#! /bin/bash -e

# debman - read a man page from an uninstalled Debian package file (.deb)

# Copyright (C) 2003 Colin Watson <cjwatson@debian.org>

# 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 2, 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, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, USA.

usage () {
    if [ "$1" -eq 1 ]; then
        FD=2
    else
        FD=1
    fi
    cat >&$FD <<EOF
Usage: debman [options] [-- man(1) options] <man page name> ...

Options should be exactly one of:
        -f package.deb          read pages from package.deb archive
        -p package              download .deb for package and read pages
                                from there
EOF
    exit "$1"
}

ARGS=`getopt -l help,filename:,package: -o hf:p: -n debman -- "$@"`
eval set -- "$ARGS"

FILENAME=
PACKAGE=

while :; do
    case "$1" in
        -h|--help)
            usage 0
            ;;
        -f|--filename)
            FILENAME="$2"
            shift 2
            ;;
        -p|--package)
            PACKAGE="$2"
            shift 2
            ;;
        --)
            shift
            break
            ;;
        *)
            echo "debman: Internal error in option parsing" >&2
            exit 1
            ;;
    esac
done

if ( [ -n "$FILENAME" ] && [ -n "$PACKAGE" ] ) || \
   ( [ -z "$FILENAME" ] && [ -z "$PACKAGE" ] ); then
    usage 1
fi

if test $# -lt 1; then
    usage 1
fi

# Directory names are duplicated with and without ./ in order to cope with
# old .debs whose data.tar.gz components had a slightly different format.
MANDIRS='usr/share/man usr/X11R6/man ./usr/share/man ./usr/X11R6/man'

TEMPDIR=`mktemp -dt debman.XXXXXXXXXX`
trap 'rm -rf "$TEMPDIR"' EXIT ERR HUP INT QUIT TERM

if [ -n "$PACKAGE" ]; then
    (cd "$TEMPDIR" && debget "$PACKAGE")
    # There should be at most one file in $TEMPDIR now.
    FILENAME="`find \"$TEMPDIR\" -name \*.deb -print`"
    if [ -z "$FILENAME" ]; then
        echo "Failed to fetch package $PACKAGE; exiting." >&2
        exit 1
    fi
fi

# Ignore errors from tar (though not dpkg). They'll generally just be of the
# form "tar: usr/share/man: Not found in archive". If they're something
# else, then man will fail to find the page anyway.

dpkg --fsys-tarfile "$FILENAME" | \
    (tar -C "$TEMPDIR" -xf - $MANDIRS 2>/dev/null || true)

MANPATH="$TEMPDIR/usr/share/man:$TEMPDIR/usr/X11R6/man" man "$@"

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