#! /bin/sh

# Set a version string for this script.
scriptversion=2012-10-21.11; # UTC

# A portable, pluggable option parser for Bourne shell.
# Written by Gary V. Vaughan, 2010

# Copyright (C) 2010-2012 Free Software Foundation, Inc.
# This is free software; see the source for copying conditions.  There is NO
# warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Please report bugs or propose patches to gary@gnu.org.


## ------ ##
## Usage. ##
## ------ ##

# This file is a library for parsing options in your shell scripts along
# with assorted other useful supporting features that you can make use
# of too.
#
# For the simplest scripts you might need only:
#
#   #!/bin/sh
#   . relative/path/to/funclib.sh
#   . relative/path/to/options-parser
#   scriptversion=1.0
#   func_options ${1+"$@"}
#   eval set dummy "$func_options_result"; shift
#   ...rest of your script...
#
# In order for the '--version' option to work, you will need to have a
# suitably formatted comment like the one at the top of this file
# starting with '# Written by ' and ending with '# warranty; '.
#
# For '-h' and '--help' to work, you will also need a one line
# description of your script's purpose in a comment directly above the
# '# Written by ' line, like the one at the top of this file.
#
# The default options also support '--debug', which will turn on shell
# execution tracing (see the comment above debug_cmd below for another
# use), and '--verbose' and the func_verbose function to allow your script
# to display verbose messages only when your user has specified
# '--verbose'.
#
# After sourcing this file, you can plug processing for additional
# options by amending the variables from the 'Configuration' section
# below, and following the instructions in the 'Option parsing'
# section further down.

## -------------- ##
## Configuration. ##
## -------------- ##

# You should override these variables in your script after sourcing this
# file so that they reflect the customisations you have added to the
# option parser.

# The usage line for option parsing errors and the start of '-h' and
# '--help' output messages. You can embed shell variables for delayed
# expansion at the time the message is displayed, but you will need to
# quote other shell meta-characters carefully to prevent them being
# expanded when the contents are evaled.
usage='$progpath [OPTION]...'

# Short help message in response to '-h' and '--help'.  Add to this or
# override it after sourcing this library to reflect the full set of
# options your script accepts.
usage_message="\
       --debug        enable verbose shell tracing
   -W, --warnings=CATEGORY
                      report the warnings falling in CATEGORY [all]
   -v, --verbose      verbosely report processing
       --version      print version information and exit
   -h, --help         print short or long help message and exit
"

# Additional text appended to 'usage_message' in response to '--help'.
long_help_message="
Warning categories include:
       'all'          show all warnings
       'none'         turn off all the warnings
       'error'        warnings are treated as fatal errors"

# Help message printed before fatal option parsing errors.
fatal_help="Try '\$progname --help' for more information."



## ------------------------- ##
## Hook function management. ##
## ------------------------- ##

# This section contains functions for adding, removing, and running hooks
# to the main code.  A hook is just a named list of of function, that can
# be run in order later on.

# func_hookable FUNC_NAME
# -----------------------
# Declare that FUNC_NAME will run hooks added with
# 'func_add_hook FUNC_NAME ...'.
func_hookable ()
{
    $debug_cmd

    func_append hookable_fns " $1"
}


# func_add_hook FUNC_NAME HOOK_FUNC
# ---------------------------------
# Request that FUNC_NAME call HOOK_FUNC before it returns.  FUNC_NAME must
# first have been declared "hookable" by a call to 'func_hookable'.
func_add_hook ()
{
    $debug_cmd

    case " $hookable_fns " in
      *" $1 "*) ;;
      *) func_fatal_error "'$1' does not accept hook functions." ;;
    esac

    eval func_append ${1}_hooks '" $2"'
}


# func_remove_hook FUNC_NAME HOOK_FUNC
# ------------------------------------
# Remove HOOK_FUNC from the list of functions called by FUNC_NAME.
func_remove_hook ()
{
    $debug_cmd

    eval ${1}_hooks='`$bs_echo "\$'$1'_hooks" |$SED "s| '$2'||"`'
}


# func_run_hooks FUNC_NAME [ARG]...
# ---------------------------------
# Run all hook functions registered to FUNC_NAME.
# It is assumed that the list of hook functions contains nothing more
# than a whitespace-delimited list of legal shell function names, and
# no effort is wasted trying to catch shell meta-characters or preserve
# whitespace.
func_run_hooks ()
{
    $debug_cmd

    case " $hookable_fns " in
      *" $1 "*) ;;
      *) func_fatal_error "'$1' does not support hook funcions.n" ;;
    esac

    eval _G_hook_fns=\$$1_hooks; shift

    for _G_hook in $_G_hook_fns; do
      eval $_G_hook '"$@"'

      # store returned options list back into positional
      # parameters for next 'cmd' execution.
      eval _G_hook_result=\$${_G_hook}_result
      eval set dummy "$_G_hook_result"; shift
    done

    func_quote_for_eval ${1+"$@"}
    func_run_hooks_result=$func_quote_for_eval_result
}



## --------------- ##
## Option parsing. ##
## --------------- ##

# In order to add your own option parsing hooks, you must accept the
# full positional parameter list in your hook function, remove any
# options that you action, and then pass back the remaining unprocessed
# options in '<hooked_function_name>_result', escaped suitably for
# 'eval'.  Like this:
#
#    my_options_prep ()
#    {
#        $debug_cmd
#
#        # Extend the existing usage message.
#        usage_message=$usage_message'
#      -s, --silent       don'\''t print informational messages
#    '
#
#        func_quote_for_eval ${1+"$@"}
#        my_options_prep_result=$func_quote_for_eval_result
#    }
#    func_add_hook func_options_prep my_options_prep
#
#
#    my_silent_option ()
#    {
#        $debug_cmd
#
#        # Note that for efficiency, we parse as many options as we can
#        # recognise in a loop before passing the remainder back to the
#        # caller on the first unrecognised argument we encounter.
#        while test $# -gt 0; do
#          opt=$1; shift
#          case $opt in
#            --silent|-s) opt_silent=: ;;
#            # Separate non-argument short options:
#            -s*)         func_split_short_opt "$_G_opt"
#                         set dummy "$func_split_short_opt_name" \
#                             "-$func_split_short_opt_arg" ${1+"$@"}
#                         shift
#                         ;;
#            *)            set dummy "$_G_opt" "$*"; shift; break ;;
#          esac
#        done
#
#        func_quote_for_eval ${1+"$@"}
#        my_silent_option_result=$func_quote_for_eval_result
#    }
#    func_add_hook func_parse_options my_silent_option
#
#
#    my_option_validation ()
#    {
#        $debug_cmd
#
#        $opt_silent && $opt_verbose && func_fatal_help "\
#    '--silent' and '--verbose' options are mutually exclusive."
#
#        func_quote_for_eval ${1+"$@"}
#        my_option_validation_result=$func_quote_for_eval_result
#    }
#    func_add_hook func_validate_options my_option_validation
#
# You'll alse need to manually amend $usage_message to reflect the extra
# options you parse.  It's preferable to append if you can, so that
# multiple option parsing hooks can be added safely.


# func_options [ARG]...
# ---------------------
# All the functions called inside func_options are hookable. See the
# individual implementations for details.
func_hookable func_options
func_options ()
{
    $debug_cmd

    func_options_prep ${1+"$@"}
    eval func_parse_options \
        ${func_options_prep_result+"$func_options_prep_result"}
    eval func_validate_options \
        ${func_parse_options_result+"$func_parse_options_result"}

    eval func_run_hooks func_options \
        ${func_validate_options_result+"$func_validate_options_result"}

    # save modified positional parameters for caller
    func_options_result=$func_run_hooks_result
}


# func_options_prep [ARG]...
# --------------------------
# All initialisations required before starting the option parse loop.
# Note that when calling hook functions, we pass through the list of
# positional parameters.  If a hook function modifies that list, and
# needs to propogate that back to rest of this script, then the complete
# modified list must be put in 'func_run_hooks_result' before
# returning.
func_hookable func_options_prep
func_options_prep ()
{
    $debug_cmd

    # Option defaults:
    opt_verbose=false
    opt_warning_types=

    func_run_hooks func_options_prep ${1+"$@"}

    # save modified positional parameters for caller
    func_options_prep_result=$func_run_hooks_result
}


# func_parse_options [ARG]...
# ---------------------------
# The main option parsing loop.
func_hookable func_parse_options
func_parse_options ()
{
    $debug_cmd

    func_parse_options_result=

    # this just eases exit handling
    while test $# -gt 0; do
      # Defer to hook functions for initial option parsing, so they
      # get priority in the event of reusing an option name.
      func_run_hooks func_parse_options ${1+"$@"}

      # Adjust func_parse_options positional parameters to match
      eval set dummy "$func_run_hooks_result"; shift

      # Break out of the loop if we already parsed every option.
      test $# -gt 0 || break

      _G_opt=$1
      shift
      case $_G_opt in
        --debug|-x)   debug_cmd='set -x'
                      func_echo "enabling shell trace mode"
                      $debug_cmd
                      ;;

        --no-warnings|--no-warning|--no-warn)
                      set dummy --warnings none ${1+"$@"}
                      shift
		      ;;

        --warnings|--warning|-W)
                      test $# = 0 && func_missing_arg $_G_opt && break
                      case " $warning_categories $1" in
                        *" $1 "*)
                          # trailing space prevents matching last $1 above
                          func_append_uniq opt_warning_types " $1"
                          ;;
                        *all)
                          opt_warning_types=$warning_categories
                          ;;
                        *none)
                          opt_warning_types=none
                          warning_func=:
                          ;;
                        *error)
                          opt_warning_types=$warning_categories
                          warning_func=func_fatal_error
                          ;;
                        *)
                          func_fatal_error \
                             "unsupported warning category: '$1'"
                          ;;
                      esac
                      shift
                      ;;

        --verbose|-v) opt_verbose=: ;;
        --version)    func_version ;;
        -\?|-h)       func_usage ;;
        --help)       func_help ;;

	# Separate optargs to long options (plugins may need this):
	--*=*)        func_split_equals "$_G_opt"
	              set dummy "$func_split_equals_lhs" \
                          "$func_split_equals_rhs" ${1+"$@"}
                      shift
                      ;;

       # Separate optargs to short options:
        -W*)
                      func_split_short_opt "$_G_opt"
                      set dummy "$func_split_short_opt_name" \
                          "$func_split_short_opt_arg" ${1+"$@"}
                      shift
                      ;;

        # Separate non-argument short options:
        -\?*|-h*|-v*|-x*)
                      func_split_short_opt "$_G_opt"
                      set dummy "$func_split_short_opt_name" \
                          "-$func_split_short_opt_arg" ${1+"$@"}
                      shift
                      ;;

        --)           break ;;
        -*)           func_fatal_help "unrecognised option: '$_G_opt'" ;;
        *)            set dummy "$_G_opt" ${1+"$@"}; shift; break ;;
      esac
    done

    # save modified positional parameters for caller
    func_quote_for_eval ${1+"$@"}
    func_parse_options_result=$func_quote_for_eval_result
}


# func_validate_options [ARG]...
# ------------------------------
# Perform any sanity checks on option settings and/or unconsumed
# arguments.
func_hookable func_validate_options
func_validate_options ()
{
    $debug_cmd

    # Display all warnings if -W was not given.
    test -n "$opt_warning_types" || opt_warning_types=" $warning_categories"

    func_run_hooks func_validate_options ${1+"$@"}

    # Bail if the options were screwed!
    $exit_cmd $EXIT_FAILURE

    # save modified positional parameters for caller
    func_validate_options_result=$func_run_hooks_result
}



## ------------------##
## Helper functions. ##
## ------------------##

# This section contains the helper functions used by the rest of the
# hookable option parser framework in ascii-betical order.


# func_fatal_help ARG...
# ----------------------
# Echo program name prefixed message to standard error, followed by
# a help hint, and exit.
func_fatal_help ()
{
    $debug_cmd

    eval \$bs_echo \""Usage: $usage"\"
    eval \$bs_echo \""$fatal_help"\"
    func_error ${1+"$@"}
    exit $EXIT_FAILURE
}


# func_help
# ---------
# Echo long help message to standard output and exit.
func_help ()
{
    $debug_cmd

    func_usage_message
    $bs_echo "$long_help_message"
    exit 0
}


# func_missing_arg ARGNAME
# ------------------------
# Echo program name prefixed message to standard error and set global
# exit_cmd.
func_missing_arg ()
{
    $debug_cmd

    func_error "Missing argument for '$1'."
    exit_cmd=exit
}


# func_split_equals STRING
# ------------------------
# Set func_split_equals_lhs and func_split_equals_rhs shell variables after
# splitting STRING at the '=' sign.
test -z "$_G_HAVE_XSI_OPS" \
    && (eval 'x=a/b/c;
      test 5aa/bb/cc = "${#x}${x%%/*}${x%/*}${x#*/}${x##*/}"') 2>/dev/null \
    && _G_HAVE_XSI_OPS=yes

if test yes = "$_G_HAVE_XSI_OPS"
then
  # This is an XSI compatible shell, allowing a faster implementation...
  eval 'func_split_equals ()
  {
      $debug_cmd

      func_split_equals_lhs=${1%%=*}
      func_split_equals_rhs=${1#*=}
      test "x$func_split_equals_lhs" = "x$1" \
        && func_split_equals_rhs=
  }'
else
  # ...otherwise fall back to using expr, which is often a shell builtin.
  func_split_equals ()
  {
      $debug_cmd

      func_split_equals_lhs=`expr "x$1" : 'x\([^=]*\)'`
      func_split_equals_rhs=
      test "x$func_split_equals_lhs" = "x$1" \
        || func_split_equals_rhs=`expr "x$1" : 'x[^=]*=\(.*\)$'`
  }
fi #func_split_equals


# func_split_short_opt SHORTOPT
# -----------------------------
# Set func_split_short_opt_name and func_split_short_opt_arg shell
# variables after splitting SHORTOPT after the 2nd character.
if test yes = "$_G_HAVE_XSI_OPS"
then
  # This is an XSI compatible shell, allowing a faster implementation...
  eval 'func_split_short_opt ()
  {
      $debug_cmd

      func_split_short_opt_arg=${1#??}
      func_split_short_opt_name=${1%"$func_split_short_opt_arg"}
  }'
else
  # ...otherwise fall back to using expr, which is often a shell builtin.
  func_split_short_opt ()
  {
      $debug_cmd

      func_split_short_opt_name=`expr "x$1" : 'x-\(.\)'`
      func_split_short_opt_arg=`expr "x$1" : 'x-.\(.*\)$'`
  }
fi #func_split_short_opt


# func_usage
# ----------
# Echo short help message to standard output and exit.
func_usage ()
{
    $debug_cmd

    func_usage_message
    $bs_echo "Run '$progname --help |${PAGER-more}' for full usage"
    exit 0
}


# func_usage_message
# ------------------
# Echo short help message to standard output.
func_usage_message ()
{
    $debug_cmd

    eval \$bs_echo \""Usage: $usage"\"
    echo
    $SED -n 's|^# ||;/^Written by/{x;p;x;};h' < "$progpath"
    echo
    eval \$bs_echo \""$usage_message"\"
}


# func_version
# ------------
# Echo version message to standard output and exit.
func_version ()
{
    $debug_cmd

    printf '%s\n' "$progname $scriptversion"
    $SED -n '/^##/q
        /(C)/!b go
        :more
        /\./!{
          N
          s|\n# | |
          b more
        }
        :go
        /^# Written by /,/# warranty; / {
          s|^# ||
          s|^# *$||
          s|\((C)\)[ 0-9,-]*[ ,-]\([1-9][0-9]* \)|\1 \2|
          p
        }
        /^# Written by / {
          s|^# ||
          p
        }
        /^warranty; /q' < "$progpath"

    exit $?
}


# Local variables:
# mode: shell-script
# sh-indentation: 2
# eval: (add-hook 'write-file-hooks 'time-stamp)
# time-stamp-pattern: "10/scriptversion=%:y-%02m-%02d.%02H; # UTC"
# time-stamp-time-zone: "UTC"
# End: