#!/bin/sh

## javaconfig.sh, v1.0
## Copyright (C) 2003 Red Hat, Inc.
##
## 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 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.

# Script to manage symbolic links for JARs and binaries.

if [ $# = 0 ]; then
    cat 1>&2 <<EOF
usage: $0 FILE...

where each FILE is the name of a JAR, shared object or binary whose
symbolic links you want to manage.  For example, if you invoke:

  $0 /usr/share/java/servlet.jar

and /usr/share/java contains, amongst other things:

  servlet-3.3.1.jar
  servlet-4.0.3.jar
  servlet-4.1.7.jar

then any existing symbolic links will be deleted and the following
will be created:

  servlet-3.jar -> servlet-3.3.1.jar
  servlet-4.jar -> servlet-4.1.7.jar
  servlet.jar -> servlet-4.jar

If the environment variable DRYRUN is set then a report of what would
have been done will be printed.
EOF
    exit 1
fi
[ "$debug" ] && [ "$debug" -gt 1 ] && set -x
for file in $@; do
    if [ -e $file -a ! -L $file ]; then
	echo 1>&2 "$file exists and is not a symbolic link"
	exit 1
    fi

    # Dissect the filename
    dir=`dirname $file`
    if [ "$dir" = . ]; then dir=; elif [ "$dir" != / ]; then dir="$dir/"; fi
    ext=`echo $file | sed 's:^.*\.:.:'`
    case "$ext" in
    .jar|.so)
        base=`basename $file $ext`
	;;
    *)
	base=`basename $file`
	unset ext
    esac
    [ "$debug" ] && echo "'$file' => ('$dir', '$base', '$ext')"

    # Build normal and regular expression format strings 
    format="$dir$base-%s$ext"
    re_format=`echo "$format" | sed -e 's:^:^:' -e 's:$:$:' -e 's:\\.:\\\\.:g'`
    [ "$debug" ] && echo "format = '$format', re_format = '$re_format'"
    
    # Build a list of existing files that we manage
    glob=`printf "$format" "*"`
    match_re=`printf "$re_format" '[0-9]\{1,\}\(\.[0-9]\{1,\}\)*'`
    unset files oldlinks
    for i in $file `echo $glob`; do
	[ -f "$i" -o -L "$i" ] || continue
	if [ "$i" != "$file" ]; then
	    if ! echo "$i" | grep "$match_re" > /dev/null; then
	        [ "$debug" ] && echo "skipping '$i', it's not one of ours"
		continue
	    fi
	fi
	if [ -L "$i" ]; then
	    oldlinks="$oldlinks${oldlinks:+ }$i"
	elif [ -f "$i" ]; then
	    files="$files${files:+ }$i"
        else
	    echo 1>&2 "$file: $i is neither a regular file or a symlink"
	    exit 1
	fi
    done
    [ "$debug" ] && echo "files = '$files', oldlinks = '$oldlinks'"

    # Sort $files in version number order, using a tagged sort (tag
    # each file with its expanded version number, sort the list, then
    # remove the tag)
    ver_re=`printf "$re_format" '\(.*\)'`
    for pass in count tag; do
	[ $pass = count ] && maxdots=-1
	[ $pass = tag ] && unset taggedfiles
        for i in $files; do
	    ver=`echo $i | sed -e "s:$ver_re:\1:"`
	    numdots=`echo $ver | sed -e 's:[^.]::g' | wc -c`
	    numdots=`expr $numdots - 1` # remove the CR
	    case $pass in
	    count)
	        [ $numdots -gt $maxdots ] && maxdots=$numdots
		;;
	    tag)
		unset tag
		j=0
		while [ $j -le $maxdots ]; do
		    if [ $j -lt $numdots ]; then
			this=`echo $ver | sed -e 's:\..*$::'`
			ver=`echo $ver | sed -e 's:^[^.]*\.::'`
		    elif [ $j = $numdots ]; then
			this=$ver
		    else
		        this=0
		    fi
		    this=`printf "%05d" $this`
	    	tag="$tag${tag:+.}$this"
	    	j=`expr $j + 1`
        	done
		taggedfiles="$taggedfiles${taggedfiles:+ }$tag,$i"
		;;
	    esac
    	done
    done
    [ "$debug" ] && echo "taggedfiles = '$taggedfiles'"
    unset files
    for i in `for i in $taggedfiles; do echo $i; done \
                  | sort -r | sed -e 's:^[^,]*,::'`; do
	files="$files${files:+ }$i"
    done
    [ "$debug" ] && echo "files = '$files'"

    # XXX Any user-defined classpath ordering should probably go here,
    # and involve tweaking the order of $files.

    # Go through $files and build a list of links we have to make
    unset links
    for i in $files; do
	links="$dir$base$ext,`basename $i`"
	break
    done
    [ "$debug" ] && echo "links = '$links'"

    # Finally, everything is ok and we can do our stuff
    if [ "$DRYRUN" ]; then
	[ "$oldlinks" ] && echo "rm -f $oldlinks"
    else
        [ "$oldlinks" ] && rm -f $oldlinks
    fi
    for i in $links; do
        target=`echo $i | sed 's:^.*,::'`
        link=`echo $i | sed 's:,.*$::'`
	if [ "$DRYRUN" ]; then
	    echo "ln -s $target $link"
	else
	    ln -s $target $link
	fi
    done
done