#!/bin/sh
# This script attempts to locate the jre directory of the current
# Java installation, even when java is not in the path

# We only support it for Sun's Java on Windows and IBM's Java on Linux

# We require an option to specify which directory is desired:
# --java: directory with java executable
# --javac: directory with javac executable
# --jni: directory where JNI code is placed

if [ "$1" = "--jni" ]; then
  jni=yes
elif [ "$1" = "--java" ]; then
  java=yes
elif [ "$1" = "--javac" ]; then
  javac=yes
else
  echo "Usage: locate-jre --java|--javac|--jni" >&2
  exit 2
fi

case `uname` in
  CYGWIN*)
        # Hopefully this will always work on cygwin with Sun's Java
	jversion=`regtool -q get '\HKLM\SOFTWARE\JavaSoft\Java Development Kit\CurrentVersion'`
	if [ $? != 0 ]; then
	    exit 1
	fi
	jhome=`regtool -q get '\HKLM\SOFTWARE\JavaSoft\Java Development Kit\'$jversion'\JavaHome'`
	if [ $? != 0 ]; then
	    exit 1
	fi
	jhome=`cygpath -u "$jhome"`
	;;
    Linux)
        # On Linux, we first try to find it from the rpm
	j=`rpm -ql IBMJava2-SDK | grep -m 1 'bin/javac$'`
	if [ $? != 0 ]; then
            # Next we try the path. This won't work within rpms, as they reset
            # the path (and we can't just execute the profile as that tends to 
            # execute locate-jre ...). Life is hard...
	    j=`which javac 2>/dev/null`
	    if [ $? != 0 ]; then
		exit 1
	    fi
	fi
	jbin=`dirname "$j"`
	jhome=`dirname "$jbin"`
	;;
    FreeBSD)
	if [ -f /usr/local/jdk1.4*/bin/java ]; then
	    jbin=/usr/local/jdk1.4*/bin
	else
	    exit 1
	fi
	jhome=`dirname $jbin`
	;;
esac

# These are correct for Sun's Window java and IBM's Linux java
if [ "$jni" = "yes" ]; then
  case `uname` in
    FreeBSD)
        UNAMEM=`uname -m`
	dir="$jhome/jre/lib/$UNAMEM"
	;;
    *)
	dir="$jhome/jre/bin"
	;;
  esac
elif [ "$javac" = "yes" ]; then
  dir="$jhome/bin"
elif [ "$java" = "yes" ]; then
  dir="$jhome/jre/bin"
fi

# Check that what we found actually exists
if [ -d "$dir" ]; then
  echo $dir
else
  exit 1
fi