functions

#!/bin/bash
# -*- coding: utf-8; mode: sh; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- vim:fenc=utf-8:ft=sh:et:sw=4:ts=4:sts=4

# Helper functions for mpbb

# Print $0 and arguments to standard error.
# Unset IFS to ensure "$*" uses spaces as separators.
msg() (unset IFS; printf >&2 '%s: %s\n' "$0" "$*")
err() { msg error: "$@"; }
warn() { msg warning: "$@"; }

unset GETOPT_COMPATIBLE
if getopt -T >/dev/null; then
    # http://frodo.looijaard.name/project/getopt
    err "Cannot find an enhanced getopt(1)"
    return 3
fi

# TODO Documentation, obviously :)
parseopt() {
    # Be stricter about this than getopt(1) is.
    if ! [[ ${1-} =~ ^[[:alnum:]-]+:{0,2}(,[[:alnum:]-]+:{0,2})*$ ]]; then
        err 'Invalid argument given to parseopt'
        return 3
    fi

    # Use "--options +" to prevent arguments from being rearranged.
    local opts
    opts=$(getopt --name "$0" --opt + --longopt "$1" -- "${@:2}")
    case $? in
        0)
            ;;
        1)
            # getopt(1) will print the bad argument to standard error.
            echo >&2 "Try \`$0 help' for more information."
            return 2
            ;;
        *)
            err 'getopt encountered an internal error'
            return 3
            ;;
    esac
    readonly opts

    local -a validopts
    IFS=, read -ra validopts <<<"$1"
    readonly validopts=("${validopts[@]/#/--}")

    eval set -- "$opts"

    local opt validopt
    # getopt(1) ensures that the options are always terminated with "--".
    while [[ $1 != -- ]]; do
        opt=$1
        shift
        # XXX Do NOT touch anything below unless you know exactly what
        # you're doing (http://mywiki.wooledge.org/BashFAQ/006#eval).
        for validopt in "${validopts[@]}"; do
            if [[ $validopt == "$opt:" || $validopt == "$opt::" ]]; then
                opt=${opt#--}
                # $1 is null for omitted optional arguments.
                eval option_"${opt//-/_}"'=$1'
                shift
                continue 2
            fi
            if [[ $validopt == "$opt" ]]; then
                opt=${opt#--}
                eval option_"${opt//-/_}"'=1'
                continue 2
            fi
        done
        # Unreachable unless there is a bug in this function or in getopt(1).
        err 'parseopt encountered an internal error'
        return 3
    done
    # shellcheck disable=SC2034
    args=("${@:2}")
}

## Compute a failcache hash for the given port
#
# Computes and prints a hash uniquely identifying a specific state of a port's
# definition files, including the Portfile's hash as well as the port's
# patchfiles. To build the hash, this function executes the following
# algorithm:
#  - For the Portfile, and each file in files/ (if any), calculate a SHA256
#    hash
#  - Sort the hash values alphabetically
#  - Hash the result using SHA256
# This means a failcache entry will not match if a patchfile changes. A common
# case where this is the desired behavior is a port committed without
# a required patchfile.
#
# Valid arguments are all arguments accepted by "port dir".
compute_failcache_hash() {
    local portdir
    local -a filelist

    portdir=$("${option_prefix}/bin/port" dir "$@")
    if [ $? -ne 0 ] || [ -z "$portdir" ]; then
        err "Could not compute failcache hash: port dir" "$@" "failed"
        return 1
    fi

    if [ ! -d "$portdir" ]; then
        err "Port directory $portdir does not exist"
        return 2
    fi

    filelist=("$portdir/Portfile")
    if [ -d "$portdir/files" ]; then
        filelist+=("$portdir/files")
    fi

    find "${filelist[@]}" -type f -exec openssl dgst -sha256 {} \; |\
        cut -d' ' -f2 |\
        sort |\
        openssl dgst -sha256 |\
        cut -d' ' -f2
}

## Compute a key that uniquely identifies a (port, variants, portfile-hash) tuple
#
# Valid arguments are a port name, optionally followed by a variant
# specification. Invokes "port dir" to find the Portfile and patchfiles and
# computes a checksum of these files that will become part of the hash.
failcache_key() {
    local port=$1
    if [ -z "$port" ]; then
        err "failcache_key expects a port argument, but none was given."
        return 1
    fi

    local checksum
    checksum=$(compute_failcache_hash "$port")
    if [ $? -ne 0 ]; then
        err "compute_failcache_hash $port failed"
        return 2
    fi

    local canonical_variants
    canonical_variants=$("${option_prefix}/bin/port-tclsh" "${thisdir}/tools/canonical-variants.tcl" "$@")
    if [ $? -ne 0 ]; then
        err "tools/canonical-variants.tcl" "$@" "failed"
        return 4
    fi

    echo "$port $canonical_variants $checksum"
}

## Delete stale failcache entries for a given port
#
# Valid arguments are the first and last parts of a key generated by
# failcache_key in order, i.e. portname and checksum.
# Returns 1 if there were no entries for the given port, 0 otherwise.
failcache_cleanup() {
    if ! compgen -G "${option_failcache_dir}/${1} *" > /dev/null; then
        return 1
    fi
    for f in "${option_failcache_dir}/${1} "*; do
        if [ "$(basename "$f" | cut -d ' ' -f3)" != "${2}" ]; then
            rm -f "${f}"
        fi
    done
    return 0
}

## Test whether a given port with variants has previously failed.
#
# Valid arguments are a port name, optionally followed by a variant
# specification. Succeeds if the port did not previously fail to build,
# fails if the port is known to fail.
failcache_test() {
    local key
    key=$(failcache_key "$@")
    if [ $? -ne 0 ]; then
        err "Could not determine failcache key for" "$@"
        return 1
    fi

    # check that it doesn't exceed NAME_MAX
    if [ "$(echo "$key" | wc -c)" -gt 255 ]; then
        printf "failcache key too long: %s\n" "${key}"
        return 0
    fi

    if [ -f "${option_failcache_dir}/${key}" ]; then
        printf "port %s previously failed in build %s\n" "${key}" "$(<"${option_failcache_dir}/${key}")"
        return 1
    else
        return 0
    fi
}

## Mark a build of a given port with variants as successful.
#
# Valid arguments are a port name, optionally followed by a variant
# specification. Removes any database entries that marked a port as failed.
failcache_success() {
    local key
    key=$(failcache_key "$@")
    if [ $? -ne 0 ]; then
        err "Could not determine failcache key for" "$@"
        return 1
    fi

    if [ "$(echo "$key" | wc -c)" -gt 255 ]; then
        printf "failcache key too long: %s\n" "${key}"
        return 0
    fi

    # Only remove the entry for the successful configuration, leaving
    # other entries in case they are explicitly requested later. These
    # can be removed manually if desired.
    rm -f "${option_failcache_dir}/${key}"
}

## Mark a build of a given port with variants as failed.
#
# Valid arguments are a port name, optionally followed by a variant
# specification. Creates or updates the timestamp of a database entry that
# marks a port as failed.
failcache_failure() {
    local key
    key=$(failcache_key "$@")
    if [ $? -ne 0 ]; then
        err "Could not determine failcache key for" "$@"
        return 1
    fi

    if [ "$(echo "$key" | wc -c)" -gt 255 ]; then
        printf "failcache key too long: %s\n" "${key}"
        return 0
    fi

    mkdir -p "${option_failcache_dir}"
    echo "${BUILDBOT_BUILDURL:-unknown}" > "${option_failcache_dir}/${key}"
}

get-maintainers() {
    # 'username@macports.org github_username' => 'username@macports.org'
    # $option_prefix is set in mpbb
    # shellcheck disable=SC2154
    "${option_prefix}/bin/port" info --index --maintainers --line "$@" \
        | tr ', ' '\n' | fgrep '@' | tr '\n' ',' | sed 's/,$//'
}