#!/bin/sh

#

# hgmerge - default merge helper for Mercurial

#

# This tries to find a way to do three-way merge on the current system.

# The result ought to end up in $1.

set -e # bail out quickly on failure

LOCAL="$1"

BASE="$2"

OTHER="$3"

if [ -z "$EDITOR" ]; then

    EDITOR="vi"

fi

# Back up our file

cp "$LOCAL" "$LOCAL.orig"

# Attempt to do a non-interactive merge

if type merge > /dev/null ; then

    if merge "$LOCAL" "$BASE" "$OTHER" 2> /dev/null; then

	# success!

	exit 0

    fi

    cp "$LOCAL.orig" "$LOCAL"

elif type diff3 > /dev/null ; then

    if diff3 -m "$LOCAL.orig" "$BASE" "$OTHER" > "$LOCAL" ; then

	# success

	exit 0

    fi

    cp "$LOCAL.orig" "$LOCAL"

fi

if [ -n "$DISPLAY" ]; then

    # try using kdiff3, which is fairly nice

    if type kdiff3 > /dev/null ; then

	if kdiff3 --auto "$BASE" "$LOCAL" "$OTHER" -o "$LOCAL" ; then

	    exit 0

	else

	    exit 1

	fi

    fi

    # try using tkdiff, which is a bit less sophisticated

    if type tkdiff > /dev/null ; then

	if tkdiff "$LOCAL" "$OTHER" -a "$BASE" -o "$LOCAL" ; then

	    exit 0

	else

	    exit 1

	fi

    fi

fi

# Attempt to do a merge with $EDITOR

if type merge > /dev/null ; then

    echo "conflicts detected in $LOCAL"

    merge "$LOCAL" "$BASE" "$OTHER" 2>/dev/null || $EDITOR "$LOCAL"

    exit 0

fi

if type diff3 > /dev/null ; then

    echo "conflicts detected in $LOCAL"

    diff3 -m "$LOCAL.orig" "$BASE" "$OTHER" > "$LOCAL" || $EDITOR "$LOCAL"

    exit 0

fi

HGTMP=""

cleanup_exit() {

    rm -rf "$HGTMP"

    exit $1

}

# attempt to manually merge with diff and patch

if type diff > /dev/null ; then

    if type patch > /dev/null ; then

	# Remove temporary files even if we get interrupted

	trap "cleanup_exit 1" TERM KILL INT QUIT ABRT

	HGTMP="${TMPDIR-/tmp}/hgmerge.$RANDOM.$RANDOM.$RANDOM.$$"

	(umask 077 && mkdir "$HGTMP") || {

	    echo "Could not create temporary directory! Exiting." 1>&2

	    exit 1

	}

	diff -u "$BASE" "$OTHER" > "$HGTMP/diff"

	if patch "$LOCAL" < "$HGTMP/diff" ; then

	    cleanup_exit 0

	else

	    $EDITOR "$LOCAL" "$LOCAL.rej"

	fi

	cleanup_exit 1

    fi

fi

echo "hgmerge: unable to find merge, tkdiff, kdiff3, or diff+patch!"

exit 1