core: Support for committing from any libarchive-supported format

We really want the ability to take a .tar.gz and directly import
it into a repository, without creating a temporary filesystem tree.

First, doing it this way is significantly faster.  Also, this allows
us to handle importing tar files with e.g. uid 0 files into packed
repositories as non-root, which is very useful for tests and builds.

tests/t0006-libarchive.sh

@@ -0,0 +1,43 @@
+#!/bin/bash
+#
+# Copyright (C) 2011 Colin Walters <walters@verbum.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 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., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
+
+set -e
+
+echo "1..1"
+
+. libtest.sh
+
+setup_test_repository "regular"
+cd ${test_tmpdir}
+mkdir foo
+cd foo
+echo hi > hi
+ln -s hi hello
+mkdir subdir
+echo contents > subdir/more
+mkdir subdir/1
+touch subdir/1/empty
+mkdir subdir/2
+touch subdir/2/empty
+echo not > subdir/2/notempty
+
+tar -c -z -f ../foo.tar.gz .
+cd ..
+$OSTREE commit -s "from tar" -b test2 --tar foo.tar.gz
+echo "ok tar commit"