc_debug() +{ + if [[ -n ${BASH_COMP_DEBUG_FILE-} ]]; then + echo "$*" >> "${BASH_COMP_DEBUG_FILE}" + fi +} + +# This function calls the lxc program to obtain the completion +# results and the directive. It fills the 'out' and 'directive' vars. +__lxc_get_completion_results() { + local requestComp lastParam lastChar args + + # Prepare the command to request completions for the program. + # Calling ${words[0]} instead of directly lxc allows handling aliases + args=("${words[@]:1}") + # Request completions from the LXC binary in LXD's Snap. + requestComp="/snap/lxd/current/bin/lxc __complete ${args[*]}" + + lastParam=${words[$((${#words[@]}-1))]} + lastChar=${lastParam:$((${#lastParam}-1)):1} + __lxc_debug "lastParam ${lastParam}, lastChar ${lastChar}" + + if [[ -z ${cur} && ${lastChar} != = ]]; then + # If the last parameter is complete (there is a space following it) + # We add an extra empty parameter so we can indicate this to the go method. + __lxc_debug "Adding extra empty parameter" + requestComp="${requestComp} ''" + fi + + # When completing a flag with an = (e.g., lxc -n=) + # bash focuses on the part after the =, so we need to remove + # the flag part from $cur + if [[ ${cur} == -*=* ]]; then + cur="${cur#*=}" + fi + + __lxc_debug "Calling ${requestComp}" + # Use eval to handle any environment variables and such + out=$(eval "${requestComp}" 2>/dev/null) + + # Extract the directive integer at the very end of the output following a colon (:) + directive=${out##*:} + # Remove the directive + out=${out%:*} + if [[ ${directive} == "${out}" ]]; then + # There is not directive specified + directive=0 + fi + __lxc_debug "The completion directive is: ${directive}" + __lxc_debug "The completions are: ${out}" +} + +__lxc_process_completion_results() { + local shellCompDirectiveError=1 + local shellCompDirectiveNoSpace=2 + local shellCompDirectiveNoFileComp=4 + local shellCompDirectiveFilterFileExt=8 + local shellCompDirectiveFilterDirs=16 + local shellCompDirectiveKeepOrder=32 + + if (((directive & shellCompDirectiveError) != 0)); then + # Error code. No completion. + __lxc_debug "Received error from custom completion go code" + return + else + if (((directive & shellCompDirectiveNoSpace) != 0)); then + __lxc_debug "Activating no space" + # Since we know the nospace completion option is supported in the LXD Snap environment, we can set it after receiving a no space completion directive from Cobra. + compopt -o nospace + fi + if (((directive & shellCompDirectiveKeepOrder) != 0)); then + # no sort isn't supported for bash less than < 4.4 + if [[ ${BASH_VERSINFO[0]} -lt 4 || ( ${BASH_VERSINFO[0]} -eq 4 && ${BASH_VERSINFO[1]} -lt 4 ) ]]; then + __lxc_debug "No sort directive not supported in this version of bash" + else + __lxc_debug "Activating keep order" + compopt -o nosort + fi + fi + if (((directive & shellCompDirectiveNoFileComp) != 0)); then + __lxc_debug "Activating no file completion" + compopt +o default + fi + fi + + # Separate activeHelp from normal completions + local completions=() + local activeHelp=() + __lxc_extract_activeHelp + + if (((directive & shellCompDirectiveFilterFileExt) != 0)); then + # File extension filtering + local fullFilter filter filteringCmd + + # Do not use quotes around the $completions variable or else newline + # characters will be kept. + # shellcheck disable=SC2048 + for filter in ${completions[*]}; do + fullFilter+="$filter|" + done + + filteringCmd="_filedir $fullFilter" + __lxc_debug "File filtering command: $filteringCmd" + $filteringCmd + elif (((directive & shellCompDirectiveFilterDirs) != 0)); then + # File completion for directories only + + local subdir + subdir=${completions[0]} + if [[ -n $subdir ]]; then + __lxc_debug "Listing directories in $subdir" + pushd "$subdir" >/dev/null 2>&1 && _filedir -d && popd >/dev/null 2>&1 || return + else + __lxc_debug "Listing directories in ." + _filedir -d + fi + else + __lxc_handle_completion_types + fi + + __lxc_handle_special_char "$cur" : + __lxc_handle_special_char "$cur" = + + # Print the activeHelp statements before we finish + if ((${#activeHelp[*]} != 0)); then + printf "\n"; + printf "%s\n" "${activeHelp[@]}" + printf "\n" + + # The prompt format is only available from bash 4.4. + # We test if it is available before using it. + # shellcheck disable=SC2034 + if (x=${PS1@P}) 2> /dev/null; then + printf "%s%s" "${PS1@P}" "${COMP_LINE[@]}" + else + # Can't print the prompt. Just print the + # text the user had typed, it is workable enough. + printf "%s" "${COMP_LINE[@]}" + fi + fi +} + +# Separate activeHelp lines from real completions. +# Fills the $activeHelp and $completions arrays. +__lxc_extract_activeHelp() { + local activeHelpMarker="_activeHelp_ " + local endIndex=${#activeHelpMarker} + + while IFS='' read -r comp; do + if [[ ${comp:0:endIndex} == "$activeHelpMarker" ]]; then + comp=${comp:endIndex} + __lxc_debug "ActiveHelp found: $comp" + if [[ -n $comp ]]; then + activeHelp+=("$comp") + fi + else + # Not an activeHelp line but a normal completion + completions+=("$comp") + fi + done <<<"${out}" +} + +__lxc_handle_completion_types() { + __lxc_debug "__lxc_handle_completion_types: COMP_TYPE is $COMP_TYPE" + + case $COMP_TYPE in + 37|42) + # Type: menu-complete/menu-complete-backward and insert-completions + # If the user requested inserting one completion at a time, or all + # completions at once on the command-line we must remove the descriptions. + # https://github.com/spf13/cobra/issues/1508 + local tab=$'\t' comp + while IFS='' read -r comp; do + [[ -z $comp ]] && continue + # Strip any description + # shellcheck disable=SC2295 + comp=${comp%%$tab*} + # Only consider the completions that match + if [[ $comp == "$cur"* ]]; then + COMPREPLY+=("$comp") + fi + done < <(printf "%s\n" "${completions[@]}") + ;; + + *) + # Type: complete (normal completion) + __lxc_handle_standard_completion_case + ;; + esac +} + +__lxc_handle_standard_completion_case() { + local tab=$'\t' comp + + # Short circuit to optimize if we don't have descriptions + if [[ "${completions[*]}" != *$tab* ]]; then + IFS=$'\n' read -ra COMPREPLY -d '' < <(compgen -W "${completions[*]}" -- "$cur") + return 0 + fi + + local longest=0 + local compline + # Look for the longest completion so that we can format things nicely + while IFS='' read -r compline; do + [[ -z $compline ]] && continue + # Strip any description before checking the length + # shellcheck disable=SC2295 + comp=${compline%%$tab*} + # Only consider the completions that match + [[ $comp == "$cur"* ]] || continue + COMPREPLY+=("$compline") + if ((${#comp}>longest)); then + longest=${#comp} + fi + done < <(printf "%s\n" "${completions[@]}") + + # If there is a single completion left, remove the description text + if ((${#COMPREPLY[*]} == 1)); then + __lxc_debug "COMPREPLY[0]: ${COMPREPLY[0]}" + comp="${COMPREPLY[0]%%$tab*}" + __lxc_debug "Removed description from single completion, which is now: ${comp}" + COMPREPLY[0]=$comp + else # Format the descriptions + # shellcheck disable=SC2086 + __lxc_format_comp_descriptions $longest + fi +} + +__lxc_handle_special_char() +{ + local comp="$1" + local char=$2 + if [[ "$comp" == *${char}* && "$COMP_WORDBREAKS" == *${char}* ]]; then + # shellcheck disable=SC2295 + local word=${comp%"${comp##*${char}}"} + local idx=${#COMPREPLY[*]} + while ((--idx >= 0)); do + COMPREPLY[idx]=${COMPREPLY[idx]#"$word"} + done + fi +} + +__lxc_format_comp_descriptions() +{ + local tab=$'\t' + local comp desc maxdesclength + local longest=$1 + + local i ci + for ci in ${!COMPREPLY[*]}; do + comp=${COMPREPLY[ci]} + # Properly format the description string which follows a tab character if there is one + if [[ "$comp" == *$tab* ]]; then + __lxc_debug "Original comp: $comp" + # shellcheck disable=SC2295 + desc=${comp#*$tab} + # shellcheck disable=SC2295 + comp=${comp%%$tab*} + + # $$(tput cols) stores the current shell width. + # Remove an extra 4 because we add 2 spaces and 2 parentheses. + maxdesclength=$(( $(tput cols) - longest - 4 )) + + # Make sure we can fit a description of at least 8 characters + # if we are to align the descriptions. + if ((maxdesclength > 8)); then + # Add the proper number of spaces to align the descriptions + for ((i = ${#comp} ; i < longest ; i++)); do + comp+=" " + done + else + # Don't pad the descriptions so we can fit more text after the completion + maxdesclength=$(( $(tput cols) - ${#comp} - 4 )) + fi + + # If there is enough space for any description text, + # truncate the descriptions that are too long for the shell width + if ((maxdesclength > 0)); then + if ((${#desc} > maxdesclength)); then + desc=${desc:0:$(( maxdesclength - 1 ))} + desc+="…" + fi + comp+=" ($desc)" + fi + COMPREPLY[ci]=$comp + __lxc_debug "Final comp: $comp" + fi + done +} + +__start_lxc() +{ + # shellcheck disable=SC2034 + local cur prev words cword split + + COMPREPLY=() + + # Call _init_completion from the bash-completion package + # to prepare the arguments properly + if declare -F _init_completion >/dev/null 2>&1; then + _init_completion -n =: || return + else + __lxc_init_completion -n =: || return + fi + + __lxc_debug + __lxc_debug "========= starting completion logic ==========" + __lxc_debug "cur is ${cur}, words[*] is ${words[*]}, #words[@] is ${#words[@]}, cword is $cword" + + # The user could have moved the cursor backwards on the command-line. + # We need to trigger completion from the $cword location, so we need + # to truncate the command-line ($words) up to the $cword location. + words=("${words[@]:0:$cword+1}") + __lxc_debug "Truncated words[*]: ${words[*]}," + + local out directive + __lxc_get_completion_results + __lxc_process_completion_results +} + +# Snap calls lxd.lxc under the hood, so we'll need to provide completions for both lxd.lxc and lxc. +complete -o default -F __start_lxc lxd.lxc lxc + +# ex: ts=4 sw=4 et filetype=sh