imapdomo/utils/mkit/include/ini.sh

#!/bin/bash
# MKit - simple install helper
# See LICENSE file for copyright and license details.

__ini_cat() {
    #
    # A no-op for text stream
    #
    local line      # each line
    while read -r line; do
        printf -- '%s\n' "$line"
    done
}

__ini_expand() {
    #
    # Expand reference value (prefix only)
    #
    local line      # each input line
    while read -r line; do                  # [foo:bar]/path
        __ini_expandln "$line"
    done
}

__ini_expandln() {
    #
    # Fully expand references in line $1
    #
    local line_orig=$1          # original line
    local line_todo=$line_orig  # current state
    local line_done             # next state
    local Depth=0               # current depth
    local MaxDepth=10           # maximum depth
    while true; do
        ((Depth++))
        debug_var line_todo
        test "$Depth" -le "$MaxDepth" || {
            warn "expansion error: reached maximum depth: $Depth > $MaxDepth" \
                 "    original line: $line_orig" \
                 "    expanded line: $line_todo"
            return 3
        }
        line_done=$(__ini_expandln_once "$line_todo")
        debug_var line_done
        test "$line_done" == "$line_todo" && break
        line_todo=$line_done
    done
    echo "$line_done"
}

__ini_expandln_once() {
    #
    # Run through line $1 once and replace all references
    #
    local line=$1   # line to expand
    local ref       # full reference (incl. brackets)
    local ipath     # just ini path from ^^ (stripped brackets)
    local value     # value of reference
    local refs=()   # all references found in line
    mapfile -t refs <<<"$(grep -Eo '[[][^]]+[]]' <<< "$line_todo")"
    debug_var refs
    for ref in "${refs[@]}"; do
        test -n "$ref" || continue
        ipath=${ref#[}; ipath=${ipath%]}
        value=$(ini 1value "$ipath")
        debug_var line ref ipath value
        line=${line//"[$ipath]"/"$value"}
    done
    echo "$line"
}

__ini_grepcmt() {
    #
    # Remove comments from INI file on stdin
    #
    grep -v '^[[:space:]]*#'
}

__ini_grepkey() {
    #
    # Read key from a normalized `key=value` section
    #
    local wnt=$1    # wanted key
    grep '.' \
      | grep -e "^$wnt=" \
      | cut -d= -f2- \
      | __ini_maybe_expand
}

__ini_greppath() {
    #
    # Read key from the right section
    #
    # E.g. `files:share:my/lib.sh` should read
    #
    #     [files:share]
    #         my/lib.sh   = proj/my/lib.sh
    #
    local wnt=$1                    # wanted path
    local wntkey=${wnt##*:}         # ^^ key part
    local wntsec=${wnt%:"$wntkey"}  # ^^ section part
    local override                  # ENV override (only ENV section)
    if test "$wntsec" = 'ENV'; then
        override=${!wntkey}
        test -n "$override" \
         && echo "$override" \
         && return
    fi
    __ini_grepsec "$wntsec" | __ini_grepkey "$wntkey"
}

__ini_grepsec() {
    #
    # Read one INI section
    #
    local wnt=$1        # wanted section name
    local ok=false      # are we in the section?
    local line          # each input line
    grep '.' \
      | while read -r line; do
            case "$line" in
                \["$wnt"\]) ok=true;  continue ;;
                \[*\])      ok=false; continue ;;
            esac
            $ok || continue
            printf -- '%s\n' "$line"
        done \
      | grep '^[[:space:]]*[^[:space:]:][^:]*[[:space:]]*[=]' \
      | sed -e 's/[[:space:]]*=[[:space:]]*/=/; s/[[:space:]]*$//; s/^[[:space:]]*//;'
}

__ini_lskeys() {
    #
    # List keys from a section
    #
    local sct=$1    # section of interest
    __ini_grepsec "$sct" | cut -d= -f1 | awk '!x[$0]++'
}

__ini_lssect() {
    #
    # List all section names
    #
    grep -x '\[.*\]' | sed 's/^.//; s/.$//'
}

__ini_maybe_expand() {
    #
    # Decide whether or not to expand
    #
    if test "$MKIT_INI_EXPAND" -gt 0; then
        MKIT_INI_EXPAND=$(( --MKIT_INI_EXPAND )) __ini_expand
    else
        __ini_cat
    fi
}

__ini_body() {
    #
    # Produce mkit.ini body including INCLUDE
    #
    # Note: recursive includes are not supported.
    #
    local inc                       # file to include
    local incre='\[INCLUDE:.*\]'    # include directive regex
    local iline                     # include directive line
    if iline=$(grep -m1 -xe "$incre" "$MKIT_INI"); then
        inc=${iline#*:}; inc=${inc%]}
        grep -vxe "$incre" "$inc"
        grep -vxe "$incre" "$MKIT_INI"
    else
        cat "$MKIT_INI"
    fi | __ini_grepcmt
}

ini() {
    #
    # do ini operation
    #
    local op=$1             # operator
    local arg=$2            # argument
    local fn                # internal function implementing $op
    local limit=__ini_cat    # limiting internal function
    case $op in
        lskeys) fn=__ini_lskeys   ;;
        lssect) fn=__ini_lssect   ;;
        sec)    fn=__ini_grepsec  ;;
        values) fn=__ini_greppath ;;
        1value) fn=__ini_greppath; limit="tail -1" ;;
        *)      die "incorrect use of \`ini()\`"
    esac
    __ini_body | $fn "$arg" | $limit
}