# wrappers.sh: various functions to be used by Java script wrappers
# Copyright 2008 by Vincent Fourmond <fourmond@debian.org>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.

# This library 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
# Lesser General Public License for more details.

# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

# Import the list of JVMs

. /usr/lib/java-wrappers/jvm-list.sh

# Display a debugging message
java_debug() {
    if [ "$DEBUG_WRAPPER" ]; then
	echo "[debug] $0: $@" >&2;
    fi
}

# Displays a warning
java_warning() {
    echo "[warning] $0: $@" >&2;
}

# Exit with an error message
java_fail() {
    echo "[error] $0: $@" >&2;
    exit 1;
}

# Try to get the amount of memory available on the machine to come up
# with a decent -Xmx argument, returned as the value of the
# determined_xmx_arg (defaults in kilobytes, so you should add k
# afterwards)
determine_xmx_arg() {
    # Yes, that's ugly, so what ??
    mem=`free -k 2>/dev/null | head -n2 | tail -n1 | sed -r s/'[^0-9]+//' | cut -d' ' -f1`

}

# Try to find a Java runtime and set JAVA_HOME and JAVA_CMD accordingly.
# If JAVA_CMD exists, nothing is done. If JAVA_HOME exists, only that
# is searched.
#
# The full list of JVM names understood can be found in the file
# /usr/lib/java-wrappers/jvm-list.sh.
#
# More than one argument can be specified; they will be taken into account
# in that order; the first one found will be selected.
#
# If JAVA_DEBUGGER is set, we try to use jdb rather than java, if it is
# present.
#
# This information is currently *far from complete* !!!
find_java_runtime() {

    if [ "$JAVA_CMD" ]; then
	if which "$JAVA_CMD" > /dev/null; then
	    java_debug "Using already set JAVA_CMD = '$JAVA_CMD' => '"`which "$JAVA_CMD"`"'"
	    return 0;		# Nothing to do
	else
	    java_warning "JAVA_CMD was set to '$JAVA_CMD', but which(1) does not find it."
	    java_warning "Therefore ignoring JAVA_CMD"
	fi
    fi

    if [ "$JAVA_BINDIR" ]; then
	if [ "$JAVA_DEBUGGER" ] && [ -x "$JAVA_BINDIR/jdb" ]; then
	    JAVA_CMD="$JAVA_BINDIR/jdb"
	elif [ -x "$JAVA_BINDIR/java" ]; then
	    JAVA_CMD="$JAVA_BINDIR/java"
	fi
	if [ "$JAVA_CMD" ]; then
	    java_debug "Using '$JAVA_CMD' from JAVA_BINDIR = '$JAVA_BINDIR'"
	    return 0;
	else
	    java_warning "JAVA_BINDIR = '$JAVA_BINDIR' does not point to a java binary"
	fi
    fi

    if [ -z "$JAVA_HOME" ]; then

        # We now try to look for a reasonable JAVA_HOME.
        # First, narrow the choices according to what
        # was asked.
	#
	# Please see the list of understood jvms in
	# /usr/lib/java-wrappers/jvm-list.sh

	DIRS=""

	# If no arguments are given, we take it as 'all'
	if test -z "$1"; then
	    set all
	fi

	while test "$1"
	do
	    if echo $1 | egrep -- '[^0-9A-Za-z_]'; then
		java_warning "JVM flavor '${1}' contains illegal characters"
	    else
		found_jvm=$(eval "echo -n \$__jvm_$1")
		if [ -z "$found_jvm" ] ; then
		    java_warning "JVM flavor '${1:-none}' not understood"
		else
		    DIRS="$DIRS $found_jvm"
		fi
	    fi
	    shift
	done
	# Nothing means everything
	if [ -z "$DIRS" ]; then
	    DIRS=$all_runtimes
	fi
	# First, we check if __jvm_alt is within the possible choices:
	if echo "$DIRS" | fgrep "$__jvm_alt" > /dev/null ; then
	    JAVA_HOME="$__jvm_alt"
	    java_debug "Picking up the JVM designated by the alternatives system: "
	    java_debug "  JAVA_HOME = '$JAVA_HOME'"
	else

        # And pick up the first one that works reasonably
	    for dir in $DIRS; do
		if [ -x $dir/bin/java ]; then
		    JAVA_HOME=$dir
		    break;
		fi
	    done
	fi
    else
	java_debug "Using provided JAVA_HOME = '$JAVA_HOME'"
    fi
    if [ "$JAVA_HOME" ] ; then
	if [ "$JAVA_DEBUGGER" ] && [ -x "$JAVA_HOME/bin/jdb" ]; then
	    JAVA_CMD="$JAVA_HOME/bin/jdb"
	else
	    JAVA_CMD="$JAVA_HOME/bin/java"
	fi
	java_debug "Found JAVA_HOME = '$JAVA_HOME'"
	java_debug "Found JAVA_CMD = '$JAVA_CMD'"
	return 0		# Fine
    else
	java_warning "No java runtime was found"
	return 1;
    fi
}


# Some initializations:
if [ "$JAVA_CLASSPATH" ]; then
    java_debug "Building classpath on JAVA_CLASSPATH = '$JAVA_CLASSPATH'"
else
    JAVA_CLASSPATH=
fi


if [ "$JAVA_JARPATH" ]; then
    java_debug "Jar lookup is done in JAVA_JARPATH = '$JAVA_JARPATH'"
else
    JAVA_JARPATH=/usr/share/java
fi


# If the user provides a JAVA_FLAVOR environment variable, we
# force the runtime to be the given flavor, such as for find_java_runtime
if [ "$JAVA_FLAVOR" ]; then
    find_java_runtime "$JAVA_FLAVOR" || \
	java_warning "Could not find runtime for user-supplied flavor '${JAVA_FLAVOR}"
fi


# Same as find_java_runtime, but fails with an error if
# nothing is found.
require_java_runtime() {
    find_java_runtime "$@" || \
	java_fail "Unable to find an appropriate java runtime. See java_wrappers(7) for help"
}

# Looks for a jar file and returns its location as the
# found_jar variable, or fails if no jar was found.
locate_jar() {
    jar="$1"
    if [ -r $JAVA_JARPATH/$jar ]; then
	found_jar=$JAVA_JARPATH/$jar
    elif [ -r $JAVA_JARPATH/$jar.jar ]; then
	found_jar=$JAVA_JARPATH/$jar.jar
    elif [ -r $jar ]; then
	found_jar=$jar
    elif [ -r $jar.jar ]; then
	found_jar=$jar.jar
    else
	return 1		# Not found
    fi
    return 0			# Found
}

# Find jars and add them to the classpath
find_jars() {
    looked_for_jars=1
    for jar in $@ ; do
	if locate_jar $jar; then
            if [ -z "$JAVA_CLASSPATH" ]; then
	        JAVA_CLASSPATH=$found_jar
            else
	        JAVA_CLASSPATH=$JAVA_CLASSPATH:$found_jar
            fi
	else
	    java_warning "Unable to locate $jar in $JAVA_JARPATH"
	fi
    done
}

# Recursively adds the jar and its classpath to the classpath
_recurse_jar_classpath() {
    if [ -r "$1" ]; then
	if echo $JAVA_CLASSPATH | fgrep "$1" > /dev/null; then
	    return 0;
	fi
	JAVA_CLASSPATH=$JAVA_CLASSPATH:$1
	java_debug "Looking at classpath of jar: '$1'"
	for jar in $(/usr/lib/java-wrappers/get-classpath "$1"); do
	    if [ "${jar##/}" = "$jar" ]; then
		# Relative path = path relative to the location of the
		# JAR file !
		jar=$(dirname $1)/$jar
	    fi
	    _recurse_jar_classpath $jar;
	done
    else
	java_debug "Unable to find file $1 that may be needed"
	return 1;
    fi
}

# This function tries to mimick the behaviour of the -jar option of
# the java executable, by adding the target jar and all its classpath
# recursively.
#
# This function is experimental for now, and its interface is not very
# well specified yet.
#
# It will return without problem if the target class already is in the
# classpath. It aborts with an error if a JAR file can't be found.
find_jar_classpath() {
    if locate_jar "$1"; then
	looked_for_jars=1
	_recurse_jar_classpath $found_jar
    else
	java_warn "Unable to find the jar file $jar"
	return 1;
    fi
}



# Adds the first jar found to the classpath. Useful for alternative
# dependencies.
find_one_jar_in() {
    looked_for_jars=1
    for jar in $@ ; do
	if locate_jar $jar; then
	    JAVA_CLASSPATH=$JAVA_CLASSPATH:$found_jar
	    return 0
	fi
    done
    java_warning "Could fine none of $@ in $JAVA_JARPATH"
    return 1
}

# Runs the program !
run_java() {
    if [ -z "$JAVA_CMD" ]; then
	java_warning "No JAVA_CMD set for run_java, falling back to JAVA_CMD = java"
	JAVA_CMD=java
    fi
    # We try to conjure up a JAVA_HOME from JAVA_CMD, if the former
    # is absent. Idea coming from bug #404728.
    if [ -z "$JAVA_HOME" ]; then
	full_cmd_path="$(readlink -f `which $JAVA_CMD`)"
	JAVA_HOME="${full_cmd_path%bin/*}"
	java_debug "Using JAVA_CMD to find JAVA_HOME = '$JAVA_HOME'"
    fi
    if [ "$FORCE_CLASSPATH" ]; then
	java_debug "Using imposed classpath : FORCE_CLASSPATH = '$FORCE_CLASSPATH'";
	cp="-classpath $FORCE_CLASSPATH";
    elif [ "$JAVA_CLASSPATH" ]; then
	cp="-classpath $JAVA_CLASSPATH";
    else
	cp="";
    fi
    # Exporting JAVA_HOME, I guess it can't hurt much, can it ?
    export JAVA_HOME
    java_debug "Environment variable CLASSPATH is '$CLASSPATH'"
    java_debug "Runnning $JAVA_CMD $JAVA_ARGS $cp $@"
    exec $JAVA_CMD $JAVA_ARGS $cp "$@"
}

# Runs a java jar.
# You don't have to use this function to run a jar, but you might find
# it useful, though.
run_jar() {
    if [ "$looked_for_jars" ]; then
	java_warning "It is most likely useless to use find_jar when running"
	java_warning "a class with run_jar (-classpath is ignored)"
    fi
    if locate_jar $1; then
	shift
	run_java -jar "$found_jar" "$@"
    else
	java_fail "Unable to find jar $1 in $JAVA_JARPATH"
    fi
}